The security of transmission line towers is crucial to industrial development. Bird damage is a significant threat to transmission line towers in the field. However, the power supply to the bird-repellent devices is limited. In this work, we propose a rotation differential triboelectric nanogenerator (RD-TENG) to harvest wind energy for supplying electrical power to bird-repellent on transmission line towers. On the transmission line towers, the RD-TENG converts wind energy into electrical energy by rotation differential structure and stores power in a 1000 μF capacitor, then supplies power to the buzzer for bird-repellent. The device mainly consists of a wind cup, an input gear, output gears, and rotors. The RD-TENG can achieve double rotation speed by rotating the differential structure compared to the single gear counterpart, hence doubling the current and power output through triboelectric nanogenerator. The RD-TENG has a starting wind speed of 4 m s−1 and can operate normally at lower wind speeds. At a wind speed of 8 m s−1, the output performance of the RD-TENG is 830 V, 13.5 μA, 330 nC, and the peak power is 19.6 mW. This work realizes a new solution for bird-repellent on transmission lines through the TENG energy harvesting technique and also contributes to the subsequent smart grid construction.