电流互感器饱和与微机保护的拟合法电流测量探讨  

Saturation of current transformer and fitting calculation for the current of microprocessor-based protection

作　　者：覃文继[1] 

机构地区：[1]上海交通大学电气工程系,上海200240

出　　处：《继电器》2007年第4期1-5,74,共6页Relay

摘　　要：电流互感器饱和是继电保护尚未妥善解决的现实问题。分析了饱和特性和微机保护在测量电流方面的不足,提出准确测量电流的非饱和基波时段拟合算法,并讨论其实现方案。该方法采用微分电路和三采样值运算法,以电流的二阶导数深度抑制非周期分量并提高对采样值的甄别。通过仿真分析拟合计算实例,评价拟合的整体性能效果,并指出了在软硬件方面的抗干扰、误拟合、采样周期、拟合度等关键性问题及处理方法。算法能比较快速准确地测量出一次系统的实际电流,大大提高微机保护的抗饱和能力,适用于中高压系统对基波电流的测量。Saturation of current transformers is a not solved reality for power relays. In this paper, characteristics of CT saturation and microprocessor-based relays＇ limits are analyzed. An algorithm based on standard frequency sine wave＇s fitting calculation and its approaches are studied. The approach utilizes 2-level derivation of secondary current and a 3-sample fitting calculation for decaying DC component depress as well as the sample data identifying. Solutions for critical problems such as interference, sample rate, fitting factor and performance of the algorithm are evaluated through several simulation calculations. The algorithm is suitable for MV and HV power system. It can overcome CT saturation scenario, return the real primary current accurately so that improve the anti-saturation performance of digital relays.

关 键 词：电流互感器(CT) 饱和 算法 导数 拟合 

分 类 号：TM452[电气工程—电器] TM774TM933.1