JPH0420812B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a power supply device for electric railways, and more particularly to a power supply device for DC electric railways that converts AC power into DC power and supplies it as a drive source for electric cars. It is something.

(Prior art and problems) In general, power supply devices for DC electric railways convert AC power input from a commercial frequency power supply bus into DC power using a forward power exchange device, and then transfer the DC power via overhead contact lines. A system similar to that used to supply electric cars is being adopted.

An example of a conventional DC electric railway power supply device is shown in FIG. In FIG. 1, SS is a DC substation that exchanges AC power input from a commercial frequency power supply bus (not shown) into DC power. 3a is the first overhead contact line, and this overhead contact line 3a is connected to the substation SS.
DC output power is supplied via the DC bus 1 and the DC high-speed circuit breaker 2a. 3b is a second overhead contact line provided to the first overhead contact line 3a via a first section 4a. DC output power from the substation SS is supplied to the overhead contact line 3b via the DC bus 1 and the DC high-speed circuit breaker 2b. 3c is a third overhead contact line provided to the second overhead contact line 3b via a second section 4b. DC output power from the substation SS is supplied to the overhead contact line 3c via the DC bus 1 and the DC high-speed circuit breaker 2c.
Note that 5 indicates an electric car. In the device configured as described above, if a ground fault occurs at point F of the overhead contact line 3c, fault current will flow from the substation SS to the fault point F via the DC bus 1 and the DC high-speed circuit breaker 2c. Flow into. In order to interrupt this fault current, it is sufficient to open the DC high-speed circuit breaker 2c. At this time, in order to prevent the so-called section over phenomenon that occurs when a power running vehicle (not shown) is present below the second contact line 3b and its pantograph passes through the section 4b, the circuit breaker 2
It is necessary to open not only the DC high-speed circuit breaker 2b but also the DC high-speed circuit breaker 2b to bring the contact line 3b into a voltage-free state.
As described above, the above device has the disadvantage that the protective operation for cutting off the current after the fact is extremely complicated. Furthermore, since a circuit breaker is provided for each of a plurality of overhead contact lines divided by sections, there are drawbacks such as an increase in the installation area of the device and a marked increase in the cost of the device.

(Object of the Invention) The present invention has been made in view of the above points, and it is possible to simplify the configuration of the device and significantly reduce the cost of the device, and also to simplify the protective operation in the event of an accident. The purpose of the present invention is to provide a DC electric railway power supply device with improved reliability.

(Summary of the Invention) The present invention provides a plurality of bridge circuits in which diodes are bridge-connected between the output end of a forward power converter of a DC substation and a plurality of contact lines separated by two sections; It is characterized in that it is configured by providing a small number of switching control elements.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In FIG. 2, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted. 1
Reference numeral 1 denotes an applicable frequency power supply bus, and an input end of a forward power converter 14 is connected to this bus 11 via an AC breaker 12 and a transformer 13. The output end of this forward power converter 14 is connected to the DC bus 1 . 15a is a first bridge circuit formed by bridge-connecting diodes 16a to 16d;
The input side of the first bridge circuit 15a is connected to the DC bus 1. First bridge circuit 15
The output side of a is connected to the first overhead contact line 3a.
15b is a second bridge circuit formed by bridge-connecting diodes 16e to 16h, and the input side of this second bridge circuit 15b is commonly connected to the DC bus 1. 15c is a diode 16i~1
The input side of this third bridge circuit 15c is commonly connected to the DC bus 1. The output side of the third bridge circuit 15c is connected to the third overhead contact line 3c. The output side of the second bridge circuit 15b is connected to the input side of a fourth bridge circuit 15d formed by bridge-connecting diodes 16m to 16p. The output side of this fourth bridge circuit 15d is connected to the second overhead contact line 3b. The cathodes of the diodes 16a, 16c, 16e, and 16g are collectively connected to a first switching control element,
For example, it is connected to the anode of the first thyristor circuit breaker 17a. Diode 16b, 16d, 1
The anodes of 6f and 16h are collectively connected to the cathode of the thyristor circuit breaker 17a. The cathodes of the diodes 16i, 16k, 16m, and 16c are collectively connected to a second switching control element,
For example, it is connected to the anode of the second thyristor circuit breaker 17b. Diode 16j, 16, 1
The anodes of 6n and 16p are collectively connected to the cathode of the thyristor circuit breaker 17b. Note that overcurrent relays and the like inserted into the DC circuits connecting the commutation circuits of the thyristor circuit breakers 17a, 17b and the output sides of the bridge circuits 15a, 15c, 15d and the contact lines 3a, 3b, 3c are omitted from the illustration. . Furthermore, the illustrated device shows one substation, and it is assumed that predetermined DC power is also supplied to the overhead contact lines 3a and 3c from adjacent substations (not shown).

Next, the operation of the apparatus configured as described above will be described. As shown in the figure, while the electric car 5 under the overhead contact line 3a is in power running, DC power is supplied from the forward power converter 14 to the electric car 5 via the diode 16a, the thyristor circuit breaker 17a, the diode 16b, and the overhead contact line 3a. At the same time, desired DC power is also supplied to the electric car 5 from an adjacent substation (not shown). Further, in the power running vehicle (not shown) existing under the overhead contact line 3b, similarly to the above, the forward power converter 14 connects the diode 16e, thyristor circuit breaker 17a, diode 16f, diode 16m,
DC power is supplied via the thyristor circuit breaker 17b, the diode 16n, and the overhead contact line 3b. Further, DC power is supplied to a power running vehicle (not shown) existing under the overhead contact line 3c from the forward power converter 14 via the diode 16i, the thyristor circuit breaker 17b, the diode 16j, and the overhead contact line 3c in the same manner as described above. At the same time, desired DC power is also supplied from an adjacent substation (not shown). Further, when the electric car 5 existing under the overhead contact line 3a performs regenerative operation, the regenerated power is transferred to the overhead contact line 3a, the diode 16c, the thyristor circuit breaker 17a, the diode 16f, the diode 16m, and the thyristor circuit breaker 1.
7b and a diode 16n (or 61j) to a power running vehicle (not shown) located below the overhead contact line 3b (or 3c). Even when regenerative vehicles exist under the overhead contact lines 3b and 3c, the regenerated power is supplied to other power running vehicles under the overhead contact lines in the same manner as described above.

