Impedance characteristics of outdoor low-voltage distribution power line communication

