Confirming the reliability and safety of MV distribution network including DG applying protection applications for earth faults

The paper describes the effects of distributed generation on the earth fault protection of a medium voltage feeder and protection coordination. Neutral isolated and compensated systems were considered. The aim was to investigate the behaviour of the production unit during automatic reclosings, especially as regards electrical safety. Methods possibly feasible for clearing a temporary earth fault without voltage break were considered. Thus disturbances affecting production and customers are less than with automatic reclosings. The method of the study was dynamic simulation of the earth faults in medium voltage system. The network model including a wind power plant was implemented applying PSCAD™ simulation software.