IMPEDANCE OF MULTIGROUNDED NEUTRALS ON RURAL DISTRIBUTION-SYSTEMS

Hydro-Quebec has conducted field tests to study the impedance of multi grounded neutrals on rural distribution systems. Phase-to-neutral faul ts were staged at different locations along a 25-kV line and the field test results are; reported. A simplified computer model implemented o n EMTP gives results very close to those yielded by field tests. The m ain conclusion is that customers' grounding systems determine the impe dance of multigrounded neutrals. Test results also show that the curre nt is shared more or less equally between the neutral conductor and th e sheaths of CATV and telephone cables. Overvoltages on phase conducto rs during phase-to-neutral faults were also measured and results are p resented.