Vidareutveckling av program för fellägesberäkningar

Sammanfattning: Group Selektivplaner at E.ON Elnät Sverige AB develops protective relay settings and perform other calculations on the transmission grid. One of the tasks is to perform fault location calculations on the effective grounded 130 kV grid. To perform these calculations PSS/E and a proprietary add called Nimi is used. There are various reasons to perform fault location calculations. The foremost of these is a requirement of governmental committee Telestörningsnämnden that requires the fault current and fault location to be reported when an earth fault has occurred. The add Nimi currently used for fault location calculations is old and written in an outdated programming language named IPLAN. This means that the update of the program could be problematic for several reasons. Lack of knowledge about the programming language IPLAN is one. The thesis aims to rewrite Nimi to the Python programming language, while the functionality is improved. For the best possible result, literature on power system engineering and foremost in the field of fault location calculations was required. The new program for fault location calculations is called Nimi2. Nimi2 contains all the essential features that were present in Nimi including improvements and additions of desired functions. A new feature in Nimi2 that were not in Nimi is that at fault location calculation of a two-phase ground fault both phase-to-phase and phase-to-ground impedances can be selected.