Research of Influence of Grid Connection of Distributed Generation on Current Protection of Distribution Network

The paper analyzed influence of grid connection of distributed generation on traditional current protection of distribution network, used Matlab/Simulink simulation software to prove influence of different capacities and grid connected positions of distributed generation on each section of current protection of distribution network, and proposed an improved scheme which can meet with protection requirement of distribution network after grid connection of distributed generation. The implementing principle of the scheme is as follows: for downstream protection of distributed generation, taking power supply of power system and distributed generation as a whole, resetting set values of each section of current protection; for upstream protection of distributed generation, installing a direction relay based on fault current component on each protector, so as to ensure reliable action of protection when over-current relay and direction relay start simultaneously.