5 DETERMINING VK FOR IEEE C-CLASS CT
Where IEEE standards are used to specify CTs, the C class voltage rating can be checked to determine the
equivalent V
k
(knee point voltage according to IEC).
The equivalence formula is:
V
k
= 1.05(C rating in volts) + 100R
CT
P543i/P545i Chapter 16 - Current Transformer Requirements
P54x1i-TM-EN-1 423