Study And Experiment Of Zero-sequence Mutual Inductance Parameter Measurement Of Transmission Line

The zero-sequence parameter of transmission lines especially of transmission lines with mutual inductances is of great important in the relay protection setting calculation of power system. So the accuracy of zero-sequence is significant. The conventional methods of measuring transmission lines with mutual inductances are only applicable when the line is out-of operation and can't accurately measure the zero-sequence parameters when there is disturbing signal. But for the lines after many years of expansion, it is impossible to measuring when all lines are out-of operation. After analyzing and comparing the four methods of live line measurement of transmission line's zero-sequence parameters—the interference method, the incremental method, the differential equation method and the integral equation method, we choose the incremental method as the chief method to study. For resolve the problem of the incremental method, we carry out thorough study and an innovational conclusion is gained. Finally, demonstrate the validity of the correctness of the conclusion by means of theoretic proving, computer simulation and Emulation tests.