Sliding Mode Control With Application To Interconnected Power System

In an interconnected power system, load demand random variation is one of its basic characteristics. Random variation of load leads to a mismatch between the power generation and the grid demand, that will cause a decline of power, especially for frequency deviation and tie line power deviation. Therefore, automatic generation control (AGC) of a interconnected power system has two goals:to minimize the dynamic frequency deviation and tie line power dynamic deviation and ensure their steady-state error to be zero. In terms of the two control objectives, it is of great theoretical and practical significance for the optimization control of AGCIn an actual interconnected power system, nonlinear problems are mainly caused by the restrictions of the governor valve position and the constraint of the generator variation rate (GRC), it is a great challenge for the controller design. They will influence the dynamic performance of the system, and lead to too long adjustment time or excessive overshoot. And the classical sliding mode control (SMC) algorithm shows good robustness, strong anti-interference ability; fuzzy algorithm can deal with a nonlinear problem. Therefore, this paper presents a fuzzy variable structure sliding mode algorithm for the load frequency control of a large-scale interconnected power system. T-S fuzzy rules are utilized to solve the model nonlinear problem of a four regional hydro-thermal power interconnected power system, the controller is designed as a discrete sliding mode controller with an observer which is used to improve the convergence precision and reduce jitter. Since that the sliding mode control more complex, and it was not the optimal choice, so the parameter selection method for proposed sliding mode controller is various, complicated, and not optimal, hence, a sliding mode control which particle swarm optimization is presented to improve the performance of the designed controller.As the large-scale grid connection of the new energy power represented by wind power, the stochastic volatility of new energy sources like wind power, changes the basic characteristic of the interconnected power system.The main feature is that the source side and load side are both random. Based on which, the sliding mode controller is designed to solve the frequency fluctuations induced by the imbalance of the generation and demand. Finally, the effectiveness of the algorithm is verified via the simulations in this paper.