Fault Location and Phase Selection for UHV Six-Phase Transmission Lines

Construction of UHV power grid is the fundamental guarantee to the growing demands of electricity in the future. Six phase transmission lines can evidently improve power transmission density, and many countries pay attention to it. A new method of fault location and phase selection on six-phase transmission lines was analyzed in this paper. The six sequence variables method to analyze the electrical signals gained form the end of transmission lines. With the help of long line equation, the fault currents can be calculated form the location of fault and electrical signals gained from the end of transmission lines. And the characteristics of amplitude for fault currents can be used for phase selection. Theoretical analysis and MATLAB simulation show that this method is not affected by distributed capacitance and transition resistance, which locates exactly. And it has the ability of adaptive adjustment on settings of phase selection as operation mode operating mode identification. So it can provide effective fault phase selection logic for distance relay protection of six-phase transmission lines.