Simulation Research on Current Distribution Characteristics of Pole Communication Base Station Based on Varistor Lightning Protection

Mobile communication base stations are the basic facilities of telecommunication operation networks. When the communication base station is struck by lightning, a very high overvoltage will appear on the top of pole, which leads the power supply cable of RRU(Remote Radio Unit) directly break through, and a large lightning current will flow through the cable, damaging the communication equipment and the power supply. Therefore, the research on the lightning current distribution characteristics of the mobile communication base station has important theoretical significance and engineering application value for the lightning protection of the mobile communication base station. In this paper, a simulation model of the current distribution characteristics of the communication pole system with overvoltage protective varistor is established, and the influence of the impulse current, the length of the pole and the DC reference voltage on the current distribution characteristics of the pole system is studied. The results show that: (1) When $8 /20\ \mu \mathrm{s}$ impulse current is injected into the 10m long pole system, the dynamic resistance $r$ of varistor decreases with the increase of impulse current peak value, the current distribution ratio of pole and core of power cable gradually approaches to 9:1. (2) As the length of the pole increases, the influence of the varistor on the current waveform parameters of the core branch of the power gradually decreases, and the front time distortion rate through the power line core branch decreases. (3) When the peak value of the impulse current and the length of the pole are the same, the lower the DC reference voltage of the varistor, the smaller the current waveform distortion of the core branch of the power, and the greater the current distribution.