Some Basics of System Grounding

11/15/2010

The previous article discussed some of the basics of grounding in substations and transmission systems. This article will conclude with an examination of similar considerations as they apply to distribution grounding. The purpose of grounding in ac distribution systems is much the same as for substations (refer to previous article), with safety of persons being the highest priority. The distribution system, of course, brings electric service to the end users and hence presents a protection challenge encompassing the general public and accordingly different from that of utility workers in substations. The challenge includes:

• Stabilization of service potentials to ground against overpotentials.

• Safety from electrical fires.

• Safe grounding of fixtures and exposed noncurrent-carrying elements of electrical systems.