Ground fault protective apparatus and method

摘要

Apparatus for protecting power distribution networks from damage due to ground faults comprises a plurality of groups of zero sequence current monitors, each group surrounding all branches of the network which enter a zone of protection. Each group is electrically connected to produce an output signal corresponding to the vector sum of differential currents flowing into and out of the zone. Each group is connected to a ground fault relay which will trip when the vector sum of the differential currents entering or leaving a zone is above a predetermined level.