10-20KA Solar Surge Arresters Solar Surge Protection Device (SPD) Surge protectors for photovoltaic systems

What is a Surge Protection Device?

In order to avoid high voltage damage to a PV system, voltage surges should have a path to ground to avoid high energy from passing through electronics. In order to provide this path, all of the wiring exiting and entering the system should be coupled to ground through a Surge Protection Device (SPD), and all conductive surfaces should be directly grounded. Examples of lines exiting and entering the system include the AC mains and communication lines, such as Ethernet cables, RS485 cabling and telephone lines. Note that SPDs on power lines provide protection that is different from circuit breakers; breakers protect equipment from over current while SPDs protect equipment from over voltage. SPDs are usually a combination of Metal Oxide Varistors (MOVs), Gas Discharge Tubes (GDT) and/or Zener diodes, and current limiting devices that act to shunt charge to ground and to divert it from entering the protected system in the event of high voltage or currentsurges. Both MOVs and GDTs have a limited lifetime, and can handle a finite number of surge events

Surge Protection for Photovoltaic Systems

Protection of PV devices against transient overvoltages

Most of the solar module manufacturers offer a warranty of 20 years or more on their products. The cost of such devices is then calculated on this very long period. However those installations are very regularly exposed to lightnings and overvoltages, which can considerably reduce the desired life expectancy. The use of adapted surge protections is then highly recommended. Several aspects have to be considered to evaluate the risk "Lightning and Overvoltages" : The more the solar panel field is expanded, the more the risk of "lightning" issue is important. The risk is multiple : direct effect (lightning impact directly on the modules) and indirect effect (overvoltages on modules, on the converter/inverter and other connections). When the Photovoltaic devices are located on industrial sites, the risk of operation overvoltages should be taken in account as well. The risks level is directly linked to the density of local lightning and the exposure of the lines.

Surge Protectors for PV devices The photovoltaic installation can be exposed to overvoltages on different networks : - AC network : surge protectors are necessary, sometimes mandatory, for the 230V monophase network (or 3-phases 230/400V) on which the PV inverter is connected. - DC network : surge protectors are necessary, sometimes mandatory, on the continuous network in between the modules and the PV inverter. - Data Network : if the PV inverter is linked to data lines (transducers, sensors, supervision) surge protectors are sometimes required.

Surge Protectors for PV installations - AC side