Title :
Behavior of ester dielectric fluids near the pour point
Author :
Rapp, K.J. ; Gauger, G.A. ; Luksich, J.
Author_Institution :
Thomas A. Edison Tech. Center, Cooper Power Syst., Franksville, WI, USA
Abstract :
The pour points of dielectric fluids based on natural esters are not reliable indicators of their fluidity at cold temperatures. A 25-day isothermal test was used to determine the time to solidification of several natural ester fluids and a synthetic ester at -15°C. The results are compared to ASTM D97 pour point measurements. Natural ester dielectric fluid properties measured before and after a 120 hour freeze/thaw cycle showed no changes occurred due to solidification. Finally, the performance of both a solidified natural ester and a high fire point high molecular weight hydrocarbon was compared to that of conventional mineral oil by energizing at full rated load transformers held at an ambient temperature of -30°C
Keywords :
dielectric liquids; melting; organic insulating materials; solidification; transformer insulation; 120 h; 243 K; 25 d; 25-day isothermal test; 258 K; ASTM D97 pour point measurements; cold temperatures; ester dielectric fluids; fluidity; freeze/thaw cycle; full rated load transformers; high fire point high molecular weight hydrocarbon; natural esters; pour points; solidification; solidified natural ester; synthetic ester; Dielectric measurements; Isothermal processes; Maintenance; Minerals; Petroleum; Power system reliability; Stability; Temperature measurement; Testing; Transformers;
Conference_Titel :
Electrical Insulation and Dielectric Phenomena, 1999 Annual Report Conference on
Conference_Location :
Austin, TX
Print_ISBN :
0-7803-5414-1
DOI :
10.1109/CEIDP.1999.807834
