Study on the characteristics of partial discharges in voids under square voltage by detecting light emission intensity

Investigation of partial discharge in piezoelectric ceramics

“…Therefore, PDs may be facilitated and become intense for soft PZT. For Polyethylene sample with an internal void, much more concentrated PD patterns have been reported when a square voltage pulse was applied compared to the patterns obtained under sinusoid and triangle waveforms [25]. This agrees with our assumption that the sudden increase of the internal field caused by domain switching in soft PZT can generate concentrated PD pattern.…”

“…Hence, no such concentrated PDs around specific fields were observed. The PD patterns show the so-called "turtle-like" shape for epoxy and "rabbit-like" shape for hard PZT [23,25,26]. The "ear" part of the "rabbit-like" pattern for hard PZT is highlighted in Fig.…”

“…Both patterns are commonly observed for insulation materials with void defects. The difference of PD patterns is usually attributed to the complexity of defect surface conditions, discharge area as well as the properties of the defect medium [23,25,26].…”

Partial discharges in SF₆ gas filled void under standard oscillating lightning and switching impulses in uniform and non-uniform background fields

“…Due to the charge memory effect, PD behaviors in void are impacted by the waveform of applied voltage [5,6]. Though the void discharges under power frequency, dc and square ac voltages have been extensively studied [5,[7][8][9], few studies so far have been focused on discharges under impulse voltages especially under the oscillation impulse voltage. Under varying voltage gaseous void discharges show some different characteristics in terms of their occurrences, propagations and the statistic distribution [10].…”

Measurement of optical signals emitted by surface discharges on bushing and post insulator

“…The methods and techniques used for detecting, locating and measuring the PD intensity have long been refined and developed in many research centers in the world [1][2][3][4][5][6][7][8][9][10][11][12][13]. Conventional methods [10] (electric, HF/VHF, UHF) and non-destructive alternative methods, such as: optical [1,2,14], mechanical (acoustic [11,[15][16][17][18][19] and optoacoustic methods [20]), as well as chemical methods are common nowadays.…”