低压电力线宽带通信信道建模方法

Modeling of Low Voltage Power Line as Broadband Communication Channel

电力线网络的高频阻抗和传输特性是设计低压电力线宽带通信系统的重要依据。该文分析趋肤效应和邻近效应对单位长度电阻和电感的影响,以及复介电常数对单位长度电容和电导的影响。基于电磁仿真方法求解单位长度参数初值,结合电力线的低损耗特性,提出一种利用开路阻抗测量结果进行单位长度参数精确求解的方法。多分支网络下的测试结果表明信道模型在30k Hz^30MHz宽带范围内具有很高的准确性。结合测试结果,分析网络结构对信道特性的影响,指出分支线路和用电设备输入阻抗的频变性是整体网络形成深度衰落的主要因素。建模方法结合仿真计算和辅助测量,具有结果准确、简单易行和适用广泛的优点。

High frequency impedance and transmission characteristics of power line network are important foundation for designing broadband communication system via low voltage power line. The influences of skin effect and proximity effect on per-unit-length resistance and inductance were analyzed, and the influence of complex dielectric permittivity on per-unit-length capacitance and conductance was also analyzed. Based on the electromagnetic simulation method, the initial values of the per-unit-length parameters were solved, and a method which is combined with the low loss characteristics of the power line, was proposed to accurately solve per-unit-length parameters by using the open circuit impedance measurement. The test results of multi-branch networks show that the channel model has high accuracy in the frequency range from 30 k Hz to 30 MHz. Based on the test results, the influences of network structure on channel characteristics were analyzed. It is pointed out that the frequency-dependent characteristics of input impedance of branch and electrical equipment are the main factor of deep fading in the whole network. The modeling methods which combine simulation and auxiliary measurement have the advantages of accuracy, simplicity and wide application.