Design of capacitive voltage divider for measuring ultrafast voltages

• Published in: International journal of electrical power & energy systems 2018-07, Vol.99, p.426-433
• Main Authors: Kovačević, Uroš D., Stanković, Koviljka Đ., Kartalović, Nenad M., Lončar, Boris B.
• Format: Article
• Language: English
• Subjects: Capacity; Fast pulse voltage; Inductivity; Measurement; Ultrafast voltages; Voltage divider
• ISSN: 0142-0615; 1879-3517
• DOI: 10.1016/j.ijepes.2018.01.030

•Effort should be made to reduce dimensions of the divider to a bare minimum.•Wire structures must be as short as possible in order to minimize parasitic inductivity.•Capacities of divider capacitor must not be unstable.•Capacities of the divider capacitor must be frequency independent.•Waveguide resistors should be used instead of discrete resistors in order to adapt the capacitance divider to characteristic impedance of the transmission. The aim of this paper is to consider and analyze design of capacitive voltage divider for measuring ultrafast voltage occurrence. Measuring pulse voltages by means of a capacitive divider in nanosecond range is affected by problems related to the construction of the divider and materials used. However, an appropriate constructive solution could minimize the budget of measuring uncertainty of the measurement pertaining to parasitic inductivity and capacitance. Consequently, the right selection of dielectric materials could offset the effects of high-voltage and low-voltage frequency characteristics of the capacitor. Four types of capacitive dividers have been constructed for the purpose of this paper. The high-voltage capacitor of each divider is a gas capacitor (intended to avoid both electrostatic and electrodynamic influence on measurement uncertainty). Ultrafast pulse response is measured by dividers constructed in this way, and compared with the corresponding response obtained from numerical simulations.