Lightning and surge protection for free field systems and solar parks

Protect your solar plant against direct lightning strikes and transient overvoltage
A lightning protection system for free field systems and solar parks has two main goals:

Protection of the power plant area from lightning-related damage
Protection of the modules, inverters and monitoring systems from the effects of electromagnetic impulses

Since the investment volume is high, operators require permanent system availability. For this reason, the lightning-related risk should be calculated according to IEC 62305-2. This risk analysis provides the basis for planning a lightning protection system.

Minimize the risk for existing systems
Existing systems are often insufficiently protected against direct lightning strikes and surges. We offer adequate products for retrofits and will be pleased to help you find a solution – just contact us: itss@dehn.de.

Have a look at some sample applications for possible configurations:

#1 - Centralised configuration with central inverter: show details

#2 - Distributed configuration with string inverter: show details

Centralised configuration with central inverter

Example 1

Extended DC cables are routed in the field in case of system concepts with central inverter technology.

A - DEHNcombo YPV

DC side - central inverter: Combined arrester specially developed for use in PV installations. Protects the DC side of the inverter against partial lightning currents and surges. Product details

C - DEHNshield

AC side: Combined lightning current and surge arrester. Protects the AC side of central and string inverters or AC-coupled battery storage systems.

D - BLITZDUCTOR XTU

Data interface: Combined arrester that protects balanced data interfaces (z.B. RS 485). Via the integrated actiVsense Technology the arrester automatically detects the operating voltage of the useful signal and optimally adapts the voltage protection level to it.

E - DEHNpatch CLE IP 66

Complete unit consisting of surge protection and outdoor enclosure (IP 66). Protects, e.g. IP camera systems.

F - UNI earthing clamps/saddle clamps

Equipotential bonding / Earthing: Clamps suitable for integrating the mounting systems of PV installations in the functional equipotential bonding / the functional earthing or the lightning equipotential bonding.

G - Angled air-termination rod

10 mm air-termination rod fixed to the metal support structure of PV modules to protect them from direct lightning strikes. Total length 1 m.

Normative regulations and notes: Supplement 5 to DIN EN 62305-3 provides information on the minimum discharge capacity of voltage-limiting or combined type 1 SPDs for a free field PV system in case of class of LPS III and a mesh size of the earth-termination system of 20 x 20 m. The values stated in this standard must be observed when selecting an adequate type 1 SPD for use on the DC side.

Comprehensive protection of electronic components

Type 1 + type 2 combined arresters are installed at the DC input of the inverters and in the generator junction boxes. Moreover, a type 1 combined arrester is used to protect the central inverter on the AC side. The data interfaces are also protected by adequate surge arresters.

Protection against direct lightning strikes

Air-termination systems are used to protect the PV array of the operations building from direct lightning strikes. The air-termination rods are often mechanically fixed on the metal mounting structures where the modules are mounted.

Distributed configuration with string inverter

Example 2

If PV power plants with distributed string inverters are used, most of the power cables are installed on the AC side.

B - DEHNguard M YPV

DC side: Type 2 arrester specially designed for application in PV systems. Protects the DC side of the inverter against surges from inductive couplings.

B - DEHNcube YPV SCI 1000

Alternatively: Type 2 arrester that provides comprehensive protection for a PV system in an enclosure. It is mounted directly upstream of the inverter and is available in two versions, 1 MPPT and 2 MPPT.

C - DEHNshield

AC side: Combined lightning current and surge arrester. Protects the AC side of central and string inverters or AC-coupled battery storage systems.

D - BLITZDUCTOR XTU

E - DEHNpatch CLE IP 66

Complete unit consisting of surge protection and outdoor enclosure (IP 66). Protects, e.g. IP camera systems.

F - UNI earthing clamps/saddle clamps

G - Angled air-termination rod

10 mm air-termination rod fixed to the metal support structure of PV modules to protect them from direct lightning strikes. Total length 1 m.

Comprehensive protection for electronic components

Type 2 arresters are installed at the DC input of the inverter. These arresters also protect the modules in close proximity. Type 1 combined arresters are installed on the AC side of the string inverter and the low-voltage side of the infeed transformer. The communication interfaces are also provided with adequate surge protective devices.

Protection against direct lightning strikes

Air-termination systems are used to protect the PV array and operations building from direct lightning strikes. These systems are often installed on the metal mounting structures.