Transformer Explosion
Transformer Explosion
(OP)
There was an explosion of a 500/230 kv transformer in southern California last Friday. The explosion escalated to a fire through the entire substation. Sabotage is not suspected.
All transformer experts out there, I would like to know what are the various causes of catastrophic transformer failures and explosions and how they can be prevented.
Thanks.
All transformer experts out there, I would like to know what are the various causes of catastrophic transformer failures and explosions and how they can be prevented.
Thanks.
Michael Sidiropoulos






RE: Transformer Explosion
Sounds like someone had a bad day.
RE: Transformer Explosion
Perhaps one way to narrow down the ramdom possibilities is to study failure statistic and apply that to the specific site. Forensic data suggest the fallow frequency of failures:
- Overvoltage stresses: (Lightning, switching surge, ferroresonance, SC,………….) ~ 45% to 50%
- Poor & infrequent maintenance (Including lost connection, dirty insulators, oil moisture, vibration...) ~ 20% to 25%
- Aging (Insulation degradation, oil degradation, ……) ~ 10% to 15%
- Overloading or LTC over-operation (if applicable)… ~ 5% to 0%
For the root-cause analysis of the catastrophic failure it is recommend gathering fault recorder/SCADA relevant system data. In term of priority, Insulation coordination assessment including surge arrester degree of protection should be one of the first areas to evaluate. Secondly, maintenance record and practices should be investigated among other causes.
RE: Transformer Explosion
Just a thought.
RE: Transformer Explosion
RE: Transformer Explosion
RE: Transformer Explosion
Are the bushings in tact? Is the tank in tact?
If there is an on-load tapchanger, check the position of the contacts to check if it got caught between taps. This sort of falut can be fatal.
Was protection operating properly at the time, (or is there no way to check the settings cause you now have molten relays)? Look for maloperations of protection (as cuky2k suggested, fault recorders will indicate if a fault held in for longer than it should).
Are bushings oil filled? When was the levels last checked?
Our main transformer failures that have resulted in fires have been cable endbox or linkbox failures. We have not only looked at this source of the problem, but also mitigation techniques for if a fire happens to start (ie blocking cable entry points through floors, fire extinguisher systems, smoke detection systems, even down to building design features such as having roofing eves flush with the external walls, to eliminate any overhang which would channel the fire inside the building.)
RE: Transformer Explosion
Michael Sidiropoulos