| Oil-immersed transformer is one of the most important equipment in the power system.Oil-paper insulation is composed of cellulose insulating paper and mineral insulating oil,which is the main component of the internal insulation of oil-immersed transformer.The insulation status and health level of equipment have an important impact on the safety and stability of the power system.The oil-paper insulation gradually deteriorates under the action of temperature,electric field,water,oxygen and other factors,and generates a series of polar aging products dissolved in the insulating oil,including acid substances,copper ions,mositure,which results in the degradation of the performance of oil-paper insulation.In order to delay the aging of equipment insulation and extend its service life,the treatment methods are usually adopted in engineering,such as adding antioxidants,purifying insulating oil with oil filter,and changing oil.However,these measures can not completely remove the aging products in oil or do not meet the economic needs.At present,physical adsorption treatment for the regeneration of insulating oil is an effective way to alleviate the deterioration of oil-paper insulation.However,for the operation of transformer,it remains to be further studied to carry out the adsorption treatment of insulating oil under charged operation.In this paper,the method of physical adsorption is proposed to regenerate the insulating oil.At first,the accelerated thermal aging test of oil-paper insulation is carried out under the laboratory conditions.Three kinds of adsorbents were used to investigate the effect of physical adsorption treatment on the characteristics of oil-paper insulation,including different adsorbent concentration,adsorption temperature,adsorption time.Secondly,the insulating oil regenerating treatment equipment can be used in on-site operation transformer,and various operation indexes of the equipment are tested to ensure the requirements of national standard.Finally,for the 35kV transformer which has been in operation for 10 years,the best adsorption effect in the above test is adopted for adsorption treatment.The physical/chemical and electrical properties of insulating oil are tested,and the inhibition effect of the adsorption treatment on the aging of insulating oil is studied.The main conclusions are as follows:?Physical adsorption treatment can absorb the polar aging products of oil-paper insulation to a certain extent,which effectively improves the performance of oil-paper insulation.For three kinds adsorbent,in view of adsorbent adsorption effect,economy as well as the transformer operation status,5 A molecular sieve has the best adsorption effect among the three types of adsorbent through comparison and analysis,and 5%concentration of adsorbent and 60? under the condition of temperature is more appropriate for the economy and the operation condition.?The adsorption treatment method is combined with the working principle of oil filter to develop an insulating oil regenerating treatment equipment,which is used in on-site operation transformer.All performance indexes of the equipment meet the standard requirements of GB 5226.1-2008 mechanical and electrical safety mechanical and electrical equipment.?In this paper,the insulating oil of 35 kV oil-immersed transformer was regenerated by the insulating oil regenerating treatment equipment,which effectively eliminated the aging products,the content of acid value,copper ion and water in the oil was greatly reduced.All performance indexes of the oil after regenerating meet the standard requirements,the adsorption treatment effectively improved the performance of insulating oil,which has great value and significance in engineering application. |
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