CT measuring conditions
CT measuring conditions
(OP)
Hi all,
Since this is my first thread, couple of words for introduction. I'm a junior project engineer at consulting/engineering European company, in the field of water treatment plants and substations. I'll appreciate ur tips/experiences/links about current transformers:
1. Can I transfer a ring type transformer from 0,4kV outgoing feeder to 10kV supply cable for similar current value? Inner diameter is ok for both cables. Would it work and how?
2. How reliable are measuring results in high current THD conditions? Is there a way to assess a influence of THD to current error, security factor, accuracy limit factor, thermal rating and avoid unwanted current paths/loops?
Thank you.
MikiBg
Since this is my first thread, couple of words for introduction. I'm a junior project engineer at consulting/engineering European company, in the field of water treatment plants and substations. I'll appreciate ur tips/experiences/links about current transformers:
1. Can I transfer a ring type transformer from 0,4kV outgoing feeder to 10kV supply cable for similar current value? Inner diameter is ok for both cables. Would it work and how?
2. How reliable are measuring results in high current THD conditions? Is there a way to assess a influence of THD to current error, security factor, accuracy limit factor, thermal rating and avoid unwanted current paths/loops?
Thank you.
MikiBg






RE: CT measuring conditions
Power/harmonic measurements
Control
Protection
As for unwanted current paths or loops; a properly connected CT circuit will have niether regardless of the CT characteristics.
RE: CT measuring conditions
RE: CT measuring conditions
Metering CTs are optimized for accuracy and will typically maintain their accuracy with currents up to 200% of nominal.
Protection CTs have a much higher saturation voltage so as to accurately reflect fault currents.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: CT measuring conditions
RE: CT measuring conditions
Any dc components in the waveform are death to the CT output, since it will saturate for any appreciable dc current.
For short term faults or events, the CTs can handle a lot of rms current. For longer term events, you need to consider the CT's Thermal Rating Factor.
"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg
RE: CT measuring conditions