The New Age of Ventilated Dry-Type Transformers

In this "Cut the Copper" blog, manufacturers use air as a transformer coolant after their attempts to replace Askarel fluids met with little to no success.

04/27/2012


After enduring all of the pain and tremendous costs associated with replacing, rehabilitating, retro-filling and remediating nasty liquid-filled transformers, the electrical industry finally said, more or less in unison, “That’s enough! I’m not going to go through this anguish one more time! No more liquid transformers in my plants ever again. The EPA will never outlaw AIR as a transformer coolant, so from now on, my indoor transformers will be air-cooled.”

 

Manufacturers like GE and Westinghouse, again, led the charge and developed new dry-type substation transformer designs. The electrical industry adopted these quickly, and dozens of other smaller manufacturers entered the transformer business with new ventilated dry-type transformer designs.

 

Dry-type secondary substation transformers. Courtesy: ABB - T&DIn general, the new dry-types worked well in service, although early adopters immediately complained about how loudly they operated compared to the liquid units they replaced, and how much heat they generated when loaded. The most prevalent early designs used 220 C winding insulation and an allowable winding temperature rise of 150 C over a 40 C ambient. That says that the windings themselves could be operating in completely normal service at temperatures nearly twice the boiling point of water, so it’s no wonder that they felt “warm” (can you spell “i2R winding losses”?)

 

Later, next generation improvements included things like Vacuum-Pressure Impregnation (VPI) process, that greatly improved uniform quality of the insulation systems, and then lower temperature rise construction (115 C and 80 C ratings), that greatly improved efficiency and also extended useful operating life. 

 

In general, life was good, again, with many tens of thousands of dry-type transformer installations now in service.



No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Additive manufacturing advancements; Machine vision enhances robotics; Fieldbus evolution; Process safety; Advice from System Integrators of the Year; Road to IANA
Salary and career survey: Benchmarks and advice; Designing controls; Remote data collection, historians; Control valve advances; Hannover Messe; Control Engineering International
System integration: Best practices and technologies to help; Virtualization virtues; Cyber security advice; Motor system efficiency, savings; Product exclusives; Road to Hannover
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
PLCs, robots, and the quest for a single controller; how OEE is key to automation solutions.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

The digital oilfield: Utilizing Big Data can yield big savings; Virtualization a real solution; Tracking SIS performance
Getting to the bottom of subsea repairs: Older pipelines need more attention, and operators need a repair strategy; OTC preview; Offshore production difficult - and crucial
Digital oilfields: Integrated HMI/SCADA systems enable smarter data acquisition; Real-world impact of simulation; Electric actuator technology prospers in production fields
click me