Internal bridge connecting and protection implementing method for linkage standby electricity supply mode

Abstract

The stand-by power supply method usually adopts an external bridge wiring way, thereby the problems that the fault is easy to be spread to the upper-layer station and the dual protection is required are caused. In order to solve the problems, the invention provides an internal bridge wiring way, fully utilizes the characteristic that the three circuit breakers of the internal bridge are arranged in a series connection way relative to the incoming line, enables the tripping-position contact of the circuit breaker in front and the tripping contact and the normally closed interlocking contact of a protector in front to be respectively accessed into a protector behind, and achieves the purpose of failure protection of the protection from the protector behind to the protection from the protector in front or the failure protection to the circuit breaker. The number of the circuit breakers and the protectors are not added, the special failure protection device or the special circuit breaker failure protection device is not required to be arranged, and the failure protection or the circuit breaker failure can be protected. When the voltage of the system is 220 kV or more, the protector is not required to be arranged according to the duality, and even if the failure protection occurs, the upper-layer station is not affected when the lower-layer station is out of service. The invention has the advantages that the fabricating cost of the system is reduced, the system design is simplified, and the operation of the transformer is not complex.

Description

technical field [0001] The invention relates to the field of electric technology, in particular to a method applicable to the protection of secondary equipment in a power supply system and the failure protection method of a circuit breaker. Background technique [0002] For important factories and stations, such as railways or factories and mines, in order to ensure reliable power supply, two independent incoming power supplies are usually required, but sometimes the power system cannot provide two independent power supplies. The solution is to connect two adjacent factories and stations , connected through the tie line, so that each factory station only needs one independent power supply. When the incoming line of the factory station fails, the power supply will be provided by the tie line. This power supply method is usually called the link backup power supply method. Such as figure 1 As shown, station A and station B are powered by incoming lines L1 and L2 respectively, ...

AI Technical Summary

Problems solved by technology

[0004] When the connection line L3 fails, and the circuit breaker CB3A fails or its corresponding protection 3A fails, the protection 9A can only be used as a failure protection action, and the circuit breaker CB9A trips to remove the fault, causing the fault to spread to the superior station (9A station)

[0005] If the optical fiber is used to transmit the failure remote signal to the protection 9A, the complexity of the system will be increased. If the optical fiber is not used to transmit the failure signal, the protection 9A can only be used as the remote backup of the A station. When the connection line L3 is very long, in order To be able to cut off the fault on the entire tie line L3, the setting range of the protection 9A must be very large, reaching the inside of the transformer T2B, but when there is a heavy load at station A, for example, when a heavy-duty train passes by, the protection 9A may malfunction

[0006] In addition, when the busbar voltage on the high-voltage side of station A is 220KV and above, in order to prevent protection failure, the protection requirements on the high-voltage side busbar are configured in a dual manner, resulting in increased costs and complex systems

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