Design of an Ultra-High-Frequency Through-Core Current Transformer for Cable Partial Discharge Detection

Aiming at the problem of the through-core current sensor based on cable partial discharge detection having difficulty in compatibility with high sensitivity and wide detection frequency band, this paper proposes a design method for an ultra-high-frequency through-core current sensor. Firstly, the sensor circuit model was established, and the relationship between the sensor hardware parameters, and the bandwidth and sensitivity was derived. Subsequently, a multi-objective particle swarm optimization model was established. The sensitivity and bandwidth were taken as the objective functions, and the hardware parameters were regarded as the decision variables. Constraint conditions were set according to the cable size, self-integration working mode, etc. The optimal hardware parameters were obtained through solution and calculation. Finally, an ultra-high-frequency through-core current sensor was fabricated, and the bandwidth and sensitivity of the sensor at different frequencies were tested. The test results of cable partial discharge signals demonstrate that the designed sensor maintains a sensitivity of no less than 20.46 V/A within the 3 MHz to 200 MHz frequency range. This performance not only satisfies the fundamental sensitivity requirement of 5 V/A in the 3–30 MHz band for cable partial discharge detection but also resolves the inherent trade-off between sensitivity and detection bandwidth, exhibiting superior performance compared to conventional sensors.