Title :
A new method for the calculation of the hot-spot temperature in power transformers with ONAN cooling
Author :
Radakovic, Z. ; Feser, K.
Abstract :
In previous work of the authors an original thermal model of transformers with ONAN cooling was developed. The model takes into account the influence of nonlinear thermal characteristics in transient thermal processes; instead of exponential functions and time constants, the numerical solution of differential equations is used. The model delivers one characteristic temperature in copper (solid insulation) and one characteristic temperature in oil. In this paper the analysis stresses the definition of the hot-spot temperature of the solid insulation by using easily measurable quantities. Then, the parameters of the model can be precisely determined from inexpensive measurements in a short-circuit heating experiment and the model can deliver the hot-spot temperature. The experimental base of this research are the measurements on a 630 kVA, 3 × 10 kV/3 × 6 kV ONAN transformer equipped with 112 temperature sensors (102 inside the central positioned 10 kV winding).
Keywords :
cooling; differential equations; power transformers; temperature measurement; temperature sensors; transformer insulation; 10 kV; 630 kVA; characteristic temperature; cooling; copper; differential equations; hot-spot temperature; nonlinear thermal characteristics; oil; power transformers; short-circuit heating experiment; solid insulation; temperature sensors; thermal factor; thermal model; transient thermal processes; Cooling; Copper; Differential equations; Oil insulation; Petroleum; Power transformer insulation; Power transformers; Solid modeling; Temperature sensors; Thermal stresses;
Conference_Titel :
Power Engineering Society General Meeting, 2003, IEEE
Print_ISBN :
0-7803-7989-6
DOI :
10.1109/PES.2003.1271004
