Rogowski Coil for Current Measurement in a Cryogenic Environment

A Rogowski coil based sensor for current measurement in a cryogenic environment and results of its application for paralleled high temperature superconducting (HTS) coil current sharing are presented. The current sensor consists of a Rogowski coil and an integrator, where the coil output voltage is proportional to the derivative of primary current and the integrator transfers the differentiation to normal state. The Rogowski coil has promising applicability at cryogenic circumstance because its body is made of low temperature materials. The integrator ensures a large bandwidth with feasible magnitude, which is vital for dynamic current measurement during the quench of the HTS coil. The proposed current sensor is used for current sharing measurement of two paralleled Bi2223 HTS coils, and the experimental results show that the measurement precision is better than 0.5%.