Disconnecting The Medium-Voltage Transformer - SMA SUNNY CENTRAL UP Service Manual

3 Disconnecting and Reconnecting
10. Hook a suitable padlock into the bracket and lock it. This will ensure that the switch lever cannot reconnect
inadvertently.
11. If external supply voltage is used, disconnect the supply voltage via upstream switching devices.
12. Disassemble the outer panel of the AC switch module
Disassembling and Mounting the Panels.
13. Verify that the switch state display of the AC disconnection unit is in the OPEN position.
14. Mount the outer panel of the AC switch module Disassembling and Mounting the Panels.
15. Ensure that 25 minutes have passed after switching off the load-break switch -Q61.
16. Open the hatch on the AC side of the inverter Opening and Closing the Hatches.
17. Ensure that no voltage is present on the -X250 terminal.
☑ The inverter must be disconnected from all voltage sources on the AC side.
18. Disconnect all poles of the String-Combiner from voltage sources, secure against reconnection and remove fuses.
19. Measure the DC voltage at the terminal -X251. Measure DC+ against DC- and both poles against the grounding
conductor. The DC voltage must be 0 V.
20. Open the hatch on the DC side of the inverter Opening and Closing the Hatches.
21. Ensure that no voltage is present for each DC input. Use the measuring points on the bottom of the fuse holders.
Tip: There are drill holes in the protective covers above the fuse holder. Through these drill holes you can
determine the voltage-free status with suitable test probes without having to disassemble the protective covers.
☑ The inverter is completely disconnected from all voltage sources.
3.2

Disconnecting the Medium-Voltage Transformer

Additionally required material (not included in the scope of delivery):
☐ 1 padlock. Diameter of the shackle: 5 mm to 8 mm
☐ Grounding and short-circuiting equipment
Procedure:
1. Ensure that the inverter is disconnected from all voltage sources (see Section 3.1, page 11).
2. Switch off the transformer panel of the medium-voltage switchgear (see manufacturer's documentation).
3. Ensure that no voltage is present.
4. Ground the transformer panel of the medium-voltage switchgear (see manufacturer's documentation).
5. Lock the circuit breaker for the medium-voltage switchgear using a padlock. This will protect the switch levers from
inadvertent reconnection.
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SMA Solar Technology AG
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Service Manual for Installers
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