Research On Peak-load And Frequency Regulation In Large-scale Intermittent Energy Grids

As energy issues and environment problems become increasingly prominent,development and utilization of new energies, such as wind power and solar energy, hasarisen widely public attention. However, these intermittent energies have intense fluctuationand stochastic behavior. It causes inaccuracy in prediction of output of intermittent powerplant and adverse influence on intermittent energy generation. To power system, access ofintermittent energy makes it more difficult for peak-load regulation and frequencyregulation. The article carries out the research about peak-load regulation and frequencyregulation in large-scale intermittent energy grids.(1) Set up peak-load regulating optimization model. In this article, scenario generationwas used to establish stochastic wind speed scenarios. Based on this, the peak-loadregulating optimization model was built using chance-constrained programming, whichused the minimum power generation cost as the objective function, and considered theimpact of deep peak-load regulation of thermal units, interruptible load and hydroelectricunits on peak-load regulating unit commitment and power generation cost. The simulationresults present the three regulating mode above can reduce the influence of the stochasticwind power, and can also reduce the times of thermal units start-stop and the total cost to acertain extent.(2) Set up peak-load regulating adequacy evaluation model. In this article, Nataftransformation was used to establish wind speed samples of correlative wind farms to getcorrelative wind power. Based on this, the peak-load regulation not enough probabilityindex was calculated to evaluate the peak-load regulating adequacy using Monte-Carlomethod considering wind stochastic behavior, forced outage rates of wind turbines andconventional generators and wind power prediction error. The simulation results present thequantitative analysis of the complementary effect in different correlation coefficients, andthe impact of correlative wind farms and wind power prediction error on peak-loadregulating adequacy. And it improved the original peak-load regulating adequacy evaluation,which has the relatively conservative results.(3) Set up frequency regulation simulation model. In this article, the original frequency regulation simulation model was established by using MATLAB/Simulink. Based on this,primary frequency bias parameters were regulated, and PI controller using artificialintelligence algorithm and dynamical generation distribution factors of AGC generatorswere used, and the prediction error of intermittent energy was calculated in extra ACE. Thesimulation results present the improved frequency regulation model has better performancethan traditional model in a wide range of stochastic power fluctuation. And it is conduciveto absorb intermittent energy. And it can also provide evidences for intermittent energy andreserve capacity selection on dynamic frequency response.