Development of Voltage-Doubling Method for Measuring the Voltage Dependence of Compressed Gas Capacitors up to 400 kV

Recent improvements of voltage-doubling method for measuring voltage dependence of compressed gas capacitor up to 400 kV are described. The capacitor is compared with a standard capacitor under the same voltage and doubling voltage separately using a commercially available current comparator bridge. A 5 nF centre-tapped capacitive divider with two identical high voltage arms is employed for voltage doubling and harmonics attenuation. The applied voltages when operating in voltage doubling state are monitored by a ground floating current comparator bridge and another two standard capacitors. None of the voltage dependence of the capacitors needs to know in advance. Expanded uncertainty evaluation for the voltage coefficient and the dissipation are estimated within 5 ppm.