JPS5846896Y2 - DC electric railway power supply device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a power supply device for a DC electric railway in which a thyristor rectifier and a thyristor circuit breaker are applied as a source power conversion device, and in particular, it simplifies the arc extinguishing circuit of a group of thyristor circuit breakers. The present invention aims to provide a power supply device that can reduce the equipment cost of the entire power supply system.

In DC electric railway power supply equipment, it is easy to coordinate protection in the event of an accident, it is also possible to suppress voltage fluctuations between dead sections to an extremely small value, and it also eliminates the complexity of maintenance. For these reasons, thyristor rectifiers are now being used instead of silicon rectifiers as raw power converters, and thyristor circuit breakers are being used instead of DC high-speed circuit breakers.

FIG. 1 shows the configuration of a typical power supply device to which such a thyristor rectifier and thyristor circuit breaker are applied.

In the figure, 1 is a commercial frequency power supply bus, and under this power supply bus, an AC circuit breaker 2, a transformer 3, and an AC line for a raw power converter 4 are connected. Thyristors are connected in a forward bridge to forwardly convert AC power input from a commercial frequency power supply bus into DC power. 5 is a DC positive bus, and below this bus there are thyristor cut-off circuits divided for each line. Device group 6□~64 and disconnector group 8□~
84, and each thyristor circuit breaker has a group of regeneration diodes positioned according to the polarity shown in the diagram so as to have approximately the same function as a conventionally well-known DC high-speed circuit breaker. 7□ to 74 are connected in antiparallel.

9□ and 9° are feeder lines that supply the required power to each vehicle, 10 and 10□ are rails, and 11 is a negative bus bar.

Now, the problem with such a power supply device is the configuration of the arc circuit for extinguishing the arc of the thyristor circuit breaker.

That is, referring to FIG. 2, which shows a thyristor circuit breaker with the symbol 6□ as a representative example in the group of thyristor circuit breakers, in order to extinguish the 6 thyristor circuit breakers, the 12 steps shown in the figure are necessary. Auxiliary thyristor and 13 commutation reactors and 1
As is well known, the operation of such an arc extinguishing circuit is such that the auxiliary thyristor 12 is once ignited by a detection signal at the time of an accident, and then The charged charge of the commutating capacitor 14, which was previously charged by polarity, was discharged to the main thyristor 61 side through the auxiliary thyristor 12, and the value of the discharge current that becomes free oscillation exceeded the current flowing through the main thyristor 6□. By forcibly extinguishing the main thyristor 61 at this point, only the faulty line is selectively cut off, and each thyristor circuit breaker requires a forced extinguishing circuit that performs the intended operation.

Therefore, if the power supply device shown in Figure 1 is used, a forced arc-extinguishing circuit for four electric lines would be required between each dead section, which would make the equipment cost of the substation extremely uneconomical. be.

What is particularly important is that each substation requires four sets of forced arc-extinguishing circuits. It is clear how uneconomical the equipment cost of the entire system becomes.

What is more important is that if a vehicle is in regenerative operation and a ground fault occurs for some reason on the DC positive bus 5 side during this regenerative operation, the regenerative current continues to flow to the accident point side and the accident itself is caused. It is about expanding.

That is, assuming that the electric car A is a regenerative vehicle, the fault current from the power supply bus 1 side flows into the fault point of the DC positive bus 5 through the raw power converter 4, and the regenerative current from the regenerative vehicle A flows into the fault point of the DC positive bus 5. , regeneration vehicle A→feeder line 91→disconnector 83→
It flows through the path from the regeneration diode 73 to the fault point of the DC positive bus 5.

With the fault current flowing into these fault points, the former power supply bus 1
A fault current from the side is detected by a detection relay (not shown),
Based on this fault detection signal, the AC circuit breaker 2 is tripped and the original power converter 4 is gate-blocked, and the fault current from the power supply bus 1 side can be immediately cut off. The regenerative current flowing to the side continues to flow until the regenerative power disappears.

