| As a carrier for coordinating and optimizing a variety of heterogeneous energy forms,the integrated energy system is of great significance to improve the comprehensive utilization rate of energy,promote the consumption of renewable energy,realize multi-energy complementarity and energy ladder utilization,and has received extensive attention and rapid development.Electric-gas regional integrated energy system consists of distribution network,gas distribution network,renewable energy power generation,coupling elements and electricity,gas,heat/cooling loads,etc.located in the same area.The reliability of the electric-gas regional integrated energy system generally refers to the adequacy reliability,which means that within the research time period and under static conditions,and considering the planned and unplanned outages of components and operating constraints,a measure of the ability of a system to supply electricity,gas,and heat/cold energy to its electricity,gas,and heat/cold users uninterruptedly according to specified quality standards and required quantities.According to the time scale of assessment,reliability assessment is divided into longterm and short-term reliability assessment.Reasonable reliability assessment is the key to ensure the reliable operation of the electricity-gas district integrated energy system.In this paper,the reliability evaluation of distribution network and gas distribution network is carried out,and the reliability evaluation of electric-gas regional integrated energy system is studied.The main work is as follows:1)Reliability assessment of distribution networks without and with microgrids.The reliability indicators of distribution network and commonly used reliability evaluation methods are analyzed,and a reliability evaluation method of distribution network combining equivalent node model and Monte Carlo simulation is proposed.According to the cause of the fault,the system fault mode is partitioned to form an equivalent node model.On this basis,the impact of the fault mode is analyzed,and then combined with the Monte Carlo simulation method,the long-term reliability of the distribution network system without microgrid and with microgrid is carried out.The calculation example results show that adding microgrid can improve the reliability level of distribution network,which verifies the effectiveness of the proposed method.2)Reliability assessment of annular and radial gas distribution networks.The network structure of the gas distribution network system is analyzed,and three reliability evaluation indicators of the gas distribution network are proposed;the failure analysis of the gas distribution network is carried out based on the equivalent node model,and the long-term reliability evaluation of the gas distribution network is carried out with the Monte Carlo simulation method.Finally,an example analysis is carried out on the 14-node annular gas distribution network and the 20-node radial gas distribution network.3)An energy supply reliability assessment method for multi-energy microsystems containing electricity,gas,heat/cold is proposed.Analyze the multienergy microsystem structure including electricity,gas,heat/cold,model the multienergy microsystem based on the Energy Hub,and give the energy supply reliability evaluation index and reliability evaluation process of the multi-energy microsystem,on this basis,develop a multi-energy microsystem energy supply reliability evaluation GUI software.According to the proposed method,the reliability of energy supply is evaluated for a multi-energy microsystem example,and the analysis results verify the effectiveness of the proposed index and method.4)A short-term reliability assessment method of electric-gas district integrated energy system based on LSSVM is proposed.Firstly,a reliability model of system components including coupling components is established,and a fault impact analysis based on the system equivalent node model is proposed.On this basis,the proposed model-driven short-term reliability evaluation method based on Monte Carlo simulation is used to construct training samples.Then,train the LSSVM model to obtain the short-term reliability evaluation LSSVM model parameters of the electricgas regional integrated energy system,and realize the online short-term reliability evaluation of the electric-gas regional integrated energy system.An example analysis of an electric-gas district integrated energy system with IEEE-RBT-BUS6 multi-branch feeder and 15-node natural gas system is carried out.The evaluation results show that the method can ensure the real-time and accuracy of evaluation,and is suitable for coupling relationship short-term reliability assessment of complex integrated energy systems. |
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