Factors affecting the dissolution of copper in transformer oils

Kalantar, A.; Levin, Martina

doi:10.1002/ls.63

Cited by 35 publications

(51 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main insulation system of a transformer consists of the insulation oil, oil‐impregnated insulation pressboard, and insulation winding. The copper winding wrapped in insulation paper is immersed in the transformer oil to provide insulation for the current and voltage transmission . Copper has stable physicochemical properties, low electrical resistivity, and is widely used in power transformers.…”

Section: Introductionmentioning

confidence: 99%

Copper catalytic effect on the thermal deterioration and surface morphology performance of transformer oil–paper insulation

Hao

Liao

Yang

et al. 2017

IEEJ Transactions Elec Engng

View full text Add to dashboard Cite

Transformer failure caused by copper corrosion in oil-paper insulation has been attracting much attention in recent years. It is necessary to get a better understanding the effect of copper on the degradation rate and the microcosmic performance of the oil-paper insulation. In this way, targeted measures could be taken to prevent harm to the transformer. The catalytic effect of copper on the thermal aging rate and the micro-/nano-level morphology of oil-paper insulation aged with and without copper are compared in this paper. The dynamic behavior of copper compounds dissolved in oil and deposited on the insulation paper surface is discussed. Results show that copper plays a catalytic role in the deterioration of oil-paper insulation, and this role becomes obvious in the later stages of aging. Compared to the oil-paper insulation sample aged without copper, in the oil-paper insulation sample aged with copper the oil has higher acidity and higher ultraviolet absorption wavelength. Besides, the degree of polymerization of the paper is lower. Scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) results show that copper is present on the innermost paper surface. SEM and atomic force microscopy clearly show the deposition of copper compounds. Higher deterioration of the paper results in more roughness of the paper surface. The content of copper compounds dissolved in oil was found to be increasing first and then decreasing in the later process of aging. The content of copper compounds deposited on the paper increases significantly when the oil is aged for a long time. The catalytic effect of copper on the thermal aging rate and the surface morphology of oil-paper insulation should be paid more attention even for a noncorrosive oil.

show abstract

Section: Introductionmentioning

confidence: 99%

Copper catalytic effect on the thermal deterioration and surface morphology performance of transformer oil–paper insulation

Hao

Liao

Yang

et al. 2017

IEEJ Transactions Elec Engng

View full text Add to dashboard Cite

show abstract

“…Therefore, for the equipment under the threaten of corrosive sulfur, we should improve the radiating effect and control the load and operating temperature of the equipment to avoid overload operation and cause local overheating [19][20][21]. Oxygen can increase oil aging and promote the reaction between corrosive sulfur and copper.…”

Section: B Improve Operation Conditionsmentioning

confidence: 99%

“…Oxygen can increase oil aging and promote the reaction between corrosive sulfur and copper. Dissolved air in oil was the main source of oxygen, so we must be strictly on the vacuum treatment of the equipment [20][21][22][23][24][25][26][27].…”

Section: B Improve Operation Conditionsmentioning

confidence: 99%

Summary of research on corrosive sulfur in oil-paper insulation system

Quan

Jun-xing

Hui-li

et al. 2014

2014 ICHVE International Conference on High Voltage Engineering and Application

View full text Add to dashboard Cite

Oil-paper insulation plays an important role in the internal insulation of power transformers.Aging of transformer insulation is a gradual procedure which can eventually threaten the safe operation of power transformers. During long-term operation of power transformers, oil-paper insulation is exposed to multiple stresses, including electrical, thermal, mechanical factors and so on. Lot of vigor is given to maintenance of the health of transformers in transmission system. Usually the reliability of power transformer is very high and is expected to have a long service life. But according to the recent report and observations, many transformers and reactors have failed prematurely due to the resultant formation of copper sulfide in the windings, which has attracted wide attention. In the past decade ,considerable amount of work has been carried out to understand the long term effects of corrosive sulfur in mineral insulating oils, which has been recognized as the culprit of failure of some shunt reactors and power transformers. However, the problem of copper corrosion is very complex because of the complicated existence of sulfur element in transformers. Depending on oil, there are many different sulfur compounds present in oil. Other components of transformer, like pressboard, paper, glue, gasket, contaminated oil deliver hose etc are all potential sources of sulfur of one form or the other, either independently or due their interaction with oil. It is not one single corrosive sulfur compound that is responsible for all corrosive sulfur issues. Therefore the main sources, detection method, corrosive mechanism, damage and suppression measures are still the puzzled research focus. This paper present a comparatively detailed summary of research status about this phenomenon, and some useful research proposals and findings are introduced as well.

show abstract

“…Open Beaker Test ASTM D 1934-95), and it has also recently been used in a study on how mineral oil oxidation products affects copper corrosion. 22 The presence of copper accelerates the oxidation of hydrocarbons such as mineral oils. 23 Glass beakers (200 mL) were each filled with 170 g very highly refined oil (severely hydrotreated sulfur free) light (8 cSt) naphthenic mineral base oil suitable for production of electrical insulating oil.…”

Section: Oven-aging Of Oil Samplesmentioning

confidence: 99%

Determination of Hydroperoxide Content in Complex Hydrocarbon Mixtures by Gas Chromatography/Mass Spectrometry

2009

View full text Add to dashboard Cite

A known principle in which triphenylphosphine is allowed to be oxidized by hydroperoxides to triphenylphosphine oxide, was developed into an analytical method for determination of hydroperoxide content in light mineral oils using GCMSdetection and quantification. By suitable choice of reagent solution solvents and internal standard, the method proved to be simple to apply and very rugged. For a series of oven-aged oil samples the developed method gave results with a satisfactory correlation to an established iodometric method (which also gave a higher standard deviation). A mechanistic explanation for interference of high concentrations of added aldehydes on measurements was also suggested, but it was found that the interference is of no practical consequence for oxidized oil samples.

show abstract

Factors affecting the dissolution of copper in transformer oils

Cited by 35 publications

References 7 publications

Copper catalytic effect on the thermal deterioration and surface morphology performance of transformer oil–paper insulation

Copper catalytic effect on the thermal deterioration and surface morphology performance of transformer oil–paper insulation

Summary of research on corrosive sulfur in oil-paper insulation system

Determination of Hydroperoxide Content in Complex Hydrocarbon Mixtures by Gas Chromatography/Mass Spectrometry

Contact Info

Product

Resources

About