JPS5833135B2 - DC electric railway power supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply system for a DC electric railway, typified by a subway power supply system, and is particularly applicable to a power supply system to which a regenerative inverter is applied, when an accident occurs in the inverter, and furthermore, To provide a power supply device that can reliably selectively cut off only a faulty line without giving any influence to a healthy line at the time of a predetermined selective cutoff.

DC electric railway power supply equipment, such as subway power supply systems, uses regenerative power from the vehicle during regenerative operation to be transferred to the commercial frequency power supply bus, in line with the trend toward resource conservation and effective use of energy. The number of cases in which regenerative inverters are used for regeneration is increasing.

Figure 1 shows a typical power supply device to which such a regenerative inverter is applied, in which 1 is a commercial frequency power supply bus to which desired AC power is supplied, 2 is an AC breaker, 3 is a transformer that steps down the input AC power to a predetermined voltage value, and 32 is an output transformer of a regenerative inverter to be described later.

Reference numeral 4 denotes a layer gravity conversion device for converting input AC power into DC power. This device is constructed by connecting thyristors in a bridge manner and is generally called a thyristor rectifier.

5 is a regenerative inverter configured by bridge-connecting thyristors, and is used to convert the regenerative power (DC power) from the regenerative vehicle into AC power and regenerate it to the commercial frequency power supply bus side. A DC positive electrode bus bar is provided on the DC output side of the layer gravity converter, and each DC current circuit in which DC high-speed circuit breakers 72 to T5 and disconnectors 8 and 84 are connected in series is connected under this bus bar. Feeder wires 91 and 92 are connected to these DC circuits so that required power is supplied to a non-illustrated vehicle.

71 is a DC high-speed breaker, and 101 and 10□ each indicate a rail.

The operation of the conventional power supply device configured in this way is to step down the AC power input from the commercial frequency power supply bus 1 to an appropriate voltage value by the transformer 31, and then transfer the stepped-down AC power to the layer gravity converter. 4 is converted into DC power, and this DC power is supplied to a car (not shown) through each DC electric circuit to perform a specified car drive. During such car drive, the feeder line 9 If there is a vehicle below that is in regenerative operation, the regenerative power from this regenerative vehicle is transferred from the regenerative vehicle → feeder line 92 → disconnector 84 (or 81) → DC high-speed breaker 75 (or 7□) → At the same time, the power is regenerated to the commercial frequency power supply bus through the path of DC positive bus 6 → DC high-speed breaker 71 → reactor L2 → regeneration inverter 5 → transformer 3□, and at the same time, the regenerative vehicle → feeder line 92 → disconnector 84 (or 81) → DC high speed breaker 75 (or 7
) → DC positive electrode bus 6 → DC high-speed breaker 73 (
or 74) → Disconnector 8□ (or 83) → Feeder wire 91 →
On the path of the vehicle (not shown), regenerative power from the regenerative vehicle is supplied as power to the vehicle located under the other feeder line.

In this way, the regenerative power from the regenerative vehicle is regenerated to the commercial frequency power supply bus side and further to the other traveling vehicle side, so it can be said to be a power feeding system that follows the current trend.

However, the problem with such a power supply device is that, first, a DC high-speed breaker is used as a breaker to protect the entire device.

As described above, since the mechanism itself of a DC type high-speed breaker is based on mechanical operation, it takes a long time to perform the breaker operation, which may unnecessarily aggravate accidents.

Furthermore, since the breaker itself is very large, it requires a space equivalent to the equipment area of the substation, making the equipment cost itself very expensive.

In order to solve the drawbacks of the power supply device shown in FIG. 1, a power supply device using a thyristor breaker instead of a DC high speed breaker as shown in FIG. 2 has already been proposed.

