配合于零序电抗继电器的方向性选相元件

A DIRECTIONAL PHASE-SELECTIVE ELEMENT COOPERATED WITH THE ZERO SEQUENCE REACTANCE RELAY

针对零序电抗继电器有较强的抗过渡电阻能力，但没有方向性和选相功能的特点，本文提出采用负序突变量方向元件来判别故障方向，采用正序电流作为极化量的选相元件来选相，即方向性选相元件。该元件与零序电抗继电器相配合，具有很强的抗过渡电阻能力，方向性明确，且能正确选相。

The zero sequence reactance relay has the ability to overcome high transition resistance, but it is notable to distinguish the direction in which the fault occurs,and does not have the ability of phase-selection. To overcome these shortcomings, a direction element which responds to the sudden increment of negative sequence currentis used as the direction distinguishing part, and polarizationbased on the positive sequence current is used for phase-selection. Supplemented with these two parts, the property ofthe above mentioned zero sequence reactance relay is improved outstandingly.