Multi-level Collaborative Approach For Highly Reliable Urban Energy System Planning Empowered By Public Transport Hub Flexibilities

Public transport hub(PTH)is an important urban transport infrastructure and also the coupling node of urban energy-transport system.How to realize the coordinated development of PTHs and urban energy systems(UESs),reduce the negative impact of public transport vehicle demands,and harnessing operational flexibility to promote the quality and efficiency improvement of energy system has become an important issue.Therefore,this paper deeply analyzes the interaction mechanism between PTH and UES,comprehensively considers the multi-domain constraints related to energytransportation system operation and reliability of energy supply/quality of public transport services,and establishes an holistic assessment framework to quantify the potential of PTH flexibility to improve the economic and reliability performances of UESs on the basis of refined modeling of PTH demand response characteristics,and further proposes a multi-layer collaborative optimization approach for highly reliable UES planning empowered by PTH flexibilities.The main contributions of this paper are threefolds:(1)Considering three flexibility exploitation methods,i.e.,energy dispatch,departure dispatch and vehicle-to-grid(V2G)programs,the demand response characteristics of PTHs are carefully modeled.On this basis,a multi-modal optimal scheduling model of PTH-integrated UESs is proposed to depict the flexibility of PTHs under normal/emergency conditions.By embedding the above optimal dispatching model into a sequential Monte Carlo simulation-based evaluation procedure,a holistic evaluation framework is established to quantify the contribution of PTHs to the reliability and economy improvement of UESs.The verification of small-scale examples shows that exploitations of PTH demand response can significantly improve the operation economy and reliability of UES s,which provides a quantitative basis for the idea of using PTH flexibility to construct a highly reliable UESs.(2)Considering investment constraints,system operation constraints and energy supply reliability constraints comprehensively,a multi-level collaborative optimization planning model of UESs with high reliability empowered by PTH flexibility is constructed with the objective of minimizing total annual costs of investment,operation and maintenance of UESs.According to the characteristics of the above model that economy and reliability are coordinated and multiple scenarios are closely coupled,a customized solution scheme based on multi-layer Benders decomposition is proposed.This method decomposes the original problem into upper,middle and lower sub-models and solves them iteratively,thus effectively reducing the dimension and computational complexity of the problem and realizing accurate and efficient solution of the model.(3)Based on the energy-transportation coupling system composed of IEEE 33bus distribution network,32-node heating network and Beijing real 3-line public transportation network,along with the real traffic data of Beijing Sihui PTH,the numerical study is conducted.The simulation results show that fully exploiting the flexibility potential of PTH can significantly improve the energy supply reliability of UESs and save the investment/operating costs.In addition,the system service quality constraints and passenger travel characteristics also have a significant impact on the planning results.