Multi-time Scale Voltage Control Based On Photovoltaic Active And Reactive Power Coordinated Optimization In Distribution Network

With a large number of distributed photovoltaic access to the distribution network,the traditional single source radial distribution network is gradually changing into a complex structure of multi-source,which has a serious impact on the voltage control of the distribution network.In addition,due to the uncertainty of distributed photovoltaic and load forecasting,it brings new challenges to the voltage regulation of the distribution network.Considering the problem of voltage fluctuation caused by distributed photovoltaic and load uncertainties in distribution network,a day-ahead robust optimization strategy for distribution network based on photovoltaic active power and reactive power coordination is proposed.Furthermore,in order to solve the conservative problem of day-ahead robust optimization strategy,a multi-time scale coordinated and optimized control method for active and reactive power distribution network is proposed based on model predictive control.The main work completed in this paper is as follows:(1)Active and reactive power coupling mechanism and multi-time scale coordinated optimization method in distribution network.By analyzing The influence of the variation of active and reactive power on the voltage and energy loss of distribution network.it is explained that the active and reactive power interactions in distribution system.It is necessary to put forward the active-reactive power coordination optimization methods to make full use of the active and reactive power resources,to improve the condition of voltage more effectively,to reduce the energy loss.In the end,the model predictive control theory briefly introduced,which lays a foundation for the multi-time scale coordinated optimization.(2)Day-ahead robust voltage control strategy based on photovoltaic active and reactive power coordinated optimization in distribution network.In order to solve the problem of voltage fluctuation exceeding the limit caused by distributed photovoltaic and load uncertainty in distribution network,a day-ahead robust optimization strategy based on photovoltaic active and reactive power coordination is proposed to find the coordination and optimization control strategy of distribution network system in the worst scenario,so that when the power in the system fluctuates in the uncertainty set,the active and reactive power can be used.(3)Multi-time scale coordinated and optimized control method for active and reactive power distribution network based on model predictive control.In view of the conservative problem of the day-ahead robust optimization strategy,a multi-time scale coordinated optimization model is established based on model predictive control,which takes day-ahead robust optimization into account and combines with day rolling optimization and real-time feedback correction.The influence of photovoltaic output and load power prediction error on system operation shall be eliminated to the greatest extent,and the active and reactive power resources shall be fully utilized.