1.Maintenance Branch Company, State Grid Jiangsu Electric Power Co.,Ltd.;2.State Grid Zhejiang Electric Power Company Wenzhou Power Supply Company
When a fault occurs in a high-voltage power network near the voltage zero-crossing point or with a large transition resistance, the generated fault transient signal is weak and the attenuation is obvious. It is difficult to detect the wave head, and the traditional fault ranging method is easy to fail. To solve this problem, a distributed traveling wave effective fault location method considering fault transient signal attenuation is proposed. First, according to the exponential decay law of the current traveling wave with the transmission distance, the maximum arrangement distance of the current traveling wave measurement unit is determined under weak faults. Second, based on the attenuation characteristics of the frequency components of the first wave head of current traveling wave, the fault interval identification is realized by the difference of amplitude ratio of frequency components between fault interval and healthy interval. Finally, the faults are accurately located by using the arrival time of the current traveling waves at the three measuring points on both sides of the fault interval. The simulation model of IEEE 30-bus system is set up in PSCAD/EMTDC，and the simulative results show that the proposed method is not affected by the fault type, fault resistance, and fault initial phase angle, and has high positioning accuracy and ideal reliability.