Thesis (M.Eng.)--Chulalongkorn University, 2014

Nowadays the electrical generation from renewable energy is extensively promoted because of the concern about greenhouse gas emission. Distributed Generation (DG) can be powered by a variety of renewable energy resources, and can be used for various objectives, for example, reduction of voltage sage, reliability improvement, and the possibility of deferral of the upgrading process of transmission and distribution infrastructure. However, the presence of PV system may have detrimental impacts on the operation of a distribution network because of the variation of solar radiation and ambient temperature. This thesis covers the following three issues 1) Evaluation of active power from PV system related to sunlight and temperature variation 2) Determination of connecting locations for PV system and 3) Calculation of optimal reactive power from inverter to improve voltage profile when active power changes. In practice, when the voltage changes and exceeds the limits, the inverter of PV system can inject or absorb reactive power to correct the voltage deviation. The optimal reactive power is calculated to minimize voltage deviation of all buses by the proposed method based on Newton-Raphson load flow and sensitivity index. The IEEE 33 bus test system is selected to analyze the voltage deviation in various conditions.