Research On Safety Verification And Coordinated Control Of Photovoltaic Battery-energy Storage Hybrid Power System As Black Start Power Supply

The social impact,economic impact,and political impact caused by power outages of large power grids are difficult to estimate.The research on the black start of power grids is imminent.With the rapid development of microgrids,it can be expected that microgrids will gradually become an important part of the power system in the near future.In recent years,the penetration rate of photovoltaics in Zhenjiang has continued to increase.Photovoltaic control technology has been advanced.Large-scale energy storage power stations have been successfully put into operation,making it necessary and possible for photovoltaic power stations and energy storage power stations to participate in system restoration.Therefore,it is of great significance to study the safety verification and coordinated control strategy of the solar-storage combined power generation system as a black-start power source.First of all,from the perspective of photovoltaic power plant operating characteristics,energy storage power plant operating characteristics,and black start load power demand,the analysis of the combined solar storage system as a black start power source is carried out.According to the seasonal and fluctuating characteristics of photovoltaic output,it is concluded that when the photovoltaic power station participate in the black start with the energy storage power station,there are executable and non-executable sections of black start.Secondly,according to the relevant regulations of the black start and the requirements of various indicators of the power grid,the safety verification of the black start of the PV battery-energy storage hybrid power system is analyzed,including the power output in the black start,the overvoltage that appears when charging a long line without loads,the self-excitation phenomenon of the unit,the inrush current of the large main transformer when charging the large main transformer,the voltage and frequency drop during the black starting.The photovoltaic ultra-short-term power prediction method based on least squares support vector machine(LS-SVM)is adopted,and the output power reference value of the PV battery-energy storage hybrid power system and the state of charge(SOC)of the energy storage system are obtained based on Model Predictive Control(MPC).Determine the safety of the black start of the PV battery-energy storage hybrid power system.Ensure the PV battery-energy storage hybrid power system can provide sufficient power for the asynchronous motor used in the large thermal power plant during the black start process.Then,based on the 35 k V energy storage power station and distributed photovoltaic on the system side,starting from the operating characteristics of the energy storage power station and distributed photovoltaic,a coordinated control strategy suitable for the black start of the PV battery-energy storage hybrid power system is carried out.A prediction model and a rolling optimization model of the PV battery-energy storage hybrid power system are constructed,and the coordinated control strategy is verified during the black start process to optimize the output power adjustment of the PV battery-energy storage hybrid power system,so as to realize the peak-shaving and valley-filling of energy storage for grid demand and restrain the output fluctuation of distributed photovoltaic power stations.Considering the time lag of the energy storage command,using the pre-compensation calculation method to improve the synchronization of the command data and reduce the impact of the time lag on the energy storage command.Considering the impact of SOC on the safe operation of energy storage,optimize the SOC charging and discharging control strategy under the condition of meeting the difference limit of the power required by the auxiliary equipment for tracking.Through the coordinated control of the PV battery-energy storage hybrid power system,the adjustment effect of energy storage is exerted,the output curve of the PV battery-energy storage hybrid power system is smoothed during the black start process,and the controllability of distributed photovoltaics and the safety of black start are improved.Finally,as a power-grid dispatcher,based on the characteristics and operation mode of the grid in Zhenjiang,combined with the power grid dispatching operation specifications and the actual grid operation data,the appropriate PV battery-energy storage hybrid power system is selected as the black start power source,and the final black start path is established.It is concluded that overvoltage and self-excitation will not occur during the black start of the PV battery-energy storage hybrid power system,and that the excitation inrush current,voltage and frequency fall within the allowable range through simulation and verification.Compared with the Power Forecast(PF)strategy,the effectiveness and superiority of the coordinated control strategy of the PV battery-energy storage hybrid power system is verified in terms of energy storage output and SOC.