A Coordinated Dispatch Model For Regional And Provincial AGC Units In A Power System With Renewable Energies

As an important part of the modern power system energy management,Automatic Generation Control(AGC)is a necessary technical method to maintain the balance of active power,the quality of system frequency,and the tie-line exchange power within the reasonable range.The rapid development of renewable energies and the interconnection of regional grids with UHV tie-lines has brought many new challenges to AGC of power system.The existing research fails to recognize the leader-follower relationship between the regional and provincial dispatch centers,and also fails to address the different regulation duties and characteristics of region-and province-units.Therefore,the study is carried out for the problems involved in researching the new model for coordinated dispatch of AGC units in regional-provincial grid with scale renewable energy integration based on the regional-provincial grid operation principles,which is well-supported by the National Natural Science Foundation of China “Dynamic optimization of AGC dispatch strategies in a power system with renewable energies”(No.51307186).The main contributions are as follows:1)A new bi-level programming model for coordinated dispatch of AGC units in regional-provincial grid,which is in compliance with the regional-provincial grid operation principles and control performance standards(CPS)in China,is thus proposed.This model is featured by is region-province coordination mechanism,i.e.,the regional dispatch center is the leader and expected to assign the overall regulation power to each provincial grid,while each provincial grid is the follower and expected to optimize regulation power of each province-unit.The upper model aims to minimize the overall AGC cost by coordinating control behavior of all provinces and considering frequency and tie-power constraints.The lower model tries to minimize the local regulation cost by coordinating all the local AGC unites subject to constraints such as CPS index.The upper and lower models are coupled through AGC task allocation and local regulation cost feedback.Numerical experiments are conducted on a sample bi-level gird including 5 provinces under two load variation scenarios to demonstrate the effectiveness of the proposed model by comparing its performance with the single-level province decision model.2)A chance constrained programming model for coordinated dispatch of AGC units in regional-provincial grid is proposed,considering the uncertainty of renewable energy output.Based on the theory of stochastic programming,random variables of prediction error of renewable energy generation are integrated into the chance constrained programming model for coordinated dispatch of AGC units in regional-provincial grid,to further consider the randomness of the renewable energy generation.The proposed model is solved by an evolutionary programming algorithm combined with Latin hypercube sampling(LHS).Numerical experiments are conducted on a sample bi-level gird with wind power to demonstrate the effectiveness and superiority of the proposed model by comparing its performance with the deterministic model.