Single pole automatic reclosing near 500 kV generation bus through negative sequence current studies

Single pole switching operation where only the faulted phase of a three phase power is opened will enable the two energized phases to continue carrying power during the period of interruption. This is crucial especially for 500 kV transmission lines to maintain the stability of the power grid. However, single pole switching operation also introduces a significant risk for nearby turbine generators during the dead time by injecting substantial negative sequence current. It will consequently cause two problems to the turbine generator which are overheating on rotor field winding and risk of damaging the blade due to blade torque amplification. This paper aims to assess the risk of single pole switching operation on turbine generators connected to 500 kV transmission lines in Peninsular Malaysia.