Documents disponibles écrits par cet auteur

Degradation of the insulating system of power transformers by copper sulfide deposition / Jelena M. Lukic in Industrial & engineering chemistry research, Vol. 49 N° 20 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9600–9608 Titre : Degradation of the insulating system of power transformers by copper sulfide deposition : Influence of oil oxidation and presence of metal passivator Type de document : texte imprimé Auteurs : Jelena M. Lukic, Auteur ; Srdjan B. Milosavljevic, Auteur ; Aleksandar M. Orlovic, Auteur Année de publication : 2011 Article en page(s) : pp. 9600–9608 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation Résumé : Deposition of conductive copper sulfide on paper insulation of power transformers was recognized as a serious risk that can result in equipment failure. The aim of this study was to investigate the influence of mineral insulating oil oxidation and the presence of metal passivator on copper sulfide (Cu2S) deposition. Oil oxidation was found to increase deposition of Cu2S on the insulating paper, as confirmed by IEC 61125 B and IEC 62535 tests. The presence of oxygen resulted in an increase of copper dissolution in the oil and facilitated progressive copper sulfide deposition on the insulating paper, as confirmed by ICP, AAS, and EDX measurements. The effectiveness of aminomethyl substituted toluylbenzotriazole (TTA) metal passivator in suppressing copper sulfide formation and deposition was studied using modified IEC 62535 test. The protective role of TTA bonded to the copper plate surface and absorbed in the insulating paper was observed in tests at 140 and 150 °C, even for highly oxidized oils. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325777 [article] Degradation of the insulating system of power transformers by copper sulfide deposition : Influence of oil oxidation and presence of metal passivator [texte imprimé] / Jelena M. Lukic, Auteur ; Srdjan B. Milosavljevic, Auteur ; Aleksandar M. Orlovic, Auteur . - 2011 . - pp. 9600–9608. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9600–9608 Mots-clés : Oxidation Résumé : Deposition of conductive copper sulfide on paper insulation of power transformers was recognized as a serious risk that can result in equipment failure. The aim of this study was to investigate the influence of mineral insulating oil oxidation and the presence of metal passivator on copper sulfide (Cu2S) deposition. Oil oxidation was found to increase deposition of Cu2S on the insulating paper, as confirmed by IEC 61125 B and IEC 62535 tests. The presence of oxygen resulted in an increase of copper dissolution in the oil and facilitated progressive copper sulfide deposition on the insulating paper, as confirmed by ICP, AAS, and EDX measurements. The effectiveness of aminomethyl substituted toluylbenzotriazole (TTA) metal passivator in suppressing copper sulfide formation and deposition was studied using modified IEC 62535 test. The protective role of TTA bonded to the copper plate surface and absorbed in the insulating paper was observed in tests at 140 and 150 °C, even for highly oxidized oils. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325777

Removal of sulfur compounds from mineral insulating oils by extractive refining with N - methyl - 2 - pyrrolidone / Jelena M. Lukic in Industrial & engineering chemistry research, Vol. 51 N° 12 (Mars 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 12 (Mars 2012) . - pp. 4472–4477 Titre : Removal of sulfur compounds from mineral insulating oils by extractive refining with N - methyl - 2 - pyrrolidone Type de document : texte imprimé Auteurs : Jelena M. Lukic, Auteur ; Draginja Nikolic, Auteur ; Valentina Mandic, Auteur Année de publication : 2012 Article en page(s) : pp. 4472–4477 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mineral  insulating  oils Résumé : Copper sulfide deposits in the insulation systems of power transformers decrease the dielectric properties of the insulation and therefore constitute a significant risk for the operation of power transformers. Disulfides, oxidized sulfur compounds, thiols, and elemental sulfur, which could be present in insulating oil, have been recognized as the sources of reactive sulfur responsible for copper sulfide formation. Selective liquid–liquid extraction using N-methyl-2-pyrrolidone solvent was investigated for the purification of mineral insulating oils through the removal of compounds and precursors responsible for copper sulfide formation. The efficiency of the extraction process was evaluated using corrosive sulfur test IEC 62535, SEM/EDX measurements of paper before and after the IEC 62535 test, and measurements of the dibenzyl disulfide concentration in the oil using GC-ECD method. The oxidation stability of refined oils was evaluated using the IEC 61125 method. Precursors of copper sulfide deposits were completely removed from different mineral oils as a result of purification by extraction with N-methyl-2-pyrrolidone and 1.0 wt % water as a cosolvent. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300450e [article] Removal of sulfur compounds from mineral insulating oils by extractive refining with N - methyl - 2 - pyrrolidone [texte imprimé] / Jelena M. Lukic, Auteur ; Draginja Nikolic, Auteur ; Valentina Mandic, Auteur . - 2012 . - pp. 4472–4477. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 12 (Mars 2012) . - pp. 4472–4477 Mots-clés : Mineral  insulating  oils Résumé : Copper sulfide deposits in the insulation systems of power transformers decrease the dielectric properties of the insulation and therefore constitute a significant risk for the operation of power transformers. Disulfides, oxidized sulfur compounds, thiols, and elemental sulfur, which could be present in insulating oil, have been recognized as the sources of reactive sulfur responsible for copper sulfide formation. Selective liquid–liquid extraction using N-methyl-2-pyrrolidone solvent was investigated for the purification of mineral insulating oils through the removal of compounds and precursors responsible for copper sulfide formation. The efficiency of the extraction process was evaluated using corrosive sulfur test IEC 62535, SEM/EDX measurements of paper before and after the IEC 62535 test, and measurements of the dibenzyl disulfide concentration in the oil using GC-ECD method. The oxidation stability of refined oils was evaluated using the IEC 61125 method. Precursors of copper sulfide deposits were completely removed from different mineral oils as a result of purification by extraction with N-methyl-2-pyrrolidone and 1.0 wt % water as a cosolvent. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300450e