An overview of technical challenges in the design of current transformers

This paper presents approximate equations that may be used to obtain the lower cutoff frequency fL and higher cutoff frequency fH and thereby the bandwidth of a current transformer. The equations are validated by a PSpice simulation. The Bode plots for both low-frequency range and high-frequency range for a selected design are presented. Also an overview of the various problems that should be considered while designing a current transformer is given, including leakage inductance, stray capacitance, ringing, parasitic resonance, saturation, and mechanical clamping