Therefore, in the event of an accident on the DC positive bus 5, it not only unnecessarily prolongs the accident itself, but also causes the accident to spread and spread to the healthy circuit side.

As described above, the conventional power supply device has a serious drawback in terms of protection coordination in the event of an accident when there is a regenerative vehicle.

The present invention has been devised in view of this point, and in particular, the present invention uses a commutating capacitor and a commutating reactor in common in a forced arc extinguishing circuit to forcibly extinguish a group of thyristor circuit breakers for four circuits. In addition, it is equipped with a DC switch that can cut off the regenerative power from the regenerative vehicle and the circulating power from the adjacent substation, and it is equipped with a dedicated arc extinguishing circuit that forcibly extinguishes the DC switch. The individual characteristics will be described in detail below based on the embodiment shown in FIG.

In the embodiment shown in Fig. 3, the same parts as in Fig. 1 are given the same reference numerals. In the figure, 15 is a DC switch, and this DC switch 15 is connected to the regenerative power from the regenerative vehicle and the adjacent substation during normal operation. For example, it is possible to use a thyristor circuit breaker or a DC high-speed circuit breaker as a DC switch, but as a configuration of the power supply device, Now that contactless circuits are being introduced, it is most desirable to use the former type of thyristor circuit breaker.

Now, the DC switch 15 is provided with a dedicated first forced arc-extinguishing circuit, and this forced arc-extinguishing circuit includes, for example, a commutating capacitor 16 - a first commutating reactor 17 - an auxiliary thyristor 18 - a second commutating circuit. It is composed of a circuit consisting of a reactor 19 and a diode 20.

21 is a reactor, and this reactor is inserted to suppress the regenerative power from the regenerative vehicle input during steady operation or the wrap-around power from the adjacent substation, and even if this suppressing reactor is removed. There are no side effects in terms of operation.

Reference numerals 22 to 224 are auxiliary thyristors provided for forcibly extinguishing the thyristor circuit breakers 61 to 64 of each DC circuit, and 23□ to 234 and 241 to 244 are auxiliary thyristors, respectively. In the second diode group, the former first diode group 231 to 234 are for guiding the discharge current to the thyristor circuit breaker group, and the latter second diode group 24,
~244 is the commutation reactor 2 at no load and under load.
It is used in conjunction with 7 to reliably extinguish each thyristor circuit breaker group.

25 is a commutating capacitor whose charging polarity is determined in advance during steady state, and 26 and 27 each indicate a commutating reactor, and these commutating reactor 26 - commutating capacitor 25 - first diode group 23 □ ~234-Auxiliary thyristor 22. .about.22 constitute a second forced extinguishing circuit that forcibly extinguishes the thyristor circuit breakers 6□-64 of each DC circuit.

Note that the commutating capacitor 16 of the first forced arc-extinguishing circuit and the commutating capacitor 25 of the second forced arc-extinguishing circuit are provided with a charging circuit, etc. composed of an AC power source and a rectifier circuit (not shown) in parallel. However, this rechargeable circuit is charged in advance with charge according to the polarity shown.

Now, to describe the operation of the present application configured as above, normally the commercial frequency power supply bus 1 → AC circuit breaker 2 → transformer 3 → forward power converter 4 → DC positive electrode bus 5 → thyristor circuit breaker group 6 to 64 →Disconnector group 81 to 84→Feeding wires 9□ to 92→Drive a group of vehicles (not shown) by power applied through the path of vehicles (not shown)
For example, if there is a vehicle under the feeder line 9 during regenerative operation, the regenerative power from this regenerative vehicle will be transferred to the regenerative vehicle (not shown) →
Feeder line 9 → Disconnector 8 → Regeneration diode 72 → Reactor 21 → DC switch 15 → DC positive bus 5 → Thyristor circuit breaker 6□ or 64 → Disconnector 8 or 84 → Feeder line 9 → At this time, the lower electric wire 92 The regenerated electric power itself flows through a route of a vehicle (not shown) connected to the feeder line, and the regenerated power itself is supplied as the necessary power to a group of vehicles connected under the other feeder line.

