Photovoltaic & Storage

Solar farm

Why protect a solar farm from overvoltages?

Solar farms or photovoltaic fields are large installations mounted on the ground and generally located in large, open areas. Due to their vast exposed surface area and the long conductor lengths, these installations have a high risk of suffering transient overvoltages caused by atmospheric phenomena.

Protecting with overvoltage protectors is essential to maintain the integrity of the installation, prevent operating loss, ensure the safety of people and comply with regulations.

The IEC 61643-32 installation standard describes the protection measures in this type of installation, are usually characterised by having highly intertwined equipotential bonding systems, generally equipped with numerous earth connections. The frames and supporting structure of the photovoltaic panels must be connected to the earthing system.

The following aspects are relevant for the correct design of these systems:

  • Equipotential connection mesh.
  • Design of the earthing system.
  • Configuration type: with central inverter or string inverters.

What may be needed for our installation?

For the selection of overvoltage protectors (SPDs) there are two possible configurations: configuration with a central inverter and configuration with string inverters.

Solar farm
Configuration with a central inverter With string inverters
LAC >10 m >10 m
LPV >10 m >10 m
SPD1 AC Type 1+2 AC Type 1+2
SPD2 AC Type 1+2 AC Type 1+2
SPD3 PV Type 1+2 PV Type 2
SPD4 PV Type 1+2 PV Type 2

Installations with a central inverter have a large amount of DC wiring. Type 1+2 protectors will be installed on both the DC and AC sides.

On the other hand, in installations with string inverters, much of the wiring is moved from the DC side to the AC side and, on the DC side, it is sufficient to install type 2 protectors to limit partial lightning currents.

Solar farm
Type Range
AC Type 1+2 PSC 12,5
PV Type 1+2 PSC YPV
PV Type 2 PSM YPV

nimbus® Project Designer

The complete protection solution for each application may require an LPS (Lightning Protection System). Our software is free and allows you to do the risk analysis and solve the geometric project with your bill of materials.

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