Controlled switching technique for minimization of switching surge during energization of uncompensated and shunt compensated transmission lines for circuit breakers having pre-insertion resistors

Controlled Switching Device (CSD) is considered to be the replacement of Pre-Insertion Resistor (PIR). Moreover, tie Circuit Breaker (CB) used in One-and-a-Half-Breaker (OHB) scheme as well as in line connected with non-switchable reactor scheme are employed with PIR and CSD. In this paper, a new methodology has been proposed using CSD with PIR-CB for further mitigation of the switching surge during energization/re-energization of Un-compensated Transmission Line (UCTL) and Shunt reactor compensated Transmission Line (SCTL). Unlike the existing methodology (both for UCTL/SCTL) which requires line side voltage signatures, the proposed methodology does not necessitate the same for SCTL and requires only the polarity of line side voltages for UCTL. The performance of the proposed methodology has been evaluated by generating diversified cases on 400 kV UCTL and SCTL using PSCAD/EMTDC software package. The proposed switching strategy is able to mitigate the switching surge of the order of 33% for UCTL and 20% for SCTL. Comparative evaluation of the proposed methodology with usual PIR methodology clearly shows its effectiveness with reference to statistical variations of CB. The proposed methodology has been validated during effects of various parameters such as weather conditions, insulation resistance, change in closing phase sequence, and Surge Arrestor (SA).