The power supply device shown in FIG. 2 includes the DC type high-speed circuit breaker group 71 to 7. shown in FIG. Thyristor breaker 1
1, to 114 and 12, and in order to give the thyristor breaker group approximately the same function as a DC high-speed breaker, each thyristor breaker 111 to 12 is replaced as shown in the figure.
114 with diodes 131 to 134 connected in parallel, which is revolutionary in that it reduces the installation area of the substation and also provides coordination in protection cutoff in the event of an accident, but it does pose a problem. is as follows.

In other words, if the regenerative inverter 5 fails to commutate for some reason, the regenerative inverter at the time of the accident will receive power from the commercial frequency power bus side: power bus 1 → AC breaker 2 transformer 31 → forward power. The path of converter 4 → reactor L1 → DC positive electrode bus 6 → reactor L2, as well as the regenerative power from the regenerative vehicle or the loop power from the adjacent substation, is routed through feeder line 9□ or 9□ → disconnector → diode. →Thyristor breaker 12→Reactor L2 flows into each path.

Therefore, to cut off these inflow currents (fault currents), for example, if it is on the power supply side, the fault current is caught and the layer gravity converter 4 is stopped immediately, and if it is on the feeder line side, it is connected in series with a regenerative inverter. If the fault current is cut off by the thyristor breaker 12, the purpose of the predetermined protective operation is achieved.

However, the layer gravity conversion device 4 and the thyristor breaker 12
In the case where each of the protection sequences is controlled to be cut off, the sequence circuit that creates the protection sequence itself becomes extremely complex and expensive.

More importantly, if the layer gravity conversion device 4 is stopped,
Since the substation itself is stopped, power supply to each vehicle is stopped, which not only reduces service to passengers but also has a serious impact on smooth operation.

Furthermore, in the event that a short circuit occurs on the feeder line and only the relevant DC circuit is selectively cut off, each thyristor breaker is equipped with an auxiliary thyristor commutation reactor.
A forced extinguishing circuit consisting of a commutating capacitor is added, and the thyristor breaker is forcibly extinguished using the charge of the commutating capacitor to cut off the fault current. During the operation process, the main element of the thyristor breaker is forcibly extinguished, and then the charge in the commutation capacitor is transferred to the diode V shown in the figure → thyristor breaker 12 → DC positive electrode bus 6 → forced extinguishment (not shown) When discharging in the path of the circuit's auxiliary thyristor → commutation/accumulator → commutation capacitor, there is no reactor in this path, so firstly the discharge current increases and the elements in the discharge path are discharged. It poses a huge threat.

Second, since the value of the commutation reactor in the forced arc-extinguishing circuit is very small, it is not possible to secure a reverse bias time sufficient to turn off the main thyristor of the thyristor breaker.

That is, the commutation margin time of the main thyristor becomes small, resulting in a lack of operational stability.

The present invention was invented in view of this point, and will be described in detail below based on the embodiment shown in FIG.

In this embodiment, the same parts as in FIGS. 1 and 2 are designated by the same reference numerals and buttons, and 14 is a diode which is a main part of the present application, and this diode is connected to each thyristor breaker group 1 as shown.
1. It is inserted between the bridge point on the anode side of 114 and the cathode side of the other thyristor breaker 12, and blocks the current flowing from the layer gravity conversion device 4 side, for example, when commutation of the regenerative inverter 5 fails. It is for 15□～
154 is a reactor which is the other main part of the present application, and these reactors are inserted in each electric circuit connecting each diode 13, to 134 and the thyristor breaker 12 in series as shown in the figure, and for example, di/dt of discharge current. At the same time, this is to increase commutation margin time during forced extinguishing of each thyristor breaker.

In this embodiment configured as described above, the operation when the regenerative inverter 5 fails to commutate for some reason will be described.As is well known, if the regenerative inverter 5 fails to commutate, an abnormally large accident will occur. Current will now flow to the transformer 3□ side.

Such commutation failure is detected by a well-known method, and based on this detection signal, the thyristor breaker 12 on the feeder line side is first forcibly extinguished.

