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1 <br />SOLAR FACILITY DESIGN – A BRIEF PRIMER <br />PV MODULES,STRINGS, AND ARRAYS <br />A generic description of fixed ground mounted solar photovoltaic (PV) cells and how they can <br />interconnect individually into an electrical infrastructure is provided below. The processes and <br />component equipment used in PV plants starts with a hand sized solar or photovoltaic cell <br />which converts light into DC electricity by the photovoltaic effect. Photovoltaic cells are <br />interconnected silicon based cells connected in series creating an additive voltage. Solar cells <br />are electrically wired together to produce a PV module. <br />A PV module encases the stringed solar cells in an all-weather protective housing. It is generally <br />made of layers which can include a transparent glass face, anti-reflective layer, solar cells, metal <br />or synthetic back sheet, an electrical junction box with wiring connections and a frame. PV <br />modules are commonly 3.5 feet wide by 6.5 feet long by 2-3 inches thick in size. PV modules <br />can be built to order; therefore electric output depends upon the specifications required by a <br />developer. Several PV modules can be electrically connected together in series and/or parallel <br />to achieve the desired electric output, and then bolted together into a racking system to make <br />a row or string (Figure 1). <br />Figure 1.Relationship among a PV module, string, and array. <br />SUPPORT STRUCTURES <br />Racking refers to the support structure that the PV modules are affixed to that allows <br />them to be properly positioned for maximum capture of the sun’s solar energy. The PV