742 / 2019-04-26 15:30:47

A New Analytical Method Of The Current Differential Protection

restraint coefficient; differential criterion; sensitivity coefficients; polar coordinates

Abstract: Current differential protection is one of the most widely used protections in power systems. The reliability of differential protection seriously affects the stability of power systems. This paper proposes a novel method, which analyses the differential protection characteristic in polar coordinates. The representation of differential protective criterions in polar coordinate is presented, the relationship of restraint coefficient between amplitude and angle difference of current is established, and the selection principle of restraint coefficient is proposed by comparing restraint portions of different differential protection criterions in polar coordinate. Sensitivity coefficient is introduced to contrast characteristic of criterions. The simulation results from the faults in 110kV line by using PSASP are consistent with the theoretical analysis.