Patent Document ID: 20170038785
Application ID: 15076638
Patent Flag: 0

Claim One:
1. A method of differential protection in the power distribution networks based on phase difference principles, wherein the method comprising the following steps: 1) collecting current and voltage signals of each loading switch; 2) calculating phase difference between the corresponding currents at two adjacent loading switches, wherein at least one of the two adjacent loading switches accords with ΔI φmax >n·ΔI T +ΔI dz ; ΔI φmax is the maximum value among the 3 phase current mutation values of a corresponding loading switch, n is a set proportional value, ΔI dz is a start value of phase current mutation, ΔI T is a threshold value; 3) tripping the two adjacent loading switches if the phase difference corresponding to the two adjacent loading switches being greater than a threshold then a section between the two adjacent loading switches determined as a fault section.