Optimal Dispatch Of Integrated Electricity And Natural Gas Energy Systems For Wind Power Consumption

With the increasing demand for energy in the world and the increasingly serious environmental pollution,renewable energy represented by wind power has developed rapidly.The inability of large-scale storage of electricity,lack of long-distance transmission capacity,the uncertainty of wind power output and peak-reversal characteristics,insufficient flexibility of generators and other factors make the problem of wind curtailment is still serious.Power to Gas(P2G)technology can convert wind power that cannot be consumed into natural gas,providing an effective way to consume wind power.However,when across-regional transmission is carried out with the help of long-distance pipeline network,the transmission speed of natural gas and the storage capacity of the natural gas network cannot be ignored when dispatching.At the same time,the wind power forecast error is uncertain.In order to reduce its impact on the safe operation of the system,the uncertainty of wind power forecast error needs to be considered in the dispatch model.For the above problem,this paper carried out the following studies.First,for the problem that the dynamic characteristics of the long-distance pipeline network cannot be ignored,this paper simplifies and differentiates the fluid equation of the natural gas pipeline,and obtains the pipeline flow equation and the node pressure equation of the time coupling and space coupling.The dynamic linepack of natural gas network is deduced and managed.This paper proposes an optimal dispatch model for integrated electricity and natural gas energy systems for long-distance pipe networks on this basis.Secondly,on the basis of the above dispatch model,the uncertainty of wind power forecast error is considered.In order to avoid the risk caused by the uncertainty of wind power forecast errors,the system needs to reserve extra reserves.When the reserve is insufficient,the system faces the risk of load abandonment and wind power wasting.When the reserve is too large,the reliability of the system is high,but the economy of the system is poor.Therefore,an optimal dispatch model for integrated electricity and natural gas energy systems considering reserve risk constraints is proposed.The system dispatcher can weigh the requirements of the system’s economy and reliability,select a certain risk threshold,and formulate a dispatch plan to make the dispatch plan more reasonable.When the system requires higher reliability,a lower risk threshold can be selected;when the system requires higher economics,a higher risk threshold can be selected.Finally,the modified 10-machine 39-node power system in England and the Belgian natural gas system are simulated separately.The simulation results show that it is necessary to establish a dynamic model when facing a long-distance pipeline network and prove the correctness and rationality of the proposed optimal dispatching model.Another simulation result shows that as the risk threshold decreases,the reserve capacity reserved by the system increases,and the total cost gradually increases.The balance between economy and reliability can be achieved by selecting the appropriate risk threshold and arranging the scheduling plan and capacity requirements of each unit within the allowable risk range.It proves the rationality and correctness of the proposed optimal dispatch model,and analyzes the effect of the dynamic characteristics of the natural gas network on buffering wind power fluctuations.