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Installers & partners

Smart grid and system protection through the integrated Fronius solution

Ensuring reliability of supply through a stable grid – with the growing number of generating systems, it is more important than ever to maintain a constant voltage and frequency range in the grid. This article explains the key role played by the ’coupling switch’, and how you can even save costs here. 

The advantages of Fronius grid and system protection at a glance:


  • Control of the coupling switch via an external interface
  • External coupling switch is superfluous
  • Space saved at the distributor
  • Certification by an accredited testing institute 

What exactly is grid and system protection?

Grid and system protection primarily serves as a protection device that permanently monitors the voltage and frequency of the grid for the specified switch-off conditions.

In the event of a fault, the photovoltaic system is disconnected from the grid in a fail-safe* manner by switching off the coupling switch through the interface of the inverter.    

* An isolated fault event does not lead to loss of the safety functionality


Cost savings through activating the inverter integrated coupling switch

It is necessary to install external grid and system protection with larger photovoltaic systems in particular; this is usually explicitly specified by the respective grid operator.

On all Fronius inverters, the integrated coupling switch can be controlled by an external system & grid protection relay via an interface. This means, for systems at a certain size, it is unnecessary to install an additional coupling switch, which in turn means potential savings of up to € 2000 with larger systems.

This also means that an additional switch cabinet can be possibly omitted, as a central NA- protection relay as well as the coupling switch take up a lot of space.



The coupling switch is controlled via the multifunctional current interface. (designed as signal contact variant on “RECERBO”)

GEN24 Plus and Tauro inverters:

The coupling switch is controlled by the WSD (wired shutdown) function.


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