JPS5915409B2 - DC power supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC power supply device for obtaining a small and economical static current interrupting device in a DC substation.

Conventionally, for example, in electric railway DC substations, mechanical DC currents and disconnectors are installed on the rectifier output side and in multiple sets of substation feeder circuits. It required a lot of manpower and expense.

Therefore, it is possible to reduce maintenance costs by replacing the mechanical DC and disconnectors with thyristor choppers and making them completely stationary devices, but the product cost5 is lower than that of conventional mechanical DC and disconnectors. It will be quite expensive. Therefore, when designing a semiconductor device, it is very important to make it economical. This invention makes it possible to economically convert conventional DC and disconnection circuits into semiconductor devices. 10 First, the configuration and operation of a conventional electric railway DC substation will be briefly explained with reference to FIG.

DC power is supplied to the substation anode bus 1 from the DC output anode side of the silicon rectifier 2 through the main DC current and the disconnector 3 .
A plurality of sets of feeder circuits 5a and 5b each having a direct current feeder circuit and a disconnector 415 are connected to the anode bus bar 1, and supply direct current power to a contact line circuit (not shown), respectively. On the other hand, the DC output cathode side of the rectifier 2 is connected to the substation cathode bus 6 and passed through the series reactor 8 of the harmonic filter T to the rail 9.
connected to. 20 and the harmonic branch 1 of the filter device T
0 is connected to the anode bus 1 and the output side of the series reactor 8.

In such a configuration, for example, if a short-circuit accident occurs in the output circuit of the feeder circuit 5a, or if you simply want to stop the power supply, only the feeder circuit or disconnector 4 25 is opened and the other feeder circuits 5b are closed. The power supply continued as it was. FIG. 2 shows an example in which a thyristor chopper is used to replace the direct current or disconnection switch in a conventional DC substation.

That is, the direct current and disconnectors 3 and 430 in FIG. 1 are replaced with thyristor choppers 3 and 4 in FIG. 2, respectively. To explain in more detail with reference to FIG. 2, the chopper devices 3 and 4 are comprised of main thyristors 11, lla, and Ilb and commutation circuits 12, 12a, and 12b. The freewheeling diodes 13m and 3513f are used to cut off the current in the chopper devices 3 and 4, and then release the energy equivalent to the inductance present on the load side from the respective chopper devices. Each of the feeder circuits 5a and 5b has a DC transformer, ie, a DCCTl4, and a detection section 15, and a signal from the detection section 15 is configured to operate a chopper device. Figure 3 shows the commutation circuits 12 and 12a in Figure 2.
, 12b.

The commutation circuit 12a includes a commutation capacitor 16 and a reactor 17.
, and an auxiliary thyristor 18 in series, and both ends of the commutating capacitor 16 are charged with the illustrated polarity by an auxiliary power source 19 having a high internal impedance. Next, the operation and problems in the configurations shown in FIGS. 2 and 3 will be explained. If a short circuit occurs in the output circuit of the feeder circuit 5a, the fault current is detected by the DCCT14 and the detector 15, and the chopper device 4 is operated to cut off only the feeder circuit 5a. At this time, the signal from the detection command device 15 causes the auxiliary thyristor 18 to fire, and the main thyristor 11a is instantly turned off by the discharge current of the commutation capacitor 16, causing the fault current Id
is commutated to the commutation circuit 12a, a rectifier power supply (not shown), a rectifier 2, a main thyristor 11 of the main chopper 3, an anode bus 1, a commutation circuit 12a of the chopper 4, a feeder circuit 5a, a short circuit not shown, and a rail 9. Column reactor 8, cathode bus, rectifier 2, rectifier power supply (not shown) circulates, and commutating capacitor 16 is overcharged in the opposite direction to that shown in Figure 3 by energy LAId2 due to the sum of inductance LA of series reactor 8 and rectifier power supply side. There is a risk of abnormal voltage being generated. On the other hand, if a large residual inductance exists in the short circuit, a freewheeling diode 13f must be provided. That is, when the commutating capacitor 16 is charged to a certain voltage, the free-wheeling diode 13f operates and bypasses the capacitor 16 as shown in FIG. 3, 1L, so that the capacitor 16 is prevented from being overcharged by the load-side inductance. By the way, the short circuit current of a DCl5OOV electric railway direct current substation generally ranges from several tens of KA to 100 KA, while the series reactor 8 is of a few tens of liters depending on the filter condition. When the total LA = 2 mH, the required capacitor capacity C to suppress the overcharge voltage Ec of the commutating capacitor 16 to 4000 or less is - LAId2 = -CES
2 From the relationship, it is found that C==100,000 ItF, which means that a huge number of commutating capacitors are required.

