Uncertainty evaluation of the waveform parameters of 1-kV low-impedance impulse voltage calibrator

The low-impedance impulse voltage calibrator of high accuracy and stability can be used as a primary reference of impulse voltage. It is recommended to be utilized in the calibration of the reference measuring system composed of impulse resistor divider and digital recorder in IEC 61083. The impulse voltage calibrator is made up of resistors and capacitors of given values. The parameters of its output waveform, U_p, T₁ , and T₂ , can be calculated based on the parameters of the circuit elements and circuit principle of the calibrator. The uncertainties of the waveform parameters are always evaluated by Guide to the Expression of Uncertainty in Measurement (GUM) in previous publications. However, GUM exhibits some limitations when it is applied. In this paper, a 1-kV low-impedance impulse voltage calibrator (1.56μs/60μs) is developed. The values and uncertainties of U_p, T₁ , and T₂ are evaluated with another two new approaches, Monte Carlo method and random fuzzy variable (RFV). Particularly, the combination of several RFVs with both random and nonrandom effects is also discussed when RFV method is applied. The detailed process of each approach is presented and the results are compared.