采用电压波形特征的电流互感器饱和检测方法

基于对电流互感器(CT)电磁感应过程的分析,提出一种采用电压波形特征的CT饱和检测新方法.该方法将饱和的发生和结束视为具有一定持续时间的过程;以二次电流三阶差分的模极大值串定位可能的饱和发生与结束时段;并根据这些时段内二次电压的波形特征最终判定饱和的发生与结束.对二次电流进行低通滤波并在二次感应电压过零点附近屏蔽检测算法,还能有效抑制噪声干扰,使新方法在不利环境下也能正常工作.该方法稳定、准确,且运算量小,便于实时实现.仿真分析和实验结果验证了该方法的有效性和实用性.

A METHOD DETECTING CURRENT TRANSFORMER SATURATION BY UTILIZING FEATURES OF SECONDARY VOLTAGE WAVEFORM

Based on the analysis of electromagnetic induction process in CT, a new CT saturation detection method utilizing character of secondary voltage waveform feature is proposed. This method regard the happen and termination of saturation as the processes which last a certain durations, the possible time intervals in which the saturation happens and terminates are located by the modulus maxima string of third order difference of secondary current, and according to the waveform features of secondary voltage in these time intervals the happen and termination can be finally judged. The interference from the noise can be effectively eliminated by applying the low pass filter to secondary current and screening the detecting algorithm at the crossover point of induced secondary voltage, thus the proposed method can also normally work in unfavorable environment. This method is accurate and stable, and its calculated amount is small, so this method is easy to realize. The results of simulation and experiments show that this method is effective and practicable.