| With the construction of the energy internet,energy hubs(EHs)containing wind power are connected to power systems,and the multi-energy coupling characteristics of the system are increasingly obvious.Energy transformation requires the preferential use of renewable and clean energy such as wind power,and wind power has both random fuzzy uncertainty and volatility.How to prioritize wind power utilization in energy hubs and how to analyze the power flow of active distribution network with energy hubs need to be studied urgently.And large fluctuations or abrupt change of interaction power between wind energy hub and power system will have an impact on the transient stability of the system.Therefore,the paper studies from the following aspects:Firstly,based on the characteristics of wind speed and random ambiguity of wind power output,the energy coupling relationship of the energy hub containing wind power is modeled for the random fuzzy wind power access energy hub.Combined with the energy hub model with random fuzzy wind power,the traditional coupling mode is improved,and the improved energy hub multi-energy coupling mode with priority wind power utilization is obtained.Then,considering the characteristics of random fuzzy wind power volatility,based on the plan of the day before,a three-phase imbalanced random fuzzy dynamic power flow method for active distribution netviwork(ADN)containing energy hubs with priority utilization of wind power is constructed.The method is based on the improved energy hub multi-energy coupling mode of priority wind power utilization in Chapter 2,and obtains the energy state of the energy hub and its random fuzzy exchange power with the active distribution network.Thus the three-phase unbalanced random fuzzy dynamic power flow model of ADN with EHs that use wind power preferentially was established by considering the wind power penetration level of direct access distribution network and exchange power of EH,the interaction states of source,load and islands between ADN and transmission network.And the model was solved by combining random fuzzy simulation,Back/Forward sweep method and unbalanced three-phase decoupling.From the simulation results of the improved IEEE33-bus system,it is suggested that the proposed method can effectively improve the wind power utilization rate of EH,and the daily scheduling power flow results with random fuzziness and volatility are more comprehensive and objective.Finally,based on the power system simulation software,the time domain simulation method is used to study the influence of the energy hub with wind power accessing power system on its transient power angle stability and transient voltage stability.Taking the four-machine two-zone system with the energy hub containing wind power as an example,according to the improved multi-energy coupling mode and the conventional coupling mode of wind power,the transient simulation results of the energy hub with wind power access systems in three scenarios are obtained.The simulation results show that the oscillation amplitude and transient power angle of the improved coupling mode of the energy hub are smaller than the conventiolal coupling mode,which indicates that the improved coupling mode of the energy hub can improve the impact of its access on the transient stability of the power system.Considering the uncertainty and volatility of wind power and load,a random fuzzy dynamic power flow model for active distribution network is constructed in the paper.Because the results of random fuzzy power flow analysis can give consideration to both randomness and fuzziness,it is more scientific and comprehensive.And through the analysis of the impact of the energy hub with wind power on the transient stability of the power system,it provides a reference for improving the stable operation of the system. |
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