JP7632826B2 - Rail vehicles - Google Patents

Description

The present invention relates to a railway vehicle that makes it easy to measure the insulation resistance of an electrical circuit.

For example, railway vehicles use a converter such as a VVVF inverter or SIV to convert the power supplied from an overhead line via a pantograph, and output the converted power to operate various electrical devices such as electric motors. Conventionally, the insulation resistance of electrical circuits, such as the power lines connecting the pantograph and converter, and the output wires connecting the converter and multiple electrical devices, has been measured during regular inspections, for example every 90 days, to evaluate the soundness of such electrical circuits.

During regular inspections, the pantograph is lowered to cut off the power supply to the railway vehicle from the overhead lines, and multiple switches are manually operated to disconnect the electrical circuit to be measured from ground, after which an insulation resistance meter is connected to the measurement target and the insulation resistance is measured. After the measurement, the insulation resistance meter must be removed, the measurement target must be grounded again, power must be supplied, and the equipment must be confirmed to be operating normally. Performing these various measurement and confirmation tasks individually for each railway vehicle requires a lot of effort and time.

Patent Document 1 discloses that the insulation resistance (leakage current) of part of the main circuit (power line) from the pantograph to the converter, which is one of the electrical circuits of a railway vehicle, is measured using a test circuit installed on the railway vehicle. Specifically, in Patent Document 1, the pantograph, which is separated from the overhead line, is separated from the converter by a high-speed circuit breaker, and the converter is separated from the ground by a contactor (switch), and then a voltage is applied by the test circuit between the main circuit on the pantograph side of the high-speed circuit breaker and the ground (car body), thereby measuring the insulation resistance of the main circuit.

JP 2012-223020 A

However, in Patent Document 1, the output wires through which output power is supplied from the converter can be easily disconnected from the main circuit by opening a high-speed circuit breaker, so measuring the insulation resistance of the output wires is not taken into consideration. Because there are a large number of switches for disconnecting each of the multiple output wires from the ground, conventional measurement of the insulation resistance of the output wires through periodic inspections has the problem that the work of manually opening and closing multiple switches takes a particularly long time and involves many work steps.

The present invention has been made to solve the above-mentioned problems, and aims to provide a railway vehicle that makes it easy to measure the insulation resistance of an electrical circuit.

To achieve this objective, the railway vehicle of the present invention runs on rails and includes a grounding part connected to the rails, a power line to which power is supplied, a converter connected to the power line and which adjusts and outputs the input voltage from the power line, an output wire to which output power is supplied from the converter, an electric device connected to the output wire and operated by the output power, an electromagnetic switch that connects the electric device to the grounding part via the output wire in an openable manner and opens when the supply of power to the power line is cut off, and a monitoring device that applies a voltage between the output wire connected to the electric device whose connection with the grounding part has been cut off and the grounding part when the electromagnetic switch is open, and measures the insulation resistance of the output wire.

Examples of conversion devices include inverters that convert DC power to AC power, converters that convert AC power to DC power, and transformers that transform voltage. A combination of multiple inverters, converters, and transformers may also be used as a conversion device.

According to the railway vehicle described in claim 1, when the power supply to the power line is cut off and the power is not being supplied, the electromagnetic switch opens, and the connection between the electrical equipment and the ground via the output wire is cut off. In this state, the monitoring device applies a voltage between the output wire connected to the electrical equipment and the ground to measure the insulation resistance of the output wire. In this way, by mounting the monitoring device on the railway vehicle, it is possible to easily measure the insulation resistance of the output wire compared to the conventional insulation resistance measurement method in which various tasks such as cutting off the power supply, disconnecting the measurement target from the ground, and connecting a measuring instrument to the measurement target were performed individually for each railway vehicle. In particular, since the measurement target is disconnected from the ground by the electromagnetic switch when the power supply is cut off, the task of manually disconnecting the measurement target from the ground is unnecessary, making it easier to measure the insulation resistance of the measurement target.

The railway vehicle of claim 2 achieves the following effects in addition to the effects of the railway vehicle of claim 1. When the power line is not energized, the power supply side switch opens, and the ground side electric wire connected to the input side of the conversion device is disconnected from the ground, and the power line on the input side of the conversion device is also disconnected from the ground. In this state, the monitoring device applies a voltage between the ground and at least one of the power line and the ground side electric wire, and measures the insulation resistance of at least one of the power line and the ground side electric wire. This makes it easier to measure the insulation resistance of the power line and the ground side electric wire compared to conventional insulation resistance measurement methods. In particular, the power supply side switch disconnects the measurement object from the ground in response to the interruption of the power supply, making it unnecessary to manually disconnect the measurement object from the ground.

According to the railway vehicle described in claim 3, in addition to the effect of the railway vehicle described in claim 1 or 2, the following effect is achieved. A first switch that can be opened and closed is connected to the electric wire whose insulation resistance is to be measured, and when the first switch is closed, the voltage detection unit is connected to the measurement object. If the voltage detected by the voltage detection unit at this time is equal to or lower than a predetermined value, it is found that the residual voltage of the measurement object when not energized is small, and that a large voltage is not applied to the measurement object when energized. In other words, it is found that the voltage that affects the measurement of the insulation resistance of the measurement object is small. In this case, by further closing a second switch that can be opened and closed and connected to the voltage detection unit and the first switch, a measurement circuit that measures the insulation resistance of the measurement object is formed. As a result of the above, the monitoring device can improve the detection accuracy of the insulation resistance of the measurement object without reducing the reliability of the existing circuit.

The railway vehicle according to claim 4 achieves the following effect in addition to the effect achieved by the railway vehicle according to claim 1 or 2. When a resistance measurement unit is connected to the electric wire of the measurement object that has been disconnected from the ground and a positive voltage is applied to the ground by the voltage application unit, the resistance measurement unit measures the insulation resistance of the measurement object based on the voltage. The connection between the resistance measurement unit and the measurement object is switched by the switching unit to a connection between the resistance measurement unit and the ground via a reference resistor. In this switched state, the resistance measurement unit measures the resistance value of the reference resistor instead of the insulation resistance based on the voltage applied by the voltage application unit. The measured resistance value can be compared with the resistance value of a predetermined reference resistor to confirm normal operation of the monitoring device.

FIG. 2 is a circuit diagram showing a schematic diagram of an electric circuit of the railway vehicle in the first embodiment. FIG. 2 is a circuit diagram showing a schematic diagram of an electrical circuit of a railway vehicle upstream of an SIV. FIG. 2 is a circuit diagram showing a schematic diagram of an electrical circuit of a railway vehicle downstream of an SIV. FIG. 2 is a block diagram showing the electrical configuration of the railway vehicle. FIG. 2 is a block diagram showing the electrical configuration of the contact monitoring device. FIG. 4 is a diagram showing the contents of each measurement result memory. 4 is a flowchart of a main process executed by a CPU of the contact-type monitoring device. 13 is a flowchart of a resistance measurement process. 13 is a flowchart of post-measurement processing. 4 is a flowchart of a self-diagnosis process. 4 is a flowchart of a main process executed by a CPU of the control device for a railway vehicle. 1 is a graph showing changes over time in insulation resistance measurement results and predictions for the future. FIG. 11 is a circuit diagram showing a schematic diagram of an electrical circuit of a railway vehicle upstream of an SIV in a second embodiment. FIG. 11 is a circuit diagram showing a schematic diagram of an electrical circuit of a railway vehicle downstream of an SIV in a second embodiment. FIG. 11 is a circuit diagram showing a schematic diagram of an electric circuit of a railway vehicle according to a third embodiment. FIG. 2 is a block diagram showing the electrical configuration of the AC monitoring device. 4 is a flowchart of a main process executed by a CPU of the AC monitoring device. FIG. 13 is a circuit diagram showing a schematic diagram of an electric circuit of a railway vehicle according to a fourth embodiment. 13 is a flowchart of a warning display process. FIG. 13 is a circuit diagram showing a schematic diagram of an electric circuit of a railway vehicle according to a fifth embodiment.

The preferred embodiment will now be described with reference to the accompanying drawings. First, an overview of a railway vehicle 10 in a first embodiment will be described with reference to FIG. 1. FIG. 1 is a circuit diagram that shows a schematic diagram of the electrical circuits of railway vehicles 10 and 11.

Both railcars 10, 11 are DC electric trains, and mainly comprise a metal car body 12, a number of wheels 13 that support the car body 12 and roll on the rails 2, coupling parts 14 provided at both ends of the car body 12 in the rail direction (front-to-back direction), and a number of electrical devices such as air conditioning equipment 15 and lighting 16. The coupling parts 14 include couplers that mechanically couple the railcars 10, 11 to transmit tensile and compressive forces between the cars, and electrical couplers that electrically couple the railcars 10, 11.

A train formation is formed by connecting the coupling parts 14 of railway cars 10 and 11 together. Railway car 10 is a powered car that has multiple electric motors 22 as a power source and runs on rails 2 by rotating wheels 13 with the electric motors 22. On the other hand, railway car 11 is a trailer car that does not have a power source and runs alongside railway car 10.

An overhead line 4 is suspended above the rails 2. A high-voltage (1500 V in this embodiment) direct current flows through this overhead line 4 by generating an electromotive force at a substation 6 with respect to the grounded rails 2. When a pantograph 17 mounted on the top of the body 12 of the railcar 10 is raised and brought into contact with the overhead line 4, direct current is supplied from the overhead line 4 via the pantograph 17 to the power line 18 of the railcar 10.

This power line 18 is connected to a VVVF inverter 20 and a SIV (static inverter) 30 mounted on the railway vehicle 10. Both the VVVF inverter 20 and the SIV 30 are conversion devices that convert and adjust the DC power input from the power line 18 into AC power and output it.

The output side of the VVVF inverter 20 is connected to a plurality of electric motors 22 via electric motor wires 24, and the electric motors 22 are operated by AC power output from the VVVF inverter 20. The VVVF inverter 20 is configured to be capable of variably controlling the voltage and frequency of the AC power it outputs. In response to the control of the voltage and frequency of this AC power, the rotation speed and torque of the electric motors 22 are controlled, and the running speed of the railway vehicle 10 is controlled.

The SIV 30 outputs AC power of a fixed voltage (440V in this embodiment) and a fixed frequency. A first low-voltage AC circuit 32 is connected to the output side of the SIV 30. This first low-voltage AC circuit 32 is laid between the coupling parts 14 at both ends of the railway vehicle 10. The first low-voltage AC circuit 32 is also laid between the coupling parts 14 of the railway vehicle 11, and the first low-voltage AC circuits 32 of the railway vehicles 10, 11 are connected to each other via the coupling parts 14. In each of the railway vehicles 10, 11, air conditioning equipment 15 is connected to the first low-voltage AC circuit 32, and the air conditioning equipment 15 is operated by the AC power supplied from the first low-voltage AC circuit 32.

The first low-voltage AC circuit 32 is connected to a second low-voltage AC circuit 36 via an isolation transformer 34. The isolation transformer 34 has a primary winding (not shown) connected to the first low-voltage AC circuit 32 and a secondary winding (not shown) connected to the second low-voltage AC circuit 36 wound around the same iron core, and the primary winding and secondary winding are insulated from each other. The isolation transformer 34 transforms the voltage of the AC power input from the first low-voltage AC circuit 32 to 100 V in this embodiment and outputs it to the second low-voltage AC circuit 36.

The second low-voltage AC circuit 36, like the first low-voltage AC circuit 32, is laid between the coupling parts 14 at both ends of the railway cars 10, 11. The second low-voltage AC circuits 36 of the railway cars 10, 11 are connected to each other via the coupling parts 14. In each of the railway cars 10, 11, a plurality of electrical devices such as lighting 16 are connected to the second low-voltage AC circuit 36, and the plurality of electrical devices are operated by power supplied from the second low-voltage AC circuit 36.

Next, the electrical circuit of the railway vehicle 10 will be described in more detail with reference to Figures 2 and 3. Figure 2 is a circuit diagram that shows a schematic of the electrical circuit of the railway vehicle 10 upstream of the SIV 30 (the pantograph 17 side). Figure 3 is a circuit diagram that shows a schematic of the electrical circuit of the railway vehicle 10 downstream of the SIV 30 (the side of electrical equipment such as the air conditioning equipment 15).

As shown in FIG. 2, the car body 12 (part of the grounding part) is connected to the rail 2 via the wheels 13, and is thereby grounded. The railway vehicle 10 is also provided with a grounding wire 40 (part of the grounding part) that runs between the coupling parts 14 (see FIG. 1) at both ends. This grounding wire 40 is connected to the rail 2 via the car body 12 and the wheels 13, and is thus grounded.

The input sides of the VVVF inverter 20 and the SIV 30 are each provided with a positive terminal to which the power line 18 is connected, and a negative terminal to which the grounding wire 42 is connected. When the grounding wire 42 is connected to the grounding wire 40 and the pantograph 17 comes into contact with the overhead line 4, a closed circuit is formed between the VVVF inverter 20 and the SIV 30 and the substation 6 via the overhead line 4 and the rails 2. This places the railway vehicle 10 in a powered state.

Two electromagnetic switches (MS) 44a are provided in parallel between the grounding wire 42 and the grounding conductor 40, and a manual switch (S) 46a is provided connected in series to the grounding conductor 40 side of the electromagnetic switches 44a. The electromagnetic switches 44a are latch-type switches that open and close with an electric signal, and open the electric circuit in response to the lowering of the pantograph 17, and close the electric circuit in response to the raising of the pantograph 17. In other words, the electromagnetic switches 44a are closed when the railway vehicle 10 is energized (when it is running). The manual switch 46a is a switch that opens and closes the electric circuit in response to manual operation.

