| With the depletion of global energy and the deterioration of the environment,people gradually develop and use clean and renewable energy.Among many new energy sources,wind energy and solar energy have been widely used in various fields because of their abundant resources,green and pollution-free advantages.However,wind energy and solar energy do not have the stability of traditional fossil fuels.In the grid-connected operation process,they will lead to the reduction of the total inertia of the power grid and the weakening of the frequency modulation ability.Meanwhile,the frequency fluctuation caused by the change of the power grid load cannot be handled by the load frequency control method like traditional fossil fuels,thus affecting the stability of the power grid and limiting the development of new energy[1].How to solve the problems of total inertia reduction and weak frequency modulation caused by the high proportion of new energy integrated into the power grid,improve power quality and enhance the anti-interference ability of the interconnected power system has profound theoretical significance and practical value for promoting the integration of new energy into the power system and transforming the traditional single power grid into a multi-regional hybrid power system.This paper aims at the frequency fluctuation caused by the integration of wind power and photovoltaic new energy into the traditional thermal power interconnected power system.Based on the load frequency control model of the two regional interconnected power system of wind power,photovoltaic and traditional thermal power,this paper adopts PI controller with filter coefficient（PI-FC）to study the load frequency control.Considering that the access of new energy leads to the decrease of the frequency modulation capacity of the power system,A PI controller（PI-FOI）with first order inertia and filter coefficient is proposed.The optimized controller parameter values are obtained,and the scaling factor and crossover probability which affect the optimization accuracy of differential evolution（DE）algorithm are improved respectively.An improved differential evolution algorithm（IDE-II）is proposed,which is used to adjust the controller parameters.A load frequency control strategy of two-region interconnected power system based on PI-FOI controller is proposed.The research content of this paper is as follows:（1）Aiming at the problem that a high proportion of new energy is incorporated into the interconnected power system,which leads to the reduction of the total inertia of the system and the weakening of the frequency modulation ability,the load frequency control model of the two-region interconnected power system of wind power,photovoltaic power and traditional thermal power is given.（2）Aiming at the problem of controller parameter setting of two-region interconnected power system containing new energy,considering the defects of the classical DE algorithm in the process of optimization,such as easy to fall into local optimal and fast convergence rate,improved differential evolution（IDE-I）algorithms are proposed by analyzing the influence of the scaling factor and crossover probability of DE algorithm on the optimization accuracy.Also,performance tests of Simulated Annealing algorithms,DE algorithms and IDE algorithms have been carried out by reference test functions,and the results have verified the effectiveness and superiority of IDE algorithms.Aiming at the difficulty of frequency regulation of interconnected power system in wind,light and fire,IDE algorithm is used to adjust the parameters of PI-FC controller,and a load frequency control strategy of interconnected power system based on adaptive operator differential evolution algorithm is proposed.（3）Aiming at the problem of load frequency in the interconnected power system of wind,light and fire,based on the load frequency control model of the interconnected power system of wind power,photovoltaic power and traditional thermal power,this paper introduces a first order of inertia to regulate the inertia of the power system containing wind and light new energy in the PI controller with filter coefficient,and designs a PI-FOI controller.Furthermore,the scale factor and crossover probability of differential evolution algorithm are improved,and the improved IDE-II algorithm is proposed.The improved IDE-II algorithm is used to set parameters of the controller of the two-region interconnected power system,and the load frequency control strategy of the two-region interconnected power system based on the PI-FOI controller is proposed.Realize frequency stability of interconnected power system.Finally,the effectiveness and superiority of the proposed control strategy are verified by simulation from the aspects of controller design and algorithm. |
