JPH0270541A - D.c. feeding system - Google Patents

Abstract

PURPOSE:To protect an inverter by cutting off a short circuit in a feeder and overcurrent generated due to an overload with a D.C. circuit breaker, and cutting off the overcurrent from the feeder at the time of regeneration with the D.C. circuit breaker. CONSTITUTION:When the accident followed by the overcurrent such as commutation failure, etc. occurs in an inverter 12, the overcurrent from a feeder 19 side flows from the feeder 19 through a diode 18, D.C. circuit breaker 16, and the inverter 12, and the current from a rectifier 11 flows through a D.C. circuit breaker 14 for the feeder, diode 17, D.C. circuit breaker 16 or 15 for regeneration, diode 18, D.C. circuit breaker 16 for regeneration. Consequently the inverter 12 can be protected by cutting off the breaker 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a DC feeding system for supplying DC power for electric railways.

(Prior Art) FIG. 2 shows a conventional example of a DC feeding system equipped with an inverter for regeneration. In the figure, 11 is a rectifier that supplies DC power to the feeder line, 12 is an inverter that regenerates power from the feeder line to the AC system, 13 is a DC bus, and 14.15 is a high-speed converter that converts the DC current supplied to the feeder line. 16 is a DC breaker that cuts off regenerative current at high speed; 17. ia is the first to prevent the regeneration circuit from going around.
19 is a DC feeder line.

In this system, overcurrent caused by a short circuit or overload in the feeder line 19 is interrupted by the DC breaker 14 or the DC breaker 15 for protection. Also, feeder wire 19 during regeneration
The overcurrent line coming from the line is cut off and protected by a DC breaker 16.

(Problem to be Solved by the Invention) In the inverter 12 in the system shown in FIG. 2, when an accident occurs that causes an overcurrent due to commutation failure or the like, the overcurrent flows from the rectifier 11 through the DC bus 13.

Overcurrent from the feeder line 19 during regeneration is interrupted and protected by the DC breaker 16, but from the rectifier 11 to the DC bus 1.
The overcurrent through 3 cannot be cut off and cannot be protected. The inverter 12 must withstand this overcurrent, so either the inverter 12 is made larger or the inverter 12
A DC breaker shall be connected in series to cut off the overcurrent. For this reason, problems arose as the system became larger and more expensive.

An object of the present invention is to provide a highly reliable, compact, and inexpensive DC feeding system that protects an inverter even from the above-mentioned overcurrent.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a rectifier whose DC side terminal is connected to a DC bus and whose AC side terminal is connected to an AC system; A DC feeding line to which DC power is supplied through the DC feeding line, and regenerative power from the DC feeding line are connected to a first diode and a regenerative DC current 1-1.
A DC energizing system is constituted by a regenerative inverter for regenerating to the AC system via a predetermined device, and a second diode provided between the regenerative DC breaker and the DC bus bar.

(Function) According to the present invention, even if an accident such as commutation failure occurs in the inverter, the overcurrent always flows through the regenerative DC breaker 16 and directly flows through the rectifier 11 to the DC bus 13 to the inverter 12. It never flows. Therefore, by turning off the DC breaker 16, the inverter 12 can be protected.

(Embodiment) FIG. 1, in which the same parts as in FIG. 2 are denoted by the same reference numerals, is a configuration diagram showing an embodiment of the present invention.

The difference from the second conventional device is that the regenerative DC breaker 16
A second diode 21 is connected in series with the second diode 21, and the inverter 12 is connected between the second diode 21 and the second diode 21.

If an accident involving an overcurrent such as commutation failure occurs in the inverter 12 of the DC feeding system as shown in Fig. 1, the overcurrent from the feeding line 19 side will be transferred from the feeding line 19 to the diode 18 and then to the DC breaker. 16, can flow through the inverter 12 and protect the inverter 12 by blocking the DC breaker 16.

In addition, the current from the rectifier 11 is passed through the DC breaker 1 for the feeder line.
4, it flows through the diode 17, the DC breaker 16 for regeneration, or the DC breaker 15, the diode 18, and the DC breaker 16 for regeneration. Therefore, the inverter 12 can be protected by cutting off the DC breaker 16. While the regular DC circuit breakers 14 and 15 are both off, the current from the rectifier 11 is blocked by the diode 21 and therefore does not flow to the inverter 12.

As described above, an overcurrent due to a small failure of the inverter 12 always flows through the DC breaker 16, and by cutting off the DC breaker 16, the inverter 12 can be shut down.

According to the DC feeding system as shown in Fig. 1, overcurrent to the inverter 12 can be cut off and protected by the DC breaker 16, so the withstand capacity of the inverter 12 can be reduced, and it can be made smaller. .

There is no need to provide a separate DC breaker to protect the inverter 12. Also, after the DC circuit breaker 16 has cut off the DC current, the DC circuit breaker 1
It is also possible to turn on the 6 again and exercise again, resulting in a highly reliable system.

Although the above description uses a semiconductor breaker as an example of a DC breaker, the same effect can be obtained even if a mechanical breaker is used as a DC breaker.

[Effects of the Invention] As explained above, according to the present invention, the overcurrent generated by the inverter can be protected by being blocked by the regenerative DC breaker. We can provide electrical system.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a DC feeding system showing an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional DC feeding system. 11... Rectifier, 12... Inverter,
13...DC bus, 14, 15.16...DC breaker, 17°18...diode, 19...DC feeder line, 21...diode.

Claims (1)

[Claims] a rectifier having a DC side terminal connected to a DC bus and an AC side terminal connected to an AC system; a DC feeder line to which DC power is supplied from the DC bus via a DC breaker; A regenerative inverter for regenerating regenerative power to the AC system via the first diode and the regenerative DC current or disconnector, and a regenerative inverter provided between the regenerative DC current or disconnector and the DC bus. A DC feeding system comprising a second diode.