If a regenerative inverter (also called a reverse power converter) is installed in the substation, the regenerative power from the regenerative vehicle is transferred from the diode 72 to the reactor 21.
It goes without saying that a part of the regenerative power is shunted to the commercial frequency power source bus side via the path → DC switch 15 → DC positive bus 5 → regenerative inverter (not shown) → commercial frequency power source bus 1.

In the present application which performs the above-mentioned constant operation, for example, there is a regenerative vehicle under the electric wire 91, and during this regenerative operation, some kind of In the event that a ground fault occurs as a result, the following predetermined protective actions are performed in this application.

That is, a fault current flows into the fault point of the DC positive bus 5 from the power supply bus 1 side through the raw power converter 4, and
Regeneration vehicle (not shown) → Feeder wire 9□ → Disconnector 83 → Regeneration diode 1° → Reactor 21 → DC switch 15
→Regenerative current flows through the path of the fault point on the DC positive bus 5.

In this case, the fault current from the power bus 1 side is detected by a relay (not shown), and based on this fault detection signal, the AC breaker 2
At the same time, the source power converter 4 is gate-blocked to immediately cut off the fault current flowing from the power supply bus 1 side.

In parallel with this operation, the auxiliary thyristor 18 of the first forced arc-extinguishing circuit is fired based on the accident detection signal, and the commutating capacitor 6 is charged with the polarity shown.

The charged charge is discharged through the path of commutation capacitor 16 → first commutation reactor 17 → auxiliary thyristor 18 → DC switch 15, and the value of the discharge current that becomes free oscillation exceeds the level of the regenerative current flowing through DC switch 15. At this point, the DC switch 15 is forcibly turned off.

After that, the discharge current flows through the path of the first commutating reactor 17 → auxiliary thyristor 18 → second commutating reactor 19 → diode 20 → commutating capacitor 16, and commutating capacitor 16 is charged with the opposite polarity to that shown in the figure. Go.

The regenerative current after the DC switch 15 is forcibly extinguished in this commutation process is transferred to the auxiliary thyristor 18 of the first forced extinguishing circuit.
The current is commutated to the side, and the regenerative vehicle (not shown) → Feeder wire 9□ → Disconnector 8 → Regeneration diode 7 → Reactor 21 → Commutation capacitor 16 → First commutation reactor 17 → Auxiliary thyristor 18 → DC positive electrode bus 5 The current flows through the path of the fault point, and the reverse charging of the commutating capacitor 16 progresses further.

When the reverse charging voltage of the commutating capacitor 16 reaches a predetermined level, the auxiliary thyristor 18 is naturally extinguished and the regenerative current flowing toward the fault point is completely cut off.

When the regenerative current is cut off in this way and the recirculation loop of regenerative energy disappears, the DC voltage of the feeder line 91 or the regenerative power tries to rise, but at this point the regenerative energy also attenuates and the regenerative vehicle side throttles the regenerative power. Since the predetermined operation is performed, the DC voltage of the feeder line 91 will not increase.

In other words, after the auxiliary thyristor 18 is naturally extinguished, the charge in the commutation capacitor 6 is used for reversal as in a general commutation device installed in parallel with the first commutation reactor 17 and the commutation capacitor, for example. By igniting the SIRISK (not shown), the reversely charged charge that is charged with the opposite polarity to that shown in the figure is reversed to the shown polarity, and the charge lost in the commutation process is replenished by a charging circuit (not shown). to return to the initial state.

As described above, according to this embodiment, even if there is a vehicle in regenerative operation at the time of an accident on the DC positive bus, the accident current flowing into the accident point can be immediately interrupted, and the spread of the accident can be prevented. .

