Implementation and Evaluation of an On-site Calibration Method for High-voltage Testing Systems up to 600 kV

Technological progress has led to the development of high-voltage testing equipment with extremely high-voltage ranges potentially reaching 600 kV or higher. Such equipment cannot be calibrated using portable devices within the same range. Therefore, this study presents an on-site calibration method for high-voltage testing equipment up to 600 kV. A standard divider with a 300 kV range and a high-resolution digital multimeter for leakage current measurements are used for the calibration. To extend the calibration above 300 kV, a scale factor for the impedance method is introduced. The results demonstrate that linearity is achieved at all calibrated points, with a linearity error not exceeding 1%, indicating that the calibration can be extended to 600 kV. The findings also confirm that the unit under calibration complied with its specified accuracy. Additionally, the expanded uncertainty is estimated for each range to assess the reliability of the results. Finally, a comparison and verification tool is introduced using a normalized error tool to ensure the validity of the proposed technique. The normalized error tool results indicate that the proposed method yields satisfactory outcomes. This study establishes an on-site calibration service for high-voltage testing equipment up to 600 kV, extending the previous limit of 300 kV.