31Characteristics
EN
3.10 Description of the equipment
This equipment is a string inverter which converts the direct current of a photovoltaic generator into
alternating current and feeds it into the public distribution grid.
Photovoltaic panels convert solar radiation into “DC” direct current electrical energy (via a photovoltaic
field, also called PV generator); in order to be used from final user, it is transformed into “AC” alternate
current. This conversion, known as inversion from DC to AC, is done in an efficient way by the ABB inverters,
without using any rotary elements, rather only via static electronic systems.
In order to allow inverter operation in safe thermal and electrical conditions, the unit automatically reduces
the value of the power fed into the grid under adverse environmental conditions or unsuitable input
voltage values.
When connected in parallel with the grid, the alternating current from the inverter flows directly into the
domestic or industrial distribution circuit, which is in turn connected to the public distribution grid.
In this way the solar energy system compensates the energy drawn from the utilities connected to the
grid to which the inverter is linked.
When the photovoltaic system is not generating enough energy to ensure proper operation of connected
loads, the remaining required power is taken from the public distribution grid. While if too much energy
is produced, it is directly fed into the grid, thus becoming available to other users.
According to national and local standards and regulations, the produced energy can be sold to the local
grid owner or credited to the user against future consumption, thus granting a great saving of money.
3.10.1 Operating diagram (example)
PVS-175
3.10.2 Mutual connection of multiple inverters
If the photovoltaic system exceeds the capacity of a single inverter, it is possible to connect multiple
inverters to the system, each of them in turn connected on the DC side to a separate section of the
photovoltaic generator, and on the AC side to the distribution grid.
Each inverter will work independently of the others and its own photovoltaic module will supply the
maximum power available to the grid.