基于二阶B样条小波模极大值的双极HVDC输电线路行波保护

摘要

针对行波保护存在波头难以捕捉或捕捉精度不高的问题,提出了一种基于二阶B样条小波模极大值的双极HVDC输电线路行波保护.首先,获取正负极整流逆变两端的暂态电流行波信息,通过计算其相关系数选出故障极,然后利用二阶B样条小波函数分解暂态电流行波获得模极大值,通过比较电流行波与小波模极大值的极性判断出区内外故障,最后根据模极大值所在位置确定波头到达时间进行故障测距.PSCAD/EMTDC仿真结果证明,所提办法可准确的实现故障的判别,测距精准度高且不易被过渡阻抗、故障类别及测量距离等要素影响.%A traveling wave protection of bipolar HVDC transmission line based on the second order B-spline wavelet modulus is proposed for the problem that the wavefront is difficult to capture or catch the high precision.Firstly,the transient current traveling wave information of both ends of the positive and negative rectifier inverter is obtained,and the fault pole is selected by calculating the correlation coefficient.Then,the second-order B-spline wavelet function is used to decompose the transient current traveling wave to obtain the modulus maxima.The inner and outer faults are judged by comparing the polarity of the current traveling wave and the maximum value of the wavelet model.Finally,the wave arrival time is determined according to the position of the modulus maxima to realize the fault distance measurement.PSCAD/EMTDC simulation results show that the proposed method can accurately identify the fault,ranging from high precision and difficult to be affected by factors such as transition resistance,fault type and fault distance.