Aging of Kraft paper in natural ester dielectric fluid

C.P. McShane1, K.J. Rapp2, J.L. Corkran3, G.A. Gauger2, J. Luksich4
1Dielectric Fluid, Cooper Power Systems, Waukesha, WI, USA
2Thomas A. Edison Technical Center, Cooper Power Systems, Franksville, WI, USA
3Transformer Products, Cooper Power Systems, Waukesha, WI, USA
4Dielectric Fluids, Cooper Power Systems, Waukesha, WI, USA

Tóm tắt

Kraft transformer insulation paper aged in natural ester (vegetable oil) dielectric fluid was compared to identical paper aged in conventional transformer mineral oil. Sealed steel aging tubes containing copper, aluminum, Kraft paper, and dielectric fluid (mineral oil and natural ester) were aged at 150/spl deg/C for 500, 1000, 2000, and 4000 hours. The extent of paper degradation after aging was determined using paper tensile strength, paper degree of polymerization, and furanic compounds in the aged fluid. Water contents of fluids and paper were compared. Paper aged in conventional transformer oil degraded at a significantly faster rate than in natural ester dielectric fluid. Paper in mineral oil reached three criteria for IEEE end-of-life (50% retained tensile strength, 25% retained tensile strength, and degree of polymerization of 200) within the first 1000 hours. After 4000 hours of aging, paper in natural ester did not degrade to any of the IEEE end-of-life criteria. At 4,000 hours, the paper aged in natural ester retained about 55% of the original tensile strength and a degree of polymerization of about 280. Paper aged in conventional transformer oil degraded to the same values in about 315 and 390 hours, respectively-an order of magnitude faster. The reduced paper-aging rate in natural ester is primarily attributed to the fluid maintaining the paper in a very dry state.

Từ khóa

#Aging #Oil insulation #Petroleum #Power transformer insulation #Minerals #Polymers #Degradation #Dielectrics and electrical insulation #Steel #Copper

Tài liệu tham khảo

emsley, 1992, A Reassessment of the Low Temperature Thermal Degradation of Cellulose, Proc 6th Int Conf Dielectric Materials Measurements Applications, 229 miyoshi, 1975, A New Additive for Improving the Thermal Aeging Characteristics of Insulating Paper, IEEE Trans EI, e1 10 unsworth, 1999, Degradation of Electrical Insulating Paper Monitored with High Performance Liquid Chromatography, IEEE Trans EI, 25, 737 1996, IEEE Guide for Loading Mineral-Oil-Immersed Transformers clark, 1962, Insulating Materials for Design and Engineering Practice, 287 10.1016/0141-3910(95)00204-9 10.1002/(SICI)1097-4628(19980411)68:2<293::AID-APP11>3.0.CO;2-Z oommen, 1999, Bubble Evolution from Transformer Overload, IEEE/PES Transmission & Distribution Conference 1998, Aerobic Aquatic Degradation, US EPA OPPTS 835.3100, Test Report No Ml-304 98 1999, Administrative Regulation on the Classification of Substances Hazardous to Waters, Water Hazard Classes (VwVwS) Annex 1 Substances Non-Hazardous to Waters Pursuant to Number 1 2a Index No 660 2002, National Electrical Code, NFPA 70 1999, Final Report: Acute Trout Toxicity Testing for Two Envirotemp FR3 Formulations, Procedure 203 OECD &#x201C;Guidelines for Toxicity of Chemicals&#x201D; 1993a and &#x201C;Biological Test Method Acute Lethality Test Using Rainbow Trouty&#x201D; Environment Canada 1990 10.1109/61.714487 10.1109/TDC.2001.971319 10.1109/TDC.1999.756167 mcshane, 1999, Use of Natural Vegetable Oil Esters as Dielectric Coolant, Proceedings of CIRED 15th International Conference on Electricity Distribution 10.1016/0141-3910(95)00100-Z