SMA TCS 500-SC Maintenance manual - Manual (Page 20)

5 Maintenance After Disconnection SMA Solar Technology AG
20 TCS-CP-WH-en-10 Maintenance manual
5.5 Checking That Interlocking Works
1. Release the key in the key box for the medium-voltage side:
• If there is one AC circuit-breaker present, open the AC circuit breaker and lock it. When
doing this, take the key from one AC circuit breaker and stick it in the key box.
• If there are two AC circuit-breakers present, open both of them and lock them. When doing
this, take the keys from two AC circuit breakers and stick them in the key box.
• Take the key for the medium-voltage control panel from the key box
2. Release the key for the medium-voltage terminations:
• Unlock the medium-voltage control panel with the key from the key box for the
medium-voltage side.
• Disconnect the medium-voltage control panel for the medium-voltage side.
• Earth the medium-voltage control panel for the medium-voltage side.
• Take the key for the medium-voltage terminations from the medium-voltage control panel.
3. Use the key for the medium-voltage terminations to open the medium-voltage termination
connection area.
4. Lock the connection area of the medium-voltage terminations using the key for the
medium-voltage terminations.
5. Stick the key for the medium-voltage terminations into the medium-voltage control panel.
6. Unlock the medium-voltage control panel for the medium-voltage side and reconnect the
medium voltage.
7. Replace the key for the medium-voltage side in the key box.
8. Take the key of the circuit breaker out of the key box and stick it into the circuit breaker.
9. Unlock the AC circuit breaker and close it.
Interlocking
The low-voltage protection is carried out with a locking system. As soon as the AC circuit
breaker is opened and locked, a key is released. You can use this key to prevent the
medium-voltage control panel switching to earth. The key is blocked and cannot be removed.
There is a second lock on the medium-voltage control panel which releases another key. This
key opens the scissors system of the MV transformer on the upper voltage side and enables
access to the medium-voltage terminations.