Study For Parameter Setting Of PSS2B Type Of Power System Stabilizer

With the rapid development of power grid of China,and the scale of power system is expanding,the factors which influence low frequency oscillation and sub-synchronous oscillation are more and more complex in the system.Power system stabilizer(PSS)is the most economical and effective means to suppress oscillation,in which the PSS2 B type of power system stabilizer is widely used for its unique performance advantages.PSS2B is a dual-input power system stabilizer,and the input signals take the generator speed deviation and electromagnetic power deviation,in order to avoid the anti-tune phenomenon.As the speed deviation signal will introduce the sub-synchronous shaft torsional vibration signal,so in the PSS2 B type of power system stabilizer set the rotor shaft torsional vibration filter(RTF)link.In the analysis of the parameter stabilization of the PSS2 B type of power system stabilizer,the influence of the sub-synchronous component on the low frequency oscillation signal and the interaction between the sub-synchronous signal and the low frequency signal are not fully taken into account.In this paper,through the analysis of the subsynchronous characteristics and low-frequency characteristics of PSS2 B,the improvement of the parameter setting of PSS2 B type of power system stabilizer is put forward.In order to analyze the problem of sub-synchronous oscillation and low-frequency oscillation,a sixth-order generator model and a six-mass spring shaft model are established based on the small interference linearization model.The analysis of the influence of the sub-synchronous signal and the low frequency signal mainly focuses on the analysis of the RTF link and the gains of PSS2 B,discussing by the method of frequency response analysis.RTF links mainly affect the lower frequency band in the sub-synchronous band,and the influence is small on the higher frequency band in the sub-synchronous band.So with the increase of the capacity of alone generator,the oscillation band will reduce and the impact of RTF will be increased.By adjusting the RTF link time constants,the sub-synchronous signals can be suppressed or eliminated.And when the low frequency signals are introduced,the phase and amplitude of the low frequency signals will also be affected,thus the setting of the time constant of PSS2 B will be affected.The gain coefficients of PSS2 B,including power matching coefficient,speed deviation gain coefficient and PSS gain coefficient,have different effects on low frequency oscillation signal and sub-synchronous torsional vibration signal,and the degree and rule of the influence are different.Therefore,when determining the gain using the method of root locus,it is necessary to analyze the influence of the gain coefficients on the sub-synchronous mode and the low frequency mode.Finally,taking a generator in the actual system as an example and combining with the above analysis,the parameter setting of PSS2 B is improved by the method of the phase compensation and the root locus.