FOPID Parameters Tuning Of Hydrogovernor Based On ESDO Algorithm

The development of hydropower energy is not only conducive to solving the problem of energy shortage in China,but also can greatly reduce the environmental pollution caused by fossil energy such as oil and coal,which conforms to the concept of green environmental protection.Because of the randomness in power system,it is necessary to improve the stability and reliability of power system when using hydraulic resources to generate electricity.The water turbine governor system plays an important role in the safety of power use and power quality,and the governor is an important part of it.The parameters selection of the governor is closely related to the safe and stable operation of the water turbine.In order to improve the quality of governor parameters and enhance the dynamic characteristics of the system,fractional-order PID(FOPID)control strategy and improved supply-demand-based intelligent optimization algorithm(ESDO)are used to tune the parameters of hydrogovernor.According to the basic principle of the water turbine governor system,each component of the system is analyzed theoretically and its respective mathematical model and transfer functions are established.and an integer-order PID controller has been constructed.In view of the poor effect of integer-order PID controller in restraining the non-linearity of the water turbine governor system,this thesis constructs the mathematical model of FOPID controller based on fractional-order calculus principle.In order to solve the problems of lack of diversity of solutions,low convergence accuracy and poor search efficiency of supply-demand-based optimization algorithm(SDO),this thesis improves SDO from the following three aspects: firstly,in order to prevent premature convergence and increase diversity of solutions,enhanced fitness-distance balance(EFDB)and Levy flight are introduced;Second,variation mechanism is introduced into the algorithm to improve search efficiency;Third,a new adaptive local search(ALS)strategy is added to improve the convergence accuracy of the algorithm.Therefore,an improved supply-demand-based intelligent optimization algorithm(ESDO)is proposed and used to tune parameters of PID controller and FOPID controller.The simulation experiments for frequency disturbance and load disturbance are carried out in MATLAB/Simulink environment respectively.The simulation results show that under the same conditions,the system overshoot of FOPID controller is smaller and the adjustment time is shorter than that of PID controller,which indicates that FOPID controller can effectively improve the stability of the system.When tuning parameters of the same FOPID controller by ESDO and supply-demand-based optimization algorithm(SDO),whale optimization(WOA),grey wolf optimization(GWO),and gravity search algorithm(GSA),it is found that the average fitness of ESDO is smaller,which indicates that the convergence accuracy and robustness of ESDO are stronger than other algorithms.In addition,ESDO can also reduce the overshoot of the system and shorten the adjustment time to a certain extent,and is superior to other algorithms,effectively improving the dynamic quality of the water turbine governor system.