A hybrid method for generator tripping

Generator tripping is one of the most effective approaches to enhance the transient stability of a power system. In this paper, an online prediction method of transient stability and an offline analysis method of generator tripping are studied respectively. First, a polynomial curve fitting technique is employed to improve the online prediction accuracy of system stability. Then, a shell program is developed to automatically generate and update look-up tables for generator tripping. Based on these, a hybrid method is proposed. It uses the look-up tables to determine generator tripping requirements and before sending out generator tripping signals, instability is confirmed by online prediction of system stability. Simulation results show that this hybrid method can avoid unnecessary generation shedding.