THE DYNAMIC STABILITY IMPROVEMENT OF MULTIMACHINE POWER SYSTEMS BY MULTILEVEL OPTIMAL CONTROL

The use of supplementary stabilizing signal to improve the dynamic stability of multimachine power system is well known. This paper propose multilevel optimal control scheme (strategies) for interconnected power systems. A large -scale power system may be viewed as an interconnection of several lower-order subsystems, with possible change of interconnection pattern during operation. A multilevel optimal control is proposed for optimization of large -scale systems composed of a number of subsystems. Local controller are used to optimize each subsystem, ignoring the interconnection. Then, a global controller may be applied to minimize the effect of interconnections and improve the performance of the overall system. An optimal state feedback control and robust pole placement are also presented for a comparison. The results for a multimachine power system consisting of two machines show the effectiveness of the control strategies.departmental bulletin pape