By closing at least one of the two electromagnetic switches 44a and the manual switch 46a, the ground side electric wire 42 and the ground wire 40 are connected. By opening both of the electromagnetic switches 44a and at least one of the manual switch 46a, the ground side electric wire 42 is disconnected from the ground wire 40.

Note that electromagnetic switches 44b to 44i, which will be described later, are configured identically to electromagnetic switch 44a except for their different locations. In each drawing other than FIG. 2, only one of the two electromagnetic switches 44a to 44i arranged in parallel is shown, and the other is not shown. Hereinafter, when the electromagnetic switches 44a to 44i are described without distinction, they will be referred to as electromagnetic switch 44. Also, manual switches 46b to 46i, which will be described later, are configured identically to manual switch 46a except for their different locations. Hereinafter, when the manual switches 46a to 46i are described without distinction, they will be referred to as manual switch 46.

Conventionally, in a periodic inspection for measuring the insulation resistance of each part of a railway vehicle 10, the pantograph 17 is first lowered and separated from the overhead line 4 to cut off the supply of power from the overhead line 4 to the power line 18. Next, the manual switch 46a is manually opened to disconnect the ground side electric wire 42 from the ground line 40, and to disconnect the ground line 40 and the power line 18 via the VVVF inverter 20 and the SIV 30. After that, an insulation resistance measuring instrument (not shown) connected to the power line 18 and the ground line 40 detects the leakage current generated in the power line 18 when a voltage is applied to the ground part such as the ground line 40 or the car body 12, and measures the insulation resistance of the power line 18 to the ground part. Similarly, an insulation resistance measuring instrument connected to the ground side electric wire 42 and the ground line 40 measures the insulation resistance of the ground side electric wire 42.

In contrast, the railway vehicle 10 of this embodiment is equipped with a contact-type monitoring device 70a that automatically measures the insulation resistance of the power line 18 or the ground side electric wire 42 with respect to the ground at a predetermined timing. The contact-type monitoring device 70a has a terminal V connected to the ground line 40 via the electric wire AV, a terminal a connected to the power line 18 via the electric wire Aa, and a terminal b connected to the ground side electric wire 42 via the electric wire Ab.

Note that contact-type monitoring devices 70b to 70g, which will be described later, are configured substantially the same as contact-type monitoring device 70a, except for their layout, the voltage value applied, and the number of terminals. In the following description, when the contact-type monitoring devices 70a to 70g are not differentiated, they will be referred to as contact-type monitoring device 70.

The timing for measuring the insulation resistance by the contact type monitoring device 70 is when the pantograph 17 is lowered and the power supply to the power line 18 of the railway vehicle 10 is cut off. Note that even when the railway vehicle 10 is not energized (when the power supply from the overhead line 4 to the railway vehicle 10 is cut off), the contact type monitoring device 70 operates using the storage battery 82 (see Figure 3).

When the power supply to the railway vehicle 10 is cut off, the electromagnetic switch 44a opens, and the power line 18 and the ground side electric wire 42 are disconnected from the ground line 40. In this state, the contact type monitoring device 70a applies a voltage between terminals V and a to measure the insulation resistance of the power line 18 connected to terminal a. In a similar state, the insulation resistance of the ground side electric wire 42 connected to terminal b can be measured by applying a voltage between terminals V and b instead of between terminals V and a.

The voltage applied by the contact type monitoring device 70a is set to be equal to or lower than the voltage of the power supplied from the overhead line 4 to the power line 18 (1500 V DC). This makes it possible to prevent insulation breakdown of the VVVF inverter 20 and other components connected to the power line 18 due to the voltage applied by the contact type monitoring device 70a.

Since the contact-type monitoring device 70a described above is installed on the railway vehicle 10, it is easier to measure the insulation resistance of the power line 18 and the ground side electric wire 42 compared to the conventional method of measuring insulation resistance during regular inspections, in which various tasks such as cutting off the power supply, disconnecting the measurement target from the ground wire 40 (grounding part), and connecting a measuring instrument to the measurement target were performed individually for each railway vehicle 10.

In addition, the lowering of the pantograph 17 triggers the automatic measurement by the contact-type monitoring device 70, making it easier to measure the insulation resistance of the object to be measured (the power line 18 and the ground wire 42 in the case of the contact-type monitoring device 70a) compared to conventional measurement methods in which insulation resistance is measured manually. Furthermore, the electromagnetic switch 44 disconnects the object to be measured from the ground wire 40 in response to the lowering of the pantograph 17, eliminating the need to manually disconnect the object to be measured from the ground wire 40 and making it easier to measure the insulation resistance of the object to be measured.

In addition, since the manual switch 46 is connected in series to the electromagnetic switch 44, the insulation resistance of each part of the railway vehicle 10 can be measured by performing a conventional periodic inspection by opening the manual switch 46. This makes it possible to measure the insulation resistance of each part of the railway vehicle 10 in detail by performing a periodic inspection when the insulation resistance of the object to be measured is suspected to have deteriorated using the contact-type monitoring device 70.

In addition, because two electromagnetic switches 44 are provided in parallel, even if one of the two parallel electromagnetic switches 44 fails to close due to a malfunction when the pantograph 17 rises, the measurement target (e.g., the grounding wire 42) can be connected to the grounding wire 40 as long as the other closes, allowing the railway vehicle 10 to run normally. In other words, even if an electromagnetic switch 44 is provided to measure insulation resistance using a contact-type monitoring device 70, the railway vehicle 10 can run normally as long as the two parallel electromagnetic switches 44 do not fail at the same time.

The VVVF inverter 20 outputs three-phase AC power to the electric motor wires 24. Therefore, the electric motor wires 24 are configured as a set of three electric wires 24u, 24v, and 24w. Each of the electric wires 24u, 24v, and 24w branches out and is connected to multiple electric motors 22.

The motor 22 is a three-phase induction motor that operates on three-phase AC power and includes a coil 22a to which electric wires 24u, 24v, and 24w are respectively connected, and a housing 22b that surrounds the coil 22a. The housing 22b is connected to a ground wire 40 via a housing ground wire 22c, and constitutes part of the ground section.

The railway vehicle 10 is equipped with a contact type monitoring device 70b that automatically measures the insulation resistance of the coil 22a and the electric wires 24u, 24v, and 24w against the grounding parts of the housing 22b and the car body 12 at a predetermined timing. The contact type monitoring device 70b has a terminal V that is connected to the grounding wire 40 via the electric wire BV, and a terminal a that is connected to the electric wire 24w via the electric wire Ba. The electric wire Ba may be connected to the electric wire 24u or the electric wire 24v.

When the electromagnetic switch 44a opens in response to the lowering of the pantograph 17 (cutting off the power supply to the power line 18) and the ground side electric wire 42 is disconnected from the ground line 40, the connection between the electric wire 24 for the motor and the coil 22a and the ground line 40 via the ground side electric wire 42 and the VVVF inverter 20 is cut. In this state, the contact type monitoring device 70b applies a voltage between terminal V and terminal a.

In this way, the contact-type monitoring device 70b measures the insulation resistance of the electric wire 24w connected to the terminal a, the coil 22a connected to the electric wire 24w, and the electric wires 24u and 24v connected to the coil 22a. As a result, by installing the contact-type monitoring device 70b on the railway vehicle 10, it is possible to easily measure the insulation resistance of the electric motor 22 and the electric motor wire 24, similar to the contact-type monitoring device 70a, compared to conventional methods of measuring insulation resistance.

The voltage applied by the contact-type monitoring device 70b is set to be equal to or lower than the voltage resistance standard of the output side of the VVVF inverter 20 (e.g., 250 to 500 V). This makes it possible to prevent insulation breakdown inside the VVVF inverter 20 due to the voltage applied by the contact-type monitoring device 70b.

As shown in FIG. 3, the first low-voltage AC circuit 32 connected to the output side of the SIV 30 is composed of a set of three electric wires 32u, 32v, and 32w. The first low-voltage AC circuit 32 also passes through the inside of the SIV 30 and is connected to the ground line 40 via an electromagnetic switch 44b and a manual switch 46b. Therefore, when the railway vehicle 10 is energized (when power is supplied from the overhead line 4 to the railway vehicle 10), the first low-voltage AC circuit 32 is grounded.

The SIV 30 outputs three-phase AC power to the electric wires 32u, 32v, and 32w to operate the air conditioner 15 connected to the electric wires 32u, 32v, and 32w. In addition, the electric wires 32u, 32v, and 32w are connected to each other by the primary winding of the isolation transformer 34.

The second low-voltage AC circuit 36 connected to the secondary winding of the isolation transformer 34 is composed of a set of three electric wires 36r, 36n, and 36t. The electric wires 36r, 36n, and 36t are connected to each other by the secondary winding of the isolation transformer 34. The electric wire 36n is connected to the ground wire 40 via the electromagnetic switch 44c and the manual switch 46c. Therefore, when the railway vehicle 10 is energized, the electric wire 36n is grounded, and the ground wire 40 also functions as the electric wire 36n (part of the second low-voltage AC circuit 36).

The isolation transformer 34 outputs single-phase AC power so that the potential difference between the electric wire 36r and the electric wire 36n and the potential difference between the electric wire 36t and the electric wire 36n are each 100 V. The light 16 is connected to the electric wire 36r, and the isolation transformer 86 of the charger 84 is connected to the electric wire 36t. Although not shown, in addition to the light 16 and the isolation transformer 86 of the charger 84, multiple AC devices that operate on AC power are connected to the electric wires 36r and 36t.

The lighting 16 and the isolation transformer 86 are connected to the ground line 40 via the electromagnetic switch 44d and the manual switch 46d. Therefore, when the railway vehicle 10 is energized and the electromagnetic switch 44d is closed, the AC devices are operated by AC power.

The charger 84 is a device for charging the storage battery 82 of the contact monitoring device 70. The charger 84 and storage battery 82 are insulated from the second low-voltage AC circuit 36 by the isolation transformer 86, so that the output voltage of the contact monitoring device 70 can be stabilized, malfunction of the contact monitoring device 70 can be suppressed, and safety against electric shock can be ensured.

In addition to the multiple AC devices, the brake 19, the control device 60, and multiple other DC devices (not shown) are connected to the electric wires 36r and 36t via the rectifier 38. The rectifier 38 is a device that converts the AC power from the second low-voltage AC circuit 36 into DC power and outputs it.

The DC devices, including the brake 19 and the control device 60, are connected to the ground line 40 via the electromagnetic switch 44e and the manual switch 46e. Therefore, when the railway vehicle 10 is energized and the electromagnetic switch 44e is closed, the DC devices operate using DC power.

The brake 19 is a device for decelerating the railcar 10 while it is moving. The control device 60 is a device for controlling the acceleration and deceleration of the railcar 10 and the operation of multiple electrical devices (AC devices and DC devices).

For example, the control device 60 controls the operation of the switch circuit 20a built into the VVVF inverter 20. The switch circuit 20a is a circuit for controlling the voltage and frequency of the power output from the VVVF inverter 20 by switching the timing for turning on and off multiple switching elements.

The control device 60 and the switch circuit 20a are connected by a number of control lines 201, 202, and 203. The control device 60 is provided with relays 201a, 202a, and 203a that switch between supplying and cutting off power to the control lines 201 to 203. Note that in FIG. 3, for convenience of illustration, the relays 201a to 203a are arranged outside the control device 60.

When relay 201a is closed and power is supplied from the second low-voltage AC circuit 36 to the control line 201 via the control device 60, switch circuit 20a is controlled to output power of the voltage and frequency corresponding to control line 201 from the VVVF inverter 20. Similarly, when relays 202a and 203a are closed, switch circuit 20a is controlled to output power of the voltage and frequency corresponding to control lines 202 and 203, respectively, from the VVVF inverter 20. Note that when the railway vehicle 10 is not energized, all relays 201a to 203a are opened and the control lines 201 to 203 are no longer connected to the second low-voltage AC circuit 36.

The railway vehicle 10 is equipped with a contact-type monitoring device 70c that automatically measures the insulation resistance of the first low-voltage AC circuit 32, the second low-voltage AC circuit 36, and the control lines 201 to 203 with respect to the grounding parts such as the grounding wire 40 and the car body 12 at a predetermined timing.

The contact type monitoring device 70c includes a terminal V connected to the ground wire 40 via the electric wire CV, a terminal a connected to the electric wire 32v via the electric wire Ca, a terminal b connected between a plurality of AC devices (such as the lighting 16 and the isolation transformer 86) and the electromagnetic switch 44d via the electric wire Cb, a terminal c connected to the control line 201 via the electric wire Cc, a terminal d connected to the control line 202 via the electric wire Cd, a terminal e connected to the control line 203 via the electric wire Ce, and a terminal f connected between a plurality of DC devices (such as the brake 19 and the control device 60) and the electromagnetic switch 44e via the electric wire Cf. The electric wire Ca may be connected to the electric wire 32u or the electric wire 32w.

When all the electromagnetic switches 44b to 44e are opened in response to the lowering of the pantograph 17 (see FIG. 2), the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 are disconnected from the ground wire 40, and the connection between the ground wire 40 and the multiple electrical devices (air conditioners 15 and lights 16) via the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 is cut off. In this state, the contact-type monitoring device 70c applies a voltage between terminal V and any one of terminals a to f.

When a voltage is applied between terminal V and terminal a, the contact type monitoring device 70c measures the insulation resistance between the electric wire 32v connected to terminal a, the primary winding of the isolation transformer 34 connected to the electric wire 32v, and the electric wires 32u and 32w connected to the primary winding.

