JPS6325973B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC power supply system, and an object of the present invention is to provide a DC power supply system that is low in cost, has little loss, and has little effect on the load during switching in a DC power supply system using a semiconductor device. belongs to.

In DC substations for electric railways, etc., a DC power supply system is known in which a thyristor switch is used instead of a DC high-speed shear switch in a DC feeder circuit. That is, FIG. 1 shows a known example thereof. 1 is a thyristor rectifier, 2 is a rectifying transformer, and the DC side anode circuit 3 of the thyristor rectifier 1 is connected to an overhead wire 6A that supplies power to direction A via a thyristor switch 4A and a switch 5A.
connected to. Similarly, the anode circuit 3 includes thyristor switches 4B, 4C, 4D and a switch 5.
It is connected to overhead wires 6B, 6C, and 6D that feed power to each direction B, C, and D via B, 5C, and 5D, respectively. Reference numeral 7 designates an inverter for returning regenerative power generated by regenerative braking of the vehicle to an AC power source, and 8 designates a transformer for the inverter. 9A, 9B, 9C, 9D
are diodes for regeneration and extended power supply, and are connected in antiparallel to the thyristor switches 4A, 4B, 4C, and 4D, respectively. 12AB,1
2CD is the overhead wire section, 12AB is the overhead wire 6A
and 6B, and 12CD electrically insulates overhead wires 6C and 6D, respectively. 13A, 13B, 13
C and 13D are CTs, and the secondary side is each overcurrent detector 1.
4A, 14B, 14C, and 14D.

Next, the operation of this known DC power supply system will be explained. For example, regarding direction A, the powering current to the vehicle is from rectifier 1, thyristor switch 4A,
It is sent via switch 5A and overhead wire 6A. On the other hand, the regenerative current from the vehicle is from the overhead line 6A to the switch 5.
A is sent back to the inverter 7 via the diode 9A. In addition, the overhead wires 6A and 6B are connected to the route of the overhead wire 6A - switch 5A - diode 9A - anode circuit 3 - thyristor switch 4B - switch 5B - overhead wire 6B, and the route of the overhead wire 6B - switch 5B - diode 9B - anode circuit 3 - thyristor. Switch 4A-Switch 5A
- Since it is connected via the route of the overhead wire 6A,
Since current can freely flow between sections A and 6B from any direction, almost no potential difference occurs between sections 12AB. The same can be said about Section 12CD. Next, a case will be described in which an abnormality occurs in the circuit of the overhead wire 6A and an overcurrent occurs in the thyristor switch 4A. Thyristor switch 4A
The overcurrent flowing through the thyristor rectifier 1 and the overhead lines 6B, 6C, 6D, and switches 5B, 5 from an adjacent substation or a vehicle undergoing regeneration, etc.
This is a combination of currents supplied via C, 5D, and diodes 9B, 9C, and 9D. This overcurrent is detected by overcurrent detector 14A. 14A sends a current cutoff signal to the thyristor rectifier 1, simultaneously stops the gate signal of the thyristor switch 4A, and also sends a current cutoff command to the adjacent substation. Next, when the current in the thyristor switch 4A becomes zero and the thyristor element turns off, the switch 5A
is opened, and then the rectifier 1 and the adjacent substation are energized again, and the other thyristor switch 4 is opened.
Sound overhead lines 6B, 6 via B, 4C, 4D
Power supply to C and 6D is restarted. Thus, by stopping the thyristor switch 4A and opening the switch 5A, the power supply to the overhead wire 6A is stopped.

In such a conventional system, each overhead wire 6A,
The current supplied to 6B, 6C, and 6D is all sent out via thyristor switches 4A, 4B, 4C, and 4D, so thyristor switches 4A, 4
B, 4C, and 4D had the disadvantage of requiring a large current carrying capacity and increasing equipment costs. Another disadvantage is that the overall efficiency of the substation is lowered due to losses caused by forward voltage drops in the thyristor switches 4A, 4B, 4C, and 4D. Furthermore, in this conventional system, in order to open the power supply circuit to area A, the thyristor rectifier 1 and the adjacent substation are temporarily stopped, so the power supply circuits to areas B, C, and D are also interrupted. Therefore, the overhead wires 6B, 6C,
The drawback was that the vehicle undervoltage relay, which receives power from the 6D, would operate, affecting the vehicle.

