Effective two-terminal numerical algorithm for overhead lines protection

In the paper an effective numerical algorithm for overhead lines protection, particularly fault location and adaptive autoreclosure, is presented. It is based on the two terminal line currents and voltages acquisition. For this purposes the synchronized sampling of all analogue input variables, i.e. the application of the Global Position System/Phasor Measurement Units, was assumed. The algorithm presented is derived in the spectral domain. By this the set of third harmonics variables and line parameters was also used. The prerequisite for successfully adaptive autoreclosure functionality realization was the suitable modelling of the electrical arc. Arc was considered as a source of higher harmonics, distorting by this other electrical variables. In the arc modelling, results of laboratory testing were used. Algorithm is tested for a typical network configuration, assuming by this that the line considered was short enough to neglect its capacitive nature. Based on the results obtained, it is very realistic that the algorithm presented could be implemented in praxis in modern Intelligent Electronic Devices (IEDs). © Springer-Verlag 2007.