JP3355818B2 - Overvoltage protection device for section switching device in AC feeding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overvoltage protection device for a section switching device in an AC power supply system, and more particularly to a system in which separate power supplies are connected by switches, for example, an overvoltage protection measure for a switching section of a Shinkansen. About.

[0002]

2. Description of the Related Art Hitherto, a section switching device of a Shinkansen has been configured as shown in FIG. In FIG. 4, reference numeral 1 denotes an electric wire connected to the AC power supply A, and 2 denotes an electric wire connected to the AC power supply B adjacent to the AC power supply A. An intermediate section 3 is provided between the feeder wires 1 and 2. A switching switch a ₁ is connected between the feeder line 1 and the intermediate section 3, and a switching switch b ₁ is connected between the feeder line 2 and the intermediate section 3. 4 is an electric car and 5 is a rail.

[0005] The switching switches a ₁ and b ₁ serve as a power supply system for supplying electric power to the electric vehicle 4 by the following operation as shown in FIG.
Is switched from A to B as shown in FIG. In FIG. 5, reference numeral 4a denotes a pantograph of the electric vehicle 4, and other parts are denoted by the same reference numerals as those in FIG.

[0004] (1) in a state before a train enters the standby state train enters the middle section 3, the switching switch a ₁ is closed, b ₁ is the open state.

(2) At the time of train entry 1 When the train enters the intermediate section 3, the switching switch a ₁
Is opened.

[0006] (3) train enters time of 2 wherein (2) the state at a certain time (0.3 seconds) has elapsed, the switching switch b ₁ is closed.

(4) At the time of passing the train ₁ After the train has passed through the intermediate section 3, b1 is opened, and the intermediate section 3 is in a state of no power supply.

[0008] (5) train passing time of 2 above (4) a predetermined time has elapsed after a ₁ from is closed, (1)
, And waits until the next train arrives.

[0009]

At the time of the opening operation under the condition (4), there is no train in the intermediate section 3 and the AC power source B is charging the unloaded line. For this reason, the system of the intermediate section 3 becomes a leading circuit, and the phase difference between the voltage and the current is 90 ° .

In general, since the switch breaks at a current zero point, the voltage of the intermediate section 3 remains at the peak value (Em) of the system after the break. The switching switch a ₁ as the (5) in the course of the closed in this state, the AC power supply A voltage phase voltage 2Em Between opposite polarity switching switch a ₁ and a peak value pole Is applied, which is very severe. Further, the switching switch a ₁ is in the closing process, and at the moment when the electrical connection is made at the time of the preceding discharge or the completion of the closing,
Theoretically, a ground voltage of 3 Em is generated, and the insulation of connected equipment is threatened, which is not preferable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide an overvoltage protection device for a section switching device in an AC feeder, which can prevent occurrence of an overvoltage due to a residual voltage when an intermediate section is disconnected. Is to do.

[0012]

SUMMARY OF THE INVENTION The present invention provides a first feeder connected to a first AC power supply, a second feeder connected to a second AC power supply adjacent to the first AC power supply, First,
An intermediate section provided between the second feeders;
An electric circuit connecting the feeder line and the intermediate section; and a switching switch interposed in the electric circuit connecting the second feeder line and the intermediate section. A section switching device in an AC feeder for switching power supply of a power supply, wherein (1) predetermined discharge means is connected between the intermediate section and a rail, and (2) the discharge means is a discharge resistor. (3) The discharge means is a discharge switch that is closed when the switching switch is controlled to open.

[0013]

The residual voltage generated when the electric vehicle passes through the intermediate section and the intermediate section is disconnected from the first and second AC power supplies is discharged by the discharging means. Therefore, generation of overvoltage due to the residual voltage is eliminated.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as those in FIG. 4 are denoted by the same reference numerals. According to the present invention, the discharge device 10 for discharging the voltage remaining when the intermediate section 3 is disconnected from the AC power supplies A and B is provided with the intermediate section 3 and the rail 5.
It is connected between.

