An Introduction to Photovoltaic Systems may include electrical generators, wind turbines, fuel cells and the electric utility grid. See Fig. 1.
PV systems are electrical power generation systems that produce energy. They vary greatly in size and their applications, and can be designed to meet very small loads from a few watts or less up to large utility-scale power plants producing tens of megawatts or more. PV systems can be designed to supply power to any type of electrical load at any service voltage.
Balance-of-system (BOS) components include all mechanical or electrical equipment and hardware used to assemble and integrate the major components in a PV system together. Electrical BOS components are used to conduct, distribute and control the flow of power in the system.
The major component in all PV systems is an array of PV modules that produces dc electricity when exposed to sunlight. Other major components may include power conditioning equipment, energy storage devices, other power sources and the electrical loads. Power conditioning equipment includes inverters, chargers, charge and load controllers, and maximum power point trackers. Energy storage devices used in PV systems are mainly batteries, but may also include advanced technologies like flywheels or other forms of storing electrical energy or the product, such as storing water delivered by a PV water pumping system. Other energy sources coupled with PV systems
Examples of BOS components include: • • • • • • • •
Conductors and wiring methods Raceways and conduits Junction and combiner boxes Disconnect switches Fuses and circuit breakers Terminals and connectors Grounding equipment Array mounting and other structural hardware
PV System Components
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1. PV modules and array 6
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2. Combiner box 3. DC disconnect 4. Inverter (charger & controller) 5. AC disconnect
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6. Utility service panel 7
2011 Dunlop Solar Figure 1. -Jim PV system components
8 • NABCEP PV Installation Professional Resource Guide
7. Battery (optional)
Solar Radiation: 2 - 2
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