IEEE 1227-1990 pdf free.IEEE Guide for the Measurement of DC Electric-Field Strength and lon Related Quantities.
IEEE 1227 While shutter-type field mills are normally operated in the ground plane in order to measure the field atground level, measurements of the field at ground level can also be made with a field mill that is mounted ona stand, provided the measurements are corrected for the associated field enhancement through some calibra-tion procedure (see form factor in Section 2). It should be noted that the geometry that exists during the calibration process shall be maintained during the measurements.For example, if grass or weeds are allowed togrow near the stand, the effective ground plane could rise. Similarly, the ground plane would be affected bythe accumulation of snow on the ground. A method for establishing a well-defined ground plane for mostweather conditions during measurements at ground level is described in 6.3.1.1.
During the measurements, the observer should be well removed from the measurement location to avoid perturbing the electric field. Some signal processing occurs in the housing that contains the sensing electrodeand shutter. The remainder of the signalprocessing circuit and field-strength display are contained in ashielded enclosure that is connected to the sensing electrode housing with a shielded cable.
Because the electric field in the vicinity of a dc power line is not uniform, it may be of interest to measurethe electricfield strength at points above the ground plane. This can be done with the second type of fieldmill, the cylindrical field mill. Typically, the charges are induced by the electric filed on two exposed half-cylinder sensing electrodes. The induced charges on the sensing electrodes are varied periodically by rotat-ing the sensing electrodes about the cylinder axis at a constant angular frequency, as shown schematically inFig 3.Expressions for the induced charge (q.) and current (i.) between the half-cylinders for a cylinder oflength L, ignoring end effects, are [39].IEEE 1227 pdf download.