Title :
Influence of element grounding generator neutral and resistance of breakdown channel on fast transient process in unit-connected generator
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); capacitance; earthing; electrical faults; equivalent circuits; machine protection; overvoltage; stators; 30 to 1600 MVA; breakdown channel; capacitance to ground; fast transient overvoltages; fast transient process; generator breakers; generator ground; generator neutral; generator phase voltage; generator stator winding; ground-fault arc quenching; ground-fault fast transients; interrupted arcing ground-faults; neutralisers; resistances; stator windings; ungrounded neutral; unit-connected generator; Capacitance; Circuit faults; Electric breakdown; Grounding; Insulation; Magnetic analysis; Power system protection; Power system transients; Stator windings; Surge protection;
Conference_Titel :
Transmission and Distribution Conference and Exhibition 2002: Asia Pacific. IEEE/PES
Print_ISBN :
0-7803-7525-4
DOI :
10.1109/TDC.2002.1177659