Thermal properties of natural ester and low viscosity natural ester in the aspect of the reliable operation of the transformer cooling system

• Autorzy: Dombek Grzegorz , Nadolny Zbigniew , Marcinkowska Agnieszka

Identyfikatory

DOI

10.17531/ein.2019.3.4

Warianty tytułu

PL

Właściwości cieplne estru naturalnego i estru naturalnego o obniżonej lepkości w aspekcie niezawodności działania układu chłodzenia transformatora

• Języki publikacji: EN

Abstrakty

EN

The paper presents the results of comparative studies of thermal properties of various types of natural esters used as electroinsulating liquids in transformers. Adequate thermal properties of electro-insulating liquids ensure reliable work of transformers. Two natural esters were selected for the study – one commonly used in distribution transformers, the other characterized by low viscosity. Fourier Transform Infrared Spectroscopy and UV-Visible spectroscopy were used to examine the chemical structure of the examined esters. Properties such as thermal conductivity coefficient λ, kinematic viscosity υ, specific heat cp, density ρ, and thermal expansion coefficient β were analyzed. Heat transfer factor α of the liquid was calculated on the basis of obtained properties. This factor defines the ability of an insulating liquid to heat transport in the transformer, thus determining its reliability. The authors put forward a thesis that a low viscosity natural ester will have a higher heat transfer factor α due to its low viscosity, which affects the factor α. The analysis of thermal properties was carried out for the following temperatures: 25, 40, 60, and 80°C. On the basis of the calculated factor α, the temperature drops in the transformer filled with the analyzed types of natural esters were determined. It has been shown that if a low viscosity natural ester is used in the cooling system of the transformer, the temperature of the hot-spot will be lower. This fact may contribute to more reliable work of transformers and extend its service life.

PL

W pracy przedstawiono wyniki badań porównawczych właściwości cieplnych różnego rodzaju estrów naturalnych stosowanych jako ciecze elektroizolacyjne w transformatorach. Odpowiednie właściwości cieplne cieczy elektroizolacyjnych zapewniają niezawodną pracę transformatorów. Do badań wybrano dwa estry naturalne – jeden powszechnie stosowany w transformatorach rozdzielczych, drugi charakteryzujący się obniżoną lepkością. Do analizy struktury chemicznej badanych estrów wykorzystano spektroskopię w podczerwieni z transformatą Fouriera (FT-IR) oraz spektroskopię w ultrafiolecie i świetle widzialnym (UV-VIS). Analizowanymi właściwościami cieczy były przewodność cieplna λ, lepkość kinematyczna υ, ciepło właściwe cp, gęstość ρ oraz rozszerzalność cieplna β. Na podstawie przedstawionych właściwości cieplnych obliczono współczynnik przejmowania ciepła α. Współczynnik ten określa zdolność cieczy elektroizolacyjnej do transportu ciepła w transformatorze, a tym samym określa jego niezawodność. Autorzy postawili tezę, że ester naturalny o obniżonej lepkości będzie miał wyższy współczynnik przejmowania ciepła α ze względu na jego obniżoną lepkość. Analizę właściwości cieplnych przeprowadzono dla czterech wartości temperatury: 25, 40, 60 i 80°C. Na podstawie obliczonego współczynnika α określono spadki temperatury w transformatorze wypełnionym analizowanymi estrami naturalnymi. Wykazano, że jeżeli w układzie chłodzenia transformatora stosowany jest ester naturalny o obniżonej lepkości, wówczas temperatura najgorętszego miejsca (ang. hot spot) będzie niższa. Fakt ten może przyczynić się do zwiększenia niezawodności pracy transformatorów i przedłużyć okres ich eksploatacji.

Słowa kluczowe

EN

natural ester; dielectrics; power transformer; thermal properties

PL

ester naturalny; dielektryki; transformator; właściwości cieplne

• Wydawca: Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne
• Czasopismo: Eksploatacja i Niezawodność
• Rocznik: 2019
• Tom: Vol. 21, no. 3
• Strony: 384--391
• Opis fizyczny: Bibliogr. 45 poz., rys., tab.

Twórcy

autor

Dombek Grzegorz

• Institute of Electric Power Engineering Poznan University of Technology ul. Piotrowo 3A, 60-965 Poznan, Poland

autor

Nadolny Zbigniew

• Institute of Electric Power Engineering Poznan University of Technology ul. Piotrowo 3A, 60-965 Poznan, Poland
• [e-mail]

autor

Marcinkowska Agnieszka

• Institute of Chemical Technology and Engineering Poznan University of Technology ul. Berdychowo 4, 60-965 Poznan, Poland

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