Development of a leader-end reclosing algorithm considering turbine-generator shaft torque

High-speed auto-reclosing is used in power system protection schemes to ensure the stability and reliability of the transmission system; leader-follower auto-reclosing is one scheme type that is widely used. However, when a leader-follower reclosing scheme responds to a permanent fault that affects a transmission line in the proximity of a generation plant, the reclosing directly impacts the turbine-generator shaft; furthermore, the nature of this impact is dependent upon the selection of the leader reclosing terminal. We therefore analyzed the transient torque of the turbine-generator shaft according to the selection of the leader-follower reclosing end between both ends of the transmission line. We used this analysis to propose an adaptive leader-end reclosing algorithm that removes the stress potential of the transient torque to prevent it from damaging the turbine-generator shaft. We conducted a simulation in actual Korean power systems based on the ElectroMagnetic Transients Program (EMTP) and the Dynamic Link Library (DLL) function in EMTP-RV (Restructured Version) to realize the proposed algorithm.