Title :
The 40-Ω ground-fault phenomenon
Author_Institution :
Clapp Res. Associates, Raleigh, NC, USA
Abstract :
Coordination of protective devices on electrical distribution systems always involves the calculation of fault currents. These calculations almost always include a minimum fault current value. This minimum fault current value is not a bolted fault calculation; it includes an assumed impedance. Many utilities have assumed this impedance to be 40 Ω. This paper examines that assumption and provides some guidance on this issue. This paper is based on a study sponsored by the Cooperative Research Network, a division of the National Rural Electric Cooperative Association, based in Arlington, VA. This original study was completed in 1997
Keywords :
earthing; electric impedance; fault currents; power distribution faults; power distribution protection; 40-Ω ground-fault phenomenon; Cooperative Research Network; National Rural Electric Cooperative Association; assumed impedance; electrical distribution systems; fault currents calculation; minimum fault current value; protective devices coordination; ANSI standards; Circuit faults; Fault currents; Impedance; Industry Applications Society; Power industry; Power system faults; Protection; Standards publication; Telephony;
Journal_Title :
Industry Applications, IEEE Transactions on
