MV Generator Ground fault arcing power damage assessment

摘要

An industrial Medium Voltage (MV) system usually consists of multiple power sources such as utility tie transformers and generators. These are normally low-resistance grounding as shown in Fig. 1. When a ground fault occurs at the generator stator, ground currents from its own neutral circuit and external power sources will flow into the fault and cause damages to the stator winding. The IEEE Generator Grounding Working Group issued a guideline for generator grounding practices, which recommends using a hybrid grounding system to minimize the ground fault damage induced by its own neutral grounding source. This paper will evaluate the total ground fault damages based on the arcing power energy to derive a maximum MV system ground current that would limit the ground damage to an acceptable level.