This paper points out the existence of a series of problems about double-circuit lines on the same pole with the main protection of phase segregated current differential protection,such as differential protection will quit when channel is in fault and common reactance’s impact on back up protection.

Zero sequence current differential protection is expected to improve the performance under high resistance earth fault conditions in phase segregated current differential protection for transmission lines.

The paper has analyzed the line two interphase current difference characteristic,according to this characteristic,proposed based on two interphase current difference auto-adapted electric current protection plan,and has carried on the analysis to the auto-adapted electricity speed of flow section protection performance.

An analysis on protection feature adaptation to four-circuit transmission lines on a same tower is discussed, with respect to line distance protection, directional protection and segregated phase current differential protection in principle respectively.

This paper proposes a novel principle of segregated phase current differential protection in UHV long distance transmission line with shunt reactor installed in the middle segment.

Research on Segregated Current Differential Protection based on Accurate Parameter Estimation for Transmission Lines;

According to the theory of fiber optical current differential protection,this paper illustrates the scheme of joint commission for line fiber optical differential protection,including checking double-ended current and differential current,simulating faults in charging or non-load,and simulating radial lines\' operating condition and remote tripping.