Nasza strona zapisuje niewielkie pliki tekstowe, nazywane ciasteczkami (ang. cookies) na Twoim urządzeniu w celu lepszego dostosowania treści oraz dla celów statystycznych. Możesz wyłączyć możliwość ich zapisu, zmieniając ustawienia Twojej przeglądarki. Korzystanie z naszej strony bez zmiany ustawień oznacza zgodę na przechowywanie cookies w Twoim urządzeniu.
For transmission network with in-phase transformers only, the nodal admittance matrix is symmetric. For such networks the short-circuit calculations can be done using sparsity-oriented factorisation of large complex symmetric matrices. In some transmission networks the phase-shifting transformers are used in order to control the real power flows. The series branch of the π-port network modelling such transformer has directional property. When such anisotropic branches are included in the network model the admittance matrix becomes asymmetric. Typically the number of phase-shifting transformers installed in transmission network is very small when compared to the whole number of transformers. It means that very few asymmetric element of the matrix imposes a larger computational effort especially for factorisation, which is the most time consuming and memory using process. In this article it is shown that (in spite of the asymmetric elements) the short-circuit calculations can be done by factorisation performed by procedure applicable to symmetric matrices. A new calculation method is proposed where the admittance model of the phase-shifting transformer is divided into the isotropic π-port network and a series anisotropic branch. The network admittance matrix is formed only from the isotropic branches and is factorised by procedure for symmetric matrices. The anisotropic branches are taken into account by modification of the impedance matrix elements using the formulas derived in this paper on the basis of the Sherman–Morrison formula. Proposed method can be easily implemented in already existing computer programs originally developed for transmission networks without the phase-shifting transformers.