In addition, the first low-voltage AC circuit 32 (electric wires 32u, 32v, 32w) of the railway vehicle 10 is connected to the first low-voltage AC circuit 32 of the railway vehicle 11 via the connecting part 14, so that the contact-type monitoring device 70c can measure the insulation resistance of the first low-voltage AC circuits 32 of both railway vehicles 10 and 11 when a voltage is applied between terminals V and a.

When a voltage is applied between terminals V and b, the contact-type monitoring device 70c measures the insulation resistance of the wires between the electromagnetic switch 44d and the multiple AC devices (such as the lighting 16 and the isolation transformer 86) connected to terminal b, the wires 36r and 36t connected to the AC devices, the secondary winding of the isolation transformer 34 connected to the wires 36r and 36t, and the wire 36n connected to the secondary winding. In this case, the contact-type monitoring device 70c can measure the insulation resistance of not only the second low-voltage AC circuit 36 (wires 36r, 36n, 36t) of the railway vehicle 10, but also the second low-voltage AC circuit 36 of the railway vehicle 11 when a voltage is applied between terminals V and b, just as when a voltage is applied between terminals V and a.

In addition, when a voltage is applied between terminal V and any of terminals c to e, the contact-type monitoring device 70c measures the insulation resistance of any of the control lines 201 to 203 connected to the terminal c to e to which the voltage is applied. In this way, the contact-type monitoring device 70c can also measure the control lines 201 to 203 that are not connected to the second low-voltage AC circuit 36 when the railway vehicle 10 is not energized.

Furthermore, when a voltage is applied between terminals V and f, the contact type monitoring device 70c measures the insulation resistance of the wires between the electromagnetic switch 44e and the multiple DC devices (brake 19, control device 60, etc.) connected to terminal f, the rectifier 38 connected to the DC devices, the wires 36r and 36t connected to the rectifier 38, the secondary winding of the isolation transformer 34 connected to the wires 36r and 36t, and the wire 36n connected to the secondary winding.

As a result, by installing the contact-type monitoring device 70c on the railway vehicle 10, similar to the contact-type monitoring devices 70a and 70b, it is possible to easily measure the insulation resistance of each part of the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 compared to conventional insulation resistance measurement methods.

When the contact-type monitoring device 70c applies a voltage between terminals V and a, the voltage is set to be equal to or lower than the voltage (440 V AC) output from the SIV 30 to the first low-voltage AC circuit 32. When the contact-type monitoring device 70c applies a voltage between terminals V and terminals b to f, the voltage is set to be equal to or lower than the voltage (100 V AC) output from the isolation transformer 34 to the second low-voltage AC circuit 36. As a result, it is possible to prevent the electrical equipment connected to the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 from being broken down due to the voltage applied by the contact-type monitoring device 70c.

The voltage applied between terminals V and a by the contact-type monitoring device 70c is also preferably 100V or less, and the voltage applied by the contact-type monitoring device 70c is preferably constant to avoid erroneous application of voltage. This makes it possible to prevent the application of a voltage intended for the first low-voltage AC circuit 32 to the second low-voltage AC circuit 36, and reduces fluctuations in the insulation resistance measured by the contact-type monitoring device 70c due to erroneous application of voltage.

In addition, because the contact-type monitoring devices 70a, 70b, and 70c are provided separately, the electric wires Aa and Ab connected to the contact-type monitoring device 70a, the electric wire Ba connected to the contact-type monitoring device 70b, and the electric wires Ca to Cf connected to the contact-type monitoring device 70c can be prevented from concentrating in one place. This can prevent short circuits between the electric wires Aa to Cf, and can also prevent noise caused by bundling the electric wires Aa to Cf.

In addition, since the insulation resistance can be measured simultaneously using the contact-type monitoring devices 70a, 70b, and 70c, the time required to measure the insulation resistance can be reduced by providing the contact-type monitoring devices 70a, 70b, and 70c separately compared to combining the contact-type monitoring devices 70a, 70b, and 70c together.

In addition, since the voltage applied to the measurement object differs for each of the contact-type monitoring devices 70a, 70b, and 70c, erroneous application of voltage to each measurement object can be suppressed compared to the case where the contact-type monitoring devices 70a, 70b, and 70c are combined. This can reduce fluctuations in the insulation resistance measurement values by the contact-type monitoring devices 70a, 70b, and 70c caused by erroneous application of voltage.

Next, the control of each part of the railway vehicle 10 equipped with the contact-type monitoring devices 70a to 70c will be described in more detail with reference to Figures 4 to 12. Figure 4 is a block diagram showing the electrical configuration of the railway vehicle 10. Figure 5 is a block diagram showing the electrical configuration of the contact-type monitoring device 70. Note that Figure 4 shows diagrammatically that the contact-type monitoring devices 70 (70a to 70c) receive power from a storage battery 82.

As shown in FIG. 4, the control device 60 of the railway vehicle 10 has a CPU 61, a hard disk drive (HDD) 62, and a RAM 63, which is a memory for rewritably storing various work data, flags, etc. when the CPU 61 executes a program, and these are each connected to an input/output port 65 via a bus line 64.

Further connected to the input/output port 65 are the pantograph 17, the electromagnetic switches 44 (44a to 44e), the power supply switch 66, the VVVF inverter 20, the SIV 30, the air conditioning equipment 15, the lighting 16, the brakes 19, the contact type monitoring devices 70a to 70c, and a wireless communication device 68 that transmits and receives information to and from an external server 90 via the Internet, etc.

The CPU 61 is a calculation device that controls each part connected by the bus line 64. The HDD 62 is a rewritable non-volatile memory that stores the programs executed by the CPU 61 and various data, and is provided with a control program 62a, a vehicle information memory 62b, and each measurement result memory 62c. When the control program 62a is executed by the CPU 61, the main processing of FIG. 11 is executed.

The vehicle information memory 62b is a memory that stores vehicle information such as the vehicle number and formation information of the railway vehicle 10. Each measurement result memory 62c is a memory that temporarily stores the insulation resistance measurement results of the contact monitoring devices 70a to 70c until they are transmitted to the external server 90.

The contents of each measurement result memory 62c will be described with reference to FIG. 6. Each measurement result memory 62c is provided with a date and time memory and a measurement result memory for each contact monitoring device 70a-70c and for each measurement object (one of measurement objects a-f, or a reference resistance). The date and time memory and the measurement result memory store the measurement dates and times and measurement results by the contact monitoring devices 70a-70c mounted on the railway vehicle 10 in sequential order.

If an error occurs during measurement by contact-type monitoring devices 70a-70c, the date and time memory for that measurement object stores "error" instead of the date and time, and the corresponding measurement result memory stores information indicating the nature of the error instead of the measurement result. For example, if an error occurs during measurement of measurement object b by contact-type monitoring device 70a, "error" is stored in the date and time memory corresponding to measurement object b of contact-type monitoring device 70a among the measurement result memories 62c, and "SW22" is stored in the measurement result memory. Note that "SW22" indicates that the second switch SW2-2 has welded and cannot be opened.

The power supply switch 66 is a switch for controlling the raising and lowering of the pantograph 17 and the opening and closing of the electromagnetic contacts 44. When the power supply switch 66 is turned off, the pantograph 17 descends, and then all the electromagnetic contacts 44 open so that the insulation resistance can be measured by the contact-type monitoring device 70. When the power supply switch 66 is turned on, all the electromagnetic contacts 44 close, and then the pantograph 17 ascends. In this way, by closing the electromagnetic contacts 44 before the pantograph 17 comes into contact with the overhead line 4, welding of the electromagnetic contacts 44 can be prevented. A storage battery 67 is provided to operate the electromagnetic contacts 44 and the like when the railway vehicle 10 is not energized.

As shown in FIG. 5, the contact-type monitoring device 70 has a CPU 71, a flash ROM 72, and a RAM 73, which is a memory for rewritably storing various work data and flags when the CPU 71 executes a program, and these are each connected to an input/output port 75 via a bus line 74. The input/output port 75 is further connected to an interface (I/F) 76, which is connected to the input/output port 65 of the railway vehicle 10, a measurement unit 77, a voltage application unit 78, and a switching unit 79.

The CPU 71 is a calculation device that controls each part connected by the bus line 74. The flash ROM 72 is a rewritable non-volatile memory that stores programs executed by the CPU 71, fixed value data, etc., and is provided with a contact monitoring program 72a, a unique number memory 72b, and a contact measurement memory 72c. When the contact monitoring program 72a is executed by the CPU 71, the main processing of FIG. 7 is executed.

The unique number memory 72b is a memory that stores the unique number of the contact monitoring device 70. This unique number is part of the information that indicates the object of insulation resistance measurement by the contact monitoring device 70. The contact measurement memory 72c is a memory for storing the results of insulation resistance measurement by the contact monitoring device 70 while the railway vehicle 10 is not energized.

The contact measurement memory 72c has substantially the same configuration as the portion of the contents of each measurement result memory 62c described using FIG. 6 that corresponds to the contact monitoring device 70 that owns the contact measurement memory 72c. For example, the contact measurement memory 72c of the contact monitoring device 70a of the railway vehicle 10 has a reduced storage capacity for the portion of each measurement result memory 62c that corresponds to the contact monitoring device 70a.

The voltage application unit 78 is a device that applies a positive DC voltage from terminal V to the ground wire 40. The measurement unit 77 is a device that calculates (measures) the value of the insulation resistance of the measurement object. Specifically, for example, the measurement unit 77 divides the voltage applied by the voltage application unit 78 between an internal resistance provided inside the measurement unit 77 and the insulation resistance of the measurement object, and calculates the value of the insulation resistance from the voltage applied to the internal resistance.

The measurement unit 77 is not limited to a device that calculates the insulation resistance value, but may be a device that detects the value of the leakage current flowing through the insulation resistance measurement target. In this case, the CPU 71 calculates the insulation resistance value of the measurement target based on the voltage applied by the voltage application unit 78 and the value of the leakage current detected by the measurement unit 77.

The switching unit 79 is a circuit for connecting one of the electric wires connected to terminals a to f to the measuring unit 77, and for measuring the insulation resistance of the electric wire connected to the measuring unit 77. In the following, the electric wire to be measured that is connected to terminal a will be referred to as the measuring target a, and similarly, the electric wires to be measured that are connected to terminals b to f will be referred to as the measuring targets b to f.

A first switch SW1-n (n: integer) and a second switch SW2-n are connected in series between each of the terminals a to f and the measurement unit 77, in that order from the terminals a to f side. In addition, a voltage detection unit VDn is connected between the first switch SW1-n and the second switch SW2-n. Terminal a (measurement object a) corresponds to n=1, terminal b to n=2, terminal c to n=3, terminal d to n=4, terminal e to n=5, and terminal f to n=6.

The first switch SW1-n and the second switch SW2-n are switches that open and close an electric circuit in response to instructions from the CPU 71, and remain open when not energized. By closing the first switch SW1-n, the corresponding measurement objects a to f are connected to the voltage detection unit VDn. As a result, the voltage detection unit VDn detects the voltage applied to the measurement objects a to f.

By closing the first switch SW1-n and then closing the second switch SW2-n connected in series to it, the corresponding measurement objects a to f are connected to the measurement unit 77. This forms a measurement circuit between the voltage application unit 78 and the measurement unit 77 that measures the insulation resistance of the measurement objects a to f.

When the railway vehicle 10 is running, all of the first switches SW1-n and second switches SW2-n are opened, so that the various parts of the contact-type monitoring device 70 that are not related to the running of the railway vehicle 10 can be disconnected from circuits related to the running, such as the power supply line 18 and the electric motor wires 24. Furthermore, even if one of the first switch SW1-n and second switch SW2-n connected in series melts, as long as the other is open, the various parts of the contact-type monitoring device 70 can be prevented from being connected to circuits related to the running of the railway vehicle 10. In other words, deterioration in the reliability of the existing circuits of the railway vehicle 10 can be suppressed.

The existing circuit refers to the electrical circuit of the railway vehicle 10 excluding the contact monitoring device 70 and the wires Aa to CV for connecting the contact monitoring device 70 to each part of the railway vehicle 10. In other words, the existing circuit refers to the equipment and circuits that were placed on the railway vehicle 10 before the contact monitoring device 70 was installed, such as the power line 18, the VVVF inverter 20, the SIV 30, and the electric motor wires 24.

In addition, the measurement objects a-f can only be connected to each other via the switching unit 79 when two or more pairs of the first switch SW1-n and the second switch SW2-n connected in series are closed at the same time. In other words, by connecting the first switch SW1-n and the second switch SW2-n in series, it is possible to make it difficult for the measurement objects a-f to be connected to each other via the switching unit 79. This makes it possible to prevent failures of the electrical devices of the measurement objects a-f caused by being connected to each other via the switching unit 79.

In addition, the switching unit 79 includes a reference resistor 81 connected to the wire branching off from between the terminal V and the voltage application unit 78, and a third switch SW3 that opens and closes the reference resistor 81 and the measurement unit 77. The reference resistor 81 is a load having a predetermined resistance value that serves as a reference. The third switch SW3 may be provided between the wire branching off from between the terminal V and the voltage application unit 78 and the reference resistor 81.

By closing the third switch SW3, the voltage application unit 78 and the measurement unit 77 are connected via the reference resistor 81. In this case, when a voltage is applied by the voltage application unit 78, the measurement unit 77 calculates the resistance value of the reference resistor 81 instead of the insulation resistance value. This calculated resistance value is compared with the predetermined resistance value of the reference resistor 81, and if the two are almost the same, it can be determined that the contact-type monitoring device 70 is operating normally. In addition, the contact-type monitoring device 70 can be calibrated so that the resistance value of the reference resistor 81 measured (calculated) by the contact-type monitoring device 70 approaches the predetermined resistance value of the reference resistor 81.

