Repair Instruction - ABB RET670 Commissioning Manual

1MRK 504 165-UEN A
15.3
Transformer protection RET670 2.2 IEC
Commissioning manual

Repair instruction

Never disconnect the secondary connection of a current transformer
circuit without short-circuiting the transformer's secondary
winding. Operating a current transformer with the secondary
winding open will cause a massive potential build up that may
damage the transformer and may cause injuries to humans.
Never connect or disconnect a wire and/or a connector to or from a
IED during normal service. Hazardous voltages and currents are
present that may be lethal. Operation may be disrupted and IED and
measuring circuitry may be damaged.
An alternative is to open the IED and send only the faulty circuit board to ABB for
repair. When a printed circuit board is sent to ABB, it must always be placed in a
metallic, ESD-proof, protection bag. The user can also purchase separate
replacement modules.
Strictly follow the company and country safety regulations.
Most electronic components are sensitive to electrostatic discharge and latent
damage may occur. Please observe usual procedures for handling electronics and
also use an ESD wrist strap. A semi-conducting layer must be placed on the
workbench and connected to earth.
Disassemble and reassemble the IED accordingly:
1. Switch off the dc supply.
2. Short-circuit the current transformers and disconnect all current and voltage
connections from the IED.
3. Disconnect all signal wires by removing the female connectors.
4. Disconnect the optical fibers.
5. Unscrew the main back plate of the IED.
6. If the transformer module is to be changed:
• Remove the IED from the panel if necessary.
• Remove the rear plate of the IED.
• Remove the front plate.
• Remove the screws of the transformer input module, both front and rear.
7. Pull out the faulty module.
8. Check that the new module has a correct identity number.
9. Check that the springs on the card rail are connected to the corresponding
metallic area on the circuit board when the new module is inserted.
10. Reassemble the IED.
Section 15
Troubleshooting
IP8767-1 v1
M11764-2 v2
M11764-10 v1
M11766-4 v2
299