Grid Connected PV Systems

Introduction of Grid connected PV Systems

A grid connected system is connected to a large public electrical grid (owned by utility company) and feeds power into the grid. Grid connected systems vary in size from residential (2-10kW) to solar power stations (1-10MW). In the case of residential or building mounted grid connected PV systems, the electricity demand of the building is met by the PV system. Only the excess is fed into the grid when there is an excess.

The feeding of PV generated electricity into the grid requires the transformation of DC into AC by a grid-controlled inverter. On the AC side, the function of grid-connected inverter is to supply electricity in sinusoidal form, synchronized to the grid frequency, limit feed in voltage to no higher than the grid voltage including disconnecting from the grid if the grid voltage is turned off. On the DC side, because the power output of a module varies as a function of the voltage that power generation can only be optimized by varying the system voltage to find the 'maximum power point'. Most inverters therefore incorporate 'maximum power point tracking'.