Research On The Characteristic Analysis And Control Of Power System Low Frequency Oscillation

Power system low frequency oscillation is an important stability issue of thelarge-scale interconnected power system. With the development of power system, analysisof the whole gird stability makes new requirements on the characteristics analysis andcontrol of low-frequency oscillation. Damping characteristics analysis of the regionalpower grid and coordination control of power system stabilizer have become the industry’sresearch focuses. Firstly, the research status of low-frequency oscillation damping anddamping control are introduced. Then based on the damping torque analysis method, adetailed study of low frequency oscillation damping characteristic was proceeded on powersystem main factors, such as the generator rotor windings, rotor inertia, excitation systemcontrol, the structural parameters of the transmission network, and the operation modes.Based on Damping Torque Analysis of Single Machine Infinite Bus power system, amethod to study the comprehensive damping characteristic of regional power grid isdeveloped in terms of dynamic equivalence. A simple equivalent model named KS/KDmodel, is considered as the one reserving the damping characteristics of regional powergrid. The parameters of KS/KD model are identified by monitoring the dynamicinformation of tie-line. And then, through mode analysis of the equivalent system, theequivalent model’s performance in low frequency oscillation characteristics isrepresentative of the damping characteristics of regional power grid.Besides damping characteristic analysis, damping control was proposed on basis ofdamping torque analysis in terms of Power System Stabilizer to ensure the overall stability.From the stability of excitation system control, the interaction between AVR andconventional PSS is discussed by means of frequency domain analysis and time domainanalysis. In need of coordination design of PSS and optimal control in multi-machinesystem, robust damping controller is proposed. A robust PSS is designed based on mixedsensitivity robust control theory, and verified effective in multiple operation modes infour-machine two-area system.