Study On Reactive Rower Optimization In Large Scale Photovoltaic Power Station

At present,with the gradual depletion of fossil energy,photovoltaic power generation,as a new way of generating,gets more and more attention.With the increasing penetration of photovoltaic power generation,the capacity of large scale photovoltaic power plants is growing,and the area of photovoltaic is also increasing.But the problem of limiting the voltage of the internal node of the power station becomes more and more serious.In this paper,the photovoltaic power station is taken as the research object,and the voltage at PCC and the voltage limit in the station are studied.Firstly,the mathematical model of large scale photovoltaic power station,which composed of unit(PV generation,PVGU),box type transformer,collector line,main transformer and high voltage transmission line,is established in this paper.On the basis of the model,the theoretical analysis of the photovoltaic power station and PCC'S voltage and the voltage limit in the station is carried out.In the mathematical model of photovoltaic power plant,the mathematical model of reactive power optimization is established based on PCC'S voltage and node voltage minimum,active power loss minimum and the maximum power stability margin targets,and the objective function is the normalized.The objective function is solved by using the improved chaotic particle swarm optimization algorithm under the constraint of power constraint and variate constraint.For the chaotic particle swarm algorithm and particle encoding of binary encoding,and the particle encoding combined into a vector group B.Determining the diversity of particles through rank of vector group B.and the maximum linear independent vector group B group,to find out the maximum linear independent group corresponding to the particle will the particle chaos transform,rest in accordance with the standard particle swarm algorithm particle evolution.This can effectively solve the problem of particle swarm optimization algorithm in the latter part of the local optimization.In the day,the light intensity is segmented,and the reactive power optimization is carried out by using the improved chaos particle swarm optimization algorithm,which makes the photovoltaic power station safe and stable operation.The results show that the improved chaotic particle swarm optimization algorithm is more powerful than the standard particle swarm optimization algorithm.In view of the continuous change of light intensity,the multi mode reactive power control strategy is adopted to control the reactive power of the photovoltaic power station.This method is used to judge the operation mode of the power station by detecting the voltage of the PV power station and the grid voltage.Point voltage is greater than the set threshold,that there is no limit voltage of photovoltaic power plants,power plant set work in unity power factor of power grid mode;point voltage is less than the threshold,that is the limit voltage of photovoltaic power plants,photovoltaic power generation unit industry set photovoltaic power plant in Q(U)model.By comparing the detection voltage and PV power plant and network parameters open value,reactive power calculation and maintenance point voltage needed,the reactive power from photovoltaic power generation unit through the relevant calculation formula in order to maintain the station corresponding to node voltage stability,the difference value by the reactive power compensation device of photovoltaic power station compensation.The correctness of the control strategy is verified by simulation.