| The traditional power system frequency modulation method is to adjust the active power output of the generation side in real time according to the change of the system frequency,so that the active power output of the generation side changes with the change of the active power demand of the load side,so as to ensure the active power balance between the generation side and the load side.Under the influence of a large number of distributed generation connected to the power grid and the increasingly complex power supply structure,the cost of traditional frequency modulation mode increases significantly.Therefore,it is of great significance to fully explore the potential of load with energy storage on the load side to participate in frequency modulation.Therefore,on the basis of EV load prediction,the control strategy of EV participating system frequency modulation is studied.First,based on the relevant statistical data of electric vehicles in the literature,a travel purpose-based travel chain model of electric vehicles is established and its validity is verified.At the same time,the nodal plot model is established based on the statistical data of a certain transportation department.On this basis,the improved Dijkstra wayfinding algorithm is used to determine ev travel nodes and travel distances,and fuzzy charging control strategy is applied to make decisions on users' charging behavior,so as to obtain the results of EV charging load prediction.Secondly,considering the frequency events of the system,the participation of electric vehicles in the system frequency modulation may have an impact on the power flow of the distribution network.On the basis of the electric vehicles load forecasting,in power distribution lines network loss and voltage offsets the minimum as the optimization goal,for distribution network line without overloading and electric vehicles in the current node can provide the limit of the frequency modulation power in order to optimize the conditions and puts forward a kind of electric vehicles to participate in the distribution network reconfiguration frequency modulation control strategy.The effectiveness of the strategy is verified by simulation analysis of IEEE 33-node distribution network.Thirdly,aiming at the problem of ev participating in secondary frequency modulation of the system,in order to avoid the problem of ev battery life being greatly affected due to frequent switching between charge and discharge states,a time-sharing grouping participating frequency modulation control strategy based on current charging requirements of EV was proposed.The AGC frequency modulation model of the power system was established,and the simulation proved that the time-sharing grouping frequency modulation control strategy could not only meet the needs of the backup of the electric vehicle to provide the system with secondary frequency modulation,but also reduce the number of charging and discharging conversion of the electric vehicle,thus providing strategic support for the electric vehicle to participate in the system's secondary frequency modulation.Finally,in order to meet the demand of power system primary frequency control,the power system primary frequency control strategy based on decentra lized control of temperature controlled load is proposed by utilizing the characteristic of fast response of temperature controlled load to power system frequency events.The strategy links the temperature control load state variation with the current syste m frequency so that the temperature control load state variation can respond to the primary frequency modulation of the system without communication.In order to solve the problem of restoring peak load in the process of temperature-controlled load recovery,the electric vehicle load was applied to respond to the restoring peak load by using the data of primary frequency modulation of temperature-controlled load response system,and the effectiveness of the control strategy was verified by simulation. |
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