Extended Partial States Observer Based Load Frequency Control Scheme Design For Multi-area Power System Considering Wind Energy Integration

Abstract With the increase of wind energy integration in power systems, frequency control meets new challenges due to the uncertainty and stochasticity of wind power. In this paper, in respect to the frequency instability problem caused by disturbances of wind power, we propose an extended partial observer based load frequency control (LFC) scheme. An extended partial states observer (EPSO) is first designed to estimate both the unmeasurable states of the LFC system and wind power disturbance. And then a composite feedback controller using estimation from EPSO as well as measurable states of the LFC system itself is designed, thus attenuating the wind energy disturbance in the output channel and achieving asymptotical stability of both frequency and tie-line interchange power of the control area. The proposed LFC scheme has better feasibility to practical application since it is in essence a linear combination of measurable states values and EPSO-observed states values. Besides, it has better control performance than PI controller and saves the lengthy computational work of parameters tuning for PI controller with the aid of pole placement technique.