Light emission in PE with a needle-like microvoid at the metal-polymer interface under impulse voltages

Abstract

Light emission from polyethylene with a needle-like microvoid has been investigated under the application of a negative impulse voltage in order to examine the temporal behavior of discharge in the microvoid at the metal-polymer interface. The light emission was observed distinctly during the voltage rise and fall phases with a period of no light emission between the two light emitting phases. The emitted light consisted of sequential light pulses which appeared regularly, according to the temporal variation rate of the voltage. The sequential light pulses corresponded to the sequential discharge in the microvoid which occurred to keep the voltage across the microvoid below the discharge inception voltage. The characteristics of light emission revealed the occurrence of intermittent discharges in the microvoid during the voltage variation phase of the impulse voltage, caused by charge deposition on the polymer surface of the microvoid.

Accumulative effect of partial discharges at impulse voltage wave tail

“…In this case, a damped sinusoidal oscillating voltage is similar to a standard AC acquisition, with a main difference relating to the period of sinusoidal part which is in the range of tens to hundreds microseconds. The PDs at impulse voltages were also analysed by light emission [33][34][35], confirming with high resolution the PD sequence during voltage rise phase. The ageing phenomena of XLPE and EPR cable insulation excited by switching impulses are presented in [36].…”

Partial discharge characteristics and mechanism in voids at impulse voltages

“…Research on the PD characteristics at impulse voltages has been focused on two aspects. (i) PD characteristics in liquid, electronegative gas and solid dielectrics are studied at a standard lightning impulse voltage by adopting optical and pulsed-current methods [8][9][10][11][12]; (ii) PD measurements and characteristics in solid dielectrics at short rise time repetitive voltage impulses [13][14][15][16][17][18][19][20]. However, studies of the PD at oscillating impulse voltages are not available yet.…”