Research On Distributed Photovoltaic Integration Capacity Of Distribution Network

Energy is the material basis of social development.With the progress of the times,fossil energy has been exploited and utilized in large quantities and brought serious environmental problems.Green and pollution-free renewable energy,such as solar energy,has developed rapidly.Distributed photovoltaic(PV)power generation has attracted more and more attention due to its advantages of cleaness,efficient,flexible installation and low investment.The policy of "PV poverty alleviation" has promoted the development of PV industry,which can achieve the goal of combining the development of poverty alleviation with the utilization of new energy,energy saving and emission reduction.However,distributed PV grid-connected will have an impact on power flow,voltage distribution,power supply reliability,power quality,protection and control of distribution network.Therefore,it is necessary to study the impact of PV grid-connected,and calculate the PV capacity that distribution network can absorb under the premise of safe,stable and economic operation of power system.This paper investigates the status quo of a power grid in a county in Hebei Province and introduces the current status of the grid of the county's distribution network.The effects of distributed poverty alleviation PV integration on grid voltage,current and network loss in the region are studied.The results show that the county power grid is currently unable to support the integration of all poverty alleviation PV villages,mainly due to severe node voltage overshoot and reverse current.In view of the above situation,it is necessary to evaluate and calculate the PV capacity of the county grid to ensure the safety,stability and economic operation of the grid,and propose relevant measures to improve the PV capacity,and promote the smooth development of the PV poverty al eviation project.A distributed PV absorptive capacity optimization model with maximum distributed poverty alleviation PV integration capacity and minimum active power loss of distribution network as objective functions and constraints of node voltage deviation,line thermal stability limit and PV generation capacity is established.An improved pollination optimization algorithm(FPA)was used to solve the optimization model.Based on the calculation model of distributed poverty alleviation PV integration in the county power grid at noon on April 28 and August 12,2016,the PV absorptive capacity of the distribution network in 2016 and 2018 is calculated to ensure the maximum distributed poverty alleviation PV integration capacity of the county distribution network under the premise of safe,stable and economic operation of the grid.The calculation results show the correctness of the optimization model and the effectiveness of the improved algorithm.Relevant measures to improve the absorptive capacity of distributed poverty alleviation PV integration to the county power grid are proposed.Reactive power and voltage control is adopted at the power side,dynamic inductive reactive power compensation capability is increased by JP cabinet,upgrading of the power grid and dynamic reactive voltage control is adopted in step-down substation.