Neutral Grounding Resistor Monitoring State-of-the-Art

Neutral grounding resistors are used to overcome safety concerns and equipment stress by controlling transient overvoltages and limiting ground overcurrents. Failure of these apparatuses is an undetected event in unfaulted condition that causes many challenges in case of ground faults. Recently, various monitoring methods have emerged to solve this issue. The literature and current state of this art are the main targets of this research work, which classifies all existing methods into three categories based on the used measurement instruments and operation characteristics. In this article, each of these methods are explained briefly including the used measurement instruments, monitoring scheme, and few performance results. Further, the evolution trend of these methods is demonstrated as well as a thorough comparison based on their performance under various conditions.