9290

8592

كارشناسي ارشد

برق -قدرت

اصفهان: دانشگاه صنعتي اصفهان،دانشكده برق و كامپيوتر

1393

يازده،77ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

مهدي معلم

8/9/93

حميدرضا حق شناس، غلامرضا يوسفي

مهندسي برق و كامپيوتر

ID8592

78 Voltage Profile Control in Distribution Networks Heavily Dependent on Photovoltaic Resources during Sudden Change in Radiation Condition Nahid Dadashpour n dadashpour@ec iut ac ir Date of Submission 2014 9 21 Department of Electrical and Computer Engineering IsfahanUniversity of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mehdi Moallem moallem@cc iut ac irAbstract Due to limitations of fossil energy resources and the environmental issues renewable energy sourceshave gained much more attention in recent decades In this regard photovoltaic system application has alsoincreased consistently Photovoltaics generated power depends on factors such as solar radiation andtemperature Since the solar radiation changes based on time and weather conditions the generated powerwould fluctuate which affect voltage profile power quality and system performance Nowadays with the increment in the number of sensitive loads and power electronic devices powerquality is considered as an important factor in distribution systems Therefore one of the main challengestoward the use of PV system is the fluctuation of generated power as clouds passing and sudden variationsoccur in solar radiation intensity Since PV systems have a static nature and there are no mass or acceleratinginertia effects of fluctuations in solar radiation and correspondingly in generated power would transferrapidly and cause voltage variations Traditional control methods utilizing shunt capacitor banks on load tap changers and voltage regulators have a slow response which cannot compensate fluctuations associated with photovoltaic generation Furthermore application of fast and advanced complementary equipments for distribution sources are notjustified economically Therefore presenting an optimal control method based on PV inverter is both fast andeconomical In this thesis first we modeled PV systems and the corresponding electronic interfaces based on activeand reactive power exchange Then we investigated the effect of variations in weather condition and solarradiation on systems generated power The power quality phenomenon of voltage sag resulting from powerfluctuations are investigated Finally an optimal algorithm is presented to control the PV inverter forreactive power injection which improves the voltage profile The extent of injected reactive power is limited to minimize grid and inverter losses and consumedenergy considering voltage standard limits Finally the effect of photovoltaic systems and grid variousparameters on the extent of voltage profile variation is investigated Keywords Optimal Reactive Power Injection Photovoltaic Systems Dynamic Modeling Voltage ProfileControl Voltage Sag Weather Condition Voltage

مهدي معلم

حميدرضا حق شناس، غلامرضا يوسفي