Wide Frequency Operation of the Inductive Current Transformer with Ni80Fe20 Toroidal Core

Abstract

Abstract—During transformation of the power frequency currents, inductive current transformers are characterized by the values of current errors and phase displacement, which determine their accuracy class. However, current transformers catalogues do not specify these metrological parameters of transformation for the sinusoidal signals at frequencies higher than 50 Hz (60 Hz). The aims of this article are the descriptions of the metrological and magnetic circuit properties of the inductive current transformers with an Ni80Fe20 toroidal core in condition of sinusoidal currents transformation of frequencies from 50 Hz to 20 kHz. Determined magnetization characteristics of tested current transformer magnetic circuit are the justification for the course of its measured wide frequency metrological characteristics. Moreover, they may be used in designing the current transformers with an Ni80Fe20 toroidal core for transformation of the above 50-Hz frequency currents. The classification procedure was used in this article to define the current transformers accuracy for wide frequency operation and measurement method for determining their current errors and phase displacement for transformation of sinusoidal signals at frequencies from 50 Hz (60 Hz) to 20 kHz are presented.

Keywords:

• current transformer
• current error
• phase displacement
• errors frequency characteristics
• hysteresis loops
• B-H characteristics
• internal capacities
• initial magnetic permeability
• normal magnetization curves
• magnetic flux density

Additional information

Notes on contributors

Michal Kaczmarek

Michal Kaczmarek was born in Lodz, Poland in 1980. In 2004 He received M.Sc degree in Industry Power Electronics and in 2009 He received Ph. D. degree in electrical engineering with specialization in electromagnetism and instrument transformers both at Technical University of Lodz, Poland. He is working as an assistant professor in the Department of Instrument Transformers and Electromagnetic Compatibility of the Institute of Electrical Power Engineering in the Lodz University of Technology. His area of work is focused mainly on instrument transformers and their operation in conditions of distorted and sinusoidal signals of frequencies above 50 Hz transformation. In EMC considerations his work concerns conductive disturbances transformation through instrument transformers and the influence of interferences on their accuracy.