分布式基站远端射频单元直流电源雷电浪涌防护

Lightning Surge Protection for DC Power Supply of Remote Radio Frequency Unit(RRU)in the Distributed Base Station

为了有效对分布式基站远端射频单元(RRU)直流电源进行雷电浪涌防护,需要对具体保护方式及效果进行研究。本文介绍了几种常见的塔放式RRU直流电源SPD防护模式,利用EM-TP软件搭建仿真模型,分析雷击通信铁塔时不同保护模式的防护效果,讨论铁塔高度和雷电流波形对RRU电源线泄散雷电流幅值的影响,最后计算不同雷电流波形下电缆与SPD承受能量占全部能量的比值。仿真结果表明:在-48 V、RTN线与铁塔三线间均安装SPD时防护效果最好,流经直流电缆的电流幅值最低,波形持续时间也最短。铁塔高度越低,流经电缆电流幅值越小,电流持续时间也越短。雷电流波头时间越短,流经电缆电流幅值越大。雷电流波形对电缆承受能量的百分比影响很小,但对SPD承受能量的百分比影响很大。

In order to protect DC power feed to remote radio unit （RRU） from lightning surge, it is necessary to study protection modes of SPD. Several common protection modes for RRU mounted at the top of the tower are introduced. Equivalent electric circuit model is established in EMTP to analyze protection effects of different protected modes. The influence of tower height and lightning current waveform on the amplitude of leakage current of RRU power line is discussed. Finally, absorbed energy percentages of the DC cable and SPD are calculated. Results show that： The protection effect is best when SPD is installed between -48 V, RTN and tower three lines ; The current amplitude of the DC cable is the lowest and the waveform duration is the shortest; The lower the tower height is, the smaller the current amplitude is, and the shorter the current duration. Shorter front time of lightning current results in higher amplitude of cable current. Absorbed energy percentage of SPD is strongly affected by lightning current waveform while absorbed energy percentage of DC cable is opposite.