Re. James et Bt. Phung, DEVELOPMENT OF COMPUTER-BASED MEASUREMENTS AND THEIR APPLICATION TO PD PATTERN-ANALYSIS, IEEE transactions on dielectrics and electrical insulation, 2(5), 1995, pp. 838-856
After referring briefly to the earlier developments of computer-based
PD measurements in the 1970s, the paper outlines how the introduction
of new technology has resulted in the design and production of a numbe
r of digital systems for use in test laboratories and on site. In orde
r to avoid overgeneralization, the basis of the hardware required for
detection and recording of the PD pulses is described by reference to
a particular system, it being understood that many detailed variations
are possible depending on the application. The paper describes a numb
er of parameters that can be calculated by software and used to charac
terize the PD behavior. These include the IEC-270 integrated quantitie
s, statistical moments and other fingerprints for recognizing the PD p
atterns within the power frequency cycle. Examples are given of the pa
tterns obtained on equipment and samples. These are necessarily select
ive and are intended to indicate how the techniques may be applied. It
is concluded that these new methods will become valuable in procedure
s for assessing the condition of electrical insulation, in particular
faults or defects, but must be used in conjunction with existing techn
iques until improved confidence is achieved in interpreting results, e
specially in respect of the various phase-resolved distributions and c
alibration procedures.