dc.contributor.author | Eberg, Espen | |
dc.contributor.author | Kantar, Emre | |
dc.contributor.author | Aakre, Torstein Grav | |
dc.date.accessioned | 2022-07-21T10:16:56Z | |
dc.date.available | 2022-07-21T10:16:56Z | |
dc.date.created | 2022-07-02T14:42:18Z | |
dc.date.issued | 2022 | |
dc.identifier.citation | Proceedings of the Nordic Insulation Symposium. 2022, 27 (1), . | en_US |
dc.identifier.issn | 2535-3969 | |
dc.identifier.uri | https://hdl.handle.net/11250/3007497 | |
dc.description.abstract | A multi-stress test rig was built to investigate the effect of many start-stops (load cycling) on hydropower generator insulation. To emulate real-life start-stops, stator bars were subjected to accelerated temperature cycling by circulating a 3.5 kA current and then cooling down with fans while high voltage (service voltage) was applied simultaneously to the insulation. A total of 250 load cycles were applied. Partial discharges (PD) were recorded on-line during load cycling, and after every 50 cycles, off-line dielectric loss and PD measurements were conducted. There was an apparent increase in dielectric losses after they had been subjected to a total of 250 load cycles. During load cycling, the PD level generally decreased with temperature, but there was a temporary increase in the PD activity during temperature rise and fall. This trend can be explained by different thermal expansion in copper and insulating material (epoxymica), suggesting that a stator bar that is load-cycled will be exposed to substantially higher PD levels than a stator bar under a uniform load and temperature, leading to further deterioration of the insulation quality. | en_US |
dc.language.iso | eng | en_US |
dc.rights | Navngivelse 4.0 Internasjonal | * |
dc.rights.uri | http://creativecommons.org/licenses/by/4.0/deed.no | * |
dc.title | Multi-stress Cyclic Testing of Roebel Stator Bars for Hydropower | en_US |
dc.title.alternative | Multi-stress Cyclic Testing of Roebel Stator Bars for Hydropower | en_US |
dc.type | Peer reviewed | en_US |
dc.type | Journal article | en_US |
dc.description.version | publishedVersion | en_US |
dc.rights.holder | The Authors | en_US |
dc.source.pagenumber | 6 | en_US |
dc.source.volume | 27 | en_US |
dc.source.journal | Proceedings of the Nordic Insulation Symposium | en_US |
dc.source.issue | 1 | en_US |
dc.identifier.doi | 10.5324/nordis.v27i1.4571 | |
dc.identifier.cristin | 2036865 | |
dc.relation.project | Norges forskningsråd: 255099 | en_US |
cristin.ispublished | true | |
cristin.fulltext | original | |
cristin.qualitycode | 1 | |