Modeling and Analysis of Stage Difference Coordination of Protective Devices in DC System

For the current existing problems of modeling on stage different coordination, it analyzes the Ampere-second characteristic of the common DC circuit breakers, which must considers the dispersion characteristic. Through correcting the Ampere-second characteristic function by time-sharing coefficient, it can draw the Pre-acring Ampere-second curve and analyze the stage different coordination. On this basis, it developed the simulation software for the Guangdong power Grid Substation DC system, to calculate the limit electric current for the upstream-downstream breakers which is closer to the engineering actual current. It can improve the reliability of the substation DC systems, and provide the basis for choosing the DC circuit breakers and transforming the old station.