Difference between CT class 5L400 & C400

[zertic1985]

Dear Members,

Please anybody tell me about the difference between the CT class 5L400 & C400

 

[mjmarkey1979]

http://www.gedigitalenergy.com/multilin/notes/artsci/art07.pdf

See page 106 for ASA Accuracy Classifications

The letter L stands for low internal secondary impedance, which is a characteristic of bushing-type CTs having completely distributed secondary windings or of window type having two to four secondary coils with low secondary leakage reactance. The number before the letter is the maximum specified ratio error in percent (= 100IRCF Ð 1I), and the number after the letter is the maximum specified secondary
terminal voltage at which the specified ratio error may exist, for a secondary current of 20
times rated.

 

[mjmarkey1979]

Classification C or K covers current transformers in which the leakage flux in the core does not have an appreciable effect on the ratio or ratios within the limit of current and burden.
K classification shall have a knee-point voltage of at least 70 percent of the secondary terminal voltage rating see IEEE C57.15 for further info.

 

[scottf]

5L400 (CSA) means 5% allowable error up to 20 times rated current into a 4 ohm burden.

C400 (IEEE) means 10% allowable error up to 20 times rated current into a 4 ohm burden.

20 x 5A x 4ohm = 400V

In practice, there is no appreciable performance difference.