Role of dissolved copper and oxygen on copper sulfide generation in insulating oil

Kawarai, H.; Fujita, Y.; Tanimura, Junji; Toyama, S; Yamada, Naoya; Nagao, E.; Hosokawa, N.; Amimoto, T.

doi:10.1109/tdei.2009.5293957

Cited by 52 publications

(24 citation statements)

References 4 publications

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“…The semi conducting copper sulfide which is formed on the copper conductor of windings, starts migrating towards inner papers layers [7,8]. This leads to dielectric loss in the insulation, followed by thermal instability and finally ends up in thermally induced dielectric breakdown of the insulating system.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Performance of Paper-Oil Insulation System in the Presence of DBDS

Khan¹,

Yaseen²,

Baig³

2016

IJRET

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Section: Introductionmentioning

confidence: 99%

Characterization of Performance of Paper-Oil Insulation System in the Presence of DBDS

Khan¹,

Yaseen²,

Baig³

2016

IJRET

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“…Many articles [1][2][3][4][5][6][7][8] have discussed the mechanisms of copper sulfide formation including the role of oxygen [2,4]. Although copper is corroded in sulfurous acidic environments to leave CuxS [1], dibenzyl disulfide (DBDS) is considered to be the major cause of CuxS deposition in transformers [2,3]; consequently it is widely used to simulate a corrosive environment in a non-corrosive oil.…”

Section: Introductionmentioning

confidence: 99%

Aging behaviour of dodecylbenzene in the presence of copper and dibenzyl disulfide (DBDS)

Hosier

Lai

Vaughan

2016

2016 IEEE International Conference on Dielectrics (ICD)

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Copper sulfide deposition remains a serious issue in high voltage power transformers and can result in equipment failure. In order to understand the chemistry of this process, dodecylbenzene was used as a model oil system. Copper and dibenzyl disulfide (DBDS) were added in controlled amounts and accelerated aging was then performed. It was found that copper sulfide (CuxS) could be formed (i.e. the included copper sheets were blackened) even under non-oxidative conditions but only when DBDS was present in the oil. The reaction was accelerated in the presence of oxygen and competes for available copper with the parallel copper carboxylate producing reaction. The AC breakdown strength was reduced after aging, but exhibited a more catastrophic reduction in oils containing DBDS, confirming the detrimental effects of CuxS on breakdown performance.

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“…The scrapyard is often the fulcrum of the diagnostic process on windings and solid insulation although, unless in the case of proactively scrapped units, it is generally after the failure occurred. Even at this point, however, visual assessment of the materials is usually the first level of investigation only eventually followed by laboratory tests like DP of paper or electron microscopy [1], [8], [15], [16]. The aim of this paper is to show the unique imaging capabilities of an advanced surface chemistry analytical technique, static secondary ion mass spectrometry (SSIMS), in the study and diagnostics of corrosion and passivation phenomena occurring at the copper surface of transformer windings, in order to increase the fundamental understanding of the chemical process involved and pave the way for further improvement in the management of such a complex and dangerous issue.…”

Section: Introductionmentioning

confidence: 99%

SSIMS molecular selective imaging: A new diagnostic tool to investigate metal passivators in scrapped transformers

Facciotti

Amaro

Brown

et al. 2015

2015 IEEE Electrical Insulation Conference (EIC)

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! In every high voltage grid, the replacement of assets is a slow but steady process that guarantees long-term reliability of the power distribution networks. The prioritisation of such interventions is based on complex rating criteria specifically designed to highlight potential issues of certain machines (or families of machines) in need of care. Given the tremendous costs of operations such as the replacement of a power transformer it is not surprising to observe constant efforts devoted to finding new and better monitoring and diagnostic tools. These are capable of delivering invaluable information about the conditions of a transformer, in service or after it is either failed or proactively scrapped, allowing a better comprehension of underlying chemical-physical phenomena occurring. Ideally, advanced monitoring and diagnostic tools should ultimately result in improved rating parameters to be applied in the evaluation of future interventions. This feasibility study evaluates the use of static secondary ion mass spectrometry (SSIMS) molecular selective imaging as a diagnostic tool for power transformer. SSIMS is herein demonstrated to be able to assess, without doubts, the presence and integrity of the passivation layer produced by Irgamet ® 39 on copper surfaces in laboratory tests. The technique has also been tested on real samples collected from one of the phases of a 400/275kV autotransformer proactively scrapped and proved to be applicable without significant sample preparation. The possibility of its use in the study of the distribution of Irgamet ® 39 across the windings is also demonstrated. Further development of SSIMS as a diagnostic tool would be significantly increasing the grade of detail at which scrapped/failed units could be inspected. A better understanding on how the operating conditions or the design of a transformer can affect the anticorrosion protection layer at the molecular level would open the way to significant ad hoc improvements of both operative guidelines and rating criteria for power transformers

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Role of dissolved copper and oxygen on copper sulfide generation in insulating oil

Cited by 52 publications

References 4 publications

Characterization of Performance of Paper-Oil Insulation System in the Presence of DBDS

Characterization of Performance of Paper-Oil Insulation System in the Presence of DBDS

Aging behaviour of dodecylbenzene in the presence of copper and dibenzyl disulfide (DBDS)

SSIMS molecular selective imaging: A new diagnostic tool to investigate metal passivators in scrapped transformers

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