ABB ACS880-77CC, Hardware Manual

Page: 14 / 128

Electrical safety in installation, start-up and maintenance
￭
Precautions before electrical work
These instructions are for the qualified electricians who do work on the converter, generator
cable or generator.
WARNING!
Obey these instructions. If you ignore them, injury or death, or damage to the
equipment can occur. If you are not a qualified electrical professional, do not do
electrical installation or maintenance work. Do these steps before you do installation
or maintenance work.
1. Clearly identify the work location.
2. Disconnect all possible voltage sources.
• Open the main circuit breaker (Q1), disconnect, lock and attach a warning notice
to it. See section
Opening and disconnecting the main circuit breaker (page 16) .
• Open the charging circuit switch-disconnector (Q10). See section Disconnecting
the charging circuit from the main circuit (page 18) .
• Open and lock out the auxiliary voltage switch-disconnector (Q2) if present. See
section
Disconnecting the auxiliary power supply (if present) (page 19) .
• Disconnect any external dangerous voltages from the control circuits (such as relay
outputs).
• Open, disconnect and lock out the breaker of the grid transformer as the main
circuit breaker of the converter does not remove the voltage from the grid cable
busbars and some auxiliary circuits. Attach a warning notice to the disconnector.
• Lock the turbine rotor (and generator shaft).
• Open the safety switch between the generator-side converter and the generator
(if any).
• After you disconnect the converter, always wait for five minutes to let the
intermediate circuit capacitors discharge before you continue.
3. Protect any other energized parts in the work location against contact.
4. Take special precautions when close to bare conductors.
5. Measure that the installation is de-energized.
• Use a multimeter with an impedance of at least 1 Mohm.
• Make sure that the voltage between the converter grid cable terminals (L1, L2, L3)
and the grounding (PE) busbar is close to 0 V.
• Make sure that the voltage between the generator cable terminals (U2, V2, W2)
and the grounding (PE) busbar is close to 0 V.
• Make sure that the voltage between the DC bus and the grounding (PE) busbar is
close to 0 V.
WARNING!
If the measurement requires removal or disassembly of shrouding or other
cabinet structures, obey the local laws and regulations applicable to live
working (including – but not limited to – electric shock and arc protection).
14 Safety instructions
3