An approach for controlled energization/re-energization of shunt compensated transmission lines

摘要

In Asia-pacific region, at Ultra High Voltage/Extra High Voltage (UHV/EHV) levels, the combination of Controlled Switching Device (CSD) and Circuit Breaker having Pre-Insertion Resistor (PIR-CB) is readily available in schemes such as tie circuit breaker used in One-and-a-Half-Breaker (OHB) scheme. Therefore, in this paper, a new strategy is presented using CSD with PIR-CB to mitigate the level of switching surge during energization/re-energization of Shunt-Compensated Transmission Line (SCTL). The proposed methodology requires lineside voltage measurement during the dead time of CB. The performance of the proposed methodology has been evaluated by modelling an existing Indian 400 kV, 400-km long SCTL using PSCAD/EMTDC software package. Moreover, its performance remains unaffected during wide variation in the length of the line, level of compensation, type of fault, duration of fault, fault inception angle, fault location, short circuit capacity of source, and inclusion/removal of Switching Arrestor (SA). At the end, comparative evaluation of the proposed methodology with the reported methodology clearly shows its effectiveness in terms of reduction in the level of the switching surge considering Mechanical Operating Time (MOT) scatter of the CB. The philosophy presented here can also be extended for discrimination between permanent fault & temporary fault and identification of fault type.