Abstract
This chapter describes the theory of overvoltages and discusses the criteria and theory of selecting a grounding system to achieve a desired level of fault current to suit a predetermined ground fault protection scheme, i.e., type of grounding and grounding impedance to suit the system voltage, type of installation, and location of installation. An ungrounded system, in the event of a ground fault, is subject to an overvoltage. It is prone to cause yet higher voltages in the healthy phases when its ground circuit becomes inductive. The overvoltage may damage the supporting insulators and the terminal equipment. The ground fault factor (GFF) is an important indicator that shows the grounding condition of a system and helps to determine the most appropriate ground fault protective scheme as well as the insulation level for that system. The most recommended practice is to ground the neutral solidly or through impedance, commensurate with the requirements of the protective scheme, and the fault current limited to a desired level. Some of the applications of different types of grounding methods include artificial neutral grounding of a three-phase three-wire system, neutral grounding transformers, and residual voltage transformer.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
