Research On The Maximum Capacity Of New Energy Based On Peak Shaving And Frequency Security Constraints

In recent years,China's new energy resources have continued to develop rapidly,and the penetration rate in the power grid has been increasing,gradually entering a stage of large-scale development.However,due to its randomness and instability,it leads to insufficient peaking ability of the power grid and the safety and stability of the frequency,which has become a constraint to the development of new energy.In view of these factors that may limit the level of new energy consumption,this thesis considers the two constraints of peaking capacity and frequency safety,and conducts research on the new energy consumption level of the grid.Firstly,based on the PSD-BPA power system simulation software,an external delivery system model including thermal power,wind power and photovoltaics is built.Based on this model,a new energy permeability calculation method based on peak shaving constraint considering the outgoing power of the tie line is proposed.The method is based on the “anti-peaking” characteristics of new energy sources,and analyzes the output methods of new energy sources during peak load and low valley under extreme conditions.Then,the peaking range of the thermal power unit in the model,the rotating reserve capacity and the outgoing power of the tie line are studied,and the new energy penetration rate is solved according to the load curve of the typical day of winter and summer,finally the assessment of the new energy consumption capacity of the grid after considering the peaking constraints is realized.Based on the above model,according to the concept of the system equivalent inertia time constant,it is inferred that with the increase of the proportion of new energy output,the variation of system frequency will be aggravated in the event of failure,and the above conclusion is verified by PSD-BPA program simulation.The different severity of faults in the power grid and the corresponding frequenc y control measures were studied: When a small disturbance occurs,it depends on the self-healing of the system;when a serious fault occurs,it is necessary to take safety control measures,and the configuration of the safety control and cutting machine strategy is carried out for the high-frequency state after the fault;when an extreme fault occurs,it is necessary to take the joint action of the safety control measures and the third line of defense.and the high frequency generator trip combined with existing safety control scheme are arranged for the high-frequency state.The frequency safety standard principle after various fault occurrences with their corresponding frequency control measures are set,which is used as a constraint to simulate the maximum new energy penetration of the system.The interaction effects of various constraints on the penetration rate of new energy were studied,and the new energy consumption capacity of the system was comprehensively evaluated.