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Project: T143700 #3711
 

This report investigates the measurement of an “effective ground impedance” and its relation to mitigating operational issues on the multigrounded neutral of an electrical distribution system. Emphasis was put on excessive neutral-to-earth voltage (NEV) caused by unbalanced loads, single line to ground (SLG) faults along the distribution system, and ground potential rise (GPR) due to substation faults. A mathematical model of a multigrounded neutral is presented and a number of overhead and underground feeders were modelled with parameters such as neutral conductor size, ground electrode density, and ground electrode resistance varied to show the effect on the NEV. Field measurements were taken using a custom network analyzer, a Megger DET2-2, and an AEMC 6472 with the 6474 current split adapter to compare neutral impedance values.

Keywords:

Stray Voltage, Neutral to Earth Voltage, Neutral Impedance, Ground Faults on Neutral