Wide Bandwidth Rogowski Coil Overvoltage Measurement System Using the Tap of the Transformer Bushing

Bushings are one of the vulnerable parts to overvoltage effects in power transformers. Therefore, it is significant to investigate the wide bandwidth overvoltage measurement system for the transformer bushing. In this paper, a wide bandwidth overvoltage measurement system using the tap of the bushing was developed. Two Rogowski coils were utilized as the main component to address the wide frequency range and large variation in ground current at the tap of the bushing. Rogowski coils with a frequency threshold of 5kHz were designed to measure the low-frequency and high-frequency components of the overvoltage separately. An integrator was used to reconstruct the overvoltage on the top of the bushing. Lightning overvoltage and operational overvoltage produced by a bushing experimental platform were measured, verifying the excellent performance of the proposed sensor.