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- Title
Space charge and insulation properties of nano-Al2O3-modified oil-impregnated paper used for HVDC convertor transformer.
- Authors
Zhang, Jinfeng; Chen, Qingguo; Chi, Minghe; Yang, Hongda; Liu, Heqian
- Abstract
Oil-paper (cellulose) insulation is the main insulation of converter transformer, and the space charge accumulation inside the oil-impregnated paper is a serious problem. To decrease the space charge accumulation and improve the breakdown field strength, the oil-impregnated paper (OIP) with different Al2O3 nanoparticles content was prepared. The test results show that the space charge accumulation in the non-modified paper and 3.75 wt% Al2O3 paper is serious under DC electric field, and the decay amplitude and decay speed of space charge are larger and faster in the short circuit test. Suppression effect of space charge in the 2.5 wt% Al2O3 paper is the best, and the decay amplitude and decay speed of space charge are the lest and slowest. Moreover, the surface potential of non-modified paper decay faster, and that of 2.5 wt% Al2O3 paper decay slowest. The breakdown field strength and resistivity of Al2O3-modified OIP are larger than those of the non-modified paper. The breakdown field strength of 2.5 wt% Al2O3 paper increases most, about 16%. Suitable Nano-Al2O3-modified increases the traps level and density of deep traps in oil-impregnated paper, resulting in the space charge suppression and breakdown field strength improvement.
- Subjects
SPACE charge; ELECTRIC fields; SURFACE potential; SHORT circuits; TRANSFORMER insulation
- Publication
Journal of Materials Science: Materials in Electronics, 2021, Vol 32, Issue 3, p3720
- ISSN
0957-4522
- Publication type
Article
- DOI
10.1007/s10854-020-05117-5