Patent attributes
The present invention relates to a method for location of a fault utilizing unsynchronized measurements of three phase voltages and currents acquired at the line terminals without synchronization. Phasors for symmetrical components of the measured quantities are determined and used in the fault location algorithm. According to one embodiment, positive sequence phasors of post-fault quantities are used for estimation of the distance to fault and it is distinctive that such an estimation of a distance to fault is performed without essentially involving iterative techniques. In this embodiment, the fault location algorithm step is performed regardless of the fault type. In later steps, the type of fault may be obtained. According to another embodiment of the invention, at the occurrence of a fault, the type of fault is determined. If it is determined that it is not a three-phase balanced fault, negative sequence phasors are used for the estimation of the distance to fault. On the other hand, if it is a three-phase balanced fault, the incremental positive sequence phasors are used.
