Title :
Fast transient overvoltages in generator stator windings during interrupted arcing ground-faults
Author :
Fulczyk, M. ; Piasecki, W. ; Bertsch, J.
Author_Institution :
ABB Corporate Res., Krakow, Poland
Abstract :
In the paper the simulation results of ground-fault fast transients in stator windings of unit-connected generators are presented. The simulations were done for different elements connected between generator neutral and ground. Ungrounded neutral, neutral grounded through neutralisers or resistances were considered. The influence of the parameters of the particular grounding elements on the fast transient overvoltages during interrupted arcing ground-faults in the generator stator winding was determined. An additional capacitance to ground of the generator breakers, a real mechanism of ground-fault arc quenching, and real changes in its resistance during fast transients were also taken into account. Comparative simulations of the ground fault overvoltages for units with the biggest difference in parameters (in range 30-1600 MVA) were carried out. It has been found that for the grounding elements analysed the maximum overvoltages will not exceed double amplitude of the generator phase voltage
Keywords :
AC generators; arcs (electric); electrical faults; equivalent circuits; machine theory; overvoltage; stators; transients; 30 to 1600 MVA; capacitance to ground; equivalent circuit; fast transient overvoltages; generator breakers; generator ground; generator neutral; generator stator winding; generator stator windings; ground-fault arc quenching; grounding elements; interrupted arcing ground-faults; neutralisers; resistances; stator windings; unit-connected generators; Capacitance; Circuit faults; Grounding; Insulation; Magnetic analysis; Power generation; Power system protection; Power system transients; Stator windings; Surge protection;
Conference_Titel :
Power Tech Proceedings, 2001 IEEE Porto
Conference_Location :
Porto
Print_ISBN :
0-7803-7139-9
DOI :
10.1109/PTC.2001.964867
