The Influence of the 3rd Harmonic of the Distorted Primary Current on the Self-Generation of the Inductive Current Transformers

This paper investigates for transformation of the distorted current the low order higher harmonic self-generation phenomenon of tested inductive current transformers. The influence of the main component and the 3rd harmonic of the distorted primary current on the RMS values of the 5th, 7th and 9th order self-generated higher harmonics is analyzed. This research indicate that the change of the RMS value of the 3rd harmonic of the distorted primary current causes variation of the lower order higher harmonics generated in to the secondary current. Therefore, this is a challenging phenomenon which have to be considered while compensating the values of current error and phase displacement of the inductive CTs during transformation of the distorted currents.