Distribution system grounding fundamentals
This article is an overview of the various relationships between neutral currents, ground currents, electrode impedances, and voltage potentials that are encountered in the operation of multi-grounded wye distribution systems. This system continuation is the most commonly used configuration among U.S. domestic utilities. Voltages range from 4.16/2.4 kV to 34.5/19.9 kV. The most common system voltages are 15- and 25-kV class systems with nominal operating voltages on rural systems generally being 12.47/7.2 kV and 24.9/14.4 kV. The article aims to review the relationships that might be encountered due to system grounding and provide an overview of common installations and their relative effectiveness.