Evaluation of unshielded Rogowski coil for measuring partial discharge signals

Due to low magnitude of partial discharge signals, special instruments are needed for measuring these signals. Traditional instruments for measuring partial discharge signals, in electrical cables, are capacitive sensors and High frequency Current transformers. Recently using Rogowski coil for measuring partial discharge signals have attracted more attention. In this paper Rogowski coil performance in wide frequency range, between 1 kHz up to 12 MHz, is investigated. As shielding has significant effect on Rogowski coil performance, here Rogowski coil performance without existence of shielding is investigated. The effect of different parameters, such as terminating impedances and deviation of current carrying conductor from central position, is investigated on Rogowski coil performance not only in frequency domain but also in time domain. Also the model of Rogowski coil is presented and its verification is studied.