SMA SUNNY CENTRAL Maintenance manual - Manual (Page 49)

SMA Solar Technology AG Checking protective devices
Maintenance Manual SCWAR-WEN094020 49
6.5 Checking the overvoltage arrester
Depending on the switch cabinet model and production version, the central inverters have several
overvoltage protectors which need to be regularly checked for correct function.
You can locate the exact position and number of overvoltage protectors using the reference
designation of the components in the provided circuit diagram.
The overvoltage protectors are inspected visually and by means of measurements.
6.5.1 Checking the Dehn Guard
Measurements
An exact statement about the state of the arrester can only be made with an appropriate test device.
The PM20 from Dehn + Söhne GmbH & Co. KG is the suitable test device for this purpose. The
measurement procedure is described in the user manual of the device and has to be carried out by
an electrically skilled person.
DANGER!
Death resulting from electric shock and burning upon touching the medium-
voltage grid's live components.
• Only work on the device when it is switched off and voltage-free.
1. Visual inspection of the arrestor for optical signs of wear.
2. Check the operating readiness of the arrester via the
function and fault signaling (A) of the protection path which
is free of operating current.
Visual display green Overvoltage protector is ready for operation.
Visual display red Overvoltage protector defective