The Influence of Transmission Corridor Tower Grounding Electrode Shapes on the Impulse Interference of Adjacent Secondary Cables

With urban land resources becoming increasingly scarce, transmission corridors are often situated close to substations and buildings. When a transmission tower is struck by lightning, the resulting transient current enters the ground through the grounding electrode, causing varying degrees of electromagnetic interference to nearby double-ended grounded secondary cables. This interference can damage equipment and disrupt signals. To study this effect and propose protective measures, this study uses CDEGS software to create a combined electromagnetic model of the tower grounding electrode, main grounding grid, and buried secondary cables. Numerical calculations show that the tower grounding electrode shape and cable grounding method significantly affect the shielding layer coupling current. While soil resistivity has a minor impact, increasing lightning current amplitude boosts the coupling current. However, the results vary with soil resistivity and grounding methods. Increasing component spacing and using shielding wires effectively reduce the shielding layer coupling current. These findings highlight the need to consider electromagnetic impacts on secondary systems in urban transmission tower design, crucial for grounding system electromagnetic compatibility analysis.