UBC Theses and Dissertations
A comparison of numerical algorithms for determining electrical resistance and reactance using subdivision of the cable conductors De Arizon, Paloma
In this work, the inductance and resistance of different cable configurations are obtained by dividing the conductors into smaller filaments of a specific cross-sectional shape. Different filament shapes are studied, and the advantages and disadvantages of each one are considered. The impedance of cables is an important parameter for most studies involving cable systems. Yet there are some types of cables, such as pipe type cables, where only experimental results are available, and where analytical results are not always accurate enough because they do not take skin and proximity effects into account. With the technique described here, the problem of cable parameter calculation has been solved. It is based on the formulation of a [Z] matrix, which can take earth return effects into account. The earth return impedance itself is included with analytical formulae, in order to speed up the calculations. The impedance of cables with nonmagnetic materials can be calculated with a high degree of accuracy. For magnetic material with saturation effects, some reasonable approximations ares made. The impedance of stranded conductors can be calculated as well, neglecting the effect of spiralling. The current distribution in a pipe type cable is used as an example to demonstrate that skin and proximity effects are taken into account with this technique.