Research On Optimal Allocation For Fast Frequency Response Reserve Considering Spatial Distribution

With the continuous development of UHV construction in China,the single fault capacity of power system is increasing,and high-power loss accidents occur from time to time.Fast frequency response in second-order time scale is the first line of defense for power system frequency control.It can prevent frequency from dropping sharply after high power loss and avoid accidents such as low frequency load shedding.A large number of grid-connected new energy sources do not have the ability of frequency adjustment,but also occupy the power generation space of conventional units with frequency modulation capability.The frequency response of the system is facing severe challenges.Most of the common frequency adjustment reserve allocation methods in our country set up the total amount of rotating reserve,but there is no clear provision with the response time of seconds.Although some foreign researchers have put forward relevant concepts according to the characteristics of frequency response,they are not suitable for the complex and changeable power system environment in China.Therefore,it is necessary to carry out research to meet the demand of frequency response under high power loss.In view of the new situation of fast frequency response available resources on the three sides of "source-network-load",the technical and economic characteristics of various reserve resources should be integrated to realize the optimal allocation of time-space and improve the level of emergency frequency control of power grid.In this paper,the optimal allocation of various fast frequency response reserve resources of "source-network-load" is studied.Four key issues are proposed,namely,the coordination of conventional generating units and new fast frequency response reserve resources,the unified description of technical and economic characteristics of multiple resources,the determination of allocation emphasis under different frequency response emergencies and the impact of network constraints on fast frequency response reserve allocation.With calculating of the lowest frequency value,the frequency response ability of conventional units under different emergency degrees are estimated,and the reserve demand of new resources are determined.The idea of normalized reserve evaluation is put forward.Based on the analytic hierarchy process,the technical and economic characteristics of various reserve resources are coordinated,and a unified description of the characteristics of various resources is obtained,so as to avoid the coupling among different factors of various resources and increasing the complexity of modeling.A fast frequency response reserve allocation optimization model without considering network constraints is established,it realizes allocation schemes under different frequency response emergencies.Based on sensitivity analysis method and considering network constraints,the reserve allocation results of fast frequency response are checked and corrected safely,and the optimal allocation of fast frequency response reserve considering spatial distribution is realized.Finally,a dynamic frequency response time-space collaborative allocation scheme is formed.The research work solves the four key problems and realizes the optimal allocation of various spare resources of "source-network-load".The example analysis based on the actual power grid data shows that the obtained configuration results can effectively support the frequency response adjustment power under high power loss,and ensure the power system's ability to cope with sudden high power loss accidents.Compared with the existing methods,the proposed configuration method can promote the time-space collaborative optimization of multiple fast frequency response resources of "source-network-load".Different emergency degree of frequency response takes into account the safety and economy requirements of frequency adjustment,which has certain advantages in economy and technology.