As is well known in the art, in this forced arc-extinguishing method, although not shown, a forced arc-extinguishing circuit consisting of an auxiliary thyristor commutation reactor and a commutation capacitor is connected in parallel to the thyristor breaker. By igniting the thyristor breaker, the electric charge of the commutating capacitor which is charged with a predetermined polarity is further charged to the thyristor breaker side.

By forcibly extinguishing the thyristor breaker 12 in this way, the loop power from the adjacent substation flowing in from the feeder line and the regenerative power from the vehicle during regenerative operation are cut off, and the regenerative power is generated at the same time as this cut-off control. By gate blocking the regenerative inverter 5, the regenerative inverter is stopped and isolated from other healthy devices.

As is clear from such a predetermined protective operation, according to the present application, in the event of an accident with the regenerative inverter, the source power can be restored by the diode 14 positioned with the polarity shown without stopping the source power converter 4 on the commercial frequency power supply bus side. Since the current flowing from the conversion device 4 side can be reliably blocked, the predetermined power supply operation of the substation can be continued, and a power supply device that does not interfere with vehicle operation can be provided.

＼・In the event that a short circuit occurs due to the insulator supporting the primary feeder wire being damaged, a circuit with only the essential parts shown in Figure 4 will be used to protect against such a short circuit. This will be explained in detail based on the diagram.

First of all, the above-mentioned short circuit accident occurred in the circuit shown in FIG.
Assume that the following occurs.

Now, when a short circuit accident occurs, the current flowing into the DC circuit from the power supply side becomes abnormally large, so the occurrence of the fault current must first be detected using a sensor such as a well-known overcurrent detection relay. This detection signal is used to selectively cut off only the thyristor breaker 111 of the DC circuit.

That is, the above detection signal once fires the auxiliary thyristor 16 of the forced extinguishing circuit shown in FIG.

When the auxiliary thyristor 16 is ignited in this manner, the charge in the commutating capacitor 18, which is charged with the illustrated polarity, is discharged through the path of commutating capacitor 18 → thyristor breaker 111 → auxiliary thyristor 16 → commutating reactor 17. Charged, commutation reactor 17 → commutation capacitor 1
The discharge current becomes a free oscillation due to the series resonant circuit of 8, and when the discharge current exceeds the fault current flowing through the thyristor breaker 111, the thyristor breaker 11
, is forcibly extinguished, and then the discharge current flows through the diode 13
．． →Reactor 151 → Thyrimeta breaker 12 → Diode 14 → Auxiliary thyristor 16 → Commutation reactor 17
→It begins to flow through the loop of the commutating capacitor 18.

In this discharge process, the thyristor breaker 111 generates a reverse voltage using a voltage drop that is the sum of the forward voltage drops of the thyristor breaker 12 and the diodes 131-14, which are connected in parallel with the breaker 111. 2 ias, and the reverse bias time is increased by inserting the thick accelerator 15 into the discharge loop, so the time required to obtain a sufficient 0FFL of the thyristor breaker 111 can be secured, thereby ensuring that the thyristor is cut off. This means that only the vessel 111 can be extinguished.

In this way, by forcibly extinguishing the thyristor breaker 111 on the fault bus side and opening the disconnector 81 at the point when the current flowing through the breaker 111 becomes approximately zero, the circuit breaker 81 on the fault bus side can be disconnected for the first time. Only the DC circuit can be cut off from the other healthy circuit, and the predetermined selective cutoff can be completed.

The above explanation is for thyristor breaker 111-disconnector 8
．． Although we have described the case where only the DC circuit is selectively cut off, since this is a short-circuit accident in the feeder line 9□, it goes without saying that the DC line between the silice breaker 114 and the disconnector 84 connected to the feeder line 9□ is also selectively cut off. Not until now.