The present invention is intended to solve the drawbacks of the conventional system. By dividing the thyristor rectifier into each negative feeding circuit and omitting the thyristor switch, the cost is low, the efficiency is high, and the impact on the vehicle is minimized. This provides a DC power supply system that allows for maximum

FIG. 2 shows an embodiment of the invention. The thyristor rectifier 1 is divided into 1A, 1B, 1C, and 1D corresponding to the feed directions A, B, C, and D, respectively. 2 is a rectifier transformer, which is divided into transformers 2AB and 2CD, each having two sets of secondary windings, and one secondary winding of transformer 2AB is connected to thyristor rectifier 1.
A and the other secondary winding are respectively connected to the thyristor rectifier 1B. Similarly, the two sets of secondary windings of transformer 2CD are connected to thyristor rectifiers 1C and 1D, respectively.
It is connected to the. Thyristor rectifier 1A, 1
B, 1C, 1D anode terminals 3A, 3B, 3C, 3
D is an overhead wire 6 that supplies power to the feeder directions A, B, C, and D via switches 5A, 5B, 5C, and 5D, respectively.
Connected to A, 6B, 6C, and 6D. Reference numeral 7 designates an inverter for returning regenerative power generated by regenerative braking of the vehicle to an AC power source, and 8 designates a transformer for the inverter. 9A is a diode for flowing regenerative current, extended power supply current, and supplementary current for other thyristor rectifiers 1B, 1C, and 1D, and the anode side is a point 15A between rectifier anode terminal 3A and switch 5A.
connected to. Similarly, the anode side of the diodes 9B, 9C, and 9D is connected to the anode terminals 3B,
Point 1 between 3C, 3D and switches 5B, 5C, 5D
5B, 15C, and 15D, respectively. The cathodes of the diodes 9A, 9B, 9C, and 9D are connected in common at a common portion 10. The diode 16A is connected so that its cathode side is common to the anode side of the diode 9A. That is, the cathode side of diode 16A is connected to point 15A. Similarly, the cathodes of diodes 16B, 16C, and 16D are connected to points 15B, 15C, and 15D, respectively. Diode 16A, 16B, 16C,
The anode sides of 16D are connected in common at a common portion 17. Reference numeral 11 denotes a thyristor shear disconnector, which is connected between the common portion 10 and the common portion 17, and is connected with a polarity such that current flows from the common portion 10 to the common portion 17. 12AB, 12CD are the same overhead wire sections as described in the known example of FIG.
DCCT 13A is connected between rectifier anode terminal 3A and point 15A to detect the current of thyristor rectifier 1A. The secondary side of the DCCT 13A is connected to a current detector 14A that detects overcurrent or current change rate. Similarly, DCCT13B, 13C, 13D connect rectifier anode terminals 3B, 3C, 3D and points 15B, 1
5C and 15D, and the secondary side is connected to current detectors 14B, 14C, and 14D, respectively. Current transformer 18A and zero current detector 19A are switch 5A
This is to detect when the current of
The primary side of current transformer 18A is connected between point 15A and switch 5A, and the secondary side is connected to zero current detector 19A. Similarly, current transformers 18B, 18C, 1
The primary side of 8D is connected between points 15B, 15C, 15D and switches 5B, 5C, 5D, respectively, and the secondary side is connected to zero current detectors 19B, 19C, 19D, respectively. Thyristor rectifier 1A, 1B, 1C,
1D cathode terminals 20A, 20B, 20C, 20D
Both are connected to the cathode circuit 21. Cathode circuit 21 is connected to rail 22. DC terminals 23 and 24 of inverter 7 are connected between common circuit 10 and cathode circuit 21, respectively.

