CT explosion 3

[scottf]

prc-

Filling with sand for mechanical strength is really only applicable to dead-tank CTs, i.e. hair-pin type, as the primary conductors are run down through the insulator, into the bottom tank, and then back up the insulator.

Modern head-type CTs have a very short primary conductor running straight through (in general) the head and hence don't have the same issues regarding short circuit forces on the primary.

 

[prc]

Scottf-I thought Ralph Christie is talking about dead tank CTs.The photos show that these are hairpin type CTs.Live tank CTs with short bar type primary etc is not modern-they are there for the past several decades.But these are not acceptable in many markets due to their poor seismic withstand strength.Anyway my only submission was that primary purpose of sand filling is for enhancing the mechanical with stand strength of primary and this practice is widely followed even today.1940's oil was not as dear as today and there was not much need for oil saving.

 

[scottf]

prc-

Perhaps we have different market experiences. Head-type CTs are widely perfered in North/South America and Europe. I can't speak as much to Asia.

Seismic concerns is much a function of design. My company builds 800 kV head-type CTs for high seismic environments in North and South America.

 

[itsmoked]

RalphChristie; Looking at your pics again I see that the top of the metal box is deformed upward and a bunch of the bolts have been ejected. What caused this? Seems if the upper porcelain structure blew this box area would be kinda bent down and the bolts would still be there.. ??

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[stevenal]

Looks like the tank got pressurized. Formerly flat surfaces bow out now.

 

[RalphChristie]

Keith:

Steve is correct. Pressure build-up in tank.

Scottf and prc:

Thanks for your comments. I always thought these CTs were just filled with oil. Learn everyday something new.....

Regards
Ralph

[red]Failure seldom stops us, it is the fear for failure that stops us - Jack Lemmon[/red]

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