FIG. 5 shows another embodiment, in which the discharge current d
Rather than inserting a glue axle in each of the electrical circuits of the diodes 13, to 134 to suppress the i/dt, etc., as in the embodiment shown in FIG. 19 is connected between the cathode side of the raw power converter 4 and the anode side of the regeneration inverter 5, and the common adhesive acdle 19
It also has the function of blocking current flowing from the raw power converter 4 side when commutation of the regenerative inverter 5 fails.

In this way, the reactor 19 has the function of suppressing the di/dt of the discharge current, the function of ensuring sufficient reverse bias time, and the function of blocking the current flowing from the heavy power converter side. This has the effect of simplifying the circuit and further reducing substation equipment costs.

In the embodiment shown in Fig. 5, if the reactor 19 cannot sufficiently block the current flowing from the raw power converter 4 side when commutation of the regenerative inverter fails, use the button shown in Figs. 3 and 4 instead of the reactor 190. By inserting 14 diodes as shown in the embodiment shown in the figure, and each reactor 15 in the embodiment shown in FIG.
゜ ~ Instead of 154, simply prepare one glue acdle,
This reactor is connected to each diode 131 to 1 shown in FIG.
Even if it is inserted between the bridge point connecting the 34 cathode sides and the anode side of the 12 silice breaker, the intended purpose can be achieved.

As described above, according to the present application, a new reactor is provided in the loop that becomes the discharge current loop when each thyristor breaker is selectively cut off, and furthermore, this reactor is used for forward power conversion when commutation of the regenerative inverter fails. A device with a function of blocking current flowing from the device side, or even with such a current blocking function, is installed between the DC positive electrode bus and the quadrature side of a thyristor breaker that cuts off regenerative power and circulating power. Since a stopper diode with defined conduction polarity is newly inserted to form a power supply device, various effects can be achieved as shown below.

■ Insert a reactor into each discharge loop of each thyristor breaker, or insert one glue handle common to each discharge loop, and use this reactor to control the discharge current d.
Since it has both the function of suppressing i/dt and the function of providing reverse bias time for the thyristor breaker to obtain sufficient 0FFL, it is possible to realize a power supply device that is extremely stable in terms of operation. .

■ A current limiting element is installed to block the current flowing into the inverter from the forward power converter side when commutation of the regenerative inverter fails, so it not only provides the required protection, but also
Since this is a power supply device that does not require stopping the power supply to the substation, it is possible to greatly improve operational efficiency and realize a highly reliable power supply device.

- Since all the circuit breakers that perform predetermined selective shutoff are thyristor circuit breakers, the selective shutoff operation is reliable and responsive, making it possible to prevent the spread of accidents.

■ Based on the advantages mentioned in item (■) above, thyristor circuit breakers are smaller than DC high-speed circuit breakers, so the installation area of substations can be reduced, and a power supply device with extremely low equipment costs can be provided. .

[Brief explanation of the drawing]

1 and 2 are specific circuit diagrams showing the configuration of a conventional power feeding device, FIG. 3 is a specific circuit diagram of a power feeding device showing an embodiment of the present invention, and FIG. 4 is a specific circuit diagram showing the configuration of a conventional power feeding device. FIG. 5 is a schematic circuit diagram of only the main parts used to explain the operation, and FIG. 5 is a schematic circuit diagram of a power supply device showing another embodiment of the invention. 1 is a commercial frequency power supply bus, 4 is a layer gravity conversion device, 5 is a regenerative inverter, 6 is a DC positive electrode bus, 81 to 84 are disconnectors, 11, to 114 and 12 are thyristor circuit breakers, 13
1 to 134 and 14 are diodes, 151 to 154.1
9 and 0. L is a beam axle, 16 is an auxiliary thyristor, 17 is a commutation reactor, and 18 is a commutation capacitor.