Suppose that, during such steady operation, a ground fault accident occurs at point F of the overhead contact line 3c. Due to this accident, the diode 1 was disconnected from the output terminal of the forward power converter 14.
6i, the thyristor circuit breaker 17b and the diode 16j, and also through the diode 16a, the thyristor circuit breaker 17a, the diode 16f, the diode 16m, the thyristor circuit breaker 17b and the diode 16j. Regenerative power flows from an electric car in regenerative operation, for example, the electric car 5, to the accident point F via the overhead contact line 3a, diode 16c, thyristor circuit breaker 17a, diode 16f, diode 16m, thyristor circuit breaker 17b, and diode 16j. When a fault current flows to the fault point F through the above path, the fault current is detected by an overcurrent relay (not shown) inserted into the DC circuit connecting the output side of the bridge circuit 15c and the overhead contact line 3c. Using this detection signal, the thyristor circuit breaker 17b is turned off by a commutation circuit (not shown). The fault current flowing into the fault point F is cut off by such a protective operation in the event of a fault. At this time, the overhead contact line 3b is in a non-voltage state, so that the so-called section over phenomenon that occurs at the section does not occur. Moreover, even if a ground fault occurs at point F in the figure and the thyristor circuit breaker 17b is turned off as described above, power is still being supplied to the contact line 3a from the adjacent healthy substation (not shown), so the contact line The electric car (for example, electric car 5) existing under 3a can continue to operate stably without being affected by the accident. If an accident occurs on the overhead contact line 3a, both the thyristor circuit breakers 17a and 17b may be turned off.

Note that the switching control element is not limited to the thyristor circuit breaker, but other devices having similar functions may be used.

(Effects) As described above, according to the present invention, the second contact line is provided to the first contact line via the first section, and the third contact line is provided to the second contact line via the second section, The input ends of first, second, and third bridge circuits each having a bridge connection of diodes are connected to the direct current output end of the forward power converter, and the output end of the first bridge circuit is connected to the first contact line. The output end of the second bridge circuit is connected to the input end of a fourth bridge circuit formed by connecting diodes in a bridge, the output end of the third bridge circuit is connected to the third overhead contact line, and the output end of the second bridge circuit is connected to the input end of a fourth bridge circuit formed by connecting diodes in a bridge. The output ends of the circuit are connected to the second overhead contact line, the positive output ends of the first and second bridge circuits are connected together to one end of the first switching control element, and the negative output ends are connected together to the first switching control element. The positive output terminals of the third and fourth bridge circuits are connected together to one end of the second switching control element, and the negative output terminals are collectively connected to the other end of the second switching control element. Since it is connected to the other end of the element, the number of switching control elements (thyristor circuit breakers) required for the entire power supply device can be reduced, and the cost of the device can be significantly reduced. In addition, it is possible to reliably supply power or regenerate power depending on the operating status of the electric car, and to ensure safety by reliably interrupting the fault current even if a ground fault occurs on any contact line. be able to. Furthermore, since the number of switching control elements (swirister circuit breakers) is small, protective operation in the event of an accident is very easy, and the protective device itself can be simplified. Further, when an accident such as a ground fault occurs, the second overhead contact line provided between the first overhead contact line and the third overhead contact line can be made to have no voltage, so that it is possible to prevent the so-called section over phenomenon from occurring. Moreover, even if the switching control element is turned off when an accident such as a ground fault occurs, the power outage range can be minimized.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of a conventional power supply device,
FIG. 2 is a circuit diagram showing one embodiment of the present invention. 11... Commercial frequency power supply bus, 14... Forward power converter, 15a, 15b, 15c, 15d... Bridge circuit, 16a to 16p... Diode, 1
7a, 17b...Thyristor circuit breaker.

Claims (1)

[Claims] 1. AC power input from a commercial frequency power supply bus is converted into DC power by a forward power exchange device, and the DC power is supplied to a plurality of overhead contact lines divided by sections. In the power supply device for a DC electric railway, a second contact line is provided to the first contact line via the first section, and a third contact line is provided to the second contact line via the second section, and the above steps are performed. The input ends of first, second, and third bridge circuits formed by bridge-connecting diodes to the DC output end of the power conversion device are connected together, and the output end of the first bridge circuit is connected to the first overhead contact line. The output end of the second bridge circuit is connected to the input end of the first bridge circuit made up of bridge-connected diodes, and the third
The output end of the bridge circuit is connected to the third contact line, the output end of the fourth bridge circuit is connected to the second contact line, and the positive output ends of the first and second bridge circuits are connected to the first contact line. At the same time, the negative output terminals of the third and fourth bridge circuits are connected to one end of the switching control element and the other ends of the first switching control element are connected together, and the positive output terminals of the third and fourth bridge circuits are connected together to the second switching control element. A power supply device for a DC electric railway, characterized in that the negative side output terminal is connected to one end of the second switching control element and the other end of the second switching control element is connected to the other end of the second switching control element. 2. The DC electric railway power supply device according to claim 1, wherein the first and second switching control elements are thyristor circuit breakers.