Transient stability research considering flux decay dynamics

Based on the structure preserving power system model,the influence of flux decay dynamics of generators on transient stability is studied.Some of the nonlinear excitation control strategies proved to be effective in damping the post-fault system oscillation may reduce the CCTs(Critical Clearing Times).The trajectory comparison of different flux decay dynamics in the rotor angle-E′q plane during a fault is provided,showing that the shorten Eq′ causes the CCT reduction.With the help of energy function method, the stability boundary is demonstrated in figures.The variation of stability boundary with the increase of load power is analyzed.An optimal method of LgV controller design is applied,which maintains the damping effect and prolongs the CCTs to improve the transient stability and dynamic performance of power system.Simulative results show the correctness and effectiveness of proposed method.