エポキシ樹脂中のトリー伸展と放射電磁波

Ueno, Hideki; Nagamachi, Takashi; Nakamura, Masaki; Nakayama, Hiroshi; Kakihana, Kunihiko

doi:10.1541/ieejfms.129.915

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…However, as the discharge continues, the void walls are eroded, and when a local strong electric field exceeds the insulation breakdown level, an electrical tree develops and higher‐frequency components appear in the radiated EM waves. This is also confirmed by the fact that EM radiation at 40 MHz to 150 MHz is observed in void discharge prior to the occurrence of electrical treeing , which is similar to the frequency characteristics of PDs in air. We may assume that when air bubbles occur in a liquid due to heating, the frequency of the EM radiation becomes relatively low, similar to void discharge.…”

Section: Discussionsupporting

confidence: 60%

“…The EM waves detected at 40 MHz to 300 MHz were also observed with different environments and instruments (Refs. and ), and therefore we may conclude that this radiation is a feature of PD in resins and it is not related to resonance or the frequency characteristics of the instrument. In addition, the frequency spectrum of EM radiation in epoxy resin was split into three bands, at 40 MHz to 100 MHz, 100 MHz to 200 MHz, and 200 MHz to 300 MHz.…”

Section: Resultsmentioning

confidence: 80%

“…Therefore it is very important to detect the origination and propagation of electrical trees in solid insulation for deterioration diagnosis. Our research group carried out a basic study of epoxy resins used in molded transformers and discovered that PDs in epoxy resin produced EM radiation above 200 MHz . Based on the accumulated results, a device to detect PDs in epoxy resin was developed .…”

Section: Introductionmentioning

confidence: 99%

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

Mutakamihigashi

Kuroishi

Ueno

2015

Electrical Engineering Japan

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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).

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Section: Discussionsupporting

confidence: 60%

Section: Resultsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

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

Mutakamihigashi

Kuroishi

Ueno

2015

Electrical Engineering Japan

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“…Ueno et al , studied treeing phenomena in epoxy resin insulating material and they could identify the point of inception and propagation adopting UHF technique [11]. However, adoption of UHF technique for identification of incipient discharges in underground cable insulation diagnostics is at an infancy stage.…”

Section: Introductionmentioning

confidence: 99%

Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

Sarathi¹,

Nandini²,

Danikas³

2011

Journal of Electrical Engineering

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A major cause for failure of underground cables is due to formation of electrical trees in the cable insulation. A variety of tree structure can form from a defect site in cable insulation viz bush-type trees, tree-like trees, fibrillar type trees, intrinsic type, depending on the applied voltage. Weibull studies indicate that a higher applied voltage enhances the rate of tree propagation thereby reducing the life of cable insulation. Measurements of injected current during tree propagation indicates that the rise time and fall time of the signal is of few nano seconds. In the present study, an attempt has been made to identify the partial discharges caused due to inception and propagation of electrical trees adopting UHF technique. It is realized that UHF signal generated during tree growth have signal bandwidth in the range of 0.5-2.0 GHz. The formation of streamer type discharge and Townsend type discharges during tree inception and propagation alters the shape of the tree formed. The UHF signal generated due to partial discharges formed during tree growth were analyzed adopting Ternary plot, which can allow one to classify the shape of tree structure formed.

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