Protection Engineering Basics and Schemes Protection Engineering | Page 9
1.1.1 Operation:
Current transformer is acted same like step up transformer, in which voltage is increased by the mention turn ratio.
V = 4.44fBAN Where f is frequency, B is magnetic field density, A is area of cross section, N is turn ratio.
1 st we need to analyze below mention simple drawing or layout of Current transformer
What happened when current flows in primary, the flux due to that flow of current cut the secondary number of turns and induce voltage in secondary, due to that induce secondary voltage the current flow in secondary windings, but remember transformers are magnetically coupled so core of transformers must need to be magnetized before any current flow, the current required to magnetized the core of transformer is excitation current, now see this equation