Next, a ground fault occurred near the connection point between the DC line, including the disconnector at No. 84, and the electric wire at No. 9, and at the time of this ground fault there was a vehicle in regenerative operation under the feeder line at No. 9. In this case, the following predetermined protection operation is performed in this embodiment.

That is, at the fault point, the source power converter 4 → DC positive bus 5 →
The fault current flows along the fault point path of thyristor circuit breaker 6 → disconnector 84 → feeder line 9°, and the regenerative vehicle (not shown) → feeder line 91 → disconnector 83 → regeneration diode 72 →
Reactor 21 → DC switch 15 → DC positive bus 5 →
A regenerative current flows in the path of the fault point of the thyristor circuit breaker 64 → the disconnector 84 → the feeder line 92.

These inflowing fault currents are detected by a relay (not shown) installed in parallel with the fault line, and based on this fault detection signal, an ignition signal is given to the auxiliary thyristor 224 for selectively cutting off the fault line, and the first forced extinguishing operation is performed. A firing signal is given to the auxiliary thyristor 18 of the arc circuit, and each of these auxiliary thyristors 18, 22
Fire 4.

When the auxiliary thyristor 224 is ignited, the path is commutated capacitor 25 of the second forced extinguishing circuit → third commutated reactor 26 → auxiliary thyristor 224 → diode 234 → thyristor breaker 64 → DC positive bus 5 Then, the commutating capacitor 25 is charged with the polarity shown and discharged.

This discharge current becomes a free oscillation, and when the value of the discharge current exceeds the value of the fault current flowing through the thyristor circuit breaker 6, the thyristor circuit breaker 64 is forcibly extinguished, and then the discharge current is transferred to the commutation capacitor 25. It flows through the path of -> third commutation reactor 26 -> capture thyristor 224 -> diode 244 -> fourth commutation reactor 27, and the commutation capacitor 25 is charged with a polarity opposite to that shown.

On the other hand, the fault current after the thyristor circuit breaker 64 is forcibly extinguished is commutated to the auxiliary thyristor 224, and the source power converter 4 → DC positive bus 5 → commutation capacitor 25 → the third
The current flows through the fault point of the commutating reactor 26 → auxiliary thyristor 224 → diode 23 → fault line disconnector 84 → feeder line 92, and the reverse charging of the commutating capacitor 25 progresses further, and the level of this reverse charging voltage increases. When the predetermined value is reached, the auxiliary thyristor 224 naturally extinguishes, the fault current flowing from the power supply bus 1 side is completely cut off, and the fault circuit is disconnected when the current flowing through the disconnector 84 becomes approximately zero. The circuit 84 is opened to disconnect only the faulty line from other healthy lines.

Note that the regenerative current flowing from the regenerative vehicle toward the accident point is the first
When the auxiliary thyristor 18 of the forced extinguishing circuit fires in response to the firing signal, the charge charged in the commutation capacitor 16 is transferred from the commutation capacitor 16 to the first commutation reactor 17 to
The DC switch 15 is forcibly extinguished when the level of the free oscillating discharge current exceeds the value of the regenerative current flowing through the DC switch 15, and then the discharge occurs. The current flows through the path of the second commutating reactor 19 → diode 20 → commutating capacitor 16, and the commutating capacitor 16 is charged with a polarity opposite to that shown in the figure, and the regenerative current is generated after the DC switch 15 is forcibly extinguished. Regeneration vehicle → Feeder wire 91 → Disconnector 83 → Diode 7° → Reactor 21 → Commutation capacitor 16 → First commutation reactor 17 → Auxiliary thyristor 1
8 → DC positive electrode bus 5 → Thyristor circuit breaker 62 (or 61
)→Disconnector 8□ (or 8□)→Feeder line 9, (or 9)
Through the flow, the regenerated power itself is given to a vehicle (not shown) during forward driving as driving power.

