Our Neutral-Grounding-Resistor Systems are essential for limiting ground-fault currents in electrical power systems. The system works by inserting a resistor between the system neutral and ground, lowering the prospective ground-fault current to a predetermined value.
A properly designed NGR system provides benefits over both ungrounded and solidly grounded systems because the NGR system is grounded, transient overvoltages do not occur and ground-fault current can flow, allowing it to be detected and measured. Also, because an NGR is used to ground the system, the very large and destructive ground-fault currents of solidly grounded systems are absent. Ground-fault relays (such as the SE-701) can be used on feeders to provide selective coordination and the ability to quickly locate or isolate the fault.