Risk Assessment Of Gas-Electric Strong Coupling System Considering Gas Supply Reliability

Under the new background of the development of the energy and power industry,the proportion of wind power and photovoltaic power generation in the power system is gradually increasing,which makes the regulation capacity of the power grid continue to decline.As a low-carbon flexible power source,gas fired power generation will play an important role in many aspects such as peak regulation in the power system.Since the gas unit in the gas-electric coupling system acts as both the load of the gas network and the power supply in the power grid,the operating condition of the natural gas system and its gas supply strategy will affect the reliability of gas supply to the gas unit,and then affect the output of the gas unit and the power supply reliability of the power system.Therefore,it is necessary to consider the uncertainty of gas supply network when evaluating the reliability and risk of gas-electric coupling system.This paper focuses on the influence of the gas supply uncertainty of the natural gas system on the power grid in the gas-electric coupling system,and studies the reliability and operation risk of the gas-electric coupling system as follows:(1)In this paper,a reliability evaluation model for gas-electric coupling systems is established,which considers both the structural reliability and energy flow calculation of the coupling system,involving most components in the transmission process of natural systems and most conventional components in power systems;A reliability evaluation method of gas-electric coupling system based on sequential Monte Carlo method is proposed;The reliability evaluation index of natural gas supply and gas-electric coupling system with urban gas cluster as the target node is established.Using the established model,the methods involved,and the proposed indicators as a means,using a gas-electricity coupling system composed of a 20 node natural gas system in Belgium and an IEEE-30 node power system as an example,energy flow calculations were conducted for the gas electricity coupling system in different scenarios.Based on this,the reliability of the gas-electric coupling system with different gas unit number ratio is evaluated.(2)On the basis of considering the probability of failure scenarios,this paper proposes a risk assessment method and multi-dimensional indicators for the operation of gas-electric coupling systems,transforming the uncertainty of natural gas supply into the output uncertainty of gas power plants.Based on the selection principle of risk assessment index,the operational risk assessment indicators for the gas-electric coupling system are established using the utility function,and the combined weighting method is used to weight and grade the indicators.Finally,the operational risk assessment was conducted on the actual gas-electric coupling system in a first-tier city,and a comparative analysis was conducted with schemes with different coupling degrees of the gas-electric coupling system.The results show that the proposed evaluation method can quantitatively analyze the reliability of coupled systems and locate the main risk sources in the system;The uncertainty of gas supply in the gas network will bring higher risks to the power system and the coupling system as the degree of gas-electricity coupling increases.