Load Frequency Control: Higher Order Sliding Mode Observer Based Integral Higher Order Sliding Mode Controller with Stochastic Perturbation

The article focuses on the design of higher order sliding mode observer-based sliding mode controller for load frequency problems in single area power system. In this article, Exogenous and Brownian white noise as stochastic perturbation along with uncertain load disturbance is considered. In practice, uneven and abnormal disturbance which are often unpredictable in single area power system is taken into consideration. The said design ensures finite time convergence of frequency and area control error under above said disturbances with chattering free control signal. Higher order sliding mode observer estimates all the system states which are difficult to measure or are unavailable. The frequency deviation is found to be within acceptable range under random load disturbance and matched uncertainty confirming robustness of the said design. Further, performance is also observed with power system nonlinearities like generation rate constraints and dead band. The stability of sliding surface is proved theoretically using classical Lyapunov theorem and validated using MATLAB R2013b.