Grid-connected PV System Modeling And Impaction Research On The Distribution Network

Solar photovoltaic (PV, photovoltaic) is inexhaustible. As one of renewable energy generations, photovoltaic power generation has a lot of advantages. It can not only moderate energy consumption,but also reduce the global environmental pollution. At the same time, it can greatly improve the reliability of power supply. Photovoltaic technology has been widely used in many related fields, which makes the photovoltaic effects further promoted in the electric power system. Grid-connected PV power generation has been the main form in the use of photovoltaic power generation. However, because the photovoltaic power also presents stochastic and the output is not stable, which will greatly influence the original operation mode of power distribution system. It’s very important to research the changes and the problems that the PV introduced into the distribution network will bring to the original operation state of power distribution system for the whole power system. Firstly, this paper verifies whether it is reasonable to establish the model of photovoltaic power generation system. Then the changes and problems of the steady state distribution network system, the static voltage distribution and the distribution network loss is analyzed.Firstly, the common photovoltaic power generation systems have been classified, the maximum power point tracking (Maximum Power Point Tracking) method is further elaborated, the grid-connected PV power generation systems convert energy levels (the realization of maximum power point tracking and the inverter section is relatively independent at the level achieved) was used as the object of study. By Simulink software platform of Matlab, solar grid-connected photovoltaic model has established and has carried on thesimulation analysis, the simulation results verify the feasibility of the model.Secondly, in view of the distribution network after PV is introduced, the steady-state voltage distribution model is established by respectively using the "negative" load model algorithm and the"power" model algorithm. According to the model, after PV was introduced into distribution network, change of voltage distribution was analyzed separately from location, capacity and power factor of PV introduced. And two cases that the single photovoltaic power generation and multiple photovoltaic are introduced into distribution network are analyzed, the specific influence of PV on the power grid voltage can be drawn from simulation curve.Then, static voltage stability index of distribution network was given, and change of static voltage stability of distribution network system were analyzed and summarized by the introduction position and capacity of PV.Finally, distribution network model with PV was established after PV was introduced into the traditional distribution network, after PV was introduced into distribution network, change of the distribution network loss was analyzed separately from location, capacity and power factor of PV introduced, the rate of change of its net loss was analyzed and the corresponding influence conclusion is presented.