Bi-level Optimization Method For Energy Micro-grid Based On The Heat-to-electric Ratio Adjustable Mode Of Energy Hub

Along with the increasing seriousness of energy and environmental protection problems,replacing the traditional energy supply structure with energy internet has become a consensus.As an important component of energy internet,energy micro-grid plays a vital role in the development of the energy internet.The existing studies on optimal operation of energy micro-grid have the following problems: 1)The regulating ability of heat-to-electric ratio of combined heat and power is unconsidered.2)In the study of energy micro-grid optimization operation method,there are few specific models for multi-level cooperative operation of energy micro-grid.3)In such scenarios,there are few studies on the specific model of integrated demand side response in energy micro-grid.Aiming to solve the problems,this paper proposed a bi-level optimal operation model of energy micro-grid synthesizing the heat-to-electric ratio adjustable mode of energy hub and integrated demand side response.Specific work is as follows:(1)The model of energy hub based on regulating heat-to-electric ratio mode is proposed.The energy hub is consists of power transformer,heat-to-electric ratio adjustable CHP and gas boiler.By analyzing the heat-to-electric ratio regulation principle of CHP,the relationship between CHP heat-to-electric ratio regulation and energy conversion of energy hub was established,and then the Heat-to-Electric Ratio adjustable mode of energy hub is built.(2)A bi-level optimization model of energy micro-grid is constructed.Under the scenario of generated flexible loads and shiftable loads to participate in the integrated demand response,considering the economic factors and environmental factors as the upper level operating objective,and power units efficiency as the lower level operating objective,a bi-level optimal model of energy micro-grid is constructed to establish the relationship between the internal power units operation and the external energy distribution of the energy micro-grid.By using the KKT condition,the lower level is transformed into the upper level as equilibrium constraints,and thus the bi-level model is transformed into a single level nonlinear optimization problem and then solved by deterministic algorithm.(3)Under the integrated demand response scenario,the generated flexible load,which participates in integrated demand response by converting the energy supply type,is established(the hot water heating storage device).At the meantime,the response model of electric vehicle changing station to participate in the integrated demand response is constructed.What's more,for the various types of response resources based on the heat-to-electric ratio adjustable mode of energy hub,the economic performance of different response modes under different load levels is compared and analyzed,and the most suitable work scenarios are obtained.(4)Taking the commercial load as an example,the working characteristics of the energy hub based on heat-to-electric ratio adjustable mode is deeply analyzed.By carrying out sensitivity experiments from the aspects of energy price,load distribution ratio and CHP installed capacity,the underlying causes of these results are explored.