| Insulation oil which plays the roles of insulating, cooling and extinguish the arc isthe main insulation material of the transformer. The quality of the insulating oil hasimportant influence on the safe operation of the transformer. Mixed insulation oil hasthe complementary advantages of mineral oil and natural ester. However, mixed oildeveloped at home and abroad are not used in the actual transformer. If mixed insulationoil can improve the thermal aging stability of insulation pressboards of the distributiontransformeror with long operation time not also needs to be studied. So new anti-agingmixed insulation oil effectively improving the thermal stability of new insulationpressboards and mid-aging insulation pressboards can be developed and applied to thedistribution transformer, which will have important research significance andapplication value.Firstly， this paper studied the producing method of new anti-aging mixedinsulation oil with batch of large-scale production. Then two kinds of oil-paperinsulation samples were prepared with new insulation pressboards and new mixedinsulation oil or new mineral oil respectively. Two other kinds of oil-paper insulationsamples were prepared with mid-aging insulation pressboards and new mixed insulationoil or new mineral oil respectively, replacing the mid-aging mineral oil. Acceleratedaging experiments were performed under the130℃to compare and analysis thephysical, chemical and electrical properties of insulation oil and insulation pressboardsin the aging process. The delaying-aging effect and the mechanism impact of newanti-aging mixed insulation oil on the new insulation pressboards and the mid-aginginsulation pressboards were also studied. Finally, this paper studied the preparationprocess of the distribution transformer impregnated with new anti-aging mixtureinsulation oil and made factory-routine tests and preventive tests for it. The the mainresults are as follows:①This paper has successfully developed new anti-aging mixture insulation oilwith batch of large-scale production, whose properties meet the requirements ofGB2536-2011in addition to the slightly higher dissipation factor and viscosity. Afterpouring new anti-aging mixed insulation oil into the distribution transformer, this paperhas developed a new distribution transformer which is impregnated with new anti-agingmixture insulation oil. This distribution transformer has successfully coupled to the power grid in Jiangbei District, Chongqing.②During the130oC thermal aging process of the two kinds of insulation systemscomposed by new insulating oil and new pressboards, the rate of decline of the degreeof polymerization of insulation pressboards impregnated with mixture insulation oil is73.8percentents of that of insulation pressboards impregnated with mineral oil.Breakdown voltage of mixture insulation oil and insulation pressboards impregnatedwith mixture insulation oil is higher than that of mineral oil and insulation pressboardsimpregnated with mineral oil. These show that mixture insulation oil can slow down theaging process of insulation pressboards and improve their insulation properties.③During the thermal aging process of the two kinds of insulation systemscomposed by new insulating oil and mid-aging insulation pressboards, the rates ofdecline of the polymerization’s degree of mid-aging insulaton pressboards impregnatedwith new mixed insulation oil or new mineral oil are respectively37.8percentents and63.9percentents of that of insulation pressboards impregnated with mineral oil withoutreplacing insulation oil. All of these shows that two kinds of new insulation oil can slowdown the aging process of mid-aging insulation pressboards and that mixture insulatonoil has better abilities to slow down the thermal aging process of mid-aging insulationpressboards than mineral oil.④After changing the mid-aging mineral oil into new mixture insulation oil ornew mineral oil, moisture becomes lower and breakdown voltage becomes higher in thetwo kinds of insulating pressboards.the relative permittivity of mid-aging insulationpressboards impregnated mixture insulation oil increases significantly. Besides, thedissipation factor of mid-aging insulation pressboards impregnated with mineral oildecreases All of these show that, after the renewal of insulating oil, new mixtureinsulation oil or new mineral oil has truely been immersed in mid-aging insulationpressboards, which can improve the physical, chemical and electrical properties ofmid-aging insulation pressboards. |
PDF Full Text Request