超/特高压线路差动保护电容电流补偿方法

Capacitive current compensation method for differential protection of EHV/UHV lines

目前常用的电容电流补偿方法是基于Π模型的相量补偿法。相对于电流差动保护,故障分量电流差动保护有更高的灵敏度,目前对故障分量电流差动保护的电容电流补偿方法也使用基于Π模型的相量补偿法。分析指出,Π模型仅能比较精确地模拟发生区外故障时的线路,而对于存在区内故障的线路,用Π模型模拟线路会带来较大的误差。对于故障分量电流差动保护使用基于Π模型的相量补偿法误差较大,整定时应考虑此因素,将定值适当抬高以免保护误动。对于全量电流差动保护,使用Π模型模拟线路进行电容电流的计算和补偿也会有误差,但误差相对较小。用EMTP建立了1000 kV、600 km线路,对该观点进行了验证。

The capacitive current compensation method widely used now for current differential protection is the phase compensation method based on Π model.Analysis shows that,Π model simulates the line with external fault quite precisely and there is bigger error when it is used to simulate the line with internal fault,which should be considered in the parameter setting of fault current differential protection.The error is relatively smaller for the full current differential protection.A 1 000 kV 600 km line is built with EMTP to verify the conclusions.