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
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.