CT/VT Calculation

First you should measure the burden (if you cannot calculate accurately) including the leads.

First Of all, you have to decide the purpose of the CT/ VT. Whether you may use it for measuring or protection purpose.

Measuring CT:

Measuring current transformers are normally class 0.5 or 1 for general use. Class 0.1 or 0.2 for precision and tariff measurements.

Protection CT:

Protection current transformers provide signals to protective relays to enable correct operation under steady state and transient conditions.

For More Information, Visit

http://myelectrical.com/wiki/ct-dimensioning/revision/7.aspx

http://cr4.globalspec.com/comment/733931

Vinu_Answers Sure_Answers

One of the above links has changed to:

http://myelectrical.com/notes/entryid/99/how-to-size-current-transformers

For anyone who is still looking for current transformer sizing information.

Ratio, Accuracy Class, Burden, Insulation Level, Type, No. of Cores, etc. need to be finalised first.