Next, the main processing executed by the CPU 71 of the contact-type monitoring device 70 will be described with reference to Figures 7 to 10. Figure 7 is a flowchart of the main processing of the contact-type monitoring device 70. Figure 8 is a flowchart of the resistance measurement processing S33 performed during the main processing. Figure 9 is a flowchart of the post-measurement processing S49 performed during the resistance measurement processing S33. Figure 10 is a flowchart of the self-diagnosis processing S53 performed during the resistance measurement processing S33. The main processing of the contact-type monitoring device 70 is executed when the power of the contact-type monitoring device 70 is turned on.

As shown in FIG. 7, the main process first checks whether the pantograph 17, which was in the raised state, has lowered (S31). This check may be based on a signal from a sensor that turns on when the pantograph 17 lowers, or on a signal from the control device 60 of the railway vehicle 10 indicating that the power supply switch 66 has been turned off.

When the pantograph 17 is lowered and the power supply from the overhead line 4 to the power line 18 is cut off, all the electromagnetic switches 44 open as described above, and the insulation resistance can be measured by the contact type monitoring device 70. Immediately after the process of S31, a process may be performed to check whether all the electromagnetic switches 44 are open using a sensor or the like.

If the pantograph 17 is lowered in the process of S31 (S31: Yes), a check is made to see if a predetermined time has passed since the pantograph 17 was lowered (S32) in order to release the remaining power in each part of the electrical circuit of the railway vehicle 10. This is because if power remains in the measurement target of the contact monitoring device 70, an overvoltage may be applied to the contact monitoring device 70, which may damage the contact monitoring device 70. There is also a concern that the measurement results of the insulation resistance of the measurement target may affect the remaining power. The predetermined time is at least as long as the discharge time of the remaining power in a capacitor (not shown) arranged inside the railway vehicle 10.

If the specified time has not elapsed in the process of S32 (S32: No), there is a high possibility that residual power will affect the insulation resistance measurement results, so the process of S32 is looped to wait for the specified time to elapse.

When the predetermined time has elapsed (S32: Yes), the possibility that residual power will affect the insulation resistance measurement result has become sufficiently low, so the resistance measurement process S33 is executed to measure the insulation resistance of the measurement target, and the process proceeds to S34. Note that in the process of S31, if the pantograph 17 is raised or if the pantograph 17 has already lowered (S31: No), the processes of S32 and S33 are skipped and the process proceeds to S34.

The resistance measurement process S33 will now be described with reference to FIG. 8. In the resistance measurement process S33, first, n=1 is set to measure the insulation resistance of the measurement object a (S41). Next, the first switch SW1-n is closed to connect the measurement object wire to the voltage detection unit VDn (S42). In the first S42 process after the process of S41, the first switch SW1-1 is closed to connect the measurement object a to the voltage detection unit VD1.

After the process of S42, it is confirmed whether the voltage detected by the voltage detection unit VDn has become equal to or lower than the threshold value (S43). Note that this threshold value is set to a value smaller than the voltage applied by the voltage application unit 78 to the electric wire to be measured. In the process of S43, if the detected voltage is higher than the threshold value (S43: No), the residual voltage of the measurement object when not energized is high, so the process waits until the residual voltage is discharged. Note that, although not shown, if the detected voltage does not become equal to or lower than the threshold value even after waiting for a certain period of time, this means that the measurement object is energized and is not in a state where the insulation resistance can be measured, so the resistance measurement process S33 is terminated without measuring the insulation resistance.

In the process of S43, if the detected voltage falls below the threshold value (S43: Yes), the voltage that affects the measurement of the insulation resistance has decreased, so the second switch SW2-n (SW2-1 in the first process after S41) is closed (S44). As a result, a measurement circuit that measures the insulation resistance of the measurement object is formed, so the voltage application unit 78 applies a voltage to the measurement object (S45).

In this way, by the processing of S43 and S44, when an excessive voltage is applied to the measurement target, the second switch SW2-n is not closed, thereby protecting the electrical circuits of the measurement unit 77 of the contact monitoring device 70 and the like from the excessive voltage. Therefore, the voltage detection unit VDn and the second switch SW2-n ensure the durability of the contact monitoring device 70 and improve the detection accuracy of the insulation resistance of the measurement target. Furthermore, the opening and closing between the measurement target and the measurement unit 77 is multiplexed by the first switch SW1-n and the second switch SW2-n to provide redundancy and increase safety. As a result, it is no longer necessary to provide the contact monitoring device 70 with durability (voltage resistance) greater than necessary, and it is expected that the cost and size of the contact monitoring device 70 can be reduced.

After processing S45, it is checked whether a predetermined time has passed since the application of voltage (S46). If the predetermined time has not passed (S46: No), the measured insulation resistance value is not stable, so processing of S46 is looped.

On the other hand, if a predetermined time has passed since the application of the voltage (S46: Yes), the measurement unit 77 measures the insulation resistance of the measurement object (S47). Next, the measurement result, the measurement object (measurement object a in the first process after S41), and the date and time of the measurement are stored in the contact measurement memory 72c (S48), and post-measurement process S49 is executed.

As shown in FIG. 9, in the post-measurement process S49, first, the second switch SW2-n that was closed in the process of S44 is opened (S61). Next, it is confirmed whether the insulation resistance of the measurement target is still being detected by the measurement unit 77 (S62).

If insulation resistance is detected in the process of S62 (S62: Yes), it can be determined that the second switch SW2-n that was instructed to open in the process of S61 did not actually open due to welding or the like. In this case, error information that the second switch SW2-n did not open is stored in the contact measurement memory 72c (S63), and the process of S64 is executed.

On the other hand, if no insulation resistance is detected in the process of S62 (S62: No), the second switch SW2-n that was instructed to open in the process of S61 was opened without any problems, so the process of S63 is skipped and the process of S64 is executed.

In the process of S64, the first switch SW1-n that was closed in the process of S42 is opened. After the process of S64, it is confirmed whether a voltage is detected by the voltage detection unit VDn to which the first switch SW1-n that should have been opened is connected (S65). If the first switch SW1-n that was instructed to be opened in the process of S64 is not actually opened due to welding or the like, a voltage is detected in the process of S65 (S65: Yes). In this case, error information that the first switch SW1-n was not opened is stored in the contact measurement memory 72c (S66), the application of voltage by the voltage application unit 78 is terminated (S67), and the post-measurement process S49 is terminated.

On the other hand, if no voltage is detected in the process of S65 (S65: No), the first switch SW1-n that was instructed to open in the process of S64 was opened without any problems, so the process of S66 is skipped and the process of S67 is executed, and the post-measurement process S49 is terminated.

In this way, in the post-measurement process S49, the first switch SW1-n and the second switch SW2-n can be opened in stages while checking their normal operation. Therefore, the contact-type monitoring device 70 can automate the checking of the operation of the first switch SW1-n and the second switch SW2-n.

Returning to FIG. 8, the following explanation will be given. After the post-measurement process S49, it is checked whether there were any errors in this process (S50). If there was an error (S50: No), the resistance measurement process S33 ends without measuring the insulation resistance of other measurement targets.

For example, if the first switch SW1-1 and the second switch SW2-1 are both welded together and cannot be opened, causing an error, then closing the first switch SW1-2 and the second switch SW2-2 to measure the insulation resistance of the measurement object b will result in the measurement object a and the measurement object b being connected. If a voltage is applied by the voltage application unit 78 in this state, the unintended voltage may cause damage to the contact monitoring device 70 and the electrical equipment of the measurement objects a and b.

In contrast, if an error occurs in the post-measurement process S49 (S50: No), the resistance measurement process S33 is terminated, which prevents multiple measurement targets from being connected to each other via the switching unit 79. As a result, it is possible to reduce the possibility that the contact-type monitoring device 70 or each electrical device being measured will break down due to an unintended voltage.

In the process of S50, if there is no error in the post-measurement process S49 (S50: Yes), n = n + 1 is set to measure the insulation resistance of the measurement object that has not yet been measured (S51). Next, it is confirmed whether n ≥ 7 (S52), and if n < 7 (S52: No), since there is still a measurement object that has not yet been measured, the process from S42 onwards is executed again.

On the other hand, if n≧7 (S52: Yes), measurement of the insulation resistance of all measurement objects has been completed, so self-diagnosis process S53 is executed and resistance measurement process S33 is terminated. In the process of S52, an upper limit is set according to the number of terminals a-f of the contact monitoring device 70 that are connected. For example, in the case of contact monitoring device 70a, where only terminals a and b are connected to the measurement object, the process of S52 checks whether n≧3. In the case of contact monitoring device 70b, where only terminal a is connected to the measurement object, the process of S52 checks whether n≧2.

As shown in FIG. 10, in the self-diagnosis process S53, first, the third switch SW3 is closed (S71) to connect the voltage application unit 78 and the measurement unit 77 via the reference resistor 81. Next, a voltage is applied by the voltage application unit 78 (S72), and it is confirmed whether a predetermined time has passed since the application of the voltage so that the value of the current passing through the reference resistor 81 becomes stable (S73). If the predetermined time has not passed since the application of the voltage (S73: No), the process of S73 is looped.

On the other hand, if a predetermined time has passed since the application of the voltage (S73: Yes), the measurement value by the measurement unit 77 has stabilized, so the measurement unit 77 measures the resistance value of the reference resistor 81 (S74). Next, the measurement result of this resistance value, the measurement target (reference resistor 81), and the date and time of the measurement are stored in the contact measurement memory 72c (S75).

The external server 90 or the like that acquires the measurement result of this resistance value compares the measurement result of the resistance value of the reference resistor 81 with the resistance value of the predetermined reference resistor 81, and if the two values are almost identical, it can be confirmed that the contact-type monitoring device 70 is operating normally. On the other hand, if there is a large discrepancy between the measurement result of the resistance value and the predetermined resistance value, the normal operation of the contact-type monitoring device 70 is suspected, and the administrator of the external server 90 or the like can be notified of the need for maintenance of the contact-type monitoring device 70.

After processing S75, the third switch SW3 that was closed in processing S71 is opened (S76), and the connection between the voltage application unit 78 and the measurement unit 77 via the reference resistor 81 is cut off. In this state, it is confirmed whether the resistance value of the reference resistor 81 is still detected by the measurement unit 77 (S77).

If the third switch SW3 that was instructed to be opened in the process of S76 does not actually open due to welding or the like, the resistance value is detected in the process of S77 (S77: Yes). In this case, error information that the third switch SW3 did not open is stored in the contact measurement memory 72c (S78), the application of voltage by the voltage application unit 78 is terminated (S79), the self-diagnosis process S53 is terminated, and the resistance measurement process S33 in FIG. 8 is terminated.

On the other hand, if no resistance value is detected in the process of S77 (S77: No), the third switch SW3 that was instructed to be opened in the process of S76 was opened without any problems, so the process of S78 is skipped and the process of S79 is executed, the self-diagnosis process S53 is ended, and the resistance measurement process S33 in FIG. 8 is ended. In this way, in the contact-type monitoring device 70, the operation check of the third switch SW3 can be automated, just like the first switch SW1-1 and the second switch SW2-1.

Returning to FIG. 7, the explanation will be given below. After the resistance measurement process S33, it is checked whether the measurement results have been requested from the control device 60 of the railway vehicle 10 (S34). If a request has been received (S34: Yes), the unsent measurement results (or error information) stored in association with the contact measurement memory 72c, the measurement target, date and time, and the unique number of the contact monitoring device 70 stored in the unique number memory 72b are transmitted to the control device 60 (S35).

Then, other processes are executed (S36), and the processes from S31 onwards are executed repeatedly. Note that the process of S36 includes, for example, controlling the charging of the storage battery 82 and checking whether or not the measurement targets a to f are connected to the terminals a to f.

Next, the main processing executed by the CPU 61 of the control device 60 of the railway vehicle 10 will be described with reference to FIG. 11. FIG. 11 is a flowchart of the main processing of the control device 60. The main processing of the control device 60 is executed when the pantograph 17 rises, power is supplied to the railway vehicle 10 from the overhead line 4, and the control device 60 is powered on.

As shown in FIG. 11, the main process first requests each contact-type monitoring device 70 to send its measurement results (S81) because the contact-type monitoring devices 70 are measuring insulation resistance while the control device 60 is not powered on. As described above, the contact-type monitoring devices 70 send any unsent measurement results, etc. to the control device 60 by the processes of S34 and S35 in FIG. 7 in response to this request.

After processing of S81, the measurement results (or error information), measurement target, date and time received from the contact-type monitoring device 70, and the unique number of that contact-type monitoring device 70 are stored in each measurement result memory 62c in association with each other (S82). By aggregating the measurement results from each contact-type monitoring device 70 in the control device 60, the memory capacity of the contact-type monitoring device 70 can be reduced, and the contact-type monitoring device 70 can be made smaller. This allows for greater freedom in the placement location of the contact-type monitoring device 70. Furthermore, reducing the memory capacity of the contact-type monitoring device 70 is expected to reduce costs.

After processing S82, it is checked whether any unsent measurement results or error information is stored in each measurement result memory 62c from the control device 60 to the external server 90 (S83). If any unsent measurement results or error information is stored (S83: Yes), it is checked whether communication between the railway vehicle 10 and the external server 90 is possible via the wireless communication device 68 in order to transmit them to the external server 90 (S84).

If communication with the external server 90 is possible (S84: Yes), the unsent measurement results (or error information) stored in each measurement result memory 62c, the measurement target, date and time, and the unique number of the contact monitoring device 70, as well as the vehicle information of the railway vehicle 10 stored in the vehicle information memory 62b, are transmitted to the external server 90 (S85).

