OPGW分段绝缘单点接地对线路保护的影响

输电线路相关参数的准确性关系到继电保护装置的正确动作。高压输电线路OPGW、地线在故障电流感应电压作用下一旦击穿会造成OPGW、地线多点接地使线路零序参数发生变化,进而影响线路继电保护的准确、可靠动作。本文以某500kV输电线路为例,分析了线路OPGW、地线在故障电流感应电压作用下一旦击穿造成OPGW、地线多点接地后对线路继电保护的影响。发生接地短路故障时,线路零序电流会变小但变化的幅度较小;单相接地短路时,距离保护的测量阻抗模值和相角均减小,且模值减小不超过9%,再计及继电器、互感器误差等因素,距离保护性能将会受到较大影响。

The Impact of Single-point Grounding Mode of OPGW Section Insulation on Relay Protection

The accuracy of parameters related to transmission line has great influence on the correct action of protection devices.In HVDC,once OPGW and ground wire breakdown caused by voltage induced by fault current,multipoint grounding of OPGW and ground wire will have influence on the zero-sequence parameters of line.The variation of zero-sequence parameters will have big impact on the relay protection.In this paper,the influence of OPGW and multipoint grounding of grounding wire on relay protection is analyzed when cable OPGW and grounding wire are breakdown by voltage induced by fault current.The zero-sequence current becomes smaller when short circuit fault occurs,but the variation magnitude is small.When single-phase earth fault occurs,the modulus and phase-angle of measured resistor are become smaller with the magnitude within 9%.And if factors such as the error of relay and transformer are considered,the performance of distance relay protection will have great difference.