Research On Active Response Model Of Virtual Power Plant For System Flexibility Requirements

With the popularity of environmental awareness,fossil energy with high pollution is being phased out and transformed,while renewable energy is widely used worldwide and has become the main primary energy in the new power system.However,the predictability of new energy power generation is limited,and the difference between traditional thermal power generation units and new energy power generation is intermittent and uncertain,which makes the dispatching difficult.In addition,some regions are affected by geographical and climatic conditions or limited by the construction status of power system,requiring traditional generating units to undertake heating and other necessary tasks,and some traditional generating units are required to generate electricity according to the minimum output limit.As a result,power generation side resources are wasted,how to give full play to the functions of each unit,mobilize the main body to participate in the transformation of the new power system,and realize the rational and effective consumption of renewable energy becomes an urgent problem to be studied.First of all,in terms of scenario configuration before building the active response model,considering that although the general seasonal typical daily curve can represent the output expectation of renewable energy units and loads,it is poor in describing the output fluctuations of each unit,which affects the determination of the system’s reserve capacity.In addition,considering that the member selection result of virtual power plant should not be changed at will if it is determined within a period of time,a renewable energy-load scenario reduction method considering load timing is proposed.Orderly clustering is used to preprocess the data of load,wind power and photovoltaic units to reduce the calculation amount for the subsequent active response model calculation.Secondly,the members of virtual power plants are classified.At present,the capacity allocation of virtual power plants is mostly carried out from the perspective of maximizing the overall income of virtual power plants.However,although this maximizes the income,it cannot meet the requirements of the absorption task of renewable energy,and the income is often damaged due to the large gap between the actual output and the plan.Therefore,in order to quantify the relationship between risks and benefits,this paper divided the members of the virtual power plant into two categories: uncontrollable members represented by renewable energy units and loads,and controllable members represented by thermal power and energy storage.Uncontrollable members bring more benefits to the virtual power plant,and controllable members provide guarantee for the virtual power plant to complete the scheduling task.In this way,virtual power plant can reach an agreement with more uncontrollable members and gain more profits.However,the power generation cost of controllable members is often high,and too large capacity configuration will affect the income of virtual power plant.Combined with the flexibility of power system,Markowitz asset portfolio principle is introduced to analyze the contribution of controllable members to the system scheduling,and the selection of virtual power plant members is discussed according to it.Finally,the active response model of virtual power plant is proposed.In the discussion on the member selection of virtual power plant,it can be found that there are a large number of new energy units wind and light abandonment and low load operation of thermal power units in some periods,which is caused by the combination mode between units affected by climate conditions or the selection mechanism between members.If the typical sunrise force can be replanned according to the ordered clustering,and the reserve capacity contract can be signed with the uncontrollable members according to the uncertainty of the uncontrollable members,the power generation cost can be saved by renting only part of the power generation capacity.The mutual cooperation between the two members has the following advantages: First,the virtual power plant uses the quick response ability of thermal power units to reserve the renewable energy units,so that the virtual power plant can reach an agreement with more renewable energy units and complete the absorption task;Second,the lower power generation cost of renewable energy units for the virtual power plant as a whole to strive for greater profit space;Third,the advantages of virtual power plant control center can be brought into play.Through advanced measurement,communication and control technology,power plants of different types and different spatial locations can be aggregated into a whole without changing the topology structure of the existing power system network,so as to realize effective utilization of existing resources.The solver Gurobi was called by MATLAB platform to solve the model and the simulation analysis was carried out.The simulation results show that the model can effectively reduce the combination of sub-sequences between units,develop a reasonable unit capacity configuration,and increase the daily net income of the virtual power plant,and increase the proportion of new energy units to generate electricity.Finally,in order to explore the effect of the model in different development stages of the virtual power plant,the influence of time-of-use price on the member selection of the virtual power plant is considered,and the correctness of the proposed method is verified.