PD detection and localization by means of acoustic measurements on hydrogenerator stator bars

Corona detection on surfaces of insulators using ultrasound sensors and fibre-optic transmission systems

“…Acoustic methods can be made immune to electromagnetic interference. Acoustic PD detection has been applied to SF 6 insulated switchgears (GIS) [3,4], capacitors [5,6], transformers [7][8][9][10], power cables [11,12], high-voltage motors and generators [13,14] and outdoor insulation [15].…”

Characterization of partial discharge pulses of power generator

“…Few papers have reported the use of multiple sensors [15] to locate and identify the type of PD on generator. For transformer, GIS and cables, multiple sensors are used.…”

“…The decomposition tree of wavelet package with 4 levels As can be seen at the 4 th level, the original signal is decomposed into 16 components from (4, 0) to(4,15). Following the sequence from left to right, it contains more approximate part at (4, 0) and detail part at(4,15) as shown inFigure 4-6 for corona data ofFigure 4-1 (a). At (4, 0), approximated signal contains the 50Hz with its harmonics and other low frequency noises.…”

“…At (4, 0), approximated signal contains the 50Hz with its harmonics and other low frequency noises. While at(4,15), the detail signal contains the high frequency components connected to PD and other noises. Other decomposed signals at (4, 1) to(4,14) contain decreasing order of approximated signal and increasing order of detail signal.…”

“…Decomposed corona signals at (4, 0) and(4,15) To extract the PD signal, the decomposed signals can be grouped and PD signal can be reconstructed. As indicated, the (4, 0) is the decomposed noise content.…”