Study On Electrical Properties Of Gas-to-Liquid Transformer Oil Immersed Pressboard

“GTL” is the abbreciation of “Gas-to-Liquid”,GTL technology can reform non-petroleum base product such as natural gas into liquid oil products.In recent years,with the increase in natural gas production,GTL technology is developing rapidly.The synthetic transformer oil which produced from GTL technology has been entering the transformer oil market.However,as a new type of transformer oil,GTL transformer oils' performance didn't get a in-depth study.Based on the research of GTL transformer oil,the electrical properties of GTL oil-immersed pressboard were being studied in this article.Under AC voltage and DC voltage,the breakdown performance and partial discharge performance of GTL oil-immersed pressboard were being stuided respectively.And choose KI50 X oil-immersed pressboard which widly used in converter transformer in conteolled trails at the same time.The test results show that the breakdowd performance of GTL oil-immersed pressboard is similar with KI50 X oil-immersed pressboard,and the power frequency breakdown field strength of GTL oil-immersed pressboard is 47 k V/mm which is higher than the national standard requirements that 45 k V/mm.And DC breakdown field strength of GTL oil-immersed pressboard is up to 181 k V/mm.GTL oil immersed pressboard under AC voltage partial discharge inception voltage is slightly higher than that of KI50 X oil immersed pressboard.Partial discharge performance test shows that GTL oil-immersed pressboard's PDIV is slightly lower than that of KI50 X oil-immersed pressboard under AC voltage.Under DC voltage,this two kinds of oil-immersed pressboards' partial discharge have the same development process,and when DC voltage up to 90 k V-110 kV,the discharge times and maximum magnitude of partial discharge of GTL oil-immersed pressboard is less than KI50 X oil-immersed pressboard.Taking both the breakdown performance and partial discharge test into account,we concluded that the electrical strength properties of GTL oil-immersed pressboard is good.Besides,dielectric frequency spectra of GTL oil-immersed pressboard is being tested in this article,and three tradition mineral transformer oil in controlled trails at the same time.The test results show that,with the increase of temperature,the imaginary part of dielectric constant of GTL oil-immersed pressboard move to high frequency's speed is the slowest than the other three kinds of oil-immersed pressboard.This is due to the higher paraffin content of the GTL transformer oil.Under power frequency,the real part of dielectric constant of GTL oil-immersed pressboard is less than the other three kinds of oil-immersed pressboard at different temperature conditions.This will help improve the dielectric strength of oil-paper combination insulation.