REFU Elektronik GmbH
REFUsol 48K-UL
49
7
Operating the Arc Fault Detection Unit (ADU)
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7.1
General Description
Important
The Arc Fault Detection Unit (ADU) is only included in the products of the
Art. No. 876P024.000 and 844P048.000.
The Arc Fault Detection Unit (ADU) is an arc fault detection device designed to detect series arcs in DC
photovoltaic installations. The ADU monitors the current flow at the string level. The ADU detects a range of
arc faults from 100 VDC 1 A to 1000 VDC 40 A. The ADU can detect arcing events over a maximum of
66 meters upstream or downstream of the installed location. When an arc fault occurs, the information is
provided using the following methods:
Buzzer provides an audio alarm
Message Arc fault detected is displayed on the inverter screen
Inverter stops operating and disconnects from the grid
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7.2
Normal Operation of the Arc Fault Detection Unit
In normal operating circumstances, the arc fault detection unit monitors the current flow and analyzes the
signal being measured to determine if there is an arc fault situation. The unit will do this continuously until
an arc fault occurs or the DC power supply is removed.
During normal operation, the following should be considered:
Make sure that the alarm can be easily heard, and that proper follow-up is assured.
Check the system monthly for faults.
7.2.1
To Operate the ADU in Normal Conditions
1.
Turn the AC/DC disconnect switch to the ON position. If the solar modules are receiving sufficient
sunlight and no fault exists, a quiet beep is emitted.
2.
Verify that the self-test procedure is complete by confirming that the START LED is continuously lit.
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7.3
Responding To An Arc Fault
When an arc fault is detected by the ADU, the inverter will provide the following signals:
A buzzer sounds for 30 seconds.
The arc fault error message is displayed.
An event is sent to REFUlog, if the inverter is using REFUlog.
After the first 30 seconds, the buzzer will sound once per minute.
