Fault Location Method Based On Double Terminal's Information Of High Voltage Transmission Line

Transmission lines which take charge in transporting electrical energy take on the important role in power system. The exact fault location will reduce the manual work and find out unclear faults. Resuming transport in time and credible power supplying would be available to stabilization and economical operation of power system. The exact fault location would bring large economic and social profit to electric power company.The fault location methods of transmission line based on voltages and currents at double terminal could eliminate the affect of transition resistance and both systems when fault occurs in the line. But the unsynchronize sampling and the unbalance of transmission line parameters would decrease the exactness of that fault location methods. After analyzing all kinds of traditional fault location methods based on fault fundamental component, this paper proposed two developed traditional fault location methods which use voltages and currents at double terminal of transmission line based on distributed parameters in the line model. The developed methods eliminate the affect of the unsynchronize sampling, transition resistance and both systems. The unbalance of transmission line parameters have been taken into account at the same time. The emulation results of EMTDC show that this method is of high accuracy. There is a new method proposed in this paper to eliminate the effect of outside fault in detected line. When the method is combined with orienting traveling wave, it would work exactly. To eliminate the dead zone of wave traveling fault location when the voltages approximate zero, there is a new method proposed in this paper, which use re-closure impulse to locate the fault in transmission line. The emulation results show that this method is of high accuracy. The fault location methods of transmission line based on voltages and currents at double terminal consists of traditional fault location based on fault fundamental component and traveling wave location based on fault transient traveling wave. There are some defects in these two methods, but these methods could be combined to a synthesis. In this paper, a new type of integrative fault location system for transmission line combining these two methods is developed. This method would improve the accuracy of traditional fault location and the credibility of traveling wave location. Aimed at upgrading software in the future and expanding automation of electric power system distribution, the fault locating module based on COM technology has been developed.