TEV characteristics of GIS enclosure under multiple breakdown conditions of disconnector

Abstract Aiming at the transient process generated by the operation of the disconnector, the fast transient overvoltage (VFTO) transmitted to the casing from the GIS system causes the induced casing voltage between the casing and the ground, posing safety hazards to the secondary equipment and operation personnel of the GIS system. This paper combines the internal VFTO and external TEV transient circuits of GIS, considers the mutual coupling of the three-phase GIS enclosures, establishes a 252 kV GIS system transient model, and studies the characteristics of the three-phase GIS enclosure TEV under multiple breakdown discharge conditions of the disconnector, providing a theoretical basis for the external measurement of the transient induced casing voltage. In the process of multiple breakdown conditions, the maximum TEV value of the operating phase is the highest, with the maximum TEV amplitude reaching 0.03 p.u. in Phase A. TEV amplitude of the operating phase is significantly higher than that of the other two phases.