What are the main components of a solar PV system
A residential solar PV installation (SHS/PPS) typically consists of the following main components:
- Solar PV modules
Solar cells use sunlight to produce electricity. Solar PV modules consist of several solar cells, which can be connected in series and in parallel to achieve the desired module output power. Solar PV modules work only during daytime, when sunlight is available, and they generate direct current. - Mounting structure: Solar PV modules can be installed on rooftops, fixed on the façade, mounted on awning supports at the façade or mounted on the ground. Additionally, adjustable systems, which allow the modules to follow the sun path and increase their output, are available on the market. The choice of mounting system depends on various factors, which will be evaluated in this technology guide.
- DC cabling and fuses: A junction box including bypass diodes, as far as needed, is an enclosure located on the solar PV module. It is the output interface between the conductor ribbons and the DC input and output cables of the solar PV module. Modules are connected in series via DC cables to form strings, and each string has its own fuse to protect the cables from overloading. Because the modules are mounted outdoors and may be exposed to harsh weather conditions, the cables have to be sufficiently robust, but also flexible, ultraviolet (UV)-resistant and waterproof. To minimise a voltage drop, the cables’ cross-section and length have to be appropriately dimensioned.
- Inverter: Both electrical distribution grids and off-grid electrical networks use alternating current. Thus, inverters are needed to convert the DC current to AC at the specified frequency and voltage (mostly 50 Hertz (Hz) and 220-240 volt (V), or in the US and Asia 60 Hz and 100-127 V). If there is no functional electricity grid, a battery system is needed. The off-grid inverter (e.g., island inverter) is able to connect the solar panels to the off-grid system and charge up the batteries that cover periods when solar power output drops too low.
- AC cabling and fuses: Because the inverter output is AC, cabling and fuses between the inverter and the grid have to meet the requirements set out in the local grid code. To minimise voltage drop, the cables’ cross-section and length have to be appropriately dimensioned.
- Battery storage and energy management system (optional): Self-consumption of the power generated by solar PV modules and off-grid systems requires rechargeable batteries and demand-side management to efficiently utilise the solar power.
