SUBSTATION AUTOMATION
NEUTRAL GROUNDING REACTOR
The Neutral Grounding Reactor is a single phase reactor in three phase power system, connected between the neutral and earth of transformer to limit the fault current. Neutral Earthing reactors re also used for reducing momentary over voltages during breaking of instantaneous fault current.
Under normal system conditions, the voltage across a neutral-earthing reactor is small and consequently, the current through the reactor is small. During system fault, the current will increase considerably, and its duration in Seconds needs to be specified.
The insulation requirements of NGR shall correspond to the insulation of the neutral of the power system or the shunt reactor in which the reactor is to be installed. For the earth terminal, the selection of a reduced insulation level may be appropriate (non-uniform insulation).
