Wavelet-Based Auto-Reclosing Technique for TCSC Compensated Lines Connecting Windfarm

Auto-reclosing improves system stability by fast restoration of the line in case of arcing faults. Conventional techniques using harmonics of voltage and current have disadvantages in series-compensation environments because of associated dynamics and control mechanisms. Again, the auto-reclosing process can be affected for systems having large scale windfarm which are very sensitive to grid disturbances. This research work proposes a technique for adaptive autoreclosing in case of phase-to-earth faults for TCSC compensated transmission line connected to windfarm. A technique is devised that utilizes the cumulative sum of wavelet energy (CSW) calculated using wavelet coefficients to derive an index (FTI) which distinguishes between permanent and transient faults. Another extinction index (AEI) is computed using CSW during the secondary arc to identify the arc extinction. This parameter is used to change the dead time set for the recloser and thus, reclosing during fault process is avoided. The performance evaluation of the proposed scheme on the real-time digital simulator (RTDS) platform with shunt compensation and neutral reactor, demonstrates its real-time applicability.