The On-grid system is connected with utility grid (like KSEB in Kerala) and this system would work only if the grid is available. In case of a power cut, the system will not work and hence the On-grid system is also termed as a Grid-tied system. Grid is required since the inverter needs to be provided a reference voltage and the inverter needs to sync with the grid in order to export energy back into the grid.
Basic components for grid connected system