Next, other processing is executed (S86), and the processing from S81 onwards is executed repeatedly. The processing of S86 includes various processing for running the railway vehicle 10.

If there are no unsent measurement results or error information in the process of S83 (S83: No), or if communication with the external server 90 is not possible in the process of S84 (S84: No), the process of S85 is skipped and the process of S86 is executed.

The external server 90 judges whether there is a suspicion of insulation resistance degradation based on the measurement results received from the railway vehicle 10. For example, as shown in FIG. 12, the external server 90 generates and displays a graph with the past insulation resistance measurement results on the vertical axis and the date and time on the horizontal axis for measurement target a of the contact monitoring device 70a of the railway vehicle 10. In the graph of FIG. 12, the solid line indicates the change over time of the past measurement results (actual values), and the two-dot chain line indicates the change over time of future measurement results (predicted values) that are an extension of a straight line that approximates the actual measurement values using the least squares method. The graph of FIG. 12 also indicates the threshold value at which insulation resistance degradation is suspected with a dashed line.

If the past measurement results are below the threshold, the administrator of the external server 90 is notified that degradation of the insulation resistance is suspected. When measuring the insulation resistance in the railway vehicle 10, the temperature and humidity at the time of measurement may also be obtained, and this information may be used to determine whether the insulation resistance has deteriorated.

The date and time when the future measurement results will be below the threshold value is predicted based on the time-dependent change in the future measurement results (predicted values) and the threshold value, and the date and time is displayed in the graph of FIG. 12. Therefore, the administrator of the external server 90 can plan schedules for maintenance of the railway vehicle 10 based on the date and time when the future measurement results will be below the threshold value, and can also plan ordering of equipment and parts that require replacement.

Next, the second embodiment will be described with reference to Figures 13 and 14. In the first embodiment, the case where power is supplied from the pantograph 17 to the power line 18, and the VVVF inverter 20 and the SIV 30 are mounted on one railway vehicle 10 is described. In contrast, in the second embodiment, a case where, in a train formation in which railway vehicles 100a, 100b, and 100c are coupled, power is supplied from a power source 102 consisting of a generator, a storage battery, etc. mounted on railway vehicle 100a to power lines 18a to 18c, the VVVF inverter 20 is mounted on railway vehicle 100c, and the SIV 30 is mounted on railway vehicle 100b is described. Note that the same reference numerals are used for the same parts as in the first embodiment, and the following description will be omitted.

Figure 13 is a circuit diagram showing the electrical circuits of railway vehicles 100a, 100b, and 100c upstream of SIV 30 in the second embodiment. Figure 14 is a circuit diagram showing the electrical circuit of railway vehicle 100b downstream of SIV 30 in the second embodiment.

As shown in FIG. 13, railcars 100a to 100c mainly comprise a car body 12, wheels 13, coupling parts 14, and multiple electrical devices. Railcars 100a to 100c are configured as a train by coupling parts 14 together. Power line 18a of railcar 100a, power line 18b of railcar 100b, and power line 18c of railcar 100c are each connected via coupling parts 14.

Similarly, the ground side electric wire 42a of the railway vehicle 100a, the ground side electric wire 42b of the railway vehicle 100b, and the ground side electric wire 42c of the railway vehicle 100c are each connected via the coupling portion 14. Also, the ground wire 40a of the railway vehicle 100a, the ground wire 40b of the railway vehicle 100b, and the ground wire 40c of the railway vehicle 100c are each connected via the coupling portion 14. Furthermore, the ground side electric wires 42a-42c and the ground wires 40a-40c of each vehicle are connected via an electromagnetic switch 44a and a manual switch 46a that is connected in series to the ground wires 40a-40c side of the electromagnetic switch 44a.

The railcar 100a is equipped with a power source 102 for running the railcars 100a to 100c. The power source 102 is made up of a generator (including a fuel cell) and a storage battery, and supplies DC power. The positive terminal of the power source 102 is connected to the power line 18a via a power switch 104. The negative terminal of the power source 102 is connected to the ground side electric wire 42a.

By closing the power switch 104, power is supplied from the power source 102 to the power lines 18a to 18c. By opening the power switch 104, the power supply from the power source 102 to the power lines 18a to 18c is cut off.

The railway vehicle 100b is equipped with an SIV 30. The positive terminal of the input side of this SIV 30 is connected to the power supply line 18b, and the negative terminal is connected to the ground side electric wire 42b. The railway vehicle 100c is equipped with a VVVF inverter 20. The positive terminal of the input side of this VVVF inverter 20 is connected to the power supply line 18c, and the negative terminal is connected to the ground side electric wire 42c.

The railway vehicle 100a is also equipped with a contact-type monitoring device 70a. The contact-type monitoring device 70a has a terminal V connected to the ground wire 40a via an electric wire AV, a terminal a connected to the power supply wire 18a via an electric wire Aa, and a terminal b connected to the ground side electric wire 42a via an electric wire Ab.

When the railway cars 100a, 100b, and 100c are connected, as in the first embodiment, when the power switch 104 is opened to cut off the power supply to the power lines 18a to 18c, the electromagnetic switch 44a opens and the power lines 18a to 18c and the ground side electric wires 42a to 42c are disconnected from the ground lines 40a to 40c. In this state, the contact type monitoring device 70a can apply a voltage between terminal V and terminal a or terminal b to measure the total insulation resistance of the power lines 18a to 18c connected to the applied terminal a, or the total insulation resistance of the ground side electric wires 42a to 42c connected to the applied terminal b.

When railway vehicle 100a is disconnected from railway vehicles 100b and 100c, contact monitoring device 70a can apply a voltage between terminal V and terminal a or terminal b when railway vehicle 100a is not energized, thereby individually measuring the insulation resistance of power line 18a connected to terminal a or ground side wire 42a connected to terminal b without affecting the insulation resistance of power line 18a or ground side wire 42a of the other railway vehicles 100b and 100c.

The railway vehicle 100b is equipped with a contact-type monitoring device 70d. The contact-type monitoring device 70d has a terminal V connected to the ground wire 40b via an electric wire DV, a terminal a connected to the power supply wire 18b via an electric wire Da, and a terminal b connected to the ground side electric wire 42b via an electric wire Db.

When the railway vehicle 100b is disconnected from the railway vehicles 100a and 100c, the power supply from the power line 18a to the power line 18b is cut off, and the connection between the ground side electric wire 42b and the ground line 40b via the ground side electric wire 42a and the ground line 40a is cut off. Furthermore, in response to the cutoff of the power supply, the electromagnetic switch 44a between the ground side electric wire 42b and the ground line 40b opens. In this state, the contact type monitoring device 70d can apply a voltage between the terminal V and the terminal a or the terminal b to measure the insulation resistance of the power line 18b connected to the applied terminal a, or the ground side electric wire 42b connected to the applied terminal b, separately from the other railway vehicles 100a and 100c.

The railway vehicle 100c is equipped with a contact-type monitoring device 70e. The contact-type monitoring device 70e has a terminal V connected to the ground wire 40c via an electric wire EV, a terminal a connected to the power supply wire 18c via an electric wire Ea, and a terminal b connected to the ground side electric wire 42c via an electric wire Eb.

When the railway vehicle 100c is disconnected from the railway vehicles 100a and 100b, the power supply from the power lines 18a and 18b to the power line 18c is cut off, and the connection between the ground side electric wire 42c and the ground line 40c via the ground side electric wires 42a and 42b and the ground lines 40a and 40b is cut off. Furthermore, in response to the cutoff of the power supply, the electromagnetic switch 44a between the ground side electric wire 42c and the ground line 40c opens. In this state, the contact type monitoring device 70e can apply a voltage between the terminal V and the terminal a or the terminal b to measure the insulation resistance of the power line 18c connected to the applied terminal a or the ground side electric wire 42c connected to the applied terminal b separately from the other railway vehicles 100a and 100c.

As described above, by mounting contact-type monitoring devices 70a, 70d, and 70e on each of the railway cars 100a to 100c, and disconnecting the electric wires that are connected via the coupling part 14 when current is applied (when the car is running) when current is not applied, the insulation resistance of the power lines 18a to 18c and the insulation resistance of the ground side electric wires 42a to 42c can be measured individually for each of the railway cars 100a to 100c.

The configuration of the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 of the railway vehicle 100b will be described using FIG. 14. Note that the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 of the railway vehicles 100a and 100c are configured substantially the same as those of the railway vehicle 100b, and therefore some of the description will be omitted.

When the railway vehicles 100a to 100c are energized, the first low-voltage AC circuit 32 of the railway vehicle 100b is supplied with AC power from the SIV 30, and the second low-voltage AC circuit 36 of the railway vehicle 100b is supplied with AC power from the isolation transformer 34. On the other hand, the first low-voltage AC circuit 32 of the railway vehicles 100a and 100c is supplied with AC power from the first low-voltage AC circuit 32 of the railway vehicle 100b, and the second low-voltage AC circuit 36 of the railway vehicles 100a and 100c is supplied with AC power from the second low-voltage AC circuit 36 of the railway vehicle 100b.

In the railway vehicle 100b, the isolation transformer 86 of the charger 84, which is an AC device, is connected to the ground wire 40b via the electromagnetic switch 44f and the manual switch 46f. The lighting 16, which is an AC device, is connected to the ground wire 40b via the electromagnetic switch 44g and the manual switch 46g. Although not shown, multiple AC devices other than the charger 84 and the lighting 16 are also individually connected to the ground wire 40b via the electromagnetic switch 44 and the manual switch 46.

The control device 60, which is a DC device, is connected to the ground line 40b via the electromagnetic switch 44h and the manual switch 46h. The brake 19, which is a DC device, is connected to the ground line 40b via the electromagnetic switch 44i and the manual switch 46i. Although not shown, multiple DC devices other than the control device 60 and the brake 19 are also individually connected to the ground line 40b via the electromagnetic switch 44 and the manual switch 46.

The railway vehicle 100b is equipped with a contact-type monitoring device 70f. The contact-type monitoring device 70f has a terminal V connected to the ground wire 40b via an electric wire FV, a terminal a connected to the electric wire 32v of the first low-voltage AC circuit 32 via an electric wire Fa, a terminal b connected between the isolation transformer 86 and the electromagnetic switch 44f via an electric wire Fb, a terminal c connected between the lighting 16 and the electromagnetic switch 44g via an electric wire Fc, a terminal d connected between the control device 60 and the electromagnetic switch 44h via an electric wire Fd, and a terminal e connected between the brake 19 and the electromagnetic switch 44i via an electric wire Fe. The terminals of the contact-type monitoring device 70f are also individually connected between other AC devices and DC devices and the electromagnetic switch 44.

When the railway vehicle 10 is de-energized and all electromagnetic switches 44b, 44c, 44f-44i are open, the contact-type monitoring device 70f applies a voltage between terminal V and one of terminals a-e and measures the insulation resistance of the part where terminals a-e are connected.

In the first embodiment, the contact monitoring device 70c is used to measure the total insulation resistance of multiple AC devices and the total insulation resistance of multiple DC devices. In contrast, in the second embodiment, multiple AC devices and DC devices are individually connected to the ground wire 40b via the electromagnetic switch 44, and multiple AC devices and DC devices are individually connected to terminals b to e of the contact monitoring device 70f. Therefore, the contact monitoring device 70f can individually measure the insulation resistance of multiple AC devices and DC devices. This makes it easy to determine which AC devices or DC devices have deteriorated insulation resistance from the measurement results of the contact monitoring device 70f.

When a voltage is applied between terminal V and terminal a, contact-type monitoring device 70f measures the insulation resistance of the first low-voltage AC circuit 32 of railway vehicle 100b connected to terminal a. At this time, when the first low-voltage AC circuit 32 of railway vehicle 100b is connected to the first low-voltage AC circuits 32 of railway vehicles 100a and 100c, the total insulation resistance of the first low-voltage AC circuits 32 of railway vehicles 100a to 100c can be measured by contact-type monitoring device 70f.

On the other hand, when the first low-voltage AC circuit 32 of the railway vehicle 100b is disconnected from the first low-voltage AC circuit 32 of the railway vehicles 100a and 100c, the insulation resistance of the first low-voltage AC circuit 32 of the railway vehicle 100b can be measured separately from the first low-voltage AC circuit 32 of the railway vehicles 100a and 100c.

The insulation resistance measurement results by the contact-type monitoring devices 70 of the railway cars 100a to 100c are stored together in each measurement result memory 62c of the railway car 100b by the processing of S81 and 82 in FIG. 11 after the railway cars 100a to 100c change from a non-energized state to an energized state. Compared to a case in which the measurement results are transmitted from each of the multiple contact-type monitoring devices 70 to the external server 90, the measurement results of the contact-type monitoring devices 70 can be transmitted from the railway car 100b to the external server 90 more smoothly.

Next, a third embodiment will be described with reference to Figures 15 to 17. In the first and second embodiments, the insulation resistance of each part of the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 is measured by a contact-type monitoring device 70. In contrast, in the third embodiment, the insulation resistance of each part of the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 is measured by an AC monitoring device 120. Note that the same parts as in the first and second embodiments are given the same reference numerals and the following description will be omitted.

Figure 15 is a circuit diagram showing a schematic diagram of an electrical circuit of a railway vehicle 110 in the third embodiment. The railway vehicle 110 mainly comprises a car body 12, wheels 13, a coupling portion 14 (see Figure 1), a number of electrical devices (such as air conditioning equipment 15 and lighting 16), and a contact-type monitoring device 70g.

