基于采样序列整形的配电网线路保护防励磁涌流误动策略

针对配网线路中配变空载合闸导致励磁涌流从而引起上游线路保护误动的问题，提出了一种基于采样序列整形的配电网线路保护防励磁涌流误动策略。当线路电流同时满足快速启动和二次谐波含量低判据时，进入电流序列整形程序。首先，根据二次谐波有效值的稳定区段将电流信号分割为正弦区段和畸变区段，并利用稳定区段的长度设置结束判据。然后，通过确定自适应窗长和标准正弦曲线对正弦区段进行相似度计算，得到原始正弦区段的幅值和相位参数，从而对畸变区段完成整形。最后，将修复后不带励磁涌流的电流信号送至线路保护进行判断。所提策略能够有效应对混叠在负荷电流和故障电流中的励磁涌流，并通过仿真分析验证了所提策略的有效性和可靠性。

An anti-excitation inrush current maloperation strategy of line protection for a distribution network based on sampling sequence shaping

There is a problem of protection maloperation of an upstream line caused by excitation inrush due to no-load closing of a distribution transformer in distribution network lines. Thus this paper proposes an anti-excitation inrush current maloperation strategy of line protection for a distribution network based on sampling sequence shaping. When the line current meets the criteria of fast start and low second harmonic content at the same time, it will enter the current sequence shaping procedure. First, the current signal is divided into sinusoidal and distortion sections according to the stable section of the second harmonic effective value, and the auxiliary criterion is set by the length of the stable section. Subsequently, the similarity of the sine segments is calculated by determining the adaptive window length and the standard sine curve. The amplitude and phase parameters of the original sinusoidal region are obtained to complete the reshaping of the distortion region. Finally, the current signal without excitation inrush current after repair is sent to line protection for judgment. The proposed strategy can effectively cope with the excitation inrush current overlapping in the load and fault currents, and the validity and reliability of the proposed strategy are verified by simulation.