Space charge, oxidation and morphology changes in low density polyethylene during high voltage DC ageing

Oldervoll, Frøydis; Ildstad, Erling

doi:10.1109/elinsl.2000.845552

“…It can also be noticed that the intensity of the small peak tends to increase with the ageing duration. Estimates of the degree of crystallinity vary between 37% and 44% (shown in Figure 14), though a slight tendency to increase with the ageing time is observed, which is in agreement with results presented in [26]. As suggested in [27], an increase of crystallinity in LDPE makes the mean free path for electrons longer and negatively affects the dielectric strength of polymeric material and lowering the tree inception voltage.…”

Section: Materials Analysessupporting

confidence: 91%

Electrical treeing behavior of DC and thermally aged polyethylenes utilizing wire-plane electrode geometries

Chen

¹

,

Mantsch

²

,

Huang

³

et al. 2014

IEEE Trans. Dielect. Electr. Insul.

13

0

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This paper presents electrical treeing behavior in low density polyethylene (LDPE) and cross-linked polyethylene (XLPE) after exposure to thermal and DC electro-thermal ageing. Both the ageing and the treeing tests were performed by means of two different types of test objects with wire-plane electrode geometry. One type of the tested objects contained only wire electrode of 10 µm diameter, whereas in the other type the wire electrode was attached through a semiconducting tab. The ageing was performed at 80°C with and without 10 kV DC voltage of both polarities connected to the wire and lasted up to 800 hours. The AC electrical treeing tests were applied afterwards for detecting changes of material properties after the ageing. The results showed that the electrical tree inception voltage consistently decreased with increasing time of thermal exposure, whereas the applied DC electric stress had a negligible effect on the observed behavior. Similar effects were found in both the tested materials (LDPE and XLPE) though the object type also influenced the results. For the objects with semiconducting tab, a higher level of the scale parameter was registered because of shielding effect of the tab on the electric field strength at the wire electrode. It also yielded less number of trees growing in parallel at the electrode. The dominant effect of thermal stress on the ageing of LDPE was elucidated by using various analytical techniques, like differential scanning calorimetry, infrared spectroscopy, inductively coupled plasma optical emission spectrometry and oxidation induction time, and it is believed to mainly affect antioxidant content in the test objects.

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“…It can also be noticed that the intensity of the small peak tends to increase with the ageing duration. Estimates of the degree of crystallinity vary between 37% and 44% (shown in Figure 14), though a slight tendency to increase with the ageing time is observed, which is in agreement with results presented in [26]. As suggested in [27], an increase of crystallinity in LDPE makes the mean free path for electrons longer and negatively affects the dielectric strength of polymeric material and lowering the tree inception voltage.…”

Section: Materials Analysessupporting

confidence: 86%

Electrical treeing behavior of DC and thermally aged polyethylenes utilizing wire-plane electrode geometries

Chen

¹

,

Mantsch

²

,

Huang³

et al. 2014

IEEE Trans. Dielect. Electr. Insul.

View full text Add to dashboard Cite

This paper presents electrical treeing behavior in low density polyethylene (LDPE) and cross-linked polyethylene (XLPE) after exposure to thermal and DC electro-thermal ageing. Both the ageing and the treeing tests were performed by means of two different types of test objects with wire-plane electrode geometry. One type of the tested objects contained only wire electrode of 10 µm diameter, whereas in the other type the wire electrode was attached through a semiconducting tab. The ageing was performed at 80°C with and without 10 kV DC voltage of both polarities connected to the wire and lasted up to 800 hours. The AC electrical treeing tests were applied afterwards for detecting changes of material properties after the ageing. The results showed that the electrical tree inception voltage consistently decreased with increasing time of thermal exposure, whereas the applied DC electric stress had a negligible effect on the observed behavior. Similar effects were found in both the tested materials (LDPE and XLPE) though the object type also influenced the results. For the objects with semiconducting tab, a higher level of the scale parameter was registered because of shielding effect of the tab on the electric field strength at the wire electrode. It also yielded less number of trees growing in parallel at the electrode. The dominant effect of thermal stress on the ageing of LDPE was elucidated by using various analytical techniques, like differential scanning calorimetry, infrared spectroscopy, inductively coupled plasma optical emission spectrometry and oxidation induction time, and it is believed to mainly affect antioxidant content in the test objects.

show abstract

Bibliography of HVDC transmission: 1998 IEEE Working Group report

Varma¹,

Litzenberger²,

Bolton³

2008

2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century

3

0

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Space charge, oxidation and morphology changes in low density polyethylene during high voltage DC ageing

Cited by 4 publications

References 6 publications

Electrical treeing behavior of DC and thermally aged polyethylenes utilizing wire-plane electrode geometries

Electrical treeing behavior of DC and thermally aged polyethylenes utilizing wire-plane electrode geometries

Electrical treeing behavior of DC and thermally aged polyethylenes utilizing wire-plane electrode geometries

Bibliography of HVDC transmission: 1998 IEEE Working Group report

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