Research On Economic Scheduling For Integrated Electricity And Natural Gas Energy Systems

With the increasing installed capacity of renewable energy power generation units,the backwardness of power grid infrastructure has resulted in the reduction of large amounts of renewable energy power generation.Moreover,people's living standards have been continuously improved,the types of loads are increasing,and the scheduling capabilities of various energy networks are facing challenges.Under the background of integrated energy system,the newly emerging large scale energy storage technology —— power to gas(P2G)technology can fully absorb renewable energy sources,improve environmental quality,and it has a peak load shifting effect on the load curve.The combination of P2 G station with gas-fired power units can enhance energy interaction within the integrated energy systems.Under the background and significance of this topic that above mentioned,the following are mainly carried out:First of all,the research status of the integrated energy system,energy storage technology,and power to gas technology is elaborated.The framework structure of integrated electricity and natural gas energy systems,the nature of each sub-energy system,and the operating mechanism are analyzed in detail.And several currently applied mathematical models of integrated electricity and natural gas energy systems are listed.Secondly,the influence of power to gas technology on energy interaction within the integrated electricity and natural gas energy systems is considered.The economic scheduling model of the integrated electricity and natural gas energy systems with the goal of minimizing the system operating costs(consisting of conventional generating unit fuel costs and natural gas costs),the curtailed wind penalty costs,and the power grid pollutant emission costs is formulated.And the teaching-learning-based optimization algorithm is improved to solve the economic scheduling problem of the integrated electricity and natural gas energy systems.Finally,the integrated electricity and natural gas energy systems are taken as a whole,energy exchange cost between subsystems within the integrated electricity and natural gas energy systems is ignored.The economic evaluation model of the integrated electricity and natural gas energy systems is proposed,which is based on the wind power participation index and the night wind power curtailment rate index.The objective function is to minimum daily cost of the whole system.In the MATLAB software,improved particle swarm optimization algorithm is used to programmatically analyze the influence of variable factors,such as operating cost of power to gas station,gas storage equipment cost and so on,on daily operating cost of the whole system.Using the modified 9-bus power system coupled with 7-node gas system as examples,the effect of power to gas station on the wind power utilization in the integrated electricity and natural gas energy systems is analyzed.The results have showed that power to gas technology has reduced the level of cutailed wind power and increased the wind power output at each time period.The participation of power to gas station has reduced the power output of coal-fired power units,and reduced the discharge of carbon-dioxide from the power grid.The gas-fired power units output has been promoted by synthetic natural gas.It confirms the good influence of power to gas technology on operating coordination of generators.However,the efficiency of the gas-fired power units is low,the increased output of those units has improved the overall environmental pollutant emission level.The power to gas station is more suitable for the scenario where the wind power output is larger and the load demand is smaller.The benefit is highest at this time.