Installing a commutation circuit including these capacitors in each feeder circuit poses a serious problem in terms of cost and size. In addition, the main thyristors 11, 11a, and 11b are expensive because they must have a short turn-off time for the chopper, but the current carrying capacity per element is also smaller than that of general thyristors, and the number of parallel thyristors is correspondingly large. Therefore, it is disadvantageous in terms of cost and size. Therefore, installing such a chopper device in a large number of feeder circuits poses problems in terms of economy and size. In addition, in FIG. 2, the feeder circuit 5a
If a short circuit or the like occurs in the output circuit of the anode bus 1, the voltage of the anode bus 1 will drop. On the other hand, in electric railway substations and the like, the DC side is generally connected in parallel with the adjacent substation, so the main thyristor 11b of the healthy feeder circuit 5b receives a voltage in the opposite direction. Therefore, it is not desirable for the device to continue sending the gate signal to the main thyristor 11b. Therefore, the gate signal to the healthy power supply circuit must be enabled and then disconnected, and the circuit must be quickly restored after the fault circuit is opened. The present invention is intended to improve these economical and dimensional deficiencies and to enable the elements of a healthy power supply circuit to continue to be supplied with power safely and with minimum interruption time. The embodiment shown in FIG. 4 will be described below. The substation anode bus 1 is connected to the DC output anode side of the thyristor rectifier 2 . The anode bus 1 includes a main thyristor 11a1 and a main thyristor 1 which detects the reverse voltage of the main thyristor 11a1.
Thyristor switch 4a, which does not have overcurrent cut-off capability, is composed of a reverse voltage detection device 16a for stopping the gate signal to 1a, and a DCC for detecting overcurrent and zero current.
A plurality of feeder circuits 5a constituted by Tl4, detection command device 15, and feeder circuits 5b similarly constituted are connected, each supplying DC power to separate contact line circuits (not shown). The overcurrent signal of the detection unit 15 is configured to operate to stop the gate signal of the main thyristor 11a of the corresponding feeder circuit 5a and at the same time operate the thyristor gate signal of the thyristor rectifier 2 to suppress the overcurrent. do. On the other hand, the harmonic filter 7 is connected in the same manner as the conventional filter explained in FIG. The DC cathode side of the thyristor rectifier 2 is connected to the substation cathode bus 6. The operation of the embodiment of the present invention shown in FIG. 4 will be described below.

When an overcurrent occurs in the feeder circuit 5a when multiple sets of feeder circuits 5a and 5b are feeding power to different loads, the DCCTl4
, the detection command device 15 detects an overcurrent, stops the gate signal of the main thyristor 11a of the feeder circuit 5a, and at the same time sends an overcurrent cut-off command to the thyristor rectifier 2 to delay the firing phase angle to 90 degrees or more. Or, the overcurrent is cut off by cutting the gate. Thus, when the current in the feeder circuit 5a becomes zero, the main thyristor 11a becomes non-conductive because the gate signal has already been cut off. On the other hand, the feed circuit 5a0) DCCT14 and the detection command device 15 detect that the current has become zero and send a re-energization command to the thyristor rectifier 2 to restart the operation. On the other hand, during the overcurrent and disconnection period of the thyristor rectifier 2, the voltage of the anode bus 1 drops instantaneously, so when the current in the healthy feeder circuit 5b becomes zero, the main thyristor 11b is affected by the back electromotive force of the load or the voltage of the adjacent substation.
receives a reverse voltage. At this time, the reverse voltage detection device 16b operates and immediately stops the gate signal of the main thyristor 11b. However, when the load circuit inductance and load current of the healthy feeder circuit 5b are large and the load circuit inductance and overcurrent amount of the feeder circuit 5a are not so large, the current of the feeder circuit 5a may become zero first. At this time, if the output voltage of the thyristor rectifier 2 is restored before the current in the healthy feed circuit 5b becomes zero, the main thyristor 11b continues to be energized and the reverse voltage detection device 16b does not operate. If the current becomes zero before the abnormal feeding circuit 5 and the reverse voltage detection device 16b of the healthy feeding circuit 5b operates, the abnormal feeding circuit 5
a is opened, the thyristor rectifier 2 is reenergized, and the anode bus 1
When the voltage is restored, the reverse voltage detection circuit 1 of the healthy feeding circuit 5b
When the operation of thyristor 6b is restored, a gate signal is again sent to main thyristor 11b, and feeder circuit 5b resumes power supply. Therefore, according to the present invention, the overcurrent is cut off by the thyristor rectifier 2, so the thyristor switches 4a and 4b of the feeder circuit do not need a current cutting ability, and therefore, the thyristor switches 4a and 4b of the feeder circuit do not need a current cutting ability. Since no flow circuit is required, the device is very compact and economical.

