Research on Shielding Performance of the Secondary Cable Armor Layer in Smart Substation

The shielding effectiveness of secondary cables is a key feature in improving the level of EMC in substations. However, the shielding effectiveness of the secondary cable armor layer is still an unclear issue, and the armor layer’s grounding method is not explained in the relevant IEEE and IEC standards. In this paper, the shunt capacity and grounding methods of shield and armor layers were tested in the laboratory and substation to clarify the respective shielding performance. The results show that the armor layer also has the same shunt capacity as the shield; and the method of double-end grounding of the armor layer, single-end grounding of the shield on the control room side can effectively reduce the core wire induced voltage. Finally, through test analysis and comparison, some engineering suggestions were put forward.