Neutral grounding resistor failure detection verification

A resistance-grounded distribution system has a critical element that is often forgotten - the neutral-grounding resistor (NGR). Because NGR's are subject to failures [1] related to thermal overload, lightning, storms, extended service life, manufacturing faults, vibration, corrosion, and improper specification or installation, the proper monitoring of NGR health is important as all other protections to preserve distribution system in safe state.