IEEE C57.124:1991 (R2009)

New IEEE Standard - Inactive-Reserved.
The detection of partial discharges occurring in the insulation of dry-type transformers or their components and the measurement of the associated apparent charge at the terminals when the alternating test voltage is applied are covered. The wideband method is used. The detection system and calibrator characteristics are described, and the test procedures are established.

This recommended practice applies to the detection of partial discharges occurring in the insulation of dry-type transformers or their components, and to the measurement of the associated apparent charge at the terminals when an alternating test voltage is applied.
Partial discharge measurements in dry-type transformers may preferably be made on the basis of measurement of the apparent charge. Relevant measuring systems are classified as narrow-band or wide-band systems. Both systems are recognized and widely used. Without giving preference to one or the other, it is the object of this document to describe the wide-band method. General principles of partial discharge measurements, including the narrow-band method, are covered in IEEE Std 454-1973, IEC 270 (1981) and IEC 76-3 (1980).