Extensions to the Finite Element Technique for the Magneto-Thermal Analysis of Aged Oil Cooled-Insulated Power Transformers

Abstract

It is well known that the hot spot temperature represents the most critical parameter identifying the power rating of a transformer. This paper investigates the effect of the degradation of core magnetic properties on temperature variation of aged oil-cooled transformers. Within this work, 2D accurate assessment of time average flux density distribution in an oil insulated-cooled 25 MVA transformer has been computed using finite-element analysis taking into account ageing and stress-induced non-uniform core permeability values. Knowing the core material specific loss and winding details, local core and winding losses are converted into heat. Based upon the ambient temperature outside the transformer tank and thermal heat transfer related factors, the detailed thermal modeling and analysis have then been carried out to determine temperature distribution everywhere. Analytical details and simulation results demonstrating effects of core magnetic properties degradation on hot spot temperatures of the transformer’s components are given in the paper

Theoretical Temperature Distribution Investigation in Electrical Transformer by Using Nano-Technology

“…Figure (10) shows the temperature distribution in the distribution transformer. As shown in this figure, this angle give slightly improved in the distribution of temperature in the inner corner of core when compared with right angle for these corner, see Figure (11).…”

“…1-The transformer can be treated as a geometric structure which is constructed from a parallel plane. Therefore, the problem is decreased from a three-dimensional (3D) to other case have only a plane (a two-dimensional (2-D)) simulation, with an acceptable accuracy when used finite elements technique [11]. The average measured values for the peak ambient temperature during the transformer operating condition are considered.…”

Magnetic circuit modelling of transformer core induction – resolution and accuracy

“…Due to the mentioned reasons, many authors use numerical methods, such as finite element method (FEM), for the estimations of B [1][2][3][4][5]. In the last 20 years, FEM has become the leading method for the assessment of magnetic quantities, such as local flux distribution, eddy current losses and so on, of laminated cores of transformers, but also of rotating machines.…”