Tom Sels

Exponential parameters measurement using a modified Prony method

The Prony method is aimed at fitting a number of exponentials to some measured curve. Despite recent advances in the computational aspects, this method can be very sensitive to noise when the sampling rate is inadequate. A novel approach addressing this problem will be presented, allowing for some degrees of freedom in choosing how to cope with inadequate sampling without resorting to decimation. This method has been applied to the problem of determining the parameter of a voltage waveform (capacitor discharge) registered in a High Voltage laboratory. The amplitude and time constant have been accurately determined, although a lot of noise was present on the measured data.

Design and Application of a Field Mill as a High-Voltage DC Meter

Field mill instruments are often employed for the measurement of electric fields, electric charges, voltage potentials and atmospheric effects. This paper discusses in more detail the application of a field mill for measuring DC voltages in high-voltage laboratories. Some specific problems, arising when voltages in the kV or MV range have to be measured, are emphasized. Safety, signal transmission and electrode design are dealt with. Field meter theory is summarized and generalized in function of this application. The design of a practical, field mill based electrostatic voltmeter is described along with some useful enhancements. Finally, test results of the voltmeter are presented