Why NGR Neutral Grounding Resistor are used. The Short form of NGR is Neutral Grounding Resistor. NGRs are used in an electrical power system to protect the star connected alternator/generator or the transformer. NGR is constructed by inserting a resistor between the star connected neutral terminal and ground terminal. NGRs grounding system provides more benefits … Continue reading 7 Purpose of NGR Neutral Grounding Resistor Transformer & Generator