Research on Lightning Current Shunting Characteristics Between Tower and Ground Wires Based on Field Test and Numerical Simulation

When lightning strikes the transmission tower, lightning current is shunted between the ground wires and the tower. The shunting changes the current waveform in the tower, which may affect the potential rise of the tower and the grounding device. A field test is conducted on a 220 kV transmission line and the characteristics of lightning current shunting are obtained in this paper. The test results are compared with the simulation results, which verifies the feasibility of the commonly used simulation models. The main influencing factors of the shunting are discussed. The results show that the current in the tower changes obviously in our case compared to the applied impulse current. The high frequency components of the impulse current mainly enter the tower, which leads to a steeper current waveform in the tower. The difference is closely related to the waveform of the applied impulse current. The slower the impulse current waveform, the greater the difference between the front time and amplitude of the current in the tower and that of the original impulse current. Although part of the current flows along ground wires, this phenomenon may put forward higher requirements for the tower grounding device.