Power Quality Analysis And Distribution Optimization Of Changxing Island Photovoltaic Power Station

The state advocates the construction of clean energy on a large scale.In the past five years,a lot of wind power grid-connected,photovoltaic grid-connected is becoming more and more popular.As distributed photovoltaic power generation will change with the change of sunshine in the natural environment.After the integration into the distribution network,the original structure of the distribution network will be affected,which will have a bad influence on the quality of electricity used by residents.The quality of power supply and distribution is related to the vital interests of residents.Power quality refers to the quality of AC power supplied to users through public power grids.Measuring the quality of power mainly includes the following contents: voltage deviation,three-phase current(or voltage)amplitude deviation beyond a certain range,voltage fluctuation and flicker,voltage sag,harmonics.This paper mainly considers three points: analysis of voltage amplitude,phase angle deviation,analysis of three-phase balance degree and simple analysis of harmonics,other factors are not focused on in this paper.The characteristics of photovoltaic array under different external conditions are studied,and a better MPPT algorithm is introduced to complete the control scheme of photovoltaic micro-power supply.The access capacity of distributed generators is directly related to the stability of grid-connected generators.The influence of the access of distributed photovoltaic power generation equipment on the power supply quality is studied through the power quality indicators such as voltage deviation,voltage fluctuation,harmonics and three-phase unbalance.The simulation is carried out by a simplified IEEE33 system of a line.This paper studies the standards of grid-connected photovoltaic power generation and power quality evaluation methods in China,and focuses on a comprehensive evaluation method of power quality based on Data Envelopment analysis.After comparing different algorithms with other power quality calculation methods,the following conclusions are drawn: the closer the feeder of access point is to the bus terminal,the larger the voltage deviation of access point is.Voltage fluctuation has a positive impact on the access location and capacity of distributed generation.The closer the access location is to the end of the distribution network and the higher the capacity of the access system,the more serious the voltage distortion of the feeder itself will become.Then,particle swarm optimization(PSO)algorithm is used to optimize the location and capacity of photovoltaic power generation access to verify the effectiveness of the evaluation method in this paper.Finally,on the basis of improving the comprehensive evaluation of particle swarm optimization(PSO)and data envelope,a photovoltaic grid-connected planning method aiming at power quality is proposed,and the flow chart of distributed photovoltaic planning method with power quality constraints is given.Finally,the access point of a new 10 kV photovoltaic line in Changxing Island has been analyzed.The simulation calculation method is used to focus on the three-phase balance and unbalance,and the voltage deviation,harmonic voltage and voltage of the selected planning method are tested.Fluctuation,three-phase unbalance,eliminate the access points that have the greatest impact on power quality,and select the access points that have less impact on power quality for the next step of optimization and actual situation investigation.