K - Factor 1

[Breaker]

Could anyone give me any good websites which discusses the K factor (US) or factor K (europe)

 

[mpparent]

I'm not sure of any websites, but, K-factor gives you and idea of how much heat a transformer can take. For example, a K-4 xfmr can take 4 times as much heat as a standard xfmr, and so on. As a side note, K-factor doesn't address harmonic mitigation, only heat.

Mike

 

[jstickley]

Which K-Factor are you talking about? As applied to ground-distance relaying, the following link may be helpful:

http://www.selinc.com/techpprs/6065.pdf

http://www.selinc.com/techpprs/6121.pdf

http://www.selinc.com/techpprs/6018.pdf

There are additional papers related to relaying at:

http://www.selinc.com/sel-lit.htm

http://pm.geindustrial.com/faq/Faq.asp

 

[SidiropoulosM]

K Factor is a measure of harmonic content and its effect on voltage distortion. The following paper describes why K Factor can be a misleading measure of power quality:

http://www.powerstudies.com/content/resources/pg000158.pdf

Michael Sidiropoulos

 

[busbar]

A description of the IEEE standard is

http://standards.ieee.org/reading/ieee/std_public/description/dtransformers/C57.110-1986_desc.html

 

[neps3]

jstickley

That was an excellent link and I vote a star for you.

 

[Breaker]

Thanks for your links,

Jstickley, the K-factor or Factor K I was talking about was to do with transformer derating due to harmonics.

 

[electricuwe]

The K-Factor (used for rating transformers for harmonic currents) was has been introduced for marketing purposes in the US and is a very peculiar way to describe how harmonic currents lead to additional heating in a transformer.

Search the IEEE Transactions on Industry Applications for a very intresting dicussion on the origin of K-Factor and the drawbacks of that definition.

In Europe it is not common to use the K-Factor rating.

Two different applications have to be distinguised:

Dedicated converter transformer:
In this case it is common (and recommend by the approbiate IEC-standard) to specify the current harmonics for the most unfavorable operating condition when buying a transformer.

Distribution transfomer:
In this case most people don't worry about harmonics (regarding transformer heating!). I guess the reason is that in Europe the lines are not as much loaded with harmonics as in the US.