A novel non-unit protection scheme based on fault generated high frequency noise on transmission lines

This paper is concerned with outlining a novel technique for the detection of power transmission line fault generated noise by employing an arrangement involving the use of conventionally connected, power line communication signal line traps and CVTs. A specially designed stack tuner (tuned to a certain frequency bandwidth) is connected to the coupling capacitor of the CVT in order to capture the high frequency signals. Digital signal processing is then applied to the captured information to determine whether the fault is inside or outside the protected zone. The paper concludes by presenting results based on extensive simulation studies carried out on a typical 400 kV vertical construction line, using the Electromagnetic Transient Program (EMTP) software. In particular, the performance of the nonunit protection scheme is examined for faults on systems with heavy loading and for high resistance arcing earth faults