Performance Evaluation ofA New Directional Protection Technique for Distribution Lines

This paper presents a new directional comparison protection scheme specially designed for distribution systems. A number of well-proved directional techniques were chosen for this study. To evaluate their performances, a typical distribution line system was modeled using EMTP, which is able to offer many variations to cover all possible fault conditions such as with different fault types, fault locations, fault inception angles and fault resistances. Furthermore, extensive simulation studies were conducted with respect to on-line variation in system conditions, such as changing in system configuration, source impedance, switching over between single and double sources and changing in load conditions with and without tapped-off-loads. An integrated solution was suggested, which combines a number of better performed directional algorithms.