三端线路差动保护中全电流差动判据的研究

通过对三端线路相对于二端线路特殊性的分析，并结合差动保护灵敏度的计算，得出了影响差动保护灵敏度的主要原因是穿越性电流。在当前故障分量判据还无法代替全电流判据的情况下，寻找一种有效消除穿越性电流影响的全电流判据，分析了全电流判据的可能组成方式后，得到了2个新的差动判据。经过对区内故障灵敏度及区外故障安全性的评价，得出了新判据2与原判据结合将有利于消除穿越性电流所带来影响的结论。

Research of Phase Current Based Differential Criteria of Three-termianl Transmission Lines Differential Protection

With analysis of specificity of three-terminal transmission hnes to two-terminal transmtsslon lines and sensitivity of differential current protection, the conclusion has been drawn out that penetration current is the major influence to sensitivity of differential current protection. As present superimposed current based percentage differential criterion can not replace phase current based percentage differential criterion, a new criterion of the latter is proposed. Two new differential criteria are achieved after possible composite form analysis about superimposed current based percentage differential criterion. With estimate of sensitivity and security, a conclusion that the integration of new and primitive criterion is got to replace the influence of penetration current.