High-Voltage Pulse Measurement with a Precision Capacitive Voltage Divider

The capacitive voltage divider can be designed to have an accurately known division ratio over a wide range of operating frequencies. A coaxial, guard-ring type geometry is described, and an analysis of possible errors due to geometrical anomalies and temperature variations is given. Due to the particular method of construction used, the division ratio of the divider itself is essentially independent of the dielectric constant of the dielectric oil used. Bridge circuits and their pertinent equations for calibrating the divider are presented. An experimental divider designed to operate on pulsed voltages up to 350 kV is described, having an over-all division ratio of 1042.3±6.0 with an expected temperature dependence of 0.01%/°C.