Ⅲ段距离保护作为后备保护的性能分析

Performance analysis of Ⅲ section distance relay as the backup protection

在阻抗继电器与距离继电器分类的基础上,对Ⅰ、Ⅱ、Ⅲ段阻抗继电器的配合问题和Ⅰ、Ⅱ、Ⅲ段距离继电器的配合问题进行了深入的探讨,分析了Ⅲ段距离保护作为后备保护应具有的条件。由于阻抗继电器具有性质1,Ⅲ段阻抗继电器作为Ⅰ、Ⅱ段阻抗继电器的后备,在任何一次系统条件下都是成立的。由于距离继电器不具有性质1,一次系统结构、参数、运行方式、短路类型变化对Ⅰ、Ⅱ、Ⅲ段距离继电器的配合都产生影响。如果Ⅲ段距离继电器支接阻抗特性不能够涵盖I、II段距离继电器的支接阻抗动作特性,则Ⅲ段保护起不到后备保护的作用。

This paper discusses the cooperation of three-section impedance relays and that of three-section distance relays, analyzes the necessary conditions of Ⅲ section distance relay qua the backup protection based on the classification of impedance relays and distance relays. Because the impedance relay has the feature one, impedance relay of section Ⅲ is regarded as the backup protection of section Ⅰ and section Ⅱ in any case. The variety of the primary system＇s structure, parameter, operating point and short-circuit style influences the cooperation of three-section distance relays. If the feature of the section Ⅲ distance relay subcircuit impedance can＇t comprise that of the section Ⅰ and section Ⅱ , the section Ⅲ can＇t act as the backup protection.