ANALYSIS OF OVERVOLTAGES OCCURRING AT GROUNDING FAULTS IN A MEDIUM VOLTAGE NETWORK DEPENDING ON THE NEUTRAL TREATMENT

Abstract

The importance of the system earthing in electrical station 110kV/MV is much known, ways to treat the neutral directly affecting the behavior of the system regarding the maximum level of earth-fault currents and of the overvoltages that can occur. In this paper the authors present considerations of the isolated and resistor treated neutral systems and make an analysis of the overvoltages that appear when the neutral is isolated comparing to the situation when it is treated by resistor. In the last part of the analysis the conclusions are presented.

Keywords

• neutral treatment
• medium voltage networks
• single phase-to-ground fault
• phase overvoltage.