Considerations on the Disturbances Occurred in the Operation of Medium Voltage Electrical Networks with Neutral Treated by Suppression Coil

Abstract

In this paper are analyzed the analytical models of theoretical calculation and analysis of the main consequences of neutral treatment by suppression coil on the operation of medium voltage electrical networks, both in normal regime and especially in single-phase fault regime. The size of stationary and transient overvoltages and fault currents is evaluated for a concrete case study. Also the authors present in this paper the results they obtained after the extension of their research and in the field of harmonic regime produced by the grounding of a power line. This type of fault occurs frequently in the case of medium voltage networks, with neutral treated with suppression coil. Thus, they managed to reconstruct the waveforms of currents and voltages during the fault period (grounding). Then, having these calculation elements available, a comparative analysis of similar incidents (earthing) from a 20 kV network with the neutral treated with classic suppression coil and modern Trench suppression coil, respectively, was made.