Antoniou Gyrator as a Tuner for Current Transformers

In field applications, leakage current in high-voltage insulators is usually acquired by using current transformers (CT). Due to the multifrequency nature of the signal, gain and phase compensations are typically required for signal reconstruction but CTs have a frequency response that resembles passband filters, posing some challenges for reconstructing the original signal. To deal with that, we carried out an investigation on using a gyrator circuit as a tuner for CTs. Our goal was to determine if it could improve the frequency response and SNR of a CT with larger windings, resulting in a more well-behaved frequency range, thereby potentially facilitating the recovery of the original signal. We conclude that both a higher number of turns together with an Antoniou gyrator or a smaller number of turns are both capable of extending the frequency range for effective leakage current measuring with similar performances. While making smaller windings is cheaper, faster and easier, an equivalent performance can be achieved using the gyrator when disassembling the sensor or replacing its winding is not a viable option.