The Research Of Fault Location New Algorithms Based On The Distributed Parameter Model For High Voltage Transmission Line

With the developing of power systems, more and more long distance HV transmission lines have been constructed .This increases the probability and severity of short circuit faults,which leads to higher requests for protective relaying and fault location sets for HV transmission lines.At first this paper introduced the history and the new directions of fault location, then presented an accurate compensation algorithm using one terminal data, and a novel phase comparison method for fault location based on the distributed parameter model.The principle of the compensation algorithm is: The measured distance of the lump parameter circuit model can be converted to the positive sequence measured impedance matching with the model. And the relation between real distance and positive sequence measured impedance of fault circuit based on distributed parameter model can be derived from solid-grounded faults. Then the compensation algorithm resulting from the relation of real distance and measured distance can be obtained. Theoretically, the proposed algorithm is independent of shunt distributed capacitance of transmission lines.The principle of the phase comparison is: The residual phase voltage at the fault point should have the same phase angle as the current through fault branch due to the pure resistive characteristics of the fault path impedance. By virtue of searching the minimum phase angle difference between the phase voltage along the transmission line and the fault-component current measured at the side equipped with protection, the fault distance can be located.The principle of double-ended fault location method is derived from the phase comparison method. By using double-ended fault data, we can calculate the current distribution factor accurately, and then the precision can be improved. Besides, the algorithms are based on power-frequency voltages and currents.Therefore, it can be implemented in the existing protection devices easily. ATP simulation results have shown the effectiveness of the algorithm.