The contact type monitoring device 70g has terminal V connected to the ground wire 40 via wire GV, terminal a connected to the motor wire 24 via wire Ga, terminal b connected to the power supply wire 18 via wire Gb, and terminal c connected to the ground side wire 42 via wire Gc. With the electromagnetic switch 44a open in response to the lowering of the pantograph 17, the contact type monitoring device 70g can apply a voltage between terminal V and any one of terminals a to c to measure the insulation resistance of the part connected to the applied terminal a to c.

In other words, the contact-type monitoring device 70g combines the contact-type monitoring device 70a and the contact-type monitoring device 70b in the first embodiment into one. This allows the number of contact-type monitoring devices 70 mounted on the railway vehicle 110 to be reduced.

Although not described in the first embodiment, the first low-voltage AC circuit 32 includes a set of three main electric wires 32u1, 32v1, and 32w1 that extend from the output side of the SIV 30 and are routed between the front and rear coupling parts 14 of the vehicle, and branch electric wires 32u2, 32v2, and 32w2 that branch off from the main electric wires 32u1, 32v1, and 32w1, respectively. Although not shown, the first low-voltage AC circuit 32 passes through the inside of the SIV 30 and is connected to the ground wire 40 via the electromagnetic switch 44b and the manual switch 46b. A plurality of sets of the branch electric wires 32u2, 32v2, and 32w2 are provided so as to be connected to a plurality of AC devices such as the air conditioning device 15, respectively.

Similarly, the second low-voltage AC circuit 36 includes main wires 36r1, 36t1 that extend from the isolation transformer 34 and are routed between the front and rear coupling parts 14 of the vehicle, and branch wires 36r2, 36t2 that branch off from the main wires 36r1, 36t1, respectively. In addition, because the main wire 36n1 that is connected to the ground wire 40 extends from the isolation transformer 34, the ground wire 40 also functions as part of the main wire 36n1, and the branch wire 36n2 branches off from the ground wire 40.

The branch electric wire 36r2 and the branch electric wire 36n2 form one set of single-phase two-wire electric circuits, and the branch electric wire 36t2 and the branch electric wire 36n2 form one set of single-phase two-wire electric circuits. A plurality of sets of these electric circuits are provided so that each can be connected to a plurality of AC devices such as the lighting 16.

The railway vehicle 110 is equipped with an AC monitoring device 120a that automatically and periodically measures the insulation resistance of the first low-voltage AC circuit 32 and electrical equipment connected thereto (e.g., air conditioning equipment 15) when the railway vehicle 110 is energized, and an AC monitoring device 120b that automatically and periodically measures the insulation resistance of the second low-voltage AC circuit 36 and electrical equipment connected thereto (e.g., lighting 16 and brakes 19) when energized.

The AC monitoring device 120a includes a zero-phase current transformer 127a through which a set of first low-voltage AC circuits 32 (main lines 32u1, 32v1, 32w1) passes, and a reference detection unit 128a that detects the voltage generated between the main lines 32u1, 32w1 of the first low-voltage AC circuit 32. Similarly, the AC monitoring device 120b includes a zero-phase current transformer 127b through which a set of second low-voltage AC circuits 36 (main lines 36r1, 36n1, 36t1) passes, and a reference detection unit 128b that detects the voltage generated between the main lines 36r1, 36t1 of the second low-voltage AC circuit 36. The power to operate the AC monitoring devices 120a and 120b may be supplied from the first low-voltage AC circuit 32 or the second low-voltage AC circuit 36 via wires (not shown), or may be supplied from wires other than the first low-voltage AC circuit 32 or the second low-voltage AC circuit 36.

Note that AC monitoring device 120a, AC monitoring device 120b, and AC monitoring devices 120c to 120h described below are configured substantially identically except for their different layouts (connection positions). Hereinafter, when the AC monitoring devices 120a to 120h are described without distinction, they will be referred to as AC monitoring device 120. Similarly, when the zero-phase current transformer 127a and reference detection unit 128a possessed by each of AC monitoring devices 120a to 120h are described without distinction, they will be referred to as zero-phase current transformer 127 and reference detection unit 128, respectively.

The zero-phase current transformer 127 is a ring-shaped current transformer through which a set of AC current circuits to be measured passes, and detects leakage current flowing through the set of AC current circuits when the railway vehicle 110 is energized. More specifically, the zero-phase current transformer 127 through which the set of AC current circuits passes detects leakage current generated in the electric wire downstream of the AC current circuit from the passing position (the side farther from the SIV 30 in the first low-voltage AC current circuit 32, and the side farther from the isolation transformer 34 in the second low-voltage AC current circuit 36) and each electrical device connected to the electric wire.

The leakage current detected by the zero-phase current transformer 127 includes the leakage current Igc caused by the capacitance to the ground, and the leakage current Igr caused by the insulation resistance to the ground, which is directly related to the insulation resistance. The leakage current Igc not only increases in capacity according to the length of the electric wire being measured, but also increases in capacity due to harmonic distortion currents caused by inverters, noise filters, etc. used in electrical equipment.

The reference detection unit 128 is a voltage probe that detects the voltage of a set of AC circuits to be measured. When the measurement target is a three-phase three-wire system, for example, when the main wire 32v1 and the branch wire 32v2 are grounded inside the SIV30 without a winding, the reference detection unit 128 detects the voltage cross point between the ungrounded U phase (main wire 32u1 or branch wire 32u2) and the W phase (main wire 32w1 or branch wire 32w2). When the measurement target is a three-phase four-wire system, for example, when the main wires 32u1, 32v1, and 32w1 are grounded inside the SIV30 via a winding and a neutral wire, the reference detection unit 128 detects the voltage cross point between the phases other than the ground wire (neutral wire). When the measurement target is a single-phase two-wire system, the reference detection unit 128 detects the cross point of the voltage between the N phase (main electric wire 36n1 or branch electric wire 36n2) and the L phase (main electric wire 36r1, 36t1, or one of the branch electric wires 36r2, 36t2).

The AC monitoring device 120 calculates the leakage current Igr of the measurement object from the detection results of the zero-phase current transformer 127 and the reference detection unit 128, and calculates the insulation resistance value of the measurement object from the leakage current Igr. The leakage current Igr and insulation resistance can be calculated using a known method, such as the method disclosed in Japanese Patent No. 4945727.

The AC monitoring device 120 may calculate the leakage current Igr caused by the insulation resistance of the measurement object as the measurement result, without calculating (measuring) the value of the insulation resistance of the measurement object as the measurement result. In this specification, when the AC monitoring device 120 measures the insulation resistance of the measurement object, this includes the case where the AC monitoring device 120 calculates the insulation resistance value itself and the case where the leakage current Igr is calculated.

As described above, the AC monitoring device 120 measures the insulation resistance of the AC circuit and electrical equipment downstream of the position where it passes through the zero-phase current transformer 127, based on the detection value of the zero-phase current transformer 127 when the railway vehicle 110 is energized. As a result, by mounting the AC monitoring device 120 on the railway vehicle 110, it is possible to measure the insulation resistance of electrical equipment that is actually in operation, and it is also possible to eliminate the need for disconnecting the electrical equipment from the ground wire 40 (ground portion), which is necessary with the contact-type monitoring device 70, which measures insulation resistance by applying a voltage.

Furthermore, the AC monitoring device 120 periodically measures the insulation resistance while the railcar 110 is running. This allows the AC monitoring device 120 to measure the insulation resistance of electrical equipment in a state that cannot be grasped while the train is stopped, such as the insulation resistance of electrical equipment that is subjected to a load associated with running.

In addition, since the trunk electric wires 32u1 to 36t1 pass through the zero-phase current transformers 127a and 127b of the AC monitoring devices 120a and 120b, rather than the branch electric wires 32u2 to 36t2, the AC monitoring devices 120a and 120b can measure the total insulation resistance of the AC devices connected to the multiple branch electric wires 32u2 to 36t2 downstream of the zero-phase current transformers 127a and 127b.

In particular, because the main electric wires 32u1 to 32w1 that are upstream of all the branch electric wires 32u2 to 32w2 pass through the zero-phase-sequence current transformer 127a, the AC monitoring device 120a can measure the total insulation resistance of all the AC devices connected to the first low-voltage AC circuit 32. In addition, because the main electric wires 36r1 to 36t1 that are upstream of all the branch electric wires 36r2 to 36t2 pass through the zero-phase-sequence current transformer 127b, the AC monitoring device 120b can measure the total insulation resistance of all the AC devices connected to the second low-voltage AC circuit 36.

Furthermore, DC devices such as brake 19 are connected via rectifier 38 to main wires 36r1, 36t1 downstream of zero-phase current transformer 127b, so leakage current from the DC devices can be detected by zero-phase current transformer 127b, and AC monitoring device 120b can measure the sum of the insulation resistance of the DC devices and the insulation resistance of the AC devices downstream of zero-phase current transformer 127b.

Next, the control of the AC monitoring device 120 will be described with reference to Figures 16 and 17. Figure 16 is a block diagram showing the electrical configuration of the AC monitoring device 120. Figure 17 is a flowchart of the main processing executed by the CPU 121 of the AC monitoring device 120.

The AC monitoring device 120 has a CPU 121, a flash ROM 122, and a RAM 123, which is a memory for rewritably storing various work data and flags when the CPU 121 executes a program, and these are each connected to an input/output port 125 via a bus line 124. The input/output port 125 is further connected to an interface (I/F) 126 connected to the input/output port 65 of the railway vehicle 110, the zero-phase current transformer 127 described above, and the reference detection unit 128 described above.

The CPU 121 is a calculation device that controls each part connected by the bus line 124. The flash ROM 122 is a rewritable non-volatile memory that stores programs executed by the CPU 121, fixed value data, etc., and is provided with an AC monitoring program 122a, a unique number memory 122b, and an AC measurement memory 122c. When the AC monitoring program 122a is executed by the CPU 121, the main processing of FIG. 17 is executed.

The unique number memory 122b is a memory that stores the unique number of the AC monitoring device 120. This unique number indicates the object of insulation resistance measurement by the AC monitoring device 120. The AC measurement memory 122c is a memory for temporarily storing the measurement results of insulation resistance by the AC monitoring device 120, and is configured substantially the same as the contact measurement memory 72c (see FIG. 6) in the first embodiment.

The main processing executed by the CPU 121 of the AC monitoring device 120 will be described with reference to FIG. 17. The main processing of the AC monitoring device 120 is executed when the AC monitoring device 120 is powered on.

The main process of the AC monitoring device 120 first checks whether the regular measurement timing for measuring the insulation resistance of the measurement target has arrived (S111). Note that, for example, the regular measurement timing is every hour, but the measurement timing may be changed as appropriate.

In the process of S111, if the regular measurement timing arrives (S111: Yes), to check whether the railway vehicle 110 is energized, it is checked whether the pantograph 17 is in the raised state (S112), and whether all the electromagnetic switches 44 are closed (S113).

When the pantograph 17 is in the raised state and all the electromagnetic switches 44 are closed (S112: Yes and S113: Yes), the railway vehicle 110 is energized and the insulation resistance of the measurement target can be measured by the AC monitoring device 120, so the insulation resistance of the measurement target is measured by the AC monitoring device 120 (S114).

In this embodiment, the AC monitoring device 120 is powered only when the railway vehicle 110 is energized with the pantograph 17 raised and all electromagnetic switches 44 closed, and is not powered when the railway vehicle 110 is not energized. Therefore, while the main processing of the AC monitoring device 120 is being executed, the pantograph 17 is in the raised state and all electromagnetic switches 44 are closed (S112: Yes and S113: Yes), so the processing of S112 and S113 may be omitted.

After processing S114, the insulation resistance measurement results obtained by the AC monitoring device 120 are associated with the date and time of measurement and stored in the AC measurement memory 122c (S115), and processing S116 is then executed.

Note that in the process of S111, if the regular measurement timing has not arrived (S111: No), the processes of S112 to S115 for measuring the insulation resistance are skipped, and the process of S116 is executed. Also, if the pantograph 17 is in the lowered state in the process of S112 (S112: No), or if the electromagnetic switch 44 is open in the process of S113 (S113: No), the railway vehicle 110 is not energized and the AC monitoring device 120 is not able to measure the insulation resistance of the measurement target, so the processes of S114 and S115 are skipped, and the process of S116 is executed.

In the process of S116, it is confirmed whether the measurement results have been requested from the control device 60 of the railway vehicle 110. Note that the request for the measurement results from this control device 60 to the AC monitoring device 120 is executed in the process of S81 in FIG. 11.

If the measurement results are requested in the process of S116 (S116: Yes), the unsent measurement results and date and time stored in association with the AC measurement memory 122c, and the unique number of the AC monitoring device 120 stored in the unique number memory 122b are transmitted to the control device 60 (S117), and the processes from S111 onwards are repeated. On the other hand, if the measurement results are not requested in the process of S116 (S116: No), the process of S117 is skipped and the processes from S111 onwards are repeated.

The measurement results, date and time, and the unique number of the AC monitoring device 120 sent in the process of S117 are stored in each measurement result memory 62c in correspondence with each other in the process of S82 in FIG. 11 by the control device 60, and are sent to the external server 90 in the process of S85 in FIG. 11. The external server 90 receives this data and uses it to determine the deterioration of the insulation resistance of the object measured by the AC monitoring device 120, and notifies the administrator if deterioration is suspected.

As described above, the insulation resistance measurement results by the AC monitoring device 120 are transmitted to the external server 90 outside the railcar 110, so that the measurement results of the AC monitoring device 120 while the railcar 110 is running can be monitored by the external server 90. This allows early planning of the timing of maintenance of the railcar 110 if an abnormality (deterioration of the insulation resistance of the object being measured by the AC monitoring device 120) is discovered during monitoring.

