4.16-0.48kV Power Transformer Deficiencies
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Transcript of 4.16-0.48kV Power Transformer Deficiencies
Power Transformer deficiencies found during inspections
• Leaking components• Overstress on bus and bushings• Damaged radiators• Damaged Paint• Power cable shielding not grounded properly• Broken compartment gasket material• Power cable to transformers and secondary cable to switchgear not lashed properly• XO cable is wrong color (green) it should be black because it carries lethal voltage and current• XO cable with wrong insulation rating, cable should have same insulation rating as other cables in the same tray.• XO cable in ferrous conduit – to be avoided.• Transformer acceptance testing not done or incomplete (no oil analysis)• Damaged secondary cables in transformer yard, two causes (1) Scaffolding was being built without consideration
of cables underneath work and not covered (2) Sabotage – on at least two occasions cable in transformer yard were cut with knives and on one occasion cable was found burned with a torch.
• Dirty termination compartments• Broken gauge lenses• Oil level gauge with water intrusion giving false alarms• Transformer alarms wired incorrectly• Transformer primary CTs wired incorrectly on systems with transformer differential relays.• Equipment numbers missing• Cables exceeding maximum unsupported length• Single core cables attached with ferrous metal unistrut clamps
Leaking components
Overstress on bus & bushings
Transformer incoming cable shields wired incorrectly
Primary and secondary cables not lashed correctly
XO cable in ferrous conduit
Termination compartments dirty with material inside
Missing gauge lenses
Transformer primary CTs are wired incorrectly
Cables exceeding maximum unsupported length
Single core cables through ferrous clamps, creates a hazard.
Important Note when told it is manufacturer’s responsibility to ensure all terminations are tight
This is what happens when good chairs go bad. I have seen Pit Bulls on smaller chains