Development of hidden discharge current sensor for overhead transmission line based on composite integral Rogowski coil

The measurement of hidden discharge current of overhead transmission line is one of the important measures to prevent line fault. In view of the characteristics of hidden discharge current of overhead transmission line, such as high bandwidth, wide range and difficult to measure, this article takes advantage of the characteristics of external integration of Rogowski coil suitable for integrating low-frequency signals and self-integration of Rogowski suitable for integrating high-frequency signals. Combining the advantages of both, a composite integral Rogowski coil current sensor is designed. Firstly, the superiority of the composite integral Rogowski coil current sensor is verified by building a simulation model of the Rogowski coil operation. Then, the bandwidth and accuracy of the developed sensor are measured through experiments. The developed sensor can measure the current with a frequency from tens of thousands of hertz to several megahertz, and an effective value from several milliamps to several amperes, it can meet the measurement of hidden discharge current of overhead transmission line.