Next, the fourth embodiment will be described with reference to Figures 18 and 19. In the third embodiment, a case where an AC monitoring device 120 is mounted on one railway car 110 is described. In contrast, in the fourth embodiment, a case where an AC monitoring device 120 is mounted on each part of each of railway cars 130a, 130b, and 130c in a train configuration in which railway cars 130a, 130b, and 130c are coupled together is described. Note that parts that are the same as those in the first to third embodiments are given the same reference numerals and the following description will be omitted.

Figure 18 is a circuit diagram showing the electrical circuits of rail vehicles 130a, 130b, and 130c in the fourth embodiment. Note that Figure 18 shows the electrical circuits of rail vehicles 130a, 130b, and 130c downstream of SIV 30. The electrical circuits of rail vehicles 130a, 130b, and 130c upstream of SIV 30 are configured in the same manner as the electrical circuits of rail vehicles 100a, 100b, and 100c in the second embodiment shown in Figure 13.

As shown in FIG. 18, railcars 130a to 130c mainly comprise a car body 12, wheels 13, couplings 14, and multiple electrical devices (such as lights 16 and brakes 19). Railcars 130a to 130c are configured into a train configuration by coupling their couplings 14 together.

The first low-voltage AC circuit 32 of the railway vehicle 130b includes a set of three main electric wires 32u1b, 32v1b, and 32w1b that extend from the SIV 30 mounted on the railway vehicle 130b and are laid between the front and rear coupling parts 14 of the railway vehicle 130b, and branch electric wires 32u2b, 32v2b, and 32w2b that branch off from the main electric wires 32u1b, 32v1b, and 32w1b, respectively. Although not shown, the first low-voltage AC circuit 32 passes through the inside of the SIV 30 and is connected to the ground line 40 via the electromagnetic switch 44b and the manual switch 46b. A plurality of sets of the branch electric wires 32u2b, 32v2b, and 32w2b are provided so that they are respectively connected to a plurality of AC devices such as air conditioning equipment 15.

The railway vehicle 130a is equipped with main electric wires 32u1a, 32v1a, and 32w1a that are connected to main electric wires 32u1b, 32v1b, and 32w1b, respectively, via coupling parts 14, and branch electric wires 32u2a, 32v2a, and 32w2a that branch off from the main electric wires 32u1a, 32v1a, and 32w1a, respectively. A plurality of sets of the branch electric wires 32u2a, 32v2a, and 32w2a are provided so that they are each connected to a plurality of AC devices such as air conditioning equipment 15.

The railway vehicle 130c is provided with main electric wires 32u1c, 32v1c, and 32w1c that are connected to main electric wires 32u1b, 32v1b, and 32w1b, respectively, via coupling parts 14, and branch electric wires 32u2c, 32v2c, and 32w2c that branch off from the main electric wires 32u1c, 32v1c, and 32w1c, respectively. A plurality of sets of the branch electric wires 32u2c, 32v2c, and 32w2c are provided so that they are each connected to a plurality of AC devices such as air conditioning equipment 15.

Rail cars 130a-130c are equipped with AC monitoring devices 120c, 120d, and 120e, one for each set of branch electric wires 32u2a-32w2c. A set of branch electric wires 32u2a-32w2a passes through a zero-phase current transformer 127c of AC monitoring device 120c, and a reference detection unit 128c of AC monitoring device 120c is connected to main electric wires 32u1a and 32w1a.

A set of branch wires 32u2b-32w2b pass through the zero-phase current transformer 127d of the AC monitoring device 120d, and the reference detection unit 128d of the AC monitoring device 120d is connected to the main wires 32u1b and 32w1b. A set of branch wires 32u2c-32w2c pass through the zero-phase current transformer 127e of the AC monitoring device 120e, and the reference detection unit 128e of the AC monitoring device 120e is connected to the main wires 32u1c and 32w1c.

Therefore, each of the AC monitoring devices 120c to 120e can measure the insulation resistance of an AC device (such as air conditioning device 15) to which one set of branch electric wires 32u2a to 32w2c is connected, without being affected by the insulation resistance of AC devices connected to other branch electric wires 32u2a to 32w2c.

The second low-voltage AC circuit 36 of the railcar 130b includes main wires 36r1b, 36t1b extending from an isolation transformer 34 mounted on the railcar 130b and laid between the front and rear couplings 14 of the railcar 130b, and branch wires 36r2b (not shown) and 36t2b branching off from the main wires 36r1b, 36t1b, respectively. In addition, because a main wire 36n1b connected to a ground wire 40b extends from the isolation transformer 34, the ground wire 40b also functions as part of the main wire 36n1b, and a branch wire 36n2b branches off from the ground wire 40b.

The railway vehicle 130a is equipped with main electric wires 36r1a, 36t1a that are connected to main electric wires 36r1b, 36t1b, respectively, via the coupling portion 14, and branch electric wires 36r2a (not shown), 36t2a that branch off from the main electric wires 36r1a, 36t1a, respectively. In addition, the ground wire 40a that is connected to the ground wire 40b functions as part of the main electric wire, and the branch electric wire 36n2a branches off from the ground wire 40a.

The railway vehicle 130c is equipped with main electric wires 36r1c, 36t1c that are connected to main electric wires 36r1b, 36t1b, respectively, via the coupling portion 14, and branch electric wires 36r2c, 36t2c (not shown) that branch off from the main electric wires 36r1c, 36t1c, respectively. In addition, the ground wire 40c that is connected to the ground wire 40b functions as part of the main electric wire, and the branch electric wire 36n2c branches off from the ground wire 40c.

Rectifiers 38 are connected to the main electric lines 36r1a, 36t1a, 36r1b, 36t1b, and 36r1c, 36t1c, respectively, and DC devices such as brakes 19 are connected between the rectifiers 38 and the main electric lines 36n1a, 36n1b, 36n1c, respectively.

Branch electric wires 36r2a and 36n2a form a set of single-phase two-wire electric circuits, and similarly, branch electric wires 36t2a and 36n2a, branch electric wires 36r2b and 36n2b, branch electric wires 36t2b and 36n2b, branch electric wires 36r2c and 36n2c, and branch electric wires 36t2c and 36n2c each form a set of single-phase two-wire electric circuits. A plurality of sets of electric circuits made of branch electric wires 36r2a to 36t2c are provided so that each set of electric circuits is connected to a plurality of AC devices such as lighting 16.

The railway vehicle 130b is equipped with an AC monitoring device 120b. The main electric wires 36r1b-36t1b at the most upstream (upstream of all branch electric wires 36r2b-36t2b) pass through the zero-phase current transformer 127b of the AC monitoring device 120b. This allows the AC monitoring device 120b to measure the total insulation resistance of multiple electrical devices (AC devices such as lighting 16 and DC devices such as brakes 19) connected to the main electric wires 36r1b-36t1b via the main electric wires 36r1a-36t1a, 36r1c-36t1c, branch electric wires 36r2a-36t2c, and rectifier 38.

Railway cars 130a-130c are equipped with AC monitoring devices 120f, 120g, and 120h for each set of electric paths made up of branch electric wires 36r2a-36t2c. A set of electric paths made up of branch electric wires 36r2a-36t2a passes through a zero-phase current transformer 127f of AC monitoring device 120f, and a reference detection unit 128f of AC monitoring device 120f is connected to main electric wire 36t1a and ground wire 40a.

A set of electric paths consisting of branch electric wires 36r2b-36t2b passes through the zero-phase current transformer 127g of the AC monitoring device 120g, and the reference detection unit 128g of the AC monitoring device 120g is connected to the main electric wire 36t1b and the ground wire 40b. A set of electric paths consisting of branch electric wires 36r2c-36t2c passes through the zero-phase current transformer 127h of the AC monitoring device 120h, and the reference detection unit 128h of the AC monitoring device 120h is connected to the main electric wire 36r1c and the ground wire 40c.

As a result, each of the AC monitoring devices 120f to 120h can measure the insulation resistance of an AC device (lighting 16) connected to one electrical circuit of the branch electric wires 36r2a to 36t2c without being affected by the insulation resistance of AC devices connected to the other branch electric wires 36r2a to 36t2c.

Furthermore, by comparing the measurement results by the AC monitoring devices 120f, 120g, and 120h with the measurement results by the AC monitoring device 120b, it is possible to determine the deterioration of the insulation resistance of DC devices such as the brake 19. This will be explained with reference to FIG. 19. FIG. 19 is a flowchart of the warning display process executed by the external server 90.

As shown in FIG. 19, the warning display process first checks whether the measurement results of the AC monitoring device 120b for the main electric wires 36r1a to 36t1c of the second low-voltage AC circuit 36 are below the threshold value (S121).

If the measurement result of the AC monitoring device 120b falls below the threshold value (S121: Yes), degradation of the insulation resistance of at least one of the multiple AC and DC devices connected to the second low-voltage AC circuit 36 of the railway cars 130a to 130c is suspected. In this case, therefore, in order to determine (estimate) which device's insulation resistance has deteriorated, it is confirmed whether any of the measurement results of the AC monitoring devices 120f to 120g on the branch electric wires 36r2a to 36t2c of the second low-voltage AC circuit 36 has fallen below the threshold value (S122).

If any of the measurement results of AC monitoring devices 120f-120g falls below the threshold (S122: Yes), it can be inferred that the reason why the measurement result of AC monitoring device 120b falls below the threshold is due to deterioration of the insulation resistance of the measurement target of AC monitoring device 120f-120g (AC device connected to a set of electric circuits formed by branch electric wires 36r2a-36t2c).

Therefore, in this case, a warning is displayed for the AC equipment that is the measurement target of the AC monitoring devices 120f to 120g whose measurement results are below the threshold (S123), and the warning display process ends. In this warning display, the measurement target suspected of having deteriorated insulation resistance is displayed on the display device of the external server 90, and the administrator of the external server 90 is notified of the suspected deterioration.

On the other hand, if none of the measurement results of AC monitoring devices 120f-120g are below the threshold in the process of S122 (S122: No), it can be inferred that the reason why the measurement result of AC monitoring device 120b is below the threshold is not due to the AC device being measured by AC monitoring devices 120f-120g, but due to deterioration of the insulation resistance of the DC device. Therefore, in this case, a warning is displayed regarding the DC device (S124), and the warning display process ends.

In addition, if the measurement result of AC monitoring device 120b is not below the threshold value in the processing of S121 (S121: No), specifically, for example, if the measurement result of AC monitoring device 120c or the measurement result of contact-type monitoring device 70d is only below the threshold value, a warning is displayed for the measurement target of AC monitoring device 120c or contact-type monitoring device 70d that is below the threshold value (S125), and the warning display processing ends.

Next, the fifth embodiment will be described with reference to FIG. 20. In the first to fourth embodiments, a contact-type monitoring device 70 and an AC monitoring device 120 are mounted on railway cars 10, 100a to 100c, 110, and 130a to 130c, which are DC electric trains. In contrast, the fifth embodiment will be described with a contact-type monitoring device 70 and an AC monitoring device 120 mounted on railway car 150, which is an AC electric train. Note that the same parts as those in the first to fourth embodiments are given the same reference numerals and the following description will be omitted.

Figure 20 is a circuit diagram showing a schematic diagram of an electrical circuit of a railway vehicle 150 in the fifth embodiment. The railway vehicle 150 is an AC electric train, and mainly comprises a car body 12, wheels 13, a coupling portion 14, and a number of electrical devices (such as air conditioning equipment 15 and lighting 16).

A high-voltage (25,000 V in this embodiment) single-phase AC current flows through the overhead wire 140 that is suspended above the rail 2 by generating an electromotive force at the substation 141 with respect to the grounded rail 2. By raising the pantograph 17 and bringing it into contact with the overhead wire 140, AC power is supplied from the overhead wire 140 via the pantograph 17 to the power line 18 of the railway vehicle 150.

The power line 18 and the ground side electric wire 42 are connected by the primary winding of the main transformer 151. The main transformer 151 is an isolation transformer that transforms and outputs the input voltage and insulates the input side from the output side, and has a secondary winding and a tertiary winding on the output side relative to the primary winding on the input side.

An AC/DC converter 152 that converts the AC power output from the main transformer 151 into DC power is connected to the secondary winding of the main transformer 151. The output side of this AC/DC converter 152 is connected to the VVVF inverter 20. AC power is supplied from the VVVF inverter 20 to the motor 22 via the motor wire 24.

A single-phase, two-wire first low-voltage AC circuit 154 is connected to the tertiary winding of the main transformer 151. Similar to the first low-voltage AC circuit 32 of the first to fourth embodiments, the first low-voltage AC circuit 154 is supplied with single-phase AC power of a fixed voltage (e.g., 440 V) and a fixed frequency from the main transformer 151.

The first low-voltage AC circuit 154 includes a pair of main electric wires 154L1, 154N1 extending from the main transformer 151 and running between the coupling parts 14 at both ends of the railway vehicle 150, and branch electric wires 154L2, 154N2 branching off from the main electric wires 154L1, 154N1, respectively. Although not shown, the main electric wire 154N1 is connected to the grounding wire 40. Multiple sets of the branch electric wires 154L2, 154N2 are provided so that they are respectively connected to multiple AC devices such as air conditioning equipment 15.

The primary winding of an isolation transformer 155 is connected to the main wires 154L1 and 154N1 of the first low-voltage AC circuit 154. A single-phase two-wire second low-voltage AC circuit 156 is connected to the secondary winding of the isolation transformer 155. The isolation transformer 155 transforms the voltage of the AC power input from the first low-voltage AC circuit 154 to 100V in this embodiment and outputs it to the second low-voltage AC circuit 156, while insulating the first low-voltage AC circuit 154 from the second low-voltage AC circuit 156.

