基于小波变换的行波故障定位法在串补输电线路中的应用

串联电容补偿线路的故障测距和继电保护是一个比较困难的问题.困难之处不在于串补电容本身,而在于与之并联的MOV的动作特性.由于串补电容和MOV一起组成了一个非线性电路,故难以建立其在故障发生时的精确模型.作者将基于连续小波变换的行波定位法应用于串补输电线故障测距,分析了MOV对行波定位法的影响,并进行了大量的仿真.该方法不依赖串补装置的模型,不受MOV非线性特性的影响,具有较高的定位精度,且不受故障类型与接地阻抗的影响.EMTP仿真结果证实了该方法的有效性.

APPLICATION OF WAVELET TRANSFORM BASED TRAVELLING WAVE FAULT LOCATION TO SERIES COMPENSATED LINES

It is rather difficult for power transmission line with series compensation to locate the fault occurred in it and to set the protective relayings, the reason does not lie in the series compensating capacitors themselves, but in the action characteristics of the MOVs in parallel with the compensating capacitors. A non-linear circuit is constituted by compensating capacitors and MOVs and it is difficult for this non-linear circuit to establish an accurate model while fault occurs. Here, the travelling wave fault location method based on continuous wavelet transform is applied to the fault location of power transmission line with series compensation. The influence of MOV on travelling wave fault location is analyzed and a lot of simulations are carried out. The presented method possesses higher fault location accuracy, it does not depend on the model of series compensation equipment and is not influenced by non-linear characteristics of MOV, the kind of fault and the grounding resistance. The effectiveness of the presented method is verified by the results from EMTP simulation.