两相电流差的特性

CHARACTERISTICS OF THE PHASE DIFFERENTIAL CURRENT

提出了两相电流差电流的新概念，对该电流的特性进行了分析，并通过两个例子，说明其在继电保护领域中的应用。其一：提出一种相间电流保护新判据，使得相间电流保护在各种相间短路条件下都有相同的保护区，从而提高了相间电流保护的灵敏度，简化了动作值的整定计算和灵敏度校验；其二：用两相电流差电流的一般表达式，对两相电流差工频变化量的选相元件进行分析，加深了人们对该选相元件动作特性的认识。

This paper describes a new concept of the phase differential current and analyzes thecharacteristic of the current in the fault cases.Two examples in the relaying protection were given to showthe use of the new concept:(1)To provide a new criterion for overcurrent phase fault protection. Theovercurrent protection using the new criterion has the same sensitivity in all types of phase faults.Therefore,the protection has higher sensitivity than the others.(2)To analyze the performance of the phase---selection element by the new concept.