Technical Research On Dynamic Characteristics Optimization Of Under Excitation Limiter Of Generator Excitation Regulator

Generator excitation control system is one of important measures of improving stability of power system.Because of expanding scale and complexity level of structure of power system,operation of EHV and UHV transmission lines,generator excitation control system is required of keeping good effect on system stability under that condit ions yet.Thus,technical research on characteristic optimization of generator excitation regulator has great significance.Relies on Research,Study of Coordinate Performance Optimization of Auxiliary Limiters of Generator Excitation Control System project,dynamic characteristic of under excitation limiter has been studied.At first,based on an accident of active power oscillation in Fangchenggang power plant in Guangxi province,this paper analyzed accident reasons caused by action of under excitation limiter under different working conditions.The effects of parameters of under excitation limiter and generator on stability of the system have been proposed.In addition,using damping torque analysis metho d,the characteristic of different influence factors ha ve been analyzed and verified in time domain.Secondly,through the test of the network performance of big field regulator factories,the realization mechanism of each link of t he different design structures have been analyzed,and the optimization method of the dynamic characteristic of the under excitation limiter has been put forward.Furthermore,the paper built up extended Philips models of superposit ion and comparative unde r excitation limiter,and inferred formulas of system damping torque by under excitation limiter.Applying root locus varied with parameters of under excitation limiter,it found that optimization method can enlarge parameters range in different kinds of under excitation limiter.Finally,this paper analyze d the existing methods for the field parameter setting of the under excitation limiter,and comprehensively considers the implementation of the method,and the adverse effects on the operation of the pow er grid.The field parameter setting method based o n N yquist stability criterion has been proposed and verified by real-time digital simulator(Real Time Digital Simulator,RTDS).The results show that this method can test for under excitation limiter para meters out of system,avoid the conditions of leading phase operation and weak system,reduce the adverse impact on the stable operation of power grid.