Research On The Voltage Control In Grid-connect Megawatt-class Photovoltaic Power Station

With the continuous development of China's national economy and the sustained growth of electricity demand,traditional energy sources have been unable to meet the needs.At the same time,photovoltaic power generation technology has been developing rapidly.The proportion of electricity sold by photovoltaic power in distribution network has increased year by year in recent years.In Suzhou area,many photovoltaic power generation projects have been put into use,which makes the traditional grid voltage have undergone tremendous changes.Therefore,it is necessary to investigate and study the grid-connected situation of existing photovoltaic power stations in Suzhou Power Grid and understand the impact of grid-connected photovoltaic power stations on the voltage of some regional power grids under the current situation,so as to improve and optimize the reactive power control strategy of photovoltaic power plants.Taking a megawatt photovoltaic power station in Changshu City of Suzhou as a typical example,based on PSCAD/EMTDC software model,in this paper,maximum power point tracking technology is used to construct a perfect and reasonable data model of local area network of photovoltaic power station.From the viewpoint of output variation characteristics and different permeability of photovoltaic power station,the connection between the gridconnected photovoltaic power station and local area grid voltage is comprehensively and systematically discussed in this paper.Secondly,it compares the peak value of large capacity,decentralized and other grid-connected strategies,and formulates two improvement measures.The first is the local voltage control strategy under different operating conditions.The second is that the grid adopts the global coordinated voltage control strategy of photovoltaic power plants,and validates the analysis by using data simulation model.It is concluded that the above two control strategies have a great impact on the stability of local power grid.Active role.The research results of this paper point out the direction for the further development of Suzhou power grid,improve the stability and reliability of voltage in Suzhou power grid,and lay a good foundation for improving the level of power service.