The establishment of 10-500/√3kV power frequency voltage ratio standard apparatus and study of the calibration method

The principle of 10-500/√3-kV power frequency voltage ratio standard apparatus and the calibration method at NHVMS, China, are presented in this paper. The substitution method which is usually used for low-voltage precise measurement was applied to the field of high-voltage measurement. A new method was developed. It is renamed “the incomplete substitution method” because the operating voltages and currents of the components of the standard apparatus are different before and after substitution. The systematic errors of the components due to the difference of operating states are measured in advance and can be corrected, so the measuring accuracy is improved greatly. The error analysis shows that the total uncertainties of the standard apparatus are better than ±10 ppm in magnitude and ±10 μrad in phase angle (the confidence factor is 3). The comparison result between China and Canada is satisfactory