ABB RELION REL670, Installation And Commissioning Manual

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Repair instruction Chapter 13
Fault tracing and repair
2 Repair instruction
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, pro-
tection bag. The user can also purchase separate replacement modules.
Most electronic components are sensitive to electrostatic discharge and latent damage may oc-
cur. 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 REx670 IED accordingly:
1. Switch off the dc supply.
2. Short-circuit the current transformers and disconnect all current and voltage con-
nections from the IED.
3. Disconnect all signal wires by removing the female connectors.
4. Disconnect the optical fibres.
5. Unscrew the main back plate of the IED.
6. If the transformer module is to be changed — unscrew the small back plate of the
IED.
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 metal-
lic area on the circuit board when the new module is inserted.
10. Reassemble the IED.
Warning!
Never disconnect the secondary connection of a current transformer circuit without short-cir-
cuiting the transformer’s secondary winding. Operating a current transformer with the second-
ary winding open will cause a massive potential build up that may damage the transformer and
may cause injuries to humans.
Warning!
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.
Note!
Strictly follow the company and country safety regulations.