一种电流互感器饱和误差补偿算法研究

An error compensation algorithm for saturated current transformer

在故障情况下,电流互感器(CT)的一次电流非常大,且含有衰减的直流分量,容易使CT饱和,导致二次电流严重失真,使继电保护装置或控制设备不能正常动作。本文提出了一种饱和二次电流的误差补偿算法。该算法根据测得的二次电流估计铁芯中的磁通量及激磁电流,并将估计的激磁电流加入到实测二次电流中,起到补偿作用,矫正失真的二次电流。EMPT仿真及算例分析证明了本文算法的有效性。

Under fault condition, primary current of a current transformer （CT） has high magnitude and may include decaying DC offset. This can result in saturation of magnetizing core of the CT and the secondary current thus is distorted. The distorted current could cause malfunction of protection relays or control devices. This paper proposes an error compensation algorithm for saturated secondary current. The algorithm estimates flux in the magnetizing core and current through the magnetizing branch from known secondary current. By adding the estimated magnetizing component, the distorted secondary current can be compensated. The proposed algorithm is evaluated by EMTP simulation data and case studies are included.