ABB UNO-DM-2.0-TL-PLUS-Q Product Manual page 139

External DC
Switch
PV Strings
External DC
Switch
PV Strings
Identification of the external switch may require the cooperation of the plant manager and it
must be included in the switching plan defined during the preparation of the work.
4. Operations on External AC switches
The diagram below represents a possible arrangement of the PV plant.
Depending on the design choices made by the developer of the plant
some of the devices could not be present. Identify the external AC
switch(es) in the plant with the support of the plant manager.
INVERTER 1
(Unit under service)
Internal DC
Switch
INVERTER 2
Internal DC
Switch
• Open the external AC disconnect switch or the main external AC
disconnect switch (blue in below picture) outside the inverter (IEC
60364-7-712.536.2.2). In case none of the LV AC switches are
present, the MV switch must be opened.
• Affix designated lock preventing operation onto any external AC
disconnect device, affixing designated tags (LOTO procedure).
• Check on the status LEDs
carried out (Missing Grid status):
- Power LED (Green): Flashing
- Alarm LED (Yellow): ON (solid)
- GFI LED (Red): OFF
- WLAN/LAN LED (Blue): Depends by the communication
status.
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OPEN+LOTO
External LV External Main LV
AC Switch AC Switch
External LV
AC Switch
LV Distriubution
Panel
the shutdown command has been
06
8 - Maintenance
LV/MW
Transformer
MW Switch