Selecting the right surge protection

Installation location and applications.

Find out more and download the brochure ‘Lightning and surge protection for photovoltaic systems’.

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Photovoltaic system on house roof

Possible rooftop systems:

Building without external lightning protection

Building without external lightning protection

Building without external lightning protection

A lightning strike on the building has not been taken into consideration. A photovoltaic system also does not increase the risk of being struck by lightning. The photovoltaic system is integrated into the equipotential bonding.

Building with external lightning protection and separation distance “s” observed

Building with external lightning protection and separation distance “s” observed

Building with external lightning protection and separation distance “s” observed

The PV panels are installed a sufficient distance from the lightning protection system in the protection zone. The photovoltaic system is optimally protected in the event of a lightning strike. The photovoltaic system is integrated into the equipotential bonding.

Building with external lightning protection but separation distance “s” not observed

Building with external lightning protection but separation distance “s” not observed

Building with external lightning protection but separation distance “s” not observed

The PV panels are installed close to the lightning protection system. Therefore, in the event of a lightning strike, there could be a dangerous sparkover to the photovoltaic system. To prevent this, the PV panels and/or the PV mounting frame are connected properly to the lightning protection system. Please note here that partial lightning currents are introduced into the building. The equipotential bonding must be able to handle lightning currents.

The right installation location

Graph: Surge protective devices near the inverter and the photovoltaic system

Surge protective devices near the inverter and the photovoltaic system

The right surge protection for the particular application

 

AC voltage 1

AC voltage 2

DC voltage 1

DC voltage 2

 
Installation location Main distribution AC side of the inverter (cable length to the main distribution ≥10 m) DC side of the inverter (cable length to the PV panels ≥10 m) Near the PV panels or the entrance to the building
Without external lightning protection Type 2 SPD Type 2 SPD Type 2 SPD Type 2 SPD
With external lightning protection, separation distance is observed Type 1 SPD Type 2 SPD Type 2 SPD Type 2 SPD
With external lightning protection, separation distance is not observed Type 1 SPD Type 1 SPD Type 1 SPD Type 1 SPD

Surge protective devices for the AC side

 

Type 1+2 combined lightning current and surge arresters
Type 1+2 combined lightning current and surge arresters
Type 2 surge protective devices
Type 2 surge protective devices
Type 1+2 combined lightning current and surge arresters

Type 1+2 combined lightning current and surge arresters

Type 2 surge protective devices

Type 2 surge protective devices

 
Power supply network 3-phase 1-phase 3-phase 1-phase
Designation VAL-MS-T1/T2 335/12.5/3+1 VAL-MS-T1/T2 335/12.5/1+1 VAL-MS 320/3+1 VAL-MS 320/1+1
Item number without remote indication contact 2800184 2800187 2859178 2804380
Item number with remote indication contact 2800183 2800186 2859181 2804393

Surge protective devices for the DC side

 

Type 2 surge protective devices
Type 2 surge protective devices
Type 2 surge protective devices
Type 2 surge protective devices
Type 2 surge protective devices

Type 2 surge protective devices

Type 2 surge protective devices

Type 2 surge protective devices

Maximum continuous voltage UCPV 1500 V DC 600 V DC 1000 V DC 1500 V DC
Total discharge surge current Itotal 40 kA 40 kA 40 kA 30 kA
Designation VAL-MB-T2 1500DC-PV/2+V VAL-MS 600DC-PV/2+V VAL-MS 1000DC-PV/2+V VAL-MS 1500DC-PV/2+V
Product feature Not pluggable Pluggable Pluggable Pluggable
Item number without remote indication contact 2905647 2800642 2800628 1033708
Item number with remote indication contact 2905646 2800641 2800627 1033725

Discharge capacity

For type 1 surge protective devices, the discharge capacity Itotal must correspond to the load values at the installation location. These specifications correspond to European standard DIN EN 62305-3. Our experts will be happy to advise you on the resulting local specifications at your site.

 

 

 

 

*) LPL I and II with fewer than four protective devices does not occur in practice.
Lightning protection class LPL Max. lightning current < 4 protective devices Itotal: I(8/20 µs) < 4 protective devices Itotal: I(10/350 µs) ≥ 4 protective devices Itotal: I(8/20 µs)
I 200 kA 34 kA* 20 kA* 20 kA
II 150 kA 25 kA* 15 kA* 15 kA
III + IV 100 kA 17 kA 10 kA 10 kA

 

 

VAL-MB-T1/T2 600DC-PV/2+V
VAL-MB-T1/T2 1000DC-PV/2+V
VAL-MB-T1/T2 1500DC-PV/2+V
VAL-MS-T1/T2 600DC-PV/2+V
VAL-MB-T1/T2 600DC-PV/2+V

VAL-MB-T1/T2 1000DC-PV/2+V

VAL-MB-T1/T2 1500DC-PV/2+V

VAL-MS-T1/T2 600DC-PV/2+V

Maximum continuous voltage UCPV 600 V DC 1000 V DC 1500 V DC 600 V DC
Total discharge current Itotal (8/20 µs) 40 kA 40 kA 40 kA 40 kA
Total discharge current Itotal (10/350 µs) 12.5 kA 12.5 kA 12.5 kA 5 kA
Product feature Not pluggable Not pluggable Not pluggable Pluggable
Item number without remote indication contact 2906293 2905639 2905641 2801163
Item number with remote indication contact 2906292 2905638 2905640 2801164

In many cases, several MPP trackers and inverters are used. It is important that each MPP tracker is configured separately. The string cables are distributed to the MPP trackers and inverters and must not be interconnected. Therefore, also use a separate surge protective device for each MPP tracker and inverter.

If two or more MPP trackers are protected with surge protective devices, the discharge current is divided once again. This allows a smaller surge protective device to be used, if necessary.

You can also order our surge protective devices as ready-to-connect versions in a housing for surface mounting. We offer the appropriate box for many inverters. Simply select your inverter and we will show you the corresponding boxes.

Surge protective devices for interfaces

In addition to the four installation locations of surge protective devices for PV systems that have been highlighted so far, there is another area that you shouldn’t forget:
The protection of communication interfaces is not necessarily required by standards, but is nevertheless highly recommended. The inverter electronics can actually be damaged by overvoltages via a network cable or a thin control line, thus disrupting the operation of the photovoltaic system.

Digital inputs for power regulation, a weather station, Ethernet, RS-485: all of these are examples of common interfaces that need to be protected.

 

 

TTC-6P-2X1-F-M-24DC-PT-I
TTC-6P-3-HF-F-M-12DC-PT-I
DT-LAN-CAT.6+
TTC-6P-2X1-F-M-24DC-PT-I

TTC-6P-3-HF-F-M-12DC-PT-I

DT-LAN-CAT.6+

Interface protection Digital signals RS-485 (2-wire) Gigabit Ethernet (up to 10 Gbps)
Item number 2906794 2906796 2881007