JPS629459B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a DC electric railway power supply system, and in particular eliminates the complexity of the circuit configuration found in individual power supply systems in which a thyristor rectifier is installed for each load, and also provides protection in the event of an accident. The purpose of this invention is to provide a power supply device using an individual power supply method that facilitates power supply.

Thyristor rectifiers are increasingly being used in place of silicon rectifiers in forward power converters installed in DC electric railway substations for reasons such as voltage accuracy of feeder lines and protection coordination in the event of an accident. In the case of a large-scale substation with an individual power supply system in which thyristor rectifiers are installed for each line, as many as four thyristor rectifiers must be installed if the feeding system has four lines including upstream and downstream lines. ,
As is well known, thyristor rectifiers are extremely expensive because special considerations are made in terms of their structure and protection, rather than the mission of the feeding system itself, which is to ensure smooth operation. ing. In other words, since thyristor rectifiers are generally configured with a pure bridge connection, each rectifier has at least six thyristor elements, six sets of self-ignition circuits for overvoltage protection of these elements, and a surge protection circuit for commutation. Six sets of absorption snubber circuits are required, and the entire substation requires 24 high-voltage, large-capacity thyristor elements, and 24 sets of overvoltage protection circuits and snubber circuits. In addition, the thyristor element group is cooled by the so-called "fluorocarbon evaporative cooling method," which involves immersing a thyristor stack made up of six integrated elements in a fluorocarbon solvent solution and cooling it to evaporation. It is clear that these factors inevitably make the thyristor rectifier itself expensive. Another problem with the individual power supply system is the transformer provided on the power supply side of each thyristor rectifier. Two transformers are installed in this transformer with a structure in which the secondary winding is divided into two sets, and power is supplied from each secondary winding to the corresponding load line. Therefore, in a large-scale substation, the transformer itself has a large capacity and occupies a large area, which is also a factor in increasing the equipment cost of the substation. The present invention was invented in view of this point, and will be described in detail below based on the embodiment shown in FIGS. 1 and 2.

Figure 1 shows the basic configuration diagram when applied to a four-line power supply system. One of the features of the present application is that only one unit is installed so that it can be shared by four line load systems. Reference numerals 2-5 each indicate a positive side thyristor group of each thyristor rectifier, and a desired DC power is extracted from the bridge point of each thyristor group. 7 to 10 are current detectors such as shunt resistors inserted in each load line, and 70 to 100 are current detectors that compare and judge the current detection level with a reference level and supply power by cutting off the load line. In the protection relay that protects the system, numeral 6 indicates a group of negative side thyristors of a thyristor rectifier, and another feature of the present application is that this load side thyristor is shared by each thyristor rectifier. The configuration of the load line connected to the DC output side of the positive side thyristor group of each thyristor rectifier is not shown, but as is well known, it is typically represented by a DC type high-speed breaker, thyristor breaker, etc. A high-speed breaker and
Disconnectors, etc. to open the line are connected in series,
Feeding power for supplying power to vehicles is directly connected to these lines.

The regular operation configured as described above is such that the commercial frequency AC power input through the transformer 1 is converted into DC power by the positive side thyristor groups 2 to 5 of each thyristor rectifier, and the DC power is converted to DC power. is fed to the feeder wires connected to each line to provide power for each vehicle, and is returned to the commercial frequency power source through a path (not shown) from the rail to the negative bus line to the negative side thyristor 6.The thyristor group of each thyristor rectifier of
When turning off, as is well known, the transmission of gate pulses is stopped and so-called "natural commutation" is performed in which the arc is extinguished by changes in the voltage of each phase of the transformer 1 on the power supply side. If for some reason the insulator supporting the wires leaks and a short circuit occurs during normal operation, the current flowing from the thyristor rectifier of the substation in question and the regenerative vehicle if there is one in regenerative operation will reach the point of the accident. The fault current itself rapidly rises due to the regenerative current flowing from the ground and the wrap-around current flowing from the substation adjacent to the illustrated substation. This fault current is 70 to 100
The protection relay is operated based on two factors: the fault current level and the current rise rate di/dt. If some kind of protection relay is activated, the contact output of the activated protection relay is used to gate shift the elements of the thyristor rectifier, temporarily operating the thyristor rectifier in the inverter region, and reducing the charge energy in the load line. The power is regenerated to the commercial frequency power supply side, and then the gate is blocked to stop the thyristor rectifier, and at the same time, the contact output of the activated protection relay is used to trip the DC current or disconnection of the fault line to select only the fault line. This disconnects the faulty line, and then opens the disconnector that is inserted into the faulty line.

