Polarity Effect and Electromagnetic Radiation of Partial Discharge Accompanying Growth of Electrical Tree

Abstract

SUMMARYWe have investigated the characteristics of radiated electromagnetic (EM) waves from positive and negative partial discharges (PD) in epoxy resin and cross-linked polyethylene. We found that there is a correlation among the EM level from PD, the positive PD current, and electrical trees. Therefore, the growth of an electrical tree produces a lot of positive PD. We have also investigated the characteristics of the frequency region of EM waves from PD in air, insulating oil, and liquid epoxy in addition to the above insulators. EM waves were detected in the frequency region of 40 MHz to 300 MHz from positive and negative PD in epoxy resin and cross-linked polyethylene. EM waves were also detected in the frequency region of 40 MHz to 150 MHz from positive and negative PD in air. In the case of insulating oil and liquid epoxy, EM waves were detected in the frequency regions of 40 MHz to 150 MHz from positive PD, and 40 MHz to 250 MHz from negative PD. The frequency region differed depending on the material and the discharge polarity. Our investigation indicates that the cause is differences in electric field strength at the time of PD occurrence. C⃝ 2015 Wiley Periodicals, Inc. Electr Eng Jpn, 192(3): 19-26, 2015; Published online in Wiley Online Library (wileyonlinelibrary.com).

Pulse Current of Multi-Needle Negative Corona Discharge and Its Electromagnetic Radiation Characteristics

“…Reid A.J. [14], Mutakamihigashi T. [15], and Nugraha F.A. [16] studied the EM radiation characteristics that were produced by partial discharge (PD).…”

Charge transport dynamics and the effects on electrical tree degradation under DC voltages in thermally aged silicone rubber

“…due to the multi-layer insulation coordination and multi-field coupling aging. Since Robinson first discovered electrical tree channels in 1936 [6], systematic studies have been carried out on electrical tree behaviors under AC voltage, including the influence of voltage frequency [7][8][9], external environment (such as temperature [10,11], pressure [12], moisture [13], radical [14], etc), nano-filler [15][16][17], etc, and the following partial discharge and tree channel characteristics have also been conducted to clarify tree mechanisms [18][19][20][21].…”