| Integrated Energy Systems(IES),as an important part of the energy strategy,ensures maximum energy utilization and realizes energy interconnection and multi-energy mutual assistance.Mastering the distribution characteristics of the integrated energy system can lay the foundation for subsequent system planning and optimal scheduling research.This thesis takes the electric-thermal integrated energy system as the research object to explore the distribution characteristics of energy flow under different energy supply equipment;when considering the connection of wind and solar distributed energy to the system,it is affected by natural conditions,and the wind and solar output are uncertain,and at the same time,with the fluctuation of load,it poses a challenge to the research on the multi energy flow distribution characteristics of the system.The main work is to solve the energy flow of the electric-thermal integrated energy system by The Newton-Raphson method,and sample the Monte Carlo simulation method based on the Latin hypercube sampling(LHS)according to the uncertain model of the wind,solar and load,to solve the probabilistic energy flow of the system,which can better fit the actual operation situation and better grasp the energy flow distribution characteristics in the system.For the above two parts of the work,the research is carried out from the following contents:(1)Modeling of an electric-thermal integrated energy system,establishing the power network model,the thermal network model,and coupling unit model.The grid energy supply side includes wind power generation,photovoltaic power generation,grid and combined heat and power(CHP)units;In addition to the CHP unit,the energy supply equipment on the heat grid side is also connected to a solar collector to provide thermal energy.The model adopts the radiation type heat network model,and the CHP works in the mode of "setting electricity by heat".(2)The energy flow solution of the electric-thermal integrated energy system The NewtonRaphson method,which is a classical method for solving power flow in power systems,is proved to be accurate for electric-thermal integrated energy system.According to the power flow model of the power grid,the hydraulic and thermal models of the heat network,and the thermoelectric conversion model of the coupling element,the model is calculated by the thermoelectric sequence method,which effectively improves the calculation efficiency of multi energy flow and solves the problem that The Newton-Raphson method is sensitive to the initial value.By setting three scenarios to calculate the energy flow of electricity and heat,the distribution characteristics of the multi-energy flow of the electric-heat integrated energy system are further explored.(3)Probabilistic energy flow solution for the electric-thermal integrated energy system.Considering the uncertainty of the random variables input to the system,the uncertainty models of wind,solar and electricity and heat loads are established.The wind speed and illuminance adopt the classical Weibull distribution and Beta distribution probability model respectively.The probability distribution models of wind and solar output electric power and heat power are obtained through wind speed power model and illumination power model.Normal distribution probability model is adopted for electric heating load;According to the constructed input random variable probability model,a Monte Carlo simulation method based on Latin hypercube is used to sample the source-load uncertainty model in the system,and the sample matrix is solved by electro-thermal multi-energy flow,and the probability distribution of state variables in the electrothermal integrated energy system is obtained.Compared with the basic Monte Carlo simulation method,the Monte Carlo simulation method based on Latin hypercube can significantly improve the efficiency and accuracy of calculation,which has good engineering practical value. |
