鉴别电力变压器励磁涌流的一种算法

An algorithm of distinguishing from magnetizing inrush current of power transformer

鉴别电力变压器内部故障电流和励磁涌流是电力变压器差动保护的主要任务。分析了励磁涌流电流和内部故障电流的特点,然后介绍鉴别电力变压器的励磁涌流电流的方法和它们的限制:二次谐波制动技术,间断角法和波形对称理论。同时,基于小波变换理论提出了鉴别电力变压器内部故障电流和励磁涌流的新算法。基于MATLAB仿真结果表明:该算法能有效地鉴别内部故障电流和励磁涌流,提高了基于微机变压器差动保护的可靠性。

The distinguishing internal fault current from magnetizing inrush current of power transformer is still the main duty of the current differential protection of power transformer. This paper presents the characteristics of magnetizing inrush currents and internal fault currents are presented. It introduces some principle for distinguishing internal faults current from magnetizing inrush current of power transformer and their limitation： the second harmonic restrains technique, intermittence angle method and wave shape symmetric theory. At the same time, it proposes a algorithm for distinguishing internal faults current from magnetizing inrush current of power transformer based on the theory of wavelet transform. The simulation results indicate the algorithm could effectively distinguishing the characteristics of magnetizing inrush current from internal faults current based MATLAB, it improves the reliability of transformer differential protection based on microcomputer.