Research On Optimal Hybrid Ac/dc Energy Supply Of Multiple Energy System

In the face of the contradiction between the increasing energy demand and the limited reserves of non-renewable energy at present social development,the development of integrated energy system is conducive to promoting the diversification of energy consumption,promoting the use of renewable energy,improving the consumption of renewable energy,improving the energy utilization and alleviating the contradiction between environmental problems and economic development.Multiple energy system is the physical carrier of integrated energy system.Based on the consideration of environmental factors,this paper studies the optimal AC/DC hybrid energy supply of multiple energy system combining with heat and power in grid-connected mode and in island mode.Firstly,this paper analyzes the mathematical model of multiple energy system.Concerning the eco-industrial parks and similar scale scenarios,the system is divided into four secondary systems: DC power supply system,AC power supply system,heating system and energy storage system.And mathematical models of distributed power supply,coal-fired boilers and energy storage devices are established respectively.Then,considering the influence of environmental factors on the output power of renewable energy and the limitation of exhaust emission of equipment in the system,an optimal simulation model of grid-connected hybrid AC/DC energy supplying multiple energy system is established.Taking the operation cost and environmental cost as the objective function,this paper realizes the hourly economic dispatch of each equipment in the multiple energy system in a day.In the simulation,multiple energy system is compared with the traditional independent AC/DC grid-connected model from total operating costs,emissions of polluted gases and coal consumption.The simulation results show that the multiple energy system with AC/DC hybrid supply has certain advantages in reducing system operation costs and coal use.Finally,concerning about the island mode of AC/DC hybrid system,the internal load of the system is classified into three important levels.In this mode,this paper takes the maximum power supply of load,minimum the number of switching operations and minimum the operating cost of the system as the optimization targets.And in order to unify the objective functions of different levels,we use the analytichierarchy process to determine the weight of each sub-objective.Besides,a hybrid integer nonlinear optimization model is proposed based on this.The proposed optimization method is applied to three fault examples of AC/DC hybrid system,and the optimization calculation is carried out by using optimization simulation software GAMS.Compared the results with the traditional independent AC/DC system,it is proved that the AC/DC hybrid system is more conducive to improving the utilization of energy,and could to some extent guarantee more load supply when the fault occurs.