Analytical Method For Reliability Evaluation Of Electricity-gas Integrated Energy System And Its Application

The exploitation of energy is at the period of transformation.On one hand,the overexploitation along with growing demand of energy increases the consumption of fossil energy,which results in fossil energy shortage as well as environmental problems.On the other hand,the development of technology has made it possible to exploit renewable sources,such as wind energy,solar energy and geothermal energy.Meanwhile,Natural gas,which has lower pollutant emission and higher energy conversion efficiency,may become an important choice of fuel in the future.Diversity of energy forms has changed energy structure.This paper focuses on the reliability performance of electricity-gas integrated energy system.Energy flows bi-directionally between the two subsystems in EGIS through coupled devices(e.g.,gas-fired electrical generator and power to gas system),which brings new challenge to operation and management.From the reliability perspective,an interruption in natural gas network may lead to a loss of gas-fired electrical generator,which reduces power supply and probably its reliability.Meanwhile,gas supply reliability may be affected since the utilisation of power-to-gas system leads to a new source of gas supply.Gas flow from terminal is reduced because part of gas demand can be supplied by the gas produced from electricity.All of the above makes reliability evaluation of EGIS an extremely challenging interdisciplinary problem.Therefore,an accurate reliability assessment of EGIS is urgently required.Reliability assessment of electricity-gas integrated energy system is undertaken via a new analytical method in this paper.Firstly,reliability models of coupling devices are developed to quantify interdependences between power distribution system and gas distribution system.Afterwards,reliability is evaluated separately in the two subsystems considering their distinctions in operation characteristics.Finally,a practical case combined a 10 kV feeder of distribution station in Guangdong with Belgain natural gas network is exploited to verify the effectiveness and practicability of the proposed method.