LU Xu-chen, LI Shuang, HAN Hong-gang, et al. Criterion for Judging Power Frequency Ferroresonance in Neutral Point Ungrounded GIS System[J]. High voltageapparatus, 2013, 49(10): 109-113.
LU Xu-chen, LI Shuang, HAN Hong-gang, et al. Criterion for Judging Power Frequency Ferroresonance in Neutral Point Ungrounded GIS System[J]. High voltageapparatus, 2013, 49(10): 109-113. DOI: 10.13296/j.1001-1609.hva.2013.10.020.
Criterion for Judging Power Frequency Ferroresonance in Neutral Point Ungrounded GIS System
Ferroresonance overvoltage is one of the most harmful factors to inner insulation of electrical equipment. For neutral-ungrounded GIS system
the failures caused by ferroresonance overvoltage account for a large proportion. In this paer
a criterion of power frequency ferroresonance in neutral-ungrounded GIS system is deduced by means of analytical method to estimate whether the ferroresonance will occour when a GIS system is switching from one working manner to another. This criterion describes the relationship between equavilent resistance of circuit and critical resistance. It can also be used to determine the zero-sequence resistance of the secondary coil of potential transformer for eliminating the ferroresonance overvoltage. The availability of this criterion is verified via a practical application to a gas insulated substation in two working conditions. In addition
the effect of connecting an arc suppression coil to neutral point of GIS system on ferroresonance overvoltage is analyzed.