Probabilistic Load Flow For Power Grid Containing Wind Farms And PV

As the fossil energy depleted and the needs of the development of low-carbon economy,wind power and photovoltaic power and other renewable energy more and more paid attention toby the countries all over the world.However, due to the wind and the light intensity has greatrandomness and intermittent, wind turbines and photovoltaic energy’s output will generaterandom changes, large-scale wind power and photovoltaic grid-connected will be impacting onthe safe operation of power system optimal power flow.This paper is studying thewind/photovoltaic hybrid generation in grid, which using the probabilistic load flow method toanalysis of the safety about power system.Firstly, introducted the probabilistic power flow calculation of mathematical researchfoundation and the analytical tools, given the concept definition of semi-invariant,gramm-Charlier series, Nataf transformation, and the application in the power flow calculation methodabout Matpower tools.Secondly, based on the Gramm-Charlier series and Nataf transformation with thewind/photovoltaic hybrid generation in grid.Given the output probability mode of wind farmsand photovoltaic electric field.And established the modle of Gramm-Charlier series and semi-invariant model and branch or node probability load flow, at the same time,generator shutdownand branch random bolt model is established.Finally, giving the probabilistic load flow process of containing wind/photovoltaic. Thispaper mainly through the Matlab combining Matpower toolbox for power flow calculation andsimulation.Examples in IEEE57system of different nodes (contains generator node and nogenerator node) were joined into the wind farms, photovoltaic, and the wind/photovoltaic hybridfarms, taking into account the system of generator shutdown or the branch being broken and thewind speed correlation, analyzing the node voltage limit probability and the influence of the flowabout distribution system when the wind farms, photovoltaic and the wind/photovoltaic hybridfarms joined on the power system.In this paper,when the wind/photovoltaic hybrid generation system injection distributionnetwork,we can through the probabilistic power flow to analyze the probability distribution ofthe branch power flow, the probability distribution of the node voltage, the probability of thevoltage limit and so on, through analyzing the power system data to give a more detailed analysisabout planning of the whole system,etc.We could find that the weak links in the system inadvance.And the operating personnel could accord to the system operation condition to decide whether to need to take preventive measures, and make the optimization control and preventionmeasures and emergency preparedness plans, keeping the system in a higher level of safeoperation.