| The power system under the requirement of low-carbon structural change gradually presents extensive interconnection,intelligent interaction,flexibility and safety control characteristics.The dependence between different grade energy is becoming more and more obvious,forming an integrated energy system with deep coupling from energy supply,transmission,distribution and utilization.The regional electricity-gas distribution network is the specific terminal embodiment of the integrated energy system in terms of geographic distribution and realization of functions,which improves energy utilization efficiency and promotes energy industry efficiency and carbon reduction,but also brings the problem of crossenergy flow propagation caused by multi-energy coupling under extreme natural disasters.How to improve the fault resistance and load recovery capability of energy systems under extreme natural disasters at the distribution network level has become a key issue to reduce load loss and maintain high resilience and stable operation of energy systems.Resilience emphasizes the ability of energy systems to adequately prevent,proactively resist,effectively adapt and quickly recover in the face of various types of n-k failure scenarios,including extreme natural disasters.It is an effective measure to enhance the security and reliability of modern energy systems.Compared with the traditional distribution network,the electric-gas regional distribution network contains energy equipment with very different characteristics,and its strong multi-energy flow coupling,diverse operation scenarios,and different interest agents bring new requirements and challenges to the resilience enhancement research.The existing resilience research has low compatibility with multi-energy interaction support scenarios,and has not yet formed a regular understanding of the highly resilient operation of multi-energy systems.Both theoretical studies on the development path of China’s energy modernization and engineering practices of energy interconnection indicate that research on the resilience assessment and enhancement methods of electricity-gas regional distribution networks should be carried out from multiple dimensions.The theoretical system of electric-gas regional distribution network resilience assessment and enhancement,which is supported by multi-energy resilience,should be established to help the safe and low-carbon transformation of China’s energy system.To address the above key issues and technical challenges,this paper focuses on the key technical issue of how to build a highly resilient electricity-gas regional distribution network,and carries out research in three dimensions: resilience analysis and assessment methods,resilience-oriented expansion planning and multi-agent resilient operation,enriching the methods to support the highly resilient and stable operation of the electricity-gas regional distribution network,and providing theoretical and technical support for operators to make decisions.The main research contents are as follows:(1)In terms of resilience analysis and evaluation methods,we propose a non-simulation resilience analysis and evaluation method considering the heterogeneous energy flow support of electricity-gas regional distribution network: this paper propose a node-dependent cell supply path solution method based on the dynamic reconfiguration of the network to provide topological data for the non-simulation resilience analysis and evaluation method.The total loss of load supply energy is characterized as the expectation of load outage based on the scenario probability.The resilience assessment indexes are constructed from both in-accident and postaccident aspects to address the lack of historical data for extreme faults with low probability/high damage.Based on the node-dependent metacell supply path model and the electric-gas network fault probability model,the probability theory is applied to achieve the non-simulation expression of the resilience index.The proposed non-simulation resilience assessment method can accurately quantify the dynamic behavior of network reconfiguration and maintenance resources while avoiding large-scale simulation of failure scenarios.The dynamic assessment of system performance under natural disasters in the electric-gas regional distribution network is realized to identify potential problems in the resilience level of planning and operation schemes and to provide feedback suggestions.(2)In terms of resilience-oriented expansion planning,considering that the resilience of the electricity-gas regional distribution network can be enhanced through cooperative multienergy support,network reconfiguration and hardening,a resilience-oriented robust expansion planning model for the meshed electricity-gas distribution network is established: based on the "defense-attack-correction" ideology,the optimal configuration of the energy network frame in pre-fault,the modeling of uncertain fault variables in fault,and the dynamic reconfiguration of the network topology in post-fault to achieve multi-stage discretization modeling that accounts for extreme N-k fault uncertainty.The capacity-constrained additional cut model is developed for the invalid cut feedback problem caused by the parameterization of integer variables in the traditional Benders-Dual decomposition method,and the adaptability of the model in a hierarchical solution framework based on Benders-Dual decomposition and column generation is analyzed.The simulation results show that the proposed expansion planning model can obtain the optimal network configuration scheme based on normal operation scenarios and extreme N-k fault operation scenarios,and output the electricity-gas regional distribution network reconfiguration strategy under various extreme fault events.(3)In terms of multi-agent resilience operation,the multi-agent distributed resilience support method is proposed to address the problem of different operating agents in the distribution system and gas system: the resilience enhancement resource potential is enhanced by digging deeper into the optimal control of units,demand response,grid reconfiguration and optimal allocation of movable maintenance resources.The feasibility and compatibility of the source-grid-load collaborative integrated resilience enhancement strategy to participate in resilient operation under multi-subject scenarios is explored.In order to quantify the cooperative resilience support capability of different operating agents under the barriers of information privacy and multi-energy support transactions,a hierarchical solution method is established by applying Nash bargaining theory to take into account the information protection and the multi-energy support economic benefits,which effectively solves the centralized optimization method’s problem of "getting something for nothing" of the faulty energy system in multi-agent scenarios.This method can improve the enthusiasm of cooperation among different interested agents. |
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