| The traditional microgrid has a simple structure,and it is difficult to meet various types of high-quality energy requirements.Since the integrated energy system including combined heating,cooling,and power can simultaneously meet the user’s needs for different types of energy,it has been increasingly used.But,due to the serious coupling between different equipment and different energy in the integrated energy system,it is difficult to configure the capacity of the equipment in the integrated energy system.Based on this,this paper solves the problem of equipment capacity configuration of integrated energy systems by building a bi-level optimized configuration model,and applies the power-to-gas technology to the integrated energy system to improve the flexibility and economy of the system.Firstly,the common structure of off-grid integrated energy system is introduced in this article.The mathematical model of energy conversion equipment and energy storage equipment in the off-grid integrated energy system is established,and the operation modes of various equipment are analyzed.Based on the concept of an energy hub(EH),an energy flow model within an off-grid integrated energy system is built.The energy exchange process between different types of energy and between different equipment is analyzed.Secondly,the kernel density estimation method and k-means clustering method are used to select typical output scenarios of renewable energy.The kernel density estimation method is used to obtain the probability density distribution of wind and sunlight in different energy supply seasons.A cumulative probability distribution is obtained from the probability density distribution.The cumulative probability density is randomly sampled,and multiple sets of wind and light output scenes are obtained.The k-means clustering method is used to reduce the generated scenes to obtain typical wind and sunlight output scenes in each energy supply season.Thirdly,A bi-level optimized configuration model for equipment capacity allocation of off-grid integrated energy systems is established.The upper level model takes the lowest total cost of the system as the optimization goal,and optimizes the equipment capacity of the off-grid integrated energy system.The lower model optimizes the system operating status with the goal of the lowest system shedding load.After multiple iterations of the upper and lower level models,the optimal device capacity configuration combination was found.Finally,based on the load demand and equipment parameters in the specific example,an optimal configuration scheme for the off-grid integrated energy system is obtained.Under this optimized configuration plan,the system operation plan for the typical day of the transition season in the region is analyzed,thereby the effectiveness of the integrated energy system optimized configuration model is verified.The influence of the power-to-gas device on the optimal configuration of the off-grid integrated energy system is analyzed.The configuration result is compared with the configuration result of the traditional energy distribution system to verify the advantages of the off-grid integrated energy system in terms of economy and cleanliness. |
