The Coulomb damping generated by friction enables the mechanical responsiveness and harvesting efficiency of triboelectric nanogenerators (TENGs) exhibit a contradictory relationship. Increasing Coulomb damping can improve the harvesting efficiency of the TENG, but also reduces its mechanical responsiveness at low frequencies due to the increased friction. To resolve this contradiction, a Coulomb damping graded regulation triboelectric nanogenerator (CDGR-TENG) is proposed according to the low-frequency vibration characteristics of transmission lines galloping. Specifically, by introducing stepped electrodes, the Coulomb damping suffered by the CDGR-TENG at different response oscillation angles can be regulated in a graded manner, thereby simultaneously improving its mechanical responsiveness and harvesting efficiency. The results show that CDGR-TENG can maximize the galloping energy harvesting ability by adjusting the Coulomb damping, which increases the operating bandwidth by 20% over the lateral-sliding TENG, and the average current by 10% over the contact-separation TENG. Furthermore, the feasibility of CDGR-TENG in facilitating the self-powered functionality of ice-covered sensors and wireless conductor temperature warning system is verified in a transmission lines galloping simulation system. This work presents an efficient energy harvesting approach for transmission lines galloping, which has the potential to provide further insights for the practical application of TENG in ice-covered monitoring.