Next, the operation of the embodiment shown in FIG. 2 will be explained.
For example, regarding direction A, the powering current to the vehicle is sent from the thyristor rectifier 1A via the switch 5A and the overhead wire 6A. When a peak current occurs in direction A and the current exceeds the rating of thyristor rectifier 1A, diodes 9B, 9C, 9D - thyristor shear disconnector 11 - diode 16A - switch 5A
Via the thyristor rectifier 1B, 1C, 1D
From there, the power running current is supplemented to the overhead wire 6A, and the current of the thyristor rectifier 1A is prevented from exceeding its rating.
On the other hand, the regenerative current from the vehicle is from the overhead line 6A to the switch 5.
It is sent back to the inverter 7 via A and the diode 9A. In addition, the overhead wires 6A and 6B are the overhead wires 6A and 6B.
- Switch 5A - Diode 9A - Thyristor shear disconnector 11 - Diode 16B - Switch 5B - Overhead line 6B route and overhead line 6B - Switch 5B - Diode 9B - Thyristor shear disconnector 11 - Diode 1
6A - switch 5A - overhead wire 6A, so current can flow freely from any direction between overhead wires 6A and 6B;
Almost no potential difference occurs between AB. Similarly, between the overhead wires 6A, 6B, 6C, and 6D, current can flow freely from any overhead wire to any overhead wire, so the regenerative current in one overhead wire is supplied to the power running vehicle existing in another overhead wire section. Therefore, the regenerative current can be transferred efficiently between vehicles, and the capacity of the thyristor rectifier 1 and inverter 7 can be reduced accordingly.
Next, a case where an abnormality occurs in the circuit of the overhead wire 6A and an overcurrent or an abnormal current increase rate occurs in the thyristor rectifier 1A will be described. Thyristor rectifier 1A
The abnormal current flowing through is detected by the current detector 14A. When the current detector 14A detects an abnormal current, it sends a current shear cut signal to the thyristor rectifier 1A and the thyristor shear cutter 11. As a result, the thyristor rectifier 1A cuts off the abnormal current by cutting off the gate shear or by operating the inverter with the phase control angle set to 90 degrees or more. On the other hand, the thyristor shear disconnector 11 performs current shear disconnection based on the signal from the current detector 14A, but at the same time it also has the function of detecting abnormal current from itself, and the other rectifiers 1B, 1C,
1D to diodes 9B, 9C, 9D - thyristor shear disconnector 11 - diode 16A - switch 5A
It is configured to detect an abnormal current supplied to the overhead wire 6A via and to cut off the current before the current detectors 14B, 14C, and 14D operate. Therefore, in response to abnormal current in the overhead wire 6A, the rectifier 1B,
1C and 1D do not perform current shearing operation. Furthermore, there is no need to shut down the adjacent substation. Therefore, the other healthy overhead wires 6B, 6C, and 6D are not affected. Next, when the shearing operation of the rectifier 1A and the thyristor shear disconnector 11 is completed and the current of the switch 5A becomes zero, the zero current detector 19A operates and sends an opening command to the switch 5A, causing the switch 5A to open. Open. When the switch 5A is opened, the thyristor rectifier 1A and the thyristor shear disconnector 11 start energizing again in response to the opening completion signal from the switch 5A.
The overhead wire 6A is thus disconnected from the substation. In order to ensure that the switch 5A is opened with zero current, when the thyristor adjuster 1A and the thyristor shear disconnector 11 perform the current shear disconnection operation based on the signal from the current detector 14A, the phase of the inverter 7 is simultaneously The control angle may be controlled to make the current in the inverter 7 zero, and energization may be started again by an open signal from the switch 5A. Alternatively, the DC terminal 23 of the inverter 7 may be connected to the common section 10 instead of the common section 10. 17, and connect the regenerative current to the thyristor shear disconnector 1.
Of course, it is also possible to cut the shear at 1.

In Fig. 2, one rectifier transformer 2 is provided for two thyristor rectifiers, but four independent transformers are provided for each thyristor rectifier 1A, 1B, 1C, and 1D. It's okay,
Alternatively, one transformer may be provided with an arbitrary number of secondary windings, and one pair of thyristor rectifiers may be connected to each secondary winding. In the example of Figure 2, 11
uses a thyristor shear disconnector, but it is of course possible to use a conventional mechanical shear disconnector instead, but the thyristor shear disconnector cuts the current much faster. Therefore, using this has the advantage that the influence on a healthy feeder circuit can be made smaller. Switches 5A, 5B in Fig. 2,
5C and 5D perform currentless switching, so a disconnector may be used, and it goes without saying that a mechanical shear disconnector may be used for backup.

