State Grid Corporation of China

China Electric Power Research Institute Company Limited

Central China Branch of State Grid Corporation of China

Lianhai Li

Xiao Dong Li

Zexin Zhou

Dingxiang Du

Xingguo Wang

Huanzhang Liu

Yarong Guo

Delin Wang

Xuming Liang

Xiangwen Chen

A concomitant impedance protection method for a half-wavelength power transmission line includes that: three-phase currents and three-phase voltages of a relay protection device mounting position at an M side and a relay protection device mounting position at an N side of the half-wavelength power transmission line are acquired respectively; it is judged whether starting amounts of an M side and an N side meet starting conditions or not; a failure point F is determined according to a time difference when the starting amounts of the M side and the N side meet the starting conditions; and a relay protection action of the half-wavelength power transmission line is started according to concomitant impedance of the half-wavelength power transmission line. According to the method, a failure may be located by a time-difference method according to a characteristic of the failure, by compensating the voltages and currents on two sides of the line to construct concomitant impedance, and failures in the region of line can be correctly reflected. Since concomitant impedance protection effectively utilizes two-terminal electrical information, the fault can be quickly and reliably operated in the line region, misoperation on the failures out of the line region can be avoided, and the protection has relatively higher sensitivity.

Concomitant impedance protection method for half-wavelength transmission line

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Wuhan, China

Lianhai Li