Inverters for PV commercial systems

The main difference between inverters for residential and commercial systems is the size. It actually determines the inverter’s employment. Usually commercial inverters are those with a power higher than 10kW.

Generally commercial inverters are certified CEI 0-21 as well as CEI 0-16, regulating the connection to low, medium and high voltage grids .

Energy conversion is not their only feature. They actually do implement technologies to make a more efficient and long-lasting system. As follows some of the involved technologies:

MPPT: Maximum Power Point Tracker

Using MPPT (Maximum Power Point Tracker) the inverter maximizes energy production by photovoltaic modules. This technology ensures that every single photovoltaic string works at its maximum power point.

Anti-PID technology

Photovoltaic modules performances are mainly affected by PID (Potential Induced Degradation). A degradation caused by voltage difference between the cells and modules’ frames.

Anti-PID technology is now implemented to all commercial inverters in order to reduce performance degradation of PV modules.

Arc Fault Circuit Interruption

Commercial inverters are usually equipped with AFCI (arc-fault circuit interrupter). A device aiming to interrupt the circuit when electric arcs are detected. An hazard to be avoided as it’s an evidence of loose connections in the wiring.

One of the most common causes of fires on roofs where PV systems are placed.

Multistring

Recent inverters manage to connect multiple strings of modules to the same MPPT. Allowing to simplify installation by avoiding junction boxes.

Technical features

Commercial inverters have a power starting from 10/20 kW. Generally it is accepted DC input up to 1000V/1100V.

MPPTs change from 2 to 10 depending on inverter power. Concerning the output it is three-phase at 400V.

These devices are usually equipped with safety systems such as:

• Reverse polarity protection
• Type I or Type II over voltage protection
• AFCI

Operation & Maintenance

In this case we refer to an ordinary and extraordinary maintenance plan necessary to guarantee full functionality and productivity.

A number of activities aiming to maintain the PV system efficient and avoiding any downtime. A fair maintenance routine plan as well as constant monitoring of the data system allow a full efficiency.

Electrical workshop

Commercial inverters are often used in electrical workshops, also known as power generation workshops.

Energy production plants from renewable sources are normally handled by the same company, with a peak power of more than 20 kW and an energy generation aimed at self-consumption.

Every plant drawing energy from renewable sources that exceeds 20 kW installed for the production of self electricity consumption, must be reported to  the office of the Customs Agency of the competent territory.

Monitoring

Monitoring plays an important role in this type of inverter, as it allows to spot any problem in the system and to intervene in time to repair the breakdown.

It is clear that being able to quickly identify the problem allows the installer to save time as well as make the operation cheaper for the end customer.

Commercial inverters are often combined with data loggers in big plants. They verify inverters’ production connected to them, and at times sensors can be added to allow recording additional measurement values, such as irradiation and the ambient temperature.