【摘要】 为识别变压器励磁涌流和内部故障电流,提出了利用波形特征识别变压器励磁涌流的1/4周波面积比较法。该算法以工频一周波为数据窗长,将数据窗内的差流波形按时间均分为4份,根据各份面积之间的比值来识别励磁涌流和内部故障电流。该算法既能识别出单向涌流,又能识别出对称涌流,算法稳定性好,高次谐波分量对其影响也较小。该识别法与二次谐波制动原理相比,不会出现某些内部故障情况下由于二次谐波大可能造成差动保护延时动作的问题。大量的软件仿真和动模实验证明了该方法的可靠性和可实施性。更多还原

【Abstract】 This paper presents an algorithm of comparing quarter-cycle areas to identify transformer’s magnetizing inrush using waveform character.The algorithm uses a cycle of 50Hz current wave as a data window.The waveform of differential current in each data window is divided into four parts averagely according to time,and the area-ratio among the four parts can be used to distinguish magnetizing inrush from internal fault current.It can identify both the single directional inrush and the symmetrical inrush.The proposed algorithm has good stability,and almost avoids the effect of harmonics.Compared with second-harmonic restraining method,this algorithm can avoid the problem of delaying action of differential relays.Digital simulations and dynamic simulations of power system verify the reliability、practicability of the proposed method.更多还原