The period of the regenerative current flowing through this freewheeling loop is extremely short, and when the reverse charging voltage of the commutating capacitor 16 of the first forced extinguishing circuit reaches a predetermined level, the auxiliary thyristor 18 naturally extinguishes. Therefore, the accident line is selected ξ
On the condition that the DC switch 15 has been cut off, the DC switch 15 is re-ignited, and the regenerative current from the regenerative vehicle is passed through the DC switch 15 to the thyristor breaker 6□ (or 6□) side of the healthy line, and the vehicle is switched on. It gives power as a power.

As described above, in the present invention, as a forced arc-extinguishing circuit that forcibly extinguishes the thyristor circuit breakers for four circuits per substation,
The commutation capacitor and commutation reactor of the circuit are shared, and a new DC switch is installed to cut off the regenerative power from the regenerative vehicle and the circulating power from the adjacent substation.
Since this direct current switch is provided with a dedicated forced arc extinguishing circuit, various effects can be achieved as shown below.

■ Only one set of commutation capacitor and commutation reactor is required for each substation for the circuit that forcibly extinguishes the thyristor circuit breakers, which simplifies the circuit configuration of the power supply equipment, making it an extremely economical DC electric railway. substation can be realized.

■ The more the number of substations installed in the power supply system of a DC electric railway increases based on the advantages mentioned in item (2) above, the further the equipment cost of the power supply system as a whole can be reduced.

■ A new DC switch has been installed to cut off the regenerative power from the regenerative vehicle and the looped power from the adjacent substation even if an accident occurs under the feeder line of a line adjacent to the line where there is a regenerative vehicle. Therefore, only the faulty line can be selectively cut off instantly, and the breaking capacity of the thyristor circuit breaker can be reduced.

■ It is possible to easily coordinate protection in the event of an accident among the four parties: raw power converter, thyristor circuit breaker group, DC switch, and disconnector group, thereby realizing an extremely reliable power supply system.

[Brief explanation of drawings]

Figure 1 is a specific circuit configuration diagram showing a typical power supply device in which a thyristor rectifier and a thyristor circuit breaker are applied.
Fig. 2 is a specific circuit diagram showing a conventional device for forcibly extinguishing a group of thyristor circuit breakers applied thereto, and Fig. 3 is a specific circuit configuration diagram of a power supply device showing an embodiment of the present invention. . 1 is a commercial frequency power supply bus, 2 is an AC breaker, 3 is a transformer,
4 is a raw power converter, 5 is a DC positive electrode bus, 6□ to 64 are thyristor breakers, 81 to 84 are disconnectors, 11 is a negative electrode bus, 15 and 221 to 224 are auxiliary thyristors, 16,
25 is a commutation capacitor, 17 and 19, 26, 27 are commutation reactors, 71 to 74 and 23, to 234, 24□
~244 is a diode.

Claims (1)

[Scope of utility model registration request] AC power is converted by a raw power converter and supplied to the DC positive bus bar side, and this DC power is supplied to multiple feeder lines through multiple DC circuits in which thyristor circuit breakers and disconnectors are connected in series. In such a device, a regeneration diode whose anode side is connected to each connection line between each thyristor circuit breaker and disconnector of the plurality of DC circuits, and a regeneration diode whose anode side is connected to each connection line between each of the thyristor circuit breakers and the disconnector, and whose cathode sides are common to the common connection line. A DC switch with a cathode side connected to the positive bus, and a first forced extinguisher, which is arranged in parallel with the DC switch and includes at least a commutating capacitor and a commutating reactor, for forcibly extinguishing the DC switch. an arc circuit, an auxiliary thyristor whose cathode side is connected to each cathode of the thyristor circuit breaker, and anode sides of these auxiliary thyristors commonly connected;
A power supply device for a DC electric railway, comprising: a second forced arc-extinguishing circuit including at least a commutating capacitor and a commutating reactor provided between the common connection line and the DC positive bus bar.