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, which arise when voltages in the kilovolt or megavolt range have to be measured, are emphasized. Safety, signal transmission, and electrode design are dealt with. Field meter theory is summarized and generalized in the 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.