高压电网电流互感器饱和对继电保护的影响应用分析与研究

摘要

In power system,the improperly selected current transformer (CT) may experience over 100 times short-circuit current in an instant when a failure occurs in the system,leading to the severe saturation of the CT.This paper presents an in-depth analysis on the characteristics and the saturation degree of both the mechanical CT and electromagnetic CT; and the effects of the performance characteristics and theoretical calculation of the analogous and microcomputer relay protection,and explores the reasonable methods in the choosing of CTs.To solve this problem,one possible solution is choosing the device at the maximum short circuit current and its protection current transformer saturation ratio,and enhancing CT saturation resistance to ensure the maximum short-circuit current is not saturated.Finally,the paper puts forward some measures in improving the correctness of actions of the relay protection device when the current transformer is saturated.%在电力系统中,由于电流互感器选择不当,故障时电流互感器可能在瞬时内承载近百倍的故障短路电流,造成电流互感器严重饱和.通过详细分析对机电式、电磁式饱和特性以及饱和程度、模拟式以及微机继电保护装置的动作特性的影响以及理论计算,探求合理的电流互感器选择方法.为解决此问题.一个可能办法是选择保护安装处最大短路电流与其电流互感器的饱和倍数来选择,同时增强电流互感器的抗饱和能力,合理选择继电保护装置和电流互感器,以保证在最大短路电流下不致饱和.提出了提高继电保护装置在电流互感器饱和时测量动作正确性的对策.