Fault Line Selection of Three-Core Armored Cables Based on the Analysis of Transient Moduli Considering Conductor Couplings

Compared with overhead lines, the three-core armored cables of the distribution network have different electromagnetic and propagation characteristics. First of all, the electromagnetic coupling relationship of the cable is complex, and the multi-conductor structure including a three-phase guide core, three-phase metal shield and armor has significant electromagnetic coupling. Second, the cable laid in the same trench will appear coupling effect affecting the line selection of the traveling wave method, and it is related to the grounding mode of the shield layer. In this paper, the model of a three-core armored cable in the distribution network is established, and the general method of decoupling is obtained by analogy with overhead lines. The influence of the change of the shape of the wave head caused by the characteristics of the transient modulus propagation in the cable and the coupling between cables caused by the same ditch laying on the route selection by the traveling wave method is discussed. Finally, simulation software is used to reproduce the failure of the traveling wave method caused by the above factors, which provides a reference for optimizing the line selection logic in actual power grid operation.