Thermal–fluid transient two-dimensional characteristic-based-split finite-element model of a distribution transformer

Abstract

This study presents a two-dimensional (2D) finite-element (FE) linear model for predicting the thermal and fluid dynamics of an oil-filled distribution transformer. The model is based on the solution of the Navier-Stokes and Maxwell equations which are weakly coupled. Two electromagnetic FE models are used to calculate the load and no load losses of the transformer. The thermal -fluid equations are solved using first-order 2D FE and the characteristic-based-split (CBS) scheme. The CBS is used for the first time in the thermal fluid modelling of a transformer thereby is the proposed contribution of this study. The CBS algorithm is applicable to all ranges of flow and gives the same results as specialised methods such as the Petrov -Galerkin and Taylor -Galerkin methods. A natural convection analysis for an incompressible Newtonian flow in a distribution transformer is presented. Convection, radiation and symmetry boundary conditions are taken into account in the model. The model predictions are compared against those obtained with a commercial software and good agreement was obtained. The proposed model was programmed in C language.

Calculation of electromagnetic force and temperature distribution of amorphous transformers in different operating modes by finite element method

“…In transformer windings, heat conduction occurs between windings of different temperatures. This heat conduction follows the formula for heat transferred per unit of isothermal surface per unit of time, and it is proportional to the temperature gradient (Arjona et al, 2012;Chen et al, 2019).…”

“…Results are presented in terms of losses, voltages, currents and magnetic flux of the transformer. Arjona et al, 2012 calculated the electromagnetic force (EMF) when a short circuit (SC) occurs using FEM to identify the highest temperature in the core or windings. The analytical or "semi-analytic" methods were used to solve temperature transfer problems and simulate heat distribution in dry transformers using FEM (Hualin et al, 2019).…”

New Analytical Formula for TemperatureAssessment on Transformer Tanks

“…Therefore, the application of advanced techniques for precise estimation of temperature distributions in steel plates due to eddy current losses is of great interest. Recent research pays special attention to the computation of the temperature distribution on transformer covers [1]- [4], transformer oil [5] using FE and analytical methods. Although FE approaches are numerically powerful and sound, they require high capacity computers, as well as, sophisticated and expensive FE software when dealing with 3D geometries and very small skin depths in nonzero permeability and conductivity regions, such as those found in tanks of power and distribution transformers.…”

Electromagnetic field and thermal distribution optimisation in shell‐type traction transformers

“…However, the shell-type traction transformer must be designed carefully because of the limited size and weight of the high-speed trains. The leakage magnetic field is prone to cause eddy current losses, which tend to overheat [6][7][8]. Thus, it is very important to analyse the distribution of the leakage magnetic-field in the metal parts and to calculate their eddy current losses.…”