CT

What is meant by 5p10 in an ct.

 

[cuky2000]

This is the designation for current transformer per IEC Standard 185 as follow:

“10”…………….Declare composite error at accuracy limit primary current (Ex 2.5 & 10)
“P”………………Indicates the CT classification (Ex. P=Protection, M=Metering, TP)
“15”……………..Rated secondary reference voltage (Ex. 10,15,20, 30, 75).

The rate accuracy factor other than 20 should be indicated in the designation.

_{NOTE: There is an equivalence ANSI designation (Ex C100 to C800)}

 

[electricpete]

two questions:
1 - cuky - should your "15" be "5"
2 - can you remind me how we determine the rated burden (needed to transform the voltage into a current).

 

[cuky2000]

Electricpete,

Thanks for your observation, I mixed-up the above numbers. Please correct as follow:

"5"....Composite error
_{<5% at rated accuracy limit primary current.}

&quot;10&quot;...Rate accuracy limit factor
_{i.e. Overcurrent = 10 x rated normal current}.

The prefer way to express the burden in IEC generally is given in VA and is calculated as follow:

S_b = Z_b.I²<sub>ns


Were:
Sb= Burden (VA)
Zb= Burden (Ohm)
Ins=Rated secondary current(amp).</sub>

 

[busbar]

cuky'-- Gnarley ^super- and _sub-script tags! For the rest of us, see the 'Process TGML' link.

 

[jbartos]

Suggestion: Visit

http://www.bender.org/ws50x80s.pdf

etc. IEC CT

 

[jbartos]

Suggestion: Check

http://www.photonicpower.com/app_notes1.pdf

for optically powered CT