Therefore precise temperature calculations ensure good quality and long life expectancy of transformers. The temperature gradient between conductor and oil consists of a gradient inside the solid winding insulation and a gradient inside the boundary layer at the winding surface. The gradient inside the ...
The calculation of unbalanced currents and voltages due, for example, to short-circuit faults requires correct and practical modelling of power transformers. In this section, we present the theory of modelling single-phase transformers, and three-phase power transformers having various numbers of windin...
The principle on the antiseismie theoretic computation, with which the calculation is made for 500kV extrahigh voltage transformer porcelain bushings, is expounded. Here the transfer matrix method and program on computation of the natural frequency of the transformer pipe are presented in detail. Hav...
temperature rise calculationloss of life assessmentoil-cooled traction transformertraction power supply systemtraction transformer life expectancywinding hot-spot temperatureTraction transformer is a major apparatus in traction power supply system. Therefore, to make economical decisions for traction transformer ...
The experimental results match with numerical calculation and the existing simulation. The maximum cooling is observed with TSMF for overload condition and increases normal life expectancy nine times. In case of planned overload condition normal life expectancy doubles for all situations. Study leads ...
Basing on a change in dissolved gas quantity with time, a time (termination of life) when a dissolved gas quantity reaches to a previously determined threshold value is predicted by calculation.HAYAMIZU EIJIMATSUMOTO KOICHISATO TOMINARI
2.7. Transformer Dielectric Characteristics and Dissolved Gases Data The predicted DP from the ANFIS model can be used as an alternative expected life estimation calculation for the transformer paper insulation if the current furfural level is unknown. Tables 1–4 show the dielectric characteristics and...
The calculation process of the fluid-thermal coupling problems is depicted in Figure 1. The LSFEM is used to get the fluid field distribution, while the UFEM is used to calculate the temperature field. Then, the linearization iteration is carried out by the indirect coupling method. The maximu...
we would be able to analyze the mechanism of the overvoltage and factors that can influence it quantitatively based on the theory of automatic control. Considering the value ranges of R, L, and C obtained from the FEM calculation inTable 3, poles of Function 2 are certainly in the form of...
Thirdly, the proposed semi-numerical method avoids the time-consuming 3D electromagnetic numerical calculation, while it keeps a detailed modeling of both fluid flow and temperature distribution, thus it can be expected to better manage the trade-off between accuracy and complexity. Due to the ...