Ispitivanje smjese mineralnog i esterskog ulja električnim i toplinskim metodama

master's thesis

• Title (english): Study of mineral and ester oils mixtures by electric and thermal methods
• Author: Ivana Vilić
• Mentor: Elvira Vidović (mentor)
• Committee member: Elvira Vidović (predsjednik povjerenstva)
• Committee member: Zlata Hrnjak-Murgić (član povjerenstva)
• Committee member: Fabio Faraguna (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2018-09-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Chemical Engineering in Material Development

Abstract

Izolacijska ulja koja se koriste u transformatorima često se nazivaju transformatorska ulja ili trafo ulja, a proizvedena su s ciljem osiguranja sigurnog rada tijekom radnog vijeka transformatora. Primjenjuju se u dvije osnovne svrhe, kao izolacijski materijal i medij za hlađenje. Danas se za izoliranje dijelova pod naponom najčešće koristi mineralno ulje kojem se već dugi niz godina, zbog dobrih toplinskih i električnih svojstava, daje prednost u primjeni. Međutim, kako ono ima i svoje nedostatke kao što su zapaljivost i korozivno djelovanje, transformatorsko izolacijsko ulje na osnovi estera se sve više koristi kao zamjena za mineralno ulje zbog visoke otpornosti na temperaturu, povećane sigurnosti od požara i visokog stupnja biorazgradivosti. U ovom radu korištene su dvije vrste transformatorskog ulja, i to mineralno transformatorsko ulje HyVolt III (Ergon), HIII i sintetsko estersko ulje Midel® 7131 (M&I Materials), M7131, ustupljeno od Končar - Distributivnih i specijalnih transformatora u različitim volumnim omjerima. Pripravljenim smjesama različitih volumnih omjera u rasponu od 1 do 50 vol.% HIII mjerena je viskoznost nakon 30 dana te se pokazalo kako se radi o homogenim mješavinama. Ostale metode kojima su karakterizirane pripravljene smjese i čisti uzorci transformatorskog ulja su toplinska vodljivost, infracrvena spektroskopija, termogravimetrijska analiza, probojni napon, ispitivanje sadržaja vode, faktor dielektričnog gubitka i specifični električni otpor. Termogravimetrijskom analizom utvrđena je bolja toplinska stabilnost sintetskog estera u odnosu na mineralno ulje. Kod svih smjesa dobiven je stabilan probojni napon unatoč porastu sadržaja vode. Također, sve pripravljene mješavine različitih volumnih udjela mineralnog i esterskog ulja pokazuju viši probojni napon u odnosu na probojni napon čistog mineralnog transformatorskog ulja. Zaključno, prema svim praćenim svojstvima, dobiveni rezultati ispitivanih smjesa mineralnog i esterskog ulja pokazuju zadovoljavajuću međusobnu kompatibilnost dielektrika.

Abstract (english)

Insulating oils used in transformers, often referred to as transformer oils, are designed to ensure safe operation during the transformer's working life. They are used for two basic purposes: as an insulating material and a cooling media. Today, mineral insulating oil, which has been used over past year due to its good thermal and electrical properties, is most preferred for isolating. However, as mineral oil it has its shortcomings such as flammability and corrosivity, ester-based transformer oil is increasingly used as a substitute for mineral oil due to high temperature resistance, increased fire safety and high biodegradability. Two types of transformer oils were used in this work: Mineral Transformer Oil HyVolt III (Ergon), HIII and Synthetic Ester Oil Midel® 7131 (M & I Materials), M7131, provided by Končar - Distributive and Special Transformers in different volumetric ratios. Prepared mixtures of different volume ratios ranging from 1 to 50 vol% of HIII were characterized by viscosity measurement after 30 days and it was found that mixtures are homogeneous. In addition prepared mixtures and pure transformer oil sample were characterized by thermal conductivity measurement, infrared spectroscopy, thermogravimetric analysis, breakdown voltage, water content test, dielectric dissipation factor and specific electrical resistivity. Thermal stability of synthetic ester is higher than thermal stability of mineral oil which was shown by thermogravimetric analysis. A stable breakdown voltage was obtained in all mixtures despite increasing water content. Also, all prepared mixtures of transformer oil exhibits higher breakdown voltage versus the breakdown voltage of pure mineral transformer oil. In conclusion, according to all observed properties, the obtained results for the tested mixtures of mineral and ester oil show satisfactory mutual compatibility of dielectrics.

• Keywords: izolacijska ulja; transformator; mineralno ulje; sintetsko estersko ulje
• Keywords (english): insulating oils; transformer; mineral oil; synthetic ester oil
• Language: croatian
• URN:NBN: urn:nbn:hr:149:540285
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-10-29 13:11:42