Research On Power System Reserve Determination Method Considering Large-Scale Wind Power Integration

The "CO2 emission peaking and carbon neutrality" target accelerates the development of new power systems suitable for large-scale renewable energy integration.The output of large-scale renewable power represented by wind power is inherently uncertain and volatile,which brings challenges to the real-time power balance,secure and reliable operation of power systems.The traditional reserve determination method to ensure the real-time power balance of power systems composed of conventional controllable and adjustable power sources is difficult to apply to new power systems.Therefore,for new power systems,the research on power system reserve determination method considering large-scale wind power integration has important theoretical significance and engineering application value.With the large-scale wind power integration,new power systems are faced with multiple uncertainties(including wind power output and load uncertainty,generator and tie-line contingency,etc.),and the total amount of uncertainty of the newly added wind power output is large,with strong temporal and spatial correlation,so the traditional reserve capacity demand criterion is no longer applicable;With the largescale fluctuating wind power integration,the uncertainties of network power flows increase,and the reserve availability problem is prominent,which puts forward new requirements for the reserve determination;To stabilize the fluctuation of renewable energy,energy storage resources have broad application prospects;To solve the contradiction between the misalignment of wind energy resources and load centers,the form of hybrid AC/DC power systems develops rapidly,the change of source-networkstorage structure of new power systems provides greater potential for reserve/regulation resources,and collaborative optimization of resources on all sides is of great significance to promote the flexible and efficient operation of the systems.Aiming at the new problems of reserve demand characterization,reserve determination method and optimal dispatch of regulation resources in new power systems,this paper focuses on the research on the reserve determination method system of new power systems.The main research contents are as follows:(1)To accurately characterize the multiple uncertainties and the uncertainties of network power flows,and quantify the reserve capacity demand,an endogenous reserve determination method of wind-power-integrated power systems with embedded security and network constraints is proposed,which overcomes the inaccuracy and subjectivity of traditional a priori reserve capacity requirements.Different from the traditional exogenous reserve determination method which determines the reserve capacity demand based on experience or probability index in advance,in the proposed method,multiple uncertainties are reasonably modeled and integrated into the security-constrained economic dispatch(SCED)model to realize the endogenous reserve determination,which comprehensively considers the network constraints before and after the occurrence of uncertain events,and ensures the availability of reserve.The model adopts affinely adjustable robust optimization(AARO)method and introduces generator participation factor to address continuous uncertainties and considers the budget of uncertainty to reduce the conservativeness of robust optimization(RO).For discrete uncertainties,the model is transformed into a two-stage problem(normal state optimization and fault verification).Benders decomposition method is used for iterative solution,and auxiliary constraints are designed to accelerate the convergence.The results show that the proposed endogenous reserve determination method can improve the operating economy of the system under the premise of ensuring robustness,and the proposed iterative solution method can effectively reduce the solution time of the model.(2)To bring into play the flexible regulation ability of energy storage resources represented by pumped storage power stations,a reserve determination method of wind-solar-pumped storage multi-source power systems is proposed.Continuous uncertainties are modeled probabilistically,then discretized into multi-state units,further coupled with discrete generator outage to establish capacity outage probability table(COPT)and formulate relationship between reserve and reliability index loss-ofload probability(LOLP).An integrated stochastic-AARO based security-constrained unit commitment(SCUC)model is established to schedule generation and reserve jointly.Therein operational characteristics of pumped storage power station are deliberated.The envelope relaxation method is used to realize the linearization transformation,together with the deterministic transformation to realize the solution of the model.The results verify the function of peak shaving and valley filling of pumped storage power station to improve the operating economy of the system,and explain the necessity of considering the network constraints before and after the contingency to reasonable reserve determination.(3)In view of the need for renewable energy itself participating in reserve in new power systems,a reserve determination method considering wind power providing reserve is proposed.A unified model of wind power output/reserve under maximum power point tracking(MPPT)mode and derating mode is designed.A two-stage SCED model considering multiple uncertainties is established,which enables optimal mode selection of wind farm.The model adopts RO method and follows the endogenous reserve determination criterion.The column and constraint generation(C&CG)algorithm is used to realize iterative solution.The results verify and explain the economic viability of wind power providing reserve,and prove the advantages of the proposed optimal operation mode selection of wind farm in the transition stage from dominance of conventional generators to 100%renewable energy integration.(4)To bring into play the flexible regulation ability of the interconnected power grids,a coordinated decentralized reserve determination method of wind-powerintegrated interconnected power systems considering mutual reserve support is proposed.A security-constrained coordinated decentralized dispatch model considering multiple uncertainties and mutual reserve support is established.An integrated stochastic-AARO optimization method is used to address discrete and continuous uncertainties,and based on the analytical target cascading(ATC)algorithm,a two-level optimization framework is constructed for coordinated decentralized scheduling of tie line power and mutual reserve.The results verify the rationality and efficiency of the proposed method to realize coordinated decentralized scheduling of tie line power and mutual reserve,and the significant positive impact ofinterconnection and mutual reserve mode on improving the the operating economy of the system.(5)To bring into play the coordinated regulation ability of the hybrid AC/DC power systems,a reserve determination method of wind-power-integrated hybrid AC/DC power systems considering coordination of AC transmission topology control and DC transmission power optimization.An SCED model considering multiple uncertainties is established to synergistically schedule power flows through high voltage direct current(HVDC)transmission network,AC transmission switching(TS).The model adopts RO method and follows the endogenous reserve determination criterion,and uses the linear power flow model of the DC grid,The C&CG algorithm is used to transform the model into a two-stage problem to realize iterative solution.The results verify the effect of the HVDC collaborating with TS on optimizing the power flow distribution,improving the operating flexibility and reducing the operating cost of hybrid AC/DC power systems.This paper focuses on the reserve demand and the regulation resources distribution characteristics in the change of source-network-storage structure of new power systems,focuses on the reserve availability problem,constructs the endogenous reserve determination method system,and makes full use of resources on the source side and network side to ensure the flexible and efficient operation of the systems.It is expected to provide method support for the reserve determination of new power systems with large-scale renewable energy integration.