Assuring the quality of impulse voltage calibration results issued by a calibration laboratory

This paper describes high voltage impulse measurements made under the controlled conditions of a calibration or national measurement laboratory to establish the best agreement that could be achieved in comparison measurements on small reference dividers. This comparison to establish mutual international traceability between NRC and National Grid has shown that the peak voltage of a smooth lightning impulse was measured by both laboratories to within 0.2% with an estimated uncertainty of +-0.2% at a level of confidence not less than 95%. The authors make recommendations on how calibrations of reference measuring systems should be performed.