Flexible limitation method of operating overvoltage for UHV AC transmission system

Abstract

The invention provides an operation overvoltage flexible limiting method for an EHV (extra-high voltage) AC power transmission system, and the method comprises the steps: installing a controllable lightning arrester at an entrance of a transformer substation line in the EHV AC power transmission system, and determining the controllable ratio of the controllable lightning arrester according to the length L of the transformer substation line; judging whether the central part of the transformer substation line is provided with a conventional lightning arrester or not according to the length L of the transformer substation line. Compared with the prior, the method can effectively reduce the overvoltage level of an EHV line, and especially reduces the operation overvoltage level of the central part of the line effectively.

Description

technical field [0001] The invention relates to an overvoltage limiting method, in particular to an operating overvoltage flexible limiting method for an UHV AC power transmission system. Background technique [0002] Starting from the ultra-high voltage (330kV ~ 750kV) power transmission system, the operating overvoltage has already played a controlling role in the insulation level of the power transmission and transformation equipment. The limit is getting lower and lower. In the UHV (1000kV) transmission system, the operating impulse discharge voltage of the air gap presents a saturation characteristic, and the operating overvoltage level has a greater impact on the cost and manufacturing difficulty of power transmission and transformation equipment. Therefore, it is necessary to deeply reduce the operating overvoltage multiple and select reasonably Equipment insulation level is very necessary. [0003] Surge arresters are the main devices for overvoltage protection in ...

AI Technical Summary

Problems solved by technology

At this time, the long-term operating charge rate of the arrester will increase from the current 0.77 to 0.83, so that the aging speed of the arrester resistance sheet under normal operation will be accelerated, and the reliability margin will be greatly reduced

Moreover, the prerequisite for using 762kV surge arresters must be to limit the power frequency overvoltage of the system to 1.2p.u. on the bus side and 1.3p.u. on the line side, and the use conditions are extremely limited.

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