长电缆分布电容对保护装置的影响及解决方法

通过现场数据和理论论证,对安徽电网某500 kV变电站微机保护装置在开关量采集过程中直流操作电源接地时导致误开入的原因进行了分析,说明了当直流操作电源接地时,与控制电缆的分布电容构成回路,产生电容电流,从而引起一些动作值较低的光耦甚至继电器发生误动作。在此分析基础上,提出了一些防范措施和对策。

Influence of Long Distance Power Cable Distributed Capacity to Relay Protections and Its Solutions

A series of fault inputs during switching value acquisition of microcomputer-based protection are analyzed when DC negative bus grounding fault occurs simultaneously in a 500kV sub-station in Anhui province by physical data and theoretical foundation.The capacitance current introduced by the distributing capacitance of control cables leads to the misoperations of sensitive relay with low action threshold when DC bus grounding fault occurs.Based on the theoretical analysis,several preventive measures and sol...