Long-term Process Analysis And Reactive Power Adaptive Control Of Distributed Photovoltaic

The output of photovoltaic generation is changed based on the level of solar radiation intensity,temperature and weather condition.It has the characteristics of randomness and intermittent.The operation of the distributed system control will be more complicated when plenty of PV switched in,and the system losses,voltage level,security and economy will be influenced as well.The way to improve the power transmission and voltage quality is arranging reactive power compensation equipment and operation mode,optimizing reactive power distribution.Furthermore,PV which switched into the system can be disposed as a kind of reactive power compensator by controlled its power factor.So it is important to do researches on optimization of reactive power control in the distribution system with PV penetration.An auto-control model of reactive power with several optimization targets is proposed in this paper based on the photovoltaic-converter system,and thus enhance the power quality and operation level of power system.This paper analyzed the pattern of PV reactive power output and the calculation method of PV's active power and reactive power output on the bases of the external characteristic and control strategy of PV.Solar energy prediction technology and load prediction technology have been added to make a better prediction of voltage and system losses when the PV penetrates.A two-stage reactive power optimization method considering optimizing costs and control number limit of Var devices is proposed in this paper to avoid switching too much more.In the pre-optimization,simulation is processed in all the period by considering system losses only.A chart of optimization can be listed using the results of the tap position of each reactive device in the pre-optimization.In the real-time optimization,all costs,the number of equipment control,voltage level are all considered and a comprehensive result of device tap can be calculated.The algorithm of the two-stage optimization is particle swarm optimization(PSO).In the end of this paper,a kind of distributed reactive power control method based on consensus control theory is also proposed to solve the condition of no-central algorithm.A IEEE13 node model and a Turpan photovoltaic roof model have been established using simulation platform OpenDSS(Open Distribution System),the PSO is programmed in MATLAB.The simulation results show that the optimizationmethod proposed in this paper has a better precision and instantaneity,which could meet the demand of power system dispatching operation decisions.This method can be effectively used in on-line reactive power optimization.