A New Ground Fault Protective System for Electrical Distribution Circuits

Distribution circuits which are solidly grounded or grounded through low impedance present a problem relative to fast clearing of ground faults. This is especially true in low-voltage grounded Y circuits which are connected to bus ducts or long runs of metallic conduct. The problem involves sensitivity in detecting low ground fault currents as well as coordination between main and feeder circuit protective devices. Fault clearing must be extremely fast where arcing is present.