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Topic Title: Designing at Very Low Temperature
Topic Summary: Electrical substation design for low temperature
Created On: 24 February 2012 02:19 PM
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 24 February 2012 02:19 PM
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iochoa

Posts: 18
Joined: 19 November 2002

I am designer of Electrical Substation system. Usually the Substations are designed at temperatures within the range of -30 to +40oC, but now I am working in a place where I was told that the temperature is -50oC. In this condiiton the substation will requiere a special design with the consecuence that it will increase the cost.

I did some research about the weather and I prepared a table where I can see that the temperature of -50oc is only 2 days or 3 days during the last 30 years, then I was wondering if I can use a statistic technique and the stress-strength analysis to get a resonable temperature value to use in my design.


Could you please give me some addres about it. To be more specific, my question is:
How Can I get that "reasonable temperature value"?
How can I create a criteria to choose the "reasonable temperature value"?

Ismael
 24 February 2012 02:28 PM
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OMS

Posts: 19592
Joined: 23 March 2004

Put it inside a structure and use the energy losses of the sub to heat the structure and create a more equitable temperature for your design condition ?


Regads

OMS

-------------------------
Failure is always an option
 24 February 2012 07:48 PM
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Jaymack

Posts: 4625
Joined: 07 April 2004

Originally posted by: iochoa
I did some research about the weather and I prepared a table where I can see that the temperature of -50oc is only 2 days or 3 days during the last 30 years,

Take -50°C as your lowest temperature then. Although there will be a heat contribution from electrical equipment in panels and switchboards etc., (when energised). I would opt for controlling thermostats and heaters, either within equipment or the room. You've mentioned temperature, what about humidity?

Regards
 24 February 2012 08:51 PM
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cookers

Posts: 205
Joined: 10 February 2012

I would not step down the climate statistical route, you cannot be sure the temperature record you wish to use will represent the actual site conditions, temperature is usually recorded at ground level in a sheltered Stevenson Screen, your subatation could well be more exposed. Also at -50 Deg C recording temperature accurately becomes difficult, due to instrument limitations.

I would review the features of the substation design that afford protection for the equipment at -30 Deg C, and feature by feature do a reasoned analysis to see if a further 20 degrees of frost will create a problem.

Best of luck.
 14 June 2012 01:49 PM
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stableford

Posts: 64
Joined: 04 April 2006

I live in Canada, and have worked on transformers here, the last couple of years, where we have had to commission them at -30c. This involved making a tent and heating it, to warm the oil. Once operating no real problems, except the there has to be a heater in the control panel of the transformer, so that freezing of contacts doesn't occur, and control condensation caused corrosion.
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