TYPES OF ROOFTOP PV SYSTEM
This section describes the common types of RTPV systems and the components that are necessary. This section is primarily aimed at the homeowner in order to get a better idea about the RTPV system. It gives an overview and highlights the importance of each component in the system.
Stand Alone PV Systems (for places with no grid electricity)
Stand-alone PV systems, which are isolated from the distribution grid usually, use stand alone inverters with batteries. The figure 1
shows a stand-alone system with both DC and AC loads and figure 2 shows a stand-alone system with only DC loads.
Grid Connected PV Systems (grid present, no or not many power cuts
Grid-connected PV systems (also known as grid-tied systems), which are directly connected to the distribution grid, use grid connected inverters, and usually do not use batteries. These systems are capable of exporting surplus power into the distribution grid. A grid-connected PV systems is designed to automatically shut down if it detects anomalies in grid parameters such as voltage, frequency, rate of change of frequency, etc.
Hybrid PV Systems (grid present, but several power cuts)
Hybrid PV systems are connected to the grid and also have a battery backup. If a hybrid PV system observes anomalies in grid parameters, it is designed to isolate the consumer from the grid and continue to supply power from the PV system and batteries. The batteries can be charged by the grid or by solar energy in such systems.