Synchrophasor based intelligent autoreclosing scheme for series compensated transmission lines

In a transmission network, autoreclosing provides quick restoration of the line for transient faults and improves system stability. Autoreclosing during permanent fault may damage power system elements. This paper presents a method to block autoreclosing for permanent line-to-ground faults on multi-circuit series compensated transmission line using synchronized measurements from both ends. The method utilizes measurements from the healthy phases of the line to calculate an index which determines the persistence of a fault to control the reclosing. In case of a transient line-to-ground fault, the index is high during the fault and zero after extinction of the secondary arc. The index can be used to modify the dead time of the recloser and thereby reclosing during fault (both transient and permanent) is avoided. The proposed method is tested using the sample data obtained from EMTDC/PSCAD simulation of an actual series compensated line in Indian power grid. Results demonstrate the accuracy of the proposed method.