A problem with a power supply device that performs such an operation is, for example, when the amount of load on the feeding system supplied with power from each load line is different for each line, causing a potential difference between each load line. In such a case, since a thyristor rectifier is installed for each load line in the case of the individual power supply system found in conventional equipment, a predetermined voltage adjustment is performed for each thyristor rectifier, and the voltage between the loads is adjusted. Voltage unbalance can be removed, but even if the individual power supply system is used as in the present application, if the negative electrode side thyristor group is shared, voltage unbalance between each load line cannot be suppressed. The embodiment shown in FIG. 2 solves this problem.

Components in the embodiment shown in FIG. 2 that are the same as those in FIG. This is achieved by providing a group of stopper diodes and a direct current or disconnector. That is, 11 is a first stopper diode group, and if the current direction is from the load line (feeder line) to the positive side thyristor group, the anode side of each individual diode in this diode group 11 is connected to each load line, respectively. The diodes are connected separately, and the cathodes of each diode are connected in common.

13 is a second stopper diode group, and in this diode group 13, the cathode side of each individual diode is connected to the output side of each positive electrode side thyristor group 2 to 5, respectively, and the anode side of each diode is common. It is connected to the. And the first of these,
A direct current or disconnector 12 is inserted between the second diode group 11 and 13.

According to this embodiment configured as described above, since the direct current and disconnector 12 are normally closed, it is possible that the load amount differs in each load line and voltage imbalance occurs. In this case, a circulating current flows from the load line with a high potential to the load line with a low potential through the path of the first stopper diode, the DC circuit breaker 12, and the second stopper diode, and this circulating current Since the voltage is consumed on the vehicle side of the load connected to the feeder line with a low potential, the voltage imbalance caused by the unbalanced load can be effectively suppressed, and there is no problem with normal operation.

As described above, in the present invention, the power supply device uses an individual power supply system in which a thyristor rectifier is installed for each load line, and the thyristor group on the negative electrode side is shared, and the power supply side transformer is also shared. It has various effects as shown below.

If the thyristor rectifier has four load lines, it can be reduced by 9 elements compared to the conventional device, and the number of overvoltage protection circuits and snubber circuits can also be reduced by 9 compared to the conventional device, making it extremely economical. It is possible to realize a power supply device that is

In addition to the above advantages, the number of power transformers can be reduced by one compared to the conventional device, so the installation space for the power supply device can be reduced and the equipment cost of the power supply device itself can be reduced.

Even if a voltage imbalance occurs due to load unbalance between each load line, stable power supply operations can be continued because it is passed as a circulating current and consumed by the load vehicle side. .

[Brief explanation of the drawing]

FIG. 1 is a specific circuit configuration diagram of a power feeding device showing one embodiment of the present invention, and FIG. 2 is a specific circuit configuration diagram of a power feeding device showing another embodiment of the present invention. 1 is the transformer, 2 to 5 are the positive side thyristors of the thyristor rectifier, 6 is the negative side thyristor, 7 to 10
is a current detector, and 70 to 100 are protection relays.

Claims (1)

[Claims] 1. One transformer that steps down the commercial frequency power supply voltage to an appropriate voltage value, and a plurality of sets of transformers that are provided corresponding to each of the plurality of load lines and that sequentially convert AC input power into DC power. inserted between the positive side thyristor group, the negative bus connected to the rail, and the secondary side of the transformer,
A circulating current loop in which a set of negative-side thyristors forming a return path for DC power and the potential difference between each load line is passed as circulating current, and this circulating current is consumed on the vehicle side of the load. A DC electric railway power supply device comprising: 2. A circulating current loop is formed by a first stopper diode inserted into each load line and with the conduction polarity set to the positive side of the thyristor group from the load line side; It consists of a second stopper diode which is located closer to the cathode side of the positive thyristor group than the cathode side of the diode, and a direct current or disconnector inserted between the second stopper diode and the first stopper diode. A power supply device for a DC electric railway according to claim 1.