Research On Integrated Energy System Planning And Dispatching Strategy Considering Multi-objective Collaborative Optimization

The integrated energy system gathers all kinds of energy such as cold,heat,electricity and gas.Compared with the conventional energy system,the integrated energy system has more complex processes and expensive costs in the two stages of preliminary planning and later dispatching.Therefore,how to simplify the construction,operation and maintenance process of the integrated energy system and reduce the total project cost through the multi-objective collaborative optimization method is the starting point of this paper.In order to realize the multi-energy complementary advantages and energy cascade utilization of the park integrated energy system containing cold,hot,electricity and gas,based on an example of a park integrated energy system project.Firstly,this paper conducts a detailed case analysis from the aspects of overall planning process,resource assessment,load forecasting,regional power supply station and pipe network planning principles.According to the above process and the actual needs of the project,the qualitative analysis is carried out to obtain the optimal site selection and capacity determination scheme of the energy supply stations and the energy pipeline networks in the close and distant shots.Finally,the integrated energy planning scheme is compared with the traditional energy distribution scheme in terms of economy and energy saving,and the feasibility of this scheme is verified.Regional integrated energy site layout optimization involves multi-energy coupling,multi-data processing and multi-objective decision making,etc.It is essentially a kind of non-convex multi-objective nonlinear programming problem,which is very difficult to solve by traditional methods.This paper proposes a decentralized optimization and comprehensive decision making planning strategy,and preprocesses the data information,so as to reduce the difficulty of solving the problem and improve the operational efficiency.Three objective functions,namely,the number of energy stations to be built,the coverage rate and the transmission load capacity of pipeline network,are constructed,normalized by linear weighting method,and solved by the improved p-median model to obtain the optimal value of comprehensive benefits.The artificial immune algorithm was improved from the three aspects of initial population screening mechanism,population updating and bidirectional cross-variation,and its performance was preliminarily verified by test function.Finally,improved artificial immune algorithm is used to solve and optimize the regional integrated energy site layout model.Finally,after a complete planning and layout of the integrated energy system,it is necessary to optimize the dispatching of internal unit output in order to reduce the cost of the system in the later stage.Aiming at the double uncertainty of new energy output and cold,hot and electric load prediction in the integrated energy micro-grid,this paper constructs the multi-energy hub and the integrated energy interval dispatching model with the help of interval mathematics.Considering the dual objective function of economy and environmental protection,the linear weighting method was used to normalize it to meet the different preference needs of decision makers.Based on the enhanced interval linear programming method,the objective function with interval variables is decomposed into two-stage sub-problems,and the interval is explicitly expressed,which is then transformed into the corresponding conventional deterministic problem.The transformed model still has the energy coupling problem.According to the principle of power flow calculation,this paper proposes a like power flow hierarchical iteration method,which transforms the problem into a two-layer optimization problem in which the minimum unbalance of the hub is solved in the outer layer and the integrated cost function is optimized in the inner layer.Simulation results show that the model and method proposed in this paper can effectively reduce the dispatching cost of integrated energy micro-grid,and can quickly and accurately obtain the unit output interval.Finally,the sensitivity analysis of different output,load fluctuation interval and weight coefficient is carried out in order to study the influence on different parameters.