Influence of External Magnetic Fields on Measurement Errors by Induction Current Transformers

Accurate information about the current in electric power systems is mandatory for the proper functioning of most automation systems, relay protection, measurements and monitoring. For the purposes of current measurement, induction-type sensors using the magnetic field created by the measured current have become the most widespread. These are current transformers (CT), Rogovsky coils, inductive sensors. All these devices are characterized by simplicity of design, reliability and durability. The disadvantages include the sensitivity of this group of sensors to the magnetic fields of neighboring current lines. To assess the effect of such fields on the useful signal, a group of experiments was carried out at various currents of external influence. The analysis of the obtained measurement results is performed.