ABB UNO-DM-2.0-TL-PLUS Manual page 163

OPEN+LOTO
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.
The time needed for the complete shut-down of the LEDs depends by the input voltage of the
inverter. The complete shut-down of the LEDs may require some minutes.
5. Operations on External DC switches (if present)
Note: In case of absence of External DC disconnect device skip this step.
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 DC
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 DC disconnect switch (blue in below picture)
outside the inverter (IEC 60364-7-712.536.2.2)
• Affix designated lock preventing operation onto any external DC
disconnect device, affixing designated tags (LOTO procedure).
• Check on the status LEDs
carried out (Missing DC voltage status): All LEDs OFF.
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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