CT Saturation Curve

[tctctraining]

how the saturation time of a CT is being calculated?
for example a 600/5 ratio with a B=0.1

 

[bacon4life]

SEL has several good papers on CT saturation such as [URL unfurl="true"]https://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&ved=0CCkQFjAA&url=https%3A%2F%2Fwww.selinc.com%2Fworkarea%2Fdownloadasset.aspx%3Fid%3D2431&ei=bvEdU7PWNcnwoASIoILIBw&usg=AFQjCNHj0xrSVbh-LCRDjaZ-o0EUtpi7fQ&sig2=-nxG7qG3K9XGG5FK1zESRA&bvm=bv.62788935,d.cGU[/url][pre][/pre]

 

[odlanor]

for B=0.1 this is CT metering; there is not problem with saturation.

 

[bacon4life]

Stated slightly differently: If a Metering CTs is operated within it's steady state nameplate thermal and accuracy limits, it won't be saturated. For measuring fault conditions, relayings CTs should be used instead because metering CTs will saturate very fast.

 

[tctctraining]

I always thought that the CT accuracy class defines the metering or protection class and not the Burden.
A 600/5 CT with B=0.1 is used for protection in this case.

 

[odlanor]

The standard burdens for relaying are 1, 2, 4, and 8 ohms.

 

[Kiribanda]

Hi tctctraining,
The time to saturation depends on various factors. IEEE C37.110 gives the equation to calculate the time to saturation knowing system time constants etc.