IEEE Std 644:2019 pdf free download – IEEE Standard for Measurement of Power FrequencyElectric and Magnetic Fields from ACPower Lines
3.1 General characteristics
Three types of meters used to measure the electric ficld strength from ac power lines are described in technicalliterature.
– Free-body meter: Measures the steady-state induced current or charge oscillating between twohalves of an isolated conductive body in an electric field (see Adler [B1] and Bracken [B2]).
– Ground-reference-type meter: Measures the current-to-ground from a flat probe introduced into anclectric field (see Miller [B21]).
– Electro-optic field meter: Measures changes in the transmission of light through a fiber or crystaldue to the influence of the electric field (see Cooke [B4] and Hamasaki[B11]).
The free-body meter is suitable for survey-type measurements because it is portable, allows measurementsabove the ground plane, and does not require a known ground reference. Therefore, this type of meter isrecommended for outdoor measurements near power lines.
This standard presents measurement techniques for only the free-body type meter.Flat ground-reference-type meters can be used only under special conditions described in 5.2.Electric field strength metersintended for characterization of radio-frequency electric fields should not be used to measure the power-firequency electric field strength from ac power lines.
An electric field strength meter consists of two primary parts, the probe and the detector. For commerciallyavailable free-body meters, the detector is usually contained in, or is an integral part of, the probe. Theprobe and detector are introduced into an electric field on an insulating handle. The detector measures thesteady-state induced current or charge oscillating between the conducting halves (electrodes) of the probe.The observer is sufficiently removed from the probe to avoid significant perturbation of the electric field atthe probe (see 4.1). The size of the probe should be such that charge distributions on the boundary surfacesgenerating the electric field(energized and ground surfaces) are, at most,weakly perturbed when the probeis introduced for measurement. The electric field should be approximately uniform in the region where theprobe will be introduced.Probes can be of any shape; however, meters commercially available in the U.S.are generally in the shape of rectangular boxes，with side dimensions ranging from approximately 7 cmto 20 cm. The meters are calibrated to read the rms value of the power frequency electric field componentalong the electrical axis (the axis of greatest electric field strength sensitivity).
Free-body meters designed for remote display of the electric field strength also are available. n this case, aportion of the signal processing circuit is contained in the probe and the remainder of the detector is in aseparate enclosure with an analog or digital display. A fiber-optic link connects the probe to the display unit.This type of probe is also introduced into an electric field on an insulating handle.
When performing measurements, it is necessary to understand the instrumentation to be able to account forfactors such as a dependence on temperature or if the electrical axis of the field strength meter is notcoincident with the geometric axis. Other relevant information, is indicated in Figure 1, section C.