The discharge device 10 uses, for example, a discharge resistor.
By connecting the discharge resistors in this way, when the switching switches a ₁ and b ₁ are in the open state as in the case of (4) described above, the residual voltage of the intermediate section 3 becomes as shown in FIG. And the potential is forcibly set to the ground potential (= 0).
Therefore, an overvoltage due to the residual voltage does not occur. FIG.
(A) shows the voltage waveform of the conventional device (FIG. 4).
When a discharge resistor is used, there is some loss because it is always connected to the system, but there is an advantage that there is no mechanical operation. Since the discharge of the residual voltage needs to consider the discharge time due to the resistance component, the discharge resistance is set to an optimum constant.

The discharge device 10 is provided with a switching switch a ₁ ,
The discharge switch which is closed to the opening control when the b ₁ may be used. Also in this case, similarly to the above, when the switching switches a ₁ and b ₁ are in the open state, the residual voltage of the intermediate section 3 is discharged by a direct short circuit as shown in FIG. At the ground potential (= 0). Therefore, an overvoltage due to the residual voltage does not occur. FIG. 3A shows a voltage waveform of the conventional device (FIG. 4). When a discharge switch is used, mechanical operation is required. However, the switch is connected to the system only when the switching switches a ₁ and b ₁ are in an open state. There is no. Further, since the discharge of the residual voltage is directly short-circuited by the switch, there is no need to consider the discharge time.

Further, the discharge device 10 of the present invention is not limited to the above-described discharge resistor and discharge switch, but may use other discharge means having the same function.

[0018]

As described above, according to the present invention, there is provided a switching circuit which is inserted between the first electric wire and the intermediate section, and the electric switch which is inserted between the second electric wire and the intermediate section. In the section switching device in the AC feeder for switching the power supply of the first and second AC power supplies by controlling the switching of the switching switch, a predetermined discharging unit is connected between the intermediate section and the rail. Such excellent effects can be obtained.

(1) When the intermediate section is disconnected from two adjacent AC power supplies, it is possible to prevent occurrence of an overvoltage due to a residual voltage. Therefore, the connected equipment is not adversely affected.

(2) When a discharge resistor is used as the discharge means, since there is no mechanical operation, it is suitable for a case where a high frequency such as a bullet train is required.

(3) When a discharging switch is used as the discharging means, the discharging switch is connected to the system only when the switching switch is controlled to be open, so that there is no need to consider a loss or the like. Also, since the discharge of the residual voltage is a direct short circuit by the switch,
There is no need to consider the discharge time.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 (a) is a voltage characteristic diagram showing a state of overvoltage generation by a conventional device, and FIG. 2 (b) is a voltage characteristic diagram by a device using a discharge resistor of the present invention.

FIG. 3 (a) is a voltage characteristic diagram showing a state of overvoltage generation by a conventional device, and FIG. 3 (b) is a voltage characteristic diagram by a device using a discharge switch of the present invention.

FIG. 4 is a circuit diagram showing an example of a section switching device in a conventional AC feeder.

FIG. 5 is an explanatory diagram showing the operation of a switching switch in the AC power feeding facility.

[Explanation of symbols]

1,2 ... feeder 3 ... middle section 4 ... electric vehicle 5 ... rail 10 ... discharge device a _1, b ₁ ... switching switch A, B ... AC power source

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60M 3/04

Claims (3)

(57) [Claims] 1. A first feeder connected to a first AC power supply, a second feeder connected to a second AC power supply adjacent to the first AC power supply, and between the first and second feeders. , A switching circuit interposed between the first feeder wire and the intermediate section, and a switching switch interposed between the second feeder wire and the electrical route connecting the intermediate section, respectively, Switching means for switching the power supply of the first and second AC power supplies by controlling the opening and closing of a section, wherein a predetermined discharging means is connected between the intermediate section and a rail. The overvoltage protection device of the section switching device. 2. The overvoltage protection device for a section switching device in an AC feeder according to claim 1, wherein the discharging means is a discharge resistor. 3. The overvoltage protection device for a section switching device in an AC feeder according to claim 1, wherein the discharging means is a discharging switch closed when the switching switch is opened. .