Impedance of multigrounded neutrals on rural distribution systems

Hydro-Quebec has conducted field tests to study the impedance of multigrounded neutrals on rural distribution systems. Phase-to-neutral faults were staged at different locations along a 25 kV line and the field test results are reported. A simplified computer model implemented on EMTP gives results very close to those yielded by field tests. The main conclusion is that customers' grounding systems determine the impedance of multigrounded neutrals. Test results also show that the current is shared more or less equally between the neutral conductor and the sheaths of CATV and telephone cables. Overvoltages on phase conductors during phase-to-neutral faults were also measured and results are presented.<
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