Research On Collaborative Optimization Operation Of Multi-energy Regional Distributed Energy System With Combined Cooling,Heating,and Power Generation

With the rapid development of global economy,the human society faces global warming,oil crisis,environmental pollution and many other challenges that have driven the need to produce,transform and utilize energy in a more efficient,clean and diversified way.DES/CCHP(Distributed Energy System and Combined Cooling,Heating,and Power Generation,DES/CCHP)is a multi-energy supply system which is integrated in the process of cooling,heating and power generation.The energy supply of the traditional DES/CCHP system is usually used in the form of independent dispersion to a single building or a park.However,there is no research on the way that multiple interconnected DES/CCHP systems can be supplied to multiple regions at the same time,and the cooperative operation mode of renewable energy and power grid is considered less.To this end,the DES/CCHP system to multi regional supply of energy as the background and considering renewable energy sources(wind,solar)access,this paper focuses on the multi region energy supply structure and operation mode which meet the needs of various energy sources.So as to promote the DES/CCHP system and renewable energy,power grid collaborative optimization operation,and ultimately achieving energy supply and demand in the direction of efficient,clean and safe.Firstly this paper introduces the structure of multi-energy complementary regional type DES/CCHP system,in energy hub the energy exchange is based on the structure of energy buses including power bus,heating bus and cooling bus.The structure contains four parts:1)energy sources(such as power generation,natural gas,solar energy,wind energy);2)energy delivery networks(such as power grid,heating/cooling pipeline);3)energy production and transformation devices(gas turbine,cold energy generator,steam turbine,heat exchange,regenerative electric boiler,electric chiller and adsorption chiller,solar and wind power generator);4)energy storage(such as PHEV or TES).The system makes full use of cold energy to generate electricity which come from LNG(Liquefied Natural Gas,LNG)gasification.This system integrates natural gas,renewable energy and electricity networks.On the basis of this structure,an optimal operation model of independent operation of regional DES/CCHP is proposed,the objective of the optimal operation model is formulated as minimizing the daily operation cost,including gas purchase cost,electricity purchase cost,and emissions cost.Case studies are undertaken on the 15-node multi-energy prosumer system.The effects of different pricing mechanisms(time sharing price and fixed price)and considering cold energy generation on the operation of the system are analyzed in detail.At the same time,the effects of renewable energy sources and non-renewable energy sources on the operation of the DES/CCHP system are analyzed and compared.The results show that the multi-energy complementary DES/CCHP under the consideration of the renewable and electricity price has better economic benefits and environmental benefits.Secondly,according to the different energy supply characteristics of different region,to enhance the reliability and economics of energy hubs in an energy region,the structure of multi-energy regional DES/CCHP interconnected system with energy hubs is proposed in this paper.These energy busesare interconnected as a ring heating/cooling network and a radial power grid to implement mutually complementary reserves of energy hubs.Moreover,the bi-directional energy flows between prosumer and the main grid are also analysed.Under the condition of meeting multiple constraints,through collaborative optimal operation with large power grid,distributed renewable energy system and each DES/CCHP unit gas system to realize the economic operation of the whole energy interconnected system.On the basis of this structure,the collaborative optimal operation model of multi-energy regional DES/CCHP interconnected system is proposed.Finally case studies are undertaken on the 15-node multi-energy prosumer system.The effects of normal and fault operation conditions on the operation of the system and the effect of natural gas price changes on the operating cost of the system are analyzed in detail.By comparing the simulation results with the independent operation of DES/CCHP,it is proved that the interconnected DES/CCHP has better economic and environmental benefits,regulating effect and operation reliability than the independent operation DES/CCHP.