IEEE Std 644-2019 pdf download
IEEE Std 644-2019 pdf download.IEEE Standard for Measurement of Power Frequency Electric and Magnetic Fields from AC Power Lines.
3.1 General characteristics
Three types of meters used to measure the electric field strength from ac power lines are described in technical
literature.
Free-body meter: Measures the steady-state induced current or charge oscillating between two halves of an isolated conductive body in an electric field (see Adler [Bi] and Bracken [B2J).
— Ground-reference-type meter: Measures the current-to-ground from a flat probe introduced into an electric field (see Miller [B2 1]).
— Electro-optic field meter: Measures changes in the transmission of light through a fiber or crystal due to the influence of the electric field (see Cooke [B4] and Harnasaki [Bi 1]).
The free-body meter is suitable for survey-type measurements because it is portable, allows measurements above the ground plane, and does not require a known ground reference. Therefore, this type of meter is recommended 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 meters intended for characterization of radio-frequency electric fields should not be used to measure the powerfrequency electric field strength from ac power lines.
An electric field strength meter consists of two primary parts, the probe and the detector. For commercially available free-body meters, the detector is usually contained in, or is an integral part of. the probe. The probe and detector are introduced into an electric field on an insulating handle. The detector measures the steady-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 at the probe (see 4.1). The size of the probe should be such that charge distributions on the boundary surfaces generating the electric field (energized and ground surfaces) are, at most, weakly perturbed when the probe is introduced for measurement. The electric field should be approximately uniform in the region where the probe will be introduced. Probes can be of any shape; however, meters commercially available in the U.S. arc generally in the shape of rectangular boxes, with side dimensions ranging from approximately 7 cm to 20 cm. The meters arc calibrated to read the iins value of the power frequency electric field component along 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. In this case, a portion of the signal processing circuit is contained in the probe and the remainder of the detector is in a separate 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 for factors such as a dependence on temperature or if the electrical axis of the field strength meter is not coincident with the geometric axis. Other relevant information, is indicated in Figure 1, section C.
It should be noted that the uniform E-field direction serves as an alignment axis for the field probe and that during field measurements this axis should be aligned with the field component of interest. The constant k can be thought of as a field strength meter constant and is determined by calibration. For more exact results, a second term not shown should be added to the right-hand side of Equation (8) because of the presence of the dielectric handle held by the observer. The influence of the handle, representing a leakage impedance, and the perturbation introduced by the observer are taken to be negligible in the above discussion.
