Precision Calibration System for Partial Discharge Calibrators

Abstract

Partial discharge calibrators need to be periodically calibrated traceable to national standards. VTT MIKES, the National Metrology Institute (NMI) of Finland, has official expertise to calibrate the apparent charge of PD calibrators from 1 pC to 100 nC according to IEC 60270. Recently, VTT MIKES has developed techniques to measure charges as low as 0.01 pC with 3 % uncertainty (k = 2). VTT MIKES has participated to an intercomparison of four NMI’s in 2018 and the results indicate that VTT MIKES can both expand their official measurement capabilities and lower their uncertainties. This paper presents VTT MIKES’s precision calibration system for PD calibrators. Additionally, an overview of commercial PD calibrators’ performance is provided and compared to the requirements of IEC 60270. Data is based on the calibrations performed during the last 10 years.