Application of Charge-Sensitive Preamplifier for the Calibration of Partial Discharge Calibrators Below 1 pC

Modern partial discharge (PD) calibrators often have their lowest range below 1 pC. However, traceable calibration services below 1-pC charges are not widely available, or their uncertainties are relatively high because of low signal levels. We have applied a commercial charge-sensitive preamplifier for the low-level calibration of PD calibrators. This calibration method both improves the signal-to-noise ratio and performs the analog integration of the PD pulse. The drooping response of the preamplifier is corrected using software. Comparison with a reference PD calibrator supports an expanded uncertainty less than 1% down to 0.1 pC and 3% for 0.01 pC.