| The "anti-peak regulation" character wind power output and the fixing power based on heat character of CHP units,as well as the random fluctuation characteristics of wind power,can easily cause insufficient system regulation and wind abandonment or pose challenges to the safe and stable operation of the power system.Application of new virtual power plant technology,utilization of demand response resources and consideration of electric and thermal energy flow characteristics can effectively improve the system’s regulation capability,but existing virtual power plant models less consider power loss allocation and demand response modeling and modeling of heating and supply links are not comprehensive or incomplete.They can easily lead to.the inconsistency of the established operating plan with the actual operating conditions.This article takes the virtual power plant composed of wind power,CHP units and flexible electric heating load as the research object.The problem of network loss allocation in virtual power plants is less considered,so the current main network loss allocation methods and characteristics are analyzed,and the improved average network loss coefficient method is selected to calculate the network loss of virtual power plant.The modeling of supply and use heat link is not comprehensive,so the thermal energy transmission delay,transmission loss,transmission energy consumption of the heat supply link and the thermal load elastic regulation characteristics of the heat use link are comprehensively and finely modeled,and the thermal load elastic regulation characteristics are taken as the incentive thermal demand response resources.In view of the shortcomings of the existing price-type power demand response(linear electricity price elastic matrix),the adaptive optimal segmentation method is applied to describe the nonlinear price type demand response.Considering the random fluctuation of price type demand response,the demand response characteristic matrix function is proposed,and the price type electricity demand response and incentive type heat demand response are taken as the comprehensive demand response.In order to make full use of the value of different types of demand response resources,in the day-ahead dispatching,electric demand response and heating characteristics are considered,and a day-ahead dispatching model considering heating characteristics and electric demand response is established.Through simulation analysis,the impact of the heating characteristics and more accurate price-based electric demand response on virtual power plants are revealed.On this basis,the conditional value-at-risk and scenario generation methods are used to characterize the random fluctuations of wind power output and electric demand response,and the regulation ability of heat demand response is flexibly used.A risk avoidance optimization model for virtual power plant considering the characteristics of supply heat and use heat and comprehensive demand response is established.Different risk preferences,different price-type power demand response relationships and different thermal load regulation capacity schemes are selected for simulation comparison.The results show that the precise price-type power demand response and flexible incentive-type thermal load demand response are regarded as comprehensive demand response,which can,to a certain extent,avoid risks and increase the expected total return.The simulation analysis results of different risk preferences reflect the law of"low return-low risk",and operators can set the risk coefficient according to their own risk preference and risk law.In the combined heat and power system,considering grid loss apportionment,supply and use heat characteristics and random fluctuations of power demand response is more in line with the actual situation.Accurate power demand response modeling and flexible use of the characteristics of different types of demand response can effectively increase revenue and avoid risks.The work done in this article can provide reference for the planning and operation of the combined heat and power system. |
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