Lightning protection method for line terminal

Abstract

The invention discloses a lightning protection method for a line terminal. When a transformer substation site permits, a gap-free transformer substation type metal oxide surge arrester is installed in a fence of a transformer substation. When the transformer substation site does not permit, a set of gap-free line type metal oxide surge arrester is mounted at a first base tower of an outgoing line of the transformer substation. Both the impulse discharge voltage and the residual voltage of the gap-free transformer substation type metal oxide surge arrester or the gap-free line type metal oxide surge arrester are smaller than half of the break impulse withstanding voltage of a circuit breaker inside the transformer substation. The method can prevent the break of the circuit breaker from breakdown or prevent the circuit breaker from exploding when the line is subjected to a lightning strike after the circuit breaker trips and before the circuit breaker is reclosed, thereby improving safety and reliability, improving the protection margin, and reducing costs.

Description

technical field [0001] The invention belongs to the technical field of electric power system lightning protection, and in particular relates to a lightning protection method for a line terminal. Background technique [0002] One of the dangers in substations is the intrusion of lightning waves generated by lightning strikes near the line. When the substation line circuit breaker is in three states: hot standby, before reclosing after tripping, and non-reclosing after tripping, the breaker of the circuit breaker and the current transformer are out of the protection of the busbar arrester. Total reflection will occur when the wave is transmitted along the line to the fracture of the circuit breaker. When the attenuation of the lightning wave transmission in the short wire is ignored, the reflected wave is superimposed on the incident wave to double the lightning overvoltage at the fracture, thus generating a very high amplitude lightning overvoltage , so that the internal ins...

AI Technical Summary

Problems solved by technology

[0010] That is to say, regardless of whether the line-type terminal arrester operates or not, the breaker fracture may withstand an impulse overvoltage of 1380kV to 1980kV, which is much greater than the breakage's impulse withstand voltage value of 1050kV, which is enough to break down the breaker fracture, indicating that the line-type Arresters are far from meeting the insulation coordination requirements of circuit breaker fractures

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