Durations of missing zero crossings of fault current contributions from shunt reactors

Abstract:
This paper aims at giving a comprehensive overview of missing zero crossings of fault currents that are fed by shunt reactors. To do so, first the theoretical fundamentals of the phenomenon are highlighted. Here, it is found that the demagnetization currents of shunt reactors are prone to long durations of missing zero crossings due to their time constants. Also, it can be shown that the length and type of the connection line of the shunt reactor has minor influence on the current shape. As a contrast, including a constant arc voltage into the simulation model leads to significant reductions in arcing times. Nonetheless, solely arcing voltages of 30 kV and higher lead to arcing times of 30 ms and lower. However, it should be pointed out that the stored energy in the shunt reactor is considerably lower than the mechanical energy in rotating machines. Therefore, the possibility of an arc collapse should be taken into consideration.