| Autor: |
Carsten Leu, Ivan Semenov |
| Rok vydání: |
2019 |
| Předmět: |
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| Zdroj: |
Lecture Notes in Electrical Engineering ISBN: 9783030316792 |
| DOI: |
10.1007/978-3-030-31680-8_35 |
| Popis: |
In the presented work we examine the effect of a high DC field on the dielectric loss tangent (tanδ) and the relative permittivity (e′) of Transformerboard, a cellulosic fibrous insulating material. The dielectric dynamics was studied by applying a harmonic voltage signal of different frequencies (50, 500 and 10 000 Hz) onto a high DC bias and by monitoring the time dependent changes of tanδ and e′. Room-humid and thoroughly dried samples were studied at different temperatures. At all three frequencies we observed significant increases of tanδ and e′ in room-humid samples right upon the application of a high DC field and their gradual decrease during the DC field stress. This effect was more pronounced at 50 and 500 Hz compared to 10 kHz. The temperature elevation enhanced these processes. After the removal of the DC field both tanδ and e′ returned to their initial values. In contrast to room-humid Transformerboard, no changes were measured in well-dried samples. The presence of a specific polarization process due to the moderate water content was confirmed for room-humid Transformerboard by means of the low field dielectric spectroscopy. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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