Modeling of photovoltaic power plants

This work deals with methods of design for the appropriate selection of a stand-alone photovoltaic power system for residential application in the absence of utility power supply. For a prescribed power demand design includes the determination of required number of photovoltaic (PV) panels and the proper total size of batteries to store part of the day collected energy for night or to supply power during cloudy times (autonomy) when the collected solar power is inadequate to meet the power demand. Generally the average solar insolation value over 30 years in the particular site is used for the design of such PV systems. Simple calculations are normally conducted to determine the proper number of the solar panels needed to meet the total energy demand during day and night as average kWh per day. The required number of panels depends on the average energy available from the sun at the selected site. With some statistical analysis it is possible to calculate the optimum size of battery storage capacity and total number of batteries required of any particular type. The selection of inverter and other supporting equipment subject to some technical considerations, like rating when operating for extended periods, and the surge capacity of the inverter is particularly important. A C++ computer program was developed to implement the selected design procedures and calculates size ratings of the various components of the PV system. The program accepts the load demand details from the client as input data together with the solar insolation. In fact the program design would be applicable to small single home or to a collection of many homes in a small village because they share similar design features i.e. they can be represented by the same mathematical model.