Grounding the neutral of electrical systems through low resistance grounding resistors: an application case

摘要

It seems common knowledge that three-phase short circuit currents are the worst possible scenario for electrical systems. In reality, single-phase ground fault currents may be significantly more intense than three-phase fault currents. With the occurrence of high single-phase fault currents, severe damage could be caused to the iron cores of electric machines included in the zero sequence fault loop. The method of neutral low resistance grounding is discussed by applying a step-by-step calculation procedure to an actual case, in order to properly size the grounding resistor thereby limiting the fault current.