基于行波原理的故障暂态量选相因所需时间短,符合目前发展超高速保护的要求。针对现有行波选相法存在准确识别波头的困难,提出基于行波固有频率的故障选相方法。该方法利用多信号分类法得到电流模分量功率谱,通过比较其中线模量的主频实现故障选相。该方法的可靠性由基于PSCAD/EMTDC搭建的晋东南—南阳—荆门1 000 kV特高压交流输电线仿真模型实验验证,选相结果不受故障距离、故障时间、过渡电阻的影响,且所需故障数据窗短,易实现超高速保护。
Because of its rapidity,the traveling wave principle-based faulty phase selection,in which the transient components appeared during the fault process are utilized,can meet the demand of developing ultra-high speed protection.In view of the defect in existing traveling wave-based faulty phase selection that it is difficult to precisely identify the wave front,a new faulty phase selection method based on natural frequencies of traveling waves is proposed.By use of multiple signal classification,the power spectrum of module component of current is obtained,and then by means of comparing the dominant frequencies of conductor modulus in the power spectrum the faulty phase can be determined.The reliability of the proposed method is verified by experimental verification,in which a simulation model of 1 000 kV AC transmission line from Southeast Shanxi via Nanyang to Jinmen is built on the platform of PSCAD/EMTDC.Simulation results show that the faulty phase selection result does not depend on the time when fault occurred,the faulty position and transition resistance,and the required data window is short,thus the ultra-high speed protection based on the proposed method is convenient to implement.