Busbar Fault Direction Identification Using Sequences of Displacement Vectors

In this paper, a novel busbar fault direction identification scheme is presented. It is based on sequences of displacement vectors. First, the proposed scheme calculates the superimposed current components. Second, it compares the values of these components to a pre‐selected threshold to detect a fault. Third, the differential elements of the superimposed components are calculated to form the sequences of displacement vectors. Fourth, the similarities of the sequences are checked using the cosine distance measure. Finally, an internal flag is activated if the fault is internal. The presented algorithm was investigated based on simulation studies of a real 400‐kV substation. The results show that the algorithm can identify evolving external‐to‐internal faults. It is also stable against severe external faults that may cause current transformers to saturate. Besides, its accuracy and speed are not affected by various fault parameters, including fault inception angle, fault resistance (up to 500 Ω), fault type, and fault location. This algorithm is fast and straightforward enough to be integrated into a differential relay to assist the percentage‐restraint differential algorithm.