Method for Capacitive Wide-Band High-Voltage Measurement in the Range from 50 Hz to 2500 Hz

In order to address the insufficient frequency response of the inductive voltage transformer and capacitive voltage transformer (CVT) in harmonic voltage measurement, a broadband high-voltage capacitive divider based on compressed gas capacitors is developed in this study. The divider integrates high-voltage and low-voltage compressed gas capacitors within a sealed shielding structure to ensure stable performance and minimize external interference. An electronic compensation circuit featuring gain adjustment and buffering functions is incorporated to enhance the load capacity and correct ratio errors. And a high-precision self-balancing voltage transformer calibrator is presented, enabling fully automated calibration of voltage transformers across broader ranges and with superior accuracy. Experimental validation demonstrates that, over the frequency range from 50 Hz to 2500 Hz, the divider maintains a ratio error of less than 0.2%, with excellent voltage stability—magnitude deviations remain below 0.001% and phase shifts under 0.25 min. Furthermore, the device successfully passed ±75 kV lightning impulse tests, confirming its compliance with insulation and accuracy standards for harmonic measurements in 10 kV power grids. This capacitive divider can be employed as a transfer standard in high-frequency voltage-ratio calibration, enabling voltage transformers to be accurately calibrated using a substitution method. The proposed system offers a practical and reliable solution for broadband, high-precision voltage measurement in power quality applications.