Research On Urban Integrated Energy System Planning Considering The Coordination Of Multiple Districts

Nowadays,the urbanization process of China has entered a period of promoting highquality development.The need for improving the quality and efficiency of the urban energy system is quite urgent.Building the urban integrated energy system,which is mainly characterized by multi-energy integration as well as multi-functional-district interconnection and coordination,can greatly alleviate the institutional contradiction among economic growth,energy consumption,and environmental protection in the urbanization process.This dissertation focuses on the scientific problem of how to realize the coordinated optimal configuration of multi-district energy resources considering the differences and complementarities of the spatial and temporal distribution of multi-energy sources and multi-energy loads.The research objective is to further improve the economy,comprehensive energy efficiency,and clean energy consumption level of the urban integrated energy system.The main contributions of this dissertation are as follows.(1)A planning method of the urban energy station considering the variable working conditions of energy devices and information devices is proposed.The structure of the urban energy station which is integrated with a data center is formulated.Based on the functional relationship between load rate and energy conversion efficiency,the energy device model with variable working conditions is established,which is represented by the combined heat and power unit.Based on the dynamic voltage frequency scaling,the information device model with variable working conditions is established,which is represented by servers.The planning model of the urban energy station considering the variable working conditions of energy devices and information devices is established.Based on the polynomial fitting method and the piecewise linearization method,the model is transformed into a mixed-integer linear programming problem.(2)A planning method of the urban energy network considering the reconfiguration of the electricity network is proposed.The multi-energy flow model of the urban energy network is formulated to describe the characteristics of the electricity,gas,heat,and cooling energy flow.Considering the flexibility of electricity network,the planning model of the urban energy network is established,which is subjected to the constraints of multi-energy flow and the reconfiguration of the electricity network.The model is transformed into a mixed-integer second-order cone programming problem based on the second-order cone relaxation of power flow equations,the piecewise linearization of gas pipeline flow equations,and the linear approximation of heat loss equations.(3)A planning method of the urban integrated energy system with multi-district coordination is proposed,in which the standardized modeling method is embedded.Based on the hierarchical directed graph of energy station,a scalable standardized modeling method for the energy station is proposed,which is appliable for different urban functional districts.Considering the interconnection and coordination of different districts via energy tie pipelines,the planning model of the urban integrated energy system with multi-district coordination is established,in which the cross-district-level balance of power and energy,as well as the standardized modeling,are involved.The energy station and the energy network of each district,as well as the energy tie pipelines between different districts,are co-optimized.(4)A planning method of the urban integrated energy system with multi-district coordination is proposed,in which the demand response program is considered.Based on the collaborative potential of load-side flexible resources,the model of the demand response program is composed of the spatiotemporal energy consumption regulation characteristic of date centers,load curtailment,load translation,load thermal inertia,as well as the orderly charging and discharging processes of electric vehicles.Considering the cost of the demand response program and the satisfaction of customers,the planning model of the urban integrated energy system with multi-district coordination is established,in which the constraints of the demand response program are involved,so as to realize the interaction of the source side and the load side.(5)A planning method of the urban integrated energy system with multi-district coordination is proposed,in which the exergy efficiency and the clean energy curtailment risk are both considered.Based on the energy quality coefficient,the linear relationships between the exergy value and the energy value are formulated,and the exergy efficiency analysis method considering the integration of clean energy is proposed.Focusing on the “tail risk” of the clean energy curtailment,the constraint of the clean energy curtailment risk is constructed based on the theory of the conditional value-at-risk.The planning model of the urban integrated energy system with multidistrict coordination is established,which is subjected to the constraints of exergy efficiency and clean energy curtailment risk,so as to take into account the economy,comprehensive energy efficiency,and clean energy consumption simultaneously.The proposed planning method in this dissertation is applied to an urban integrated energy system in north China.The results indicate that the proposed planning method can effectively improve the economy and the clean energy consumption level of the urban integrated energy system on the premise of ensuring the comprehensive energy efficiency.