| The extensive energy utilization has been unable to satisfy the development requirements of our country at the present stage,and the development of energy will be more intensive and efficient.Two different forms of energy,electricity and heat are included in integrated electricity-heat system.By taking full advantage of the complementary potential of different forms of energy,energy can be transferred between different systems and efficiently utilized.In addition,the integrated electricity-heat energy system can be used as a stable and reliable energy supply system to adapt to the renewable energy contribution and realize the cooperative energy supply.Therefore,it is necessary to fully understand the interaction mechanism of power grid,heat network and thermoelectric coupling module in the integrated electricity-heat system,and establish its mathematical model.Based on the established model,an appropriate integrated electricity-heat energy system energy management method is proposed to optimize the output of each part of the system,so as to realize the safe and economic operation of the integrated electricity-heat energy system.Integrated electricity-heat energy system is taken as the study object,the main contents of this thesis are given as follows:Firstly,the thermodynamic network in the integrated electricity-heat energy system is modeled according to the principles of thermodynamics,fluid mechanics and the law of conservation of energy.In the modeling of the heat network,the local head loss phenomenon that increases the heat loss is modeled,and a new integrated electricity-heat energy system energy flow model including the local head loss model is established.The model can more accurately represent the operating state of the heat network,which will be a foundation for the research of system energy management strategy.Then the Newton-Raphson method is applied to solve the integrated electricity-heat energy system equations.The results show that the heat loss caused by the local head loss affects the flow direction in the heat network,increases the output of the heat source in the system,and changes the operation state of the power network accordingly.Secondly,the mathematical modeling of the electric heat pump was carried out and it was added into the integrated electricity-heat energy system to realize the decoupling operation of the thermoelectric output of CHP unit to improve the flexibility and economy of the operation of the integrated electricity-heat energy system and make full use of the energy saving and high efficiency of the electric heat pump.An optimal energy flow solving model was established with the goal of minimizing the operating cost of the whole system and considering the constraints of power grid,heat network and coupling modules.The planning model was solved based on the interior point algorithm.The results show that the proposed energy management method optimizes the output of electricity power and heat power in the system,reduces the operating cost of the system,and also reflects the energy saving and high efficiency of the heat pump equipment and the ability to realize thermoelectric decoupling.Finally,in order to make full use of renewable energy,mining coupling equipment joint use of renewable energy and electric energy potential,consider integrated electricity-heat energy system as connected with external power grid energy supply system,considering the volatility of new energy output and load under the condition of using the theory of interval optimization can solve the integrated electricity-heat energy system interval optimal flow problem.The interval optimal energy flow problem considering uncertainty can be solved by decomposing it into two deterministic optimal energy flow problems according to interval theory.The proposed method of integrated electricity-heat energy system energy management under uncertain conditions can provide a certain reference for the safe and economic operation of integrated electricity-heat energy system. |
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