Abstract: To address the engineering challenge of lightning strikes causing ground potential rise (GPR) and subsequent damage to secondary equipment in substations, this paper proposes a lightning attenuation controller based on the principle of high-frequency energy coupling dissipation. The device comprises a coupling inductor, a bypass capacitor, an energy-dissipating damping resistor, and a mechanical actuation unit, enabling differentiated treatment of low- and high-frequency lightning currents: under low-frequency conditions, the device operates as a low-impedance direct path to ensure normal current discharge through the grounding grid; under high-frequency conditions, the current is first shunted by the bypass capacitor, while the remaining energy is routed into the damping branch via the coupling inductor for dissipation. This effectively suppresses the transient potential of the grounding grid and mitigates the risk of GPR. Lightning simulation results demonstrate that the device can reduce the amplitude of high-frequency transient ground potential above 10 kHz on the main grounding grid by 80.3%, meeting the deep lightning protection requirements for substations with high soil resistivity. Furthermore, its installation requires no major modifications to existing grounding systems. It can operate synergistically with traditional lightning protection devices, thereby enhancing the current lightning protection framework of substations.