基于改进模态分解的中压地埋电缆载波通信信道特性分析

对中压电力线信道特性的研究是构建中压载波通信系统的重要基础。针对目前中压地埋电缆的多模传输特性尚未明确，屏蔽层与钢铠接地对信道特性的影响尚未被详细考虑的情况，将多导体传输线模型与回路分析相结合，通过改进模态分解确定了中压地埋电缆的4类传输模态及其传输特性，并通过比较该方法与高频结构仿真(HFSS)的计算结果验证了所提方法的有效性。之后，基于模态分解的结果计算了载波信号的衰减与相移特性，并通过实验测量验证了其可信性。最后，结合多模态传输特性讨论了屏蔽层与钢铠接地对中压地埋电缆信道特性的影响。结果表明:当信号通过芯线与屏蔽耦合时，其信道特性几乎不受屏蔽层与钢铠接地的影响；当信号通过屏蔽与地耦合时，信道特性与接地阻抗密切相关。

Modified Mode Decomposition Based Channel Characteristic Analysis of Power Line Carrier Communication of Medium-voltage Underground Cables

Medium-voltage(MV)power-line channel characteristics are essential for constructing MV power line communication(PLC)systems. However, the multi-mode transmission characteristics of MV underground cables and the effects of grounded shields and armors on the channel characteristics have not been considered in detail. Four types of transmission modes and their transmission characteristics of MV underground cables are determined based on modified mode decomposition, where the multi-conductor transmission line model and loop analysis are combined. The effectiveness of the modified mode decomposition is verified by comparing its calculation results with that of high frequency structure simulation(HFSS). Then, the attenuation and phase shift characteristics of carrier signal in MV underground cables are calculated based on the results of modified mode decomposition, and the results are verified by experimental measurements. Finally, the effects of grounded shields and armors on MV underground cable channel characteristics are discussed. The calculation results show that, when the core-shield-coupling mode is adopted, the grounded shields and armors have little effects on the channel characteristics of MV underground cables, while when the shield-shield-coupling mode is adopted, the channel characteristics of MV underground cables are closely related to the grounding impedances.