The second low-voltage AC circuit 156 includes a main electric line 156L1 that extends from the isolation transformer 155 and is routed between the coupling parts 14 at both ends of the railcar 150, and a branch electric line 156L2 that branches off from the main electric line 156L1. In addition, because a main electric line 156N1 that is connected to a ground line 40 extends from the isolation transformer 155, the ground line 40 also functions as part of the main electric line 156N1, and a branch electric line 156N2 branches off from the ground line 40.

Multiple sets of branch electric wires 156L2, 156N2 are provided so that each can be connected to a plurality of AC devices such as lights 16. A rectifier 38 is connected to the main electric wire 156L1, and DC devices such as brakes 19 are connected between the rectifier 38 and the ground wire 40 (main electric wire 156N1).

Such a railway vehicle 150 is equipped with a contact-type monitoring device 70a and AC monitoring devices 120a, 120b, and 120i for measuring the insulation resistance of each part.

The contact type monitoring device 70a has terminal V connected to the ground wire 40 via wire AV, and terminal a connected to the power line 18 via wire Aa. When the railway vehicle 150 is not energized (with the pantograph 17 lowered and the electromagnetic switch 44a open), a voltage is applied between terminal V and terminal a, making it possible to measure the total insulation resistance of the power line 18, the primary winding of the main transformer 151, and the ground side wire 42, which are all connected to each other.

The AC monitoring devices 120a and 120b are equipped with zero-phase current transformers 127a and 127b through which the most upstream of a set of trunk electric wires 154L1 and 154N1 or a set of trunk electric wires 156L1 and 156N1 passes, and reference detection units 128a and 128b that detect the voltage between the set of trunk electric wires 154L1 to 156N1. Based on the detection value of the zero-phase current transformer 127a and the detection value of the reference detection unit 128a, the AC monitoring device 120a measures the total insulation resistance of the first low-voltage AC circuit 154 and the multiple current devices connected thereto. Based on the detection value of the zero-phase current transformer 127b and the detection value of the reference detection unit 128b, the AC monitoring device 120b measures the total insulation resistance of the second low-voltage AC circuit 156 and the multiple current devices connected thereto.

The AC monitoring device 120i includes a zero-phase current transformer 127i through which the set of three electric wires 24u, 24v, and 24w of the electric motor wires 24 passes, and a reference detection unit 128i that detects the voltage between the non-grounded electric wires 24u and 24w. Based on the detection value of the zero-phase current transformer 127i and the detection value of the reference detection unit 128i, the AC monitoring device 120i can measure the insulation resistance of the electric motor wires 24 and the electric motor 22.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above-mentioned embodiments, and it can be easily assumed that various improvements and modifications are possible within the scope of the present invention. For example, the voltage of the overhead line 4, the value of the output voltage from the SIV 30, and the number of railway cars 10, 11, 100a-100c, 110, 130a-130c, and 150 connected to each other may be changed as appropriate. In addition, the detailed electrical circuits of each part of the railway cars 10, 11, 100a-100c, 110, 130a-130c, and 150 may be changed as appropriate.

In the above embodiment, the railcars 10, 11, 100a-100c, 110, 130a-130c, and 150 run on rails 2, but this is not limited to the above. For example, the present invention may be applied to railcars suspended from rails.

In the above embodiment, a case where power is supplied from the overhead line 4, 140 (pantograph 17) or the power source 102 to the power line 18 has been described, but this is not limited to the above. For example, it may be possible to switch between the supply from the overhead line 4, 140 to the power line 18 and the supply from the power source 102 to the power line 18.

In the above embodiment, the following conversion devices that convert and output the voltage input from the power line 18 are exemplified: the VVVF inverter 20, the SIV 30, the combination of the SIV 30 and the isolation transformer 34, the main transformer 151, the combination of the main transformer 151, the AC/DC converter 152 and the VVVF inverter 20, and the combination of the main transformer 151 and the isolation transformer 155. However, the conversion device is not limited to this. For example, a device that reduces the DC power from the power line 18 by voltage division and outputs it may be used as the conversion device.

In the above embodiment, a case has been described in which either the contact-type monitoring device 70 or the AC monitoring device 120 is provided for the measurement target of one AC circuit (motor wire 24, first low-voltage AC circuit 32, or second low-voltage AC circuit 36), but this is not limited to this. Both the contact-type monitoring device 70 and the AC monitoring device 120 may be provided for the measurement target of one AC circuit.

In the above embodiment, the electromagnetic contacts 44 are opened and closed by the storage battery 67, but this is not limiting. For example, the electromagnetic contacts 44 may be opened and closed by the storage battery 82 of the contact monitoring device 70. In this case, in the main processing of the CPU 71 of the contact monitoring device 70 in FIG. 7, if the pantograph 17 is lowered (S31: Yes), the CPU 71 may send a signal to open all the electromagnetic contacts 44, and then proceed to processing of S32 and S33. After processing of S33, the CPU 71 may send a signal to close all the electromagnetic contacts 44.

In addition, while the electromagnetic contactor 44 has been described as a latch-type contactor that opens and closes with an electrical signal, it may be possible for the electromagnetic contactor 44 to be maintained in an open state by an electromagnet when current is applied to the electromagnetic contactor 44, and to be maintained in a closed state by a spring when current is not applied to the electromagnetic contactor 44. In this case, even if the power supply circuit to the electromagnetic contactor 44 fails, the electromagnetic contactor 44 can be maintained in a closed state when the railway cars 10, 11, 100a-100c, 110, 130a-130c, 150 are running (when current is applied), and the cars can run normally.

In the above embodiment, a case has been described in which all electromagnetic switches 44 are arranged in parallel in pairs, but one switch or three or more switches may be arranged in parallel. Also, depending on the circuit in which the electromagnetic switches 44 are provided, a combination of a portion in which multiple switches are arranged in parallel and a portion in which only one switch is arranged may be used.

In the above embodiment, the contact-type monitoring device 70c is used to measure the control lines 201-203 that are not connected to the second low-voltage AC circuit 36, the power line 18, the first low-voltage AC circuit 32, etc., when the railcar 10 is not energized. When the railcar 10 is energized, only one of the control lines 201-203 is selectively connected to the second low-voltage AC circuit 36 via the control device 60, so it is difficult to measure the insulation resistance of the control lines 201-203 using the second low-voltage AC circuit 36 by the AC monitoring device 120. In contrast, the contact-type monitoring device 70 can easily measure the insulation resistance of the control lines 201-203. In addition to the control lines 201-203, the contact-type monitoring device 70 may also measure the insulation resistance of various control lines that are not connected to the second low-voltage AC circuit 36, the power line 18, the first low-voltage AC circuit 32, etc., when the railcar 10 is not energized.

In the above embodiment, the contact-type monitoring device 70 is used to measure the resistance value of the reference resistor 81, thereby confirming that the contact-type monitoring device 70 is operating normally. For purposes other than this confirmation of normal operation, the third switch SW3 may be closed, and the measurement unit 77 and the switching unit 79 may be connected to the ground line 40 via the reference resistor 81. In this case, residual voltage and capacitance parasitic within the contact-type monitoring device 70 may be discharged using the reference resistor 81.

In the above embodiment, the contact-type monitoring devices 70c and 70f are used to measure the insulation resistance of each part of the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36, but this is not limiting. For example, a contact-type monitoring device 70 that measures the insulation resistance of the first low-voltage AC circuit 32 and a contact-type monitoring device 70 that measures the insulation resistance of each part of the second low-voltage AC circuit 36 may be provided separately. In this case, since the first low-voltage AC circuit 32 and the second low-voltage AC circuit 36 have different voltages, the insulation resistance of each circuit can be measured with high accuracy by installing a dedicated contact-type monitoring device 70 for each. Furthermore, the application of a voltage intended for the first low-voltage AC circuit 32 to the second low-voltage AC circuit 36 can be suppressed.

In addition, the voltage applied during measurement by the contact-type monitoring device 70 is set to be lower than the voltage that flows through each electrical circuit being measured when current is applied to the railway cars 10, 100a-100c, 110, 130a-130c, and 150, so measurements can be made using the contact-type monitoring device 70 while electrical equipment that is prohibited from being subjected to conventional insulation resistance tests that apply excessive voltages is still connected to each electrical circuit.

In addition, a contact-type monitoring device 70 may be provided for one or more measurement objects, regardless of the value of the voltage applied between terminal V and terminals a-f. In addition, the number of terminals a-f of the contact-type monitoring device 70 may be increased to measure the insulation resistance of each part of one railway vehicle 10, 100a-100c, 110, 130a-130c, 150 with one contact-type monitoring device 70.

In the above embodiment, the AC monitoring device 120 calculates the insulation resistance of the measurement object from the detection result of the zero-phase current transformer 127 and the detection result of the reference detection unit 128, but this is not limited to the above. For example, the reference detection unit 128 may be omitted. However, by calculating the insulation resistance of the measurement object from the detection result of the zero-phase current transformer 127 and the detection result of the reference detection unit 128, the detection accuracy of the insulation resistance measurement result by the AC monitoring device 120 can be improved.

In the above embodiment, the brake 19 and the control device 60 are connected to the second low-voltage AC circuit 36, 156 via the rectifier 38, but this is not limited to the above. For example, the brake 19 and the control device 60 may be connected to the battery via a wire different from the second low-voltage AC circuit 36, 156 and the first low-voltage AC circuit 32, 154. This allows the brake 19 and the control device 60 to operate even if the power supply from the overhead line 4, 140 is cut off.

In the above embodiment, the case where the air conditioner 15 is connected to the first low-voltage AC circuit 32, 154 is illustrated, but this is not limited to the above. In addition to the air conditioner 15, AC equipment that may be connected to the first low-voltage AC circuit 32, 154 may include an electric air compressor, a ventilation device, and various cooling fans.

2 Rail 10, 100a to 100c, 110, 130a to 130c, 150 Railway vehicle 12 Car body (part of the ground contact portion)
15. Air conditioning equipment (electrical equipment)
16 Lighting (electrical equipment)
18, 18a to 18c Power line 19 Brake (electrical equipment)
20 VVVF inverter (conversion device or part of conversion device)
22 Electric motors (electrical equipment)
22b Housing (part of the grounding part)
24 Electric motor wire (output wire)
30 SIV (conversion device or part of a conversion device)
32,154 First low voltage AC circuit (output wire)
34,155 Isolation transformer (part of the conversion device)
36,156 Second low voltage AC circuit (output wire)
40, 40a to 40c: Ground wire (part of the grounding portion)
42, 42a to 42c Ground side wire 44, 44b to 44i Electromagnetic switch 44a Electromagnetic switch (power supply side switch)
60 Control device (electrical equipment)
70,70a~70g Contact type monitoring device (monitoring device)
77 Measurement unit (resistance measurement unit)
78 Voltage application section 79 Switching section VDn (n=1 to 6) Voltage detection section SW1-n (n=1 to 6) First switch SW2-n (n=1 to 6) Second switch 81 Reference resistor 86 Isolation transformer (electrical device)
151 Main transformer (converter or part of converter)
152 AC/DC converter (part of the conversion device)

Claims (4)

A railway vehicle that runs on rails,
A ground portion connected to the rail;
A power line through which power is supplied;
A conversion device connected to the power supply line and regulating an input voltage from the power supply line and outputting the adjusted voltage;
an output wire through which output power is supplied from the converter;
an electric device connected to the output wire and operated by the output power;
an electromagnetic switch that connects the electrical device and the grounding portion via the output electric wire in an openable manner and opens in response to interruption of the supply of power to the power supply line;
a monitoring device that applies a voltage between the output wire connected to the electrical device whose connection with the ground part has been cut off and the ground part while the electromagnetic switch is in an open state, and measures the insulation resistance of the output wire;
A railway vehicle comprising: A ground side electric wire connecting the input side of the conversion device and the ground part;
a power supply side switch that opens in response to interruption of the supply of power to the power line to thereby separate the ground side electric wire from the ground portion,
2. The railway vehicle according to claim 1, wherein the monitoring device applies a voltage between the grounding portion and at least one of the power supply line and the grounding side electric wire while the power supply side switch is open, and measures the insulation resistance of at least one of them. The monitoring device includes:
a first switch that is openably connected to an electric wire whose insulation resistance is to be measured;
a voltage detection unit connected to the measurement object via the closed first switch to detect a voltage applied to the measurement object;
a second switch connected to the voltage detection unit and the first switch in an openable/closable manner and configured to close when the voltage detected by the voltage detection unit is equal to or lower than a predetermined value;
3. The railway vehicle according to claim 1, wherein a measurement circuit is formed that measures the insulation resistance of an object to be measured that is connected to the first switch by closing a first switch and a second switch that are connected to each other. The monitoring device includes:
A voltage application unit that applies a positive voltage to the ground unit;
a resistance measurement unit that is connected to the electric wire to be measured that has been disconnected from the grounding unit and that measures the insulation resistance of the measurement target based on the voltage applied by the voltage application unit;
a reference resistor having a predetermined resistance value, the reference resistor being disposed between the resistance measurement unit and the ground unit;
a switching unit that switches a connection between the resistance measurement unit and the measurement target to a connection between the resistance measurement unit and the ground unit via the reference resistor,
3. The railway vehicle according to claim 1, wherein the resistance measurement unit measures a resistance value of the reference resistor instead of an insulation resistance based on a voltage applied by the voltage application unit when the resistance measurement unit is switched by the switching unit to connect the resistance measurement unit to the ground unit via the reference resistor.

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