A Volt/Var Control Strategy For Large-scale Distributed Photovoltaic Access To Rural Power Grid

China’s rural areas are rich in solar energy resources,and the photovoltaic poverty alleviation has become an important new measure.However,most rural power grids in China are at the end of the grid,with low voltage levels,small loads,strong dispersion,and weak grid structure.After the large-scale integration of distributed photovoltaics,the voltage of the rural power grid fluctuates greatly and the problem of voltage exceeding the limit is particularly prominent which brings great challenges to the safe operation of the rural power grid.To this end,this article starts from the perspective of volt/var control,and studies the volt/var control strategies in rural power grids with large-scale distributed photovoltaics in order to promote the healthy development of photovoltaic poverty alleviation.This article first analyzes the reactive voltage operating characteristics of large-scale distributed photovoltaics connected to rural power grids.Secondly,the volt/var control mechanism of large-scale distributed photovoltaics access to rural power grids is studied.On the basis of the analysis of the regulation characteristics of the reactive power control equipment of the rural power grid,this paper studies intra-area/inter-area coordination volt/var control mechanism of the large-scale distributed photovoltaic access to the rural power grid.On this basis,combined with the matching of voltage regulation requirements and the regulation characteristics of reactive power control equipment under different time scales,a multi-time scale volt/var partition control mechanism for large-scale distributed photovoltaic access to rural power grids is studied.Then,a volt/var control strategy for large-scale distributed photovoltaic access to rural power grids is proposed.Based on the volt/var control mechanism of rural power grids,a volt/var zone control mode in multi-time scale for large-scale distributed photovoltaic access to rural power grids is proposed.Based on this,in the day-ahead time scale,a day-ahead coordinated volt/var control model with the goal of minimizing the voltage limit in rural power grid is established;In the intraday time scale,combined with the decomposition and coordination theory,a intraday regional cooperative volt/var control model with the goal of minimizing the voltage offset in rural power grid is established.Then,the differential evolution algorithm and the auxiliary problem principle algorithm are used to solve the day-ahead and intra-day models respectively.In the end,a volt/var control strategy for large-scale distributed photovoltaic access to the rural power grid is formed.Finally,the actual operation data of a rural power grid is used for simulation to verify the feasibility and effectiveness of the volt/var control strategy for the large-scale distributed photovoltaic access to the rural power grid proposed in this paper.