As explained above, according to the present invention, the feeder circuit does not require a thyristor switch unlike the conventional system, so the equipment cost is reduced, and each overhead wire is directly supplied with power from the thyristor rectifier without going through a thyristor switch. Therefore, the loss generated in the feeder circuit is greatly reduced compared to the conventional system, and the efficiency of the substation is improved. In addition, since the normal power running current is directly supplied from each rectifier to each corresponding overhead wire, diodes 9A, 9B, 9C, 9D and diode 1
6A, 16B, 16C, and 16D only need to have a current carrying capacity for regenerative current, supplementary power from other rectifiers, or extended power supply, and need only have a smaller current capacity than conventional thyristor switches. Therefore, the total capacity of the semiconductor devices installed in the feeder circuit can be small, and equipment costs and equipment dimensions can be reduced. Furthermore, according to the present invention, in the event of an accident, only the thyristor rectifiers connected to the overhead wire where the accident occurred are temporarily stopped, and the thyristor rectifiers connected to other healthy overhead wires continue to operate. Therefore, the substation will not be completely shut down, and there is no need to cause a power outage to the adjacent substation, so it is possible to prevent the operation of undervoltage relays of vehicles that are supplied with power from intact overhead lines.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional DC power supply system, and FIG. 2 is a block diagram showing an embodiment of the present invention. 1A, 1B, 1C, 1D are thyristor rectifiers,
3A, 3B, 3C, 3D are rectifier anode terminals, 5
A, 5B, 5C, 5D are switches, 6A, 6B, 6
C, 6D are overhead wires, 9A, 9B, 9C, 9D are diodes, 10 is a common part on the diode cathode side, 1
1 is thyristor shear disconnector, 13A, 13B, 13
C, 13D is DCCT, 14A, 14B, 14C,
14D is a current detector, 15A, 15B, 15C,
15D is the diode connection point, 16A, 16B, 1
6C and 16D are diodes, 17 is a common part on the diode anode side, 18A, 18B, 18C, 18
D is a current transformer, 19A, 19B, 19C, 19D are zero current detectors, 20A, 20B, 20C, 20D
is a rectifier cathode terminal, and 21 is a cathode circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. In a DC power supply system for supplying power to a plurality of sets of electrically isolated load circuits, an abnormality in at least a thyristor rectifier, a switch, a first diode, a second diode, and the thyristor rectifier A power supply circuit having a means for detecting current and a means for detecting zero current of the switch is provided corresponding to each of the plurality of load circuits, and one DC terminal of the thyristor rectifier is connected to the power supply circuit. The anode side of the first diode is connected to the load circuit through the switch, and in each of the power supply circuits, the anode side of the first diode is connected to the circuit portion connecting between the switch and one DC terminal of the thyristor rectifier. The cathodes of the second diodes are connected to each other, the cathodes of the first diodes of each of the power supply circuits are connected in common to form a first common circuit section, and the second diodes of each of the power supply circuits are connected together. The anode side is commonly connected to form a second common circuit section, and the first common circuit section and the second common circuit section are connected via a shear disconnector. DC power supply method. 2. It has an inverter for converting DC regenerative current into AC, one of the DC terminals of the inverter is connected to the first common circuit section or the second common circuit section, and the first diode or the second 2. The DC power supply system according to claim 1, wherein the regenerative current from the load circuit is returned to the inverter via a diode. 3. When the means for detecting the abnormal current of the thyristor rectifier of a given power supply circuit (hereinafter referred to as the first power supply circuit) among the plurality of power supply circuits is activated, the thyristor of the first power supply circuit is activated. By gate shear cutting or phase control of the rectifier, the first
The current of the thyristor rectifier of the power supply circuit is cut off, and the shear cutter connected between the first common circuit section and the second common circuit section is operated to cut off the current of the thyristor rectifier, and then the first power supply circuit After confirming that the current in the switch has become zero using a means for detecting zero current in the switch in the circuit, the switch is opened, and after the opening of the switch is completed, Claim 1 or 2, characterized in that the shear disconnector alone or the shear disconnector and the thyristor rectifier of the first power supply circuit are controlled so as to return to the energized state again. DC power supply method. 4 When the means for detecting the abnormal current of the thyristor rectifier of any of the plurality of power supply circuits (hereinafter referred to as the first power supply circuit) is activated, the thyristor rectifier of the first power supply circuit is activated. The current of the thyristor rectifier of the first power supply circuit is cut off by the gate shear cutoff or phase control, and the shear cutoff operation of the shear cutter connected between the first common circuit section and the second common circuit section is performed. and controlling the inverter current to zero by phase control of the inverter, and then in the first power supply circuit, the switching is performed by the means for detecting the zero current of the switch. After confirming that the current in the device has become zero, open the switch,
After the opening of the switch is completed, the shear breaker and inverter, or the shear breaker and inverter, and the thyristor rectifier of the first power supply circuit are controlled so as to return to the energized state again. DC power supply method described in item 2.