In addition, since the overcurrent is interrupted by a semiconductor device such as the thyristor rectifier 2, the operating time is extremely short, ranging from a fraction of that of a conventional mechanical interrupter to less than 1/10, including operation time. In this way, the power outage time for a healthy power supply circuit can be reduced to several cycles or less, and electric railway loads, motor loads, etc. can be recovered within a time that does not pose a problem. Further, according to this system, the feed circuit thyristors 11a and 11b do not require high-speed thyristors with short turn-off times such as those for choppers. That is, in a device having a commutation circuit as shown in FIG. 3, after the main thyristor 11a stops current, the overcurrent 1d charges the capacitor 16 with the polarity opposite to that shown in the figure.
1 is immediately applied with a voltage in the forward direction. Therefore, unless the main thyristor 11 has a short turn-off time, the capacitance of the capacitor 16 will become enormous. However, according to the present invention shown in FIG. 4, the feed circuit thyristor switches 4a and 4b do not have a commutation circuit, so there is no need for forward voltage application by a commutation capacitor. Therefore, after the overcurrent in the abnormal feeding circuit 5a becomes zero, restarting the energization of the thyristor rectifier 2 can be delayed for the general-use thyristor turn-off time of 200 μs to 1000 μs, and the power outage in the healthy feeding circuit 5b can be reduced by this amount. Even if the time is longer, there will be no problem with the electric railway load and other motor loads as described above.
Therefore, as the main thyristors 11a and 11b, general thyristors having a long turn-off time can be used, which is economical. Furthermore, in this invention, each feeder circuit has an overcurrent detection function, and when an overcurrent occurs, the feeder circuit detects it.
As shown in the thyristor rectifier 2 shown in the figure, the power is cut off on the power supply side to the bus bar. However, in general, the rated current of the feeder circuit is selected to be lower than the rated current of the thyristor rectifier, so the detection setting value can be lowered compared to detecting with the output of the thyristor rectifier 2, so detection is faster and the operating time is shortened accordingly. At the same time, the overcurrent peak value can be kept low. In addition, this invention has a zero current detection function in each feeding circuit, detects that the current in the abnormal feeding circuit becomes zero, and restarts the thyristor rectifier. If the current in the faulty feeder circuit drops to zero first during the period when the current is turned on or off, the bus voltage will recover, so the healthy feeder circuit will continue to supply power without cutting off the current. I can do it. On the other hand, even if the current in the healthy feeder circuit becomes zero before the current in the faulty feeder circuit becomes zero, if the bus voltage is restored and the operation of the reverse voltage detection device is canceled, the normal feeder circuit suddenly returns to zero. will resume power supply,
Power outage time can be minimized. FIG. 5 shows another embodiment of the present invention, and FIG. 5a shows a silicon rectifier 2 replacing the thyristor rectifier 2 in FIG. The configuration is such that the overcurrent is cut off by the chopper device 2a in response to a signal from the circuit.

Fig. 5b shows a configuration in which a thyristor device 2a having an overcurrent cutting ability is installed on the alternating current side of the silicon rectifier 2, and the thyristor device 2a is configured to cut off the overcurrent in response to a signal from the abnormal feeding circuit. It is. Furthermore, although the embodiments shown in FIGS. 4 and 5 show one set of rectifiers and semiconductor overcurrent shielding devices, multiple sets of rectifiers and semiconductor overcurrent shielding devices are connected to a DC bus and fed in parallel. It goes without saying that the present invention is applicable even in such cases.

[Brief explanation of drawings]

Figure 1 is a connection diagram showing the configuration of a conventional DC substation, Figure 2 is a connection diagram showing an example of replacing conventional mechanical DC and disconnectors with thyristor choppers, and Figure 3 is a connection diagram showing the configuration of a conventional DC substation. 3 is a connection diagram showing details of a part of the embodiment of the present invention, FIG. 4 is a connection diagram showing an embodiment of the present invention, and FIG. 5 is a connection diagram showing details of the chopper commutation circuit shown in the figure. A and b are connection diagrams showing another embodiment of the present invention. In the figure, 2a is a semiconductor device with overcurrent breaking capability, 4a and 4b are thyristor switches without overcurrent breaking function, 11a and 11b are main thyristor elements, 14 is a DC current transformer, and 15 is an overcurrent current transformer. Current and zero current detection command device, 1
6a and 16b are reverse voltage detection devices.

Claims (1)

[Claims] 1 A rectifier with an overcurrent shielding function is connected in parallel with a plurality of DC feeder circuits to which DC power is supplied via a DC bus, and each DC feeder circuit is equipped with an overcurrent shielder that opens and closes the DC power supply path. A main thyristor that does not have a disconnection function, a current detection device that detects the current flowing through the main thyristor, and when an overcurrent is detected by the current detected by the current detection device, a gate signal stop command is given to the main thyristor, and the rectifier is A DC power supply device comprising: a detection command device which gives a gate signal operation command to the rectifier to quickly cut off an overcurrent, and sends a power supply restart command to the rectifier when zero current is detected.