Claims (1)

[Scope of Claims] 1. A forward power converter that converts AC power input from a commercial frequency power supply bus into DC power, a DC positive bus that is provided on the DC output side of this device, and a DC positive bus that is connected below this bus. and a plurality of sets of DC electric lines divided into lines and having thyristor breakers and disconnectors connected in series, feeder lines of the plurality of lines to which the required power is supplied from these DC electric lines, and the forward power conversion device. A regenerative inverter that is connected in antiparallel and regenerates regenerative power from the regenerative vehicle to the commercial frequency power supply bus side, and a thyristor that is provided on the DC input side of the regenerative inverter and shuts off the fault current in the event of a fault in the regenerative inverter. It is inserted between the breaker A, the bridge point between the breaker A and the regenerative inverter, and the bridge point connecting the anode sides of the thyristor breaker group, and is connected to the regenerative inverter from the forward power converter. A stopper element for blocking current flowing backwards to the side is inserted between each bridge point of each thyristor breaker and each disconnector in the plurality of sets of DC circuits and the anode side of the thyristor breaker A. In addition, the regenerative power from the regenerative vehicle, the wrap-around power from the adjacent substation, and the discharge current of the thyristor breaker when extinguished are respectively input, and multiple sets of series circuits in which diodes and current limiting elements are connected in series are used. A DC electric railway power supply device characterized by comprising: 2. A forward power converter that converts AC power input from a commercial frequency power supply bus into DC power, a DC positive bus provided on the DC output side of this equipment, and a forward power converter that converts AC power input from a commercial frequency power supply bus into DC power; A plurality of sets of DC circuits in which a thyristor breaker and a disconnector are connected in series, a plurality of feeder lines to which the required power is supplied from these DC circuits, and a regeneration circuit connected in antiparallel to the forward power converter described above. A regenerative inverter that regenerates regenerative power from a vehicle to the commercial frequency power supply bus side, a thyristor breaker A that is provided on the DC input side of the regenerative inverter and that interrupts the fault current in the event of a fault in the regenerative inverter; It is inserted between the bridge point between breaker A and the regenerative inverter and the bridge point connecting the anode sides of the thyristor breaker group, and prevents current from flowing backward from the forward conversion device to the regenerative inverter side. A stopper element is inserted between each bridge point of each thyristor breaker and each disconnector in the plurality of sets of DC circuits and the anode side of the thyristor breaker A, and A bridge point connects multiple diodes divided for each line and the cathode sides of these diodes, which input power, input power from an adjacent substation, and discharge current when extinguishing a thyristor breaker. 1. A power supply device for a DC electric railway, characterized in that it comprises a set of current limiting elements connected in series. 3. A forward power converter that converts AC power input from a commercial frequency power supply bus into DC power, a DC positive bus provided on the DC output side of this equipment, and a forward power converter that converts AC power input from a commercial frequency power supply bus into DC power; A plurality of sets of DC circuits in which a thyristor breaker and a disconnector are connected in series, a plurality of feeder lines to which the required power is supplied from these DC circuits, and a regeneration circuit connected in antiparallel to the forward power converter described above. a regenerative inverter that regenerates regenerative power from the vehicle to the commercial frequency power supply bus side; a thyristor breaker A that is provided on the DC input side of the regenerative inverter and that interrupts the fault current in the event of a fault in the regenerative inverter; A plurality of sets of DC electrical circuits are inserted between the respective bridge points of each thyristor breaker and each disconnector and the anode side of the thyristor breaker A, and the regenerative power from the regenerative vehicle and the adjacent substation are connected to each other. A plurality of diodes which input the circulating power and the discharge current at the time of extinguishing the thyristor breaker and are divided for each line, the bridge point between the thyristor breaker A and the regenerative inverter, and the thyristor breaker group A current limiting element that is inserted between the anode sides of the inverter and a bridging point that connects the anode sides of the inverter and blocks the current flowing back from the layer gravity conversion device to the regenerative inverter side, and at the same time suppresses the di/dt of the discharge current. A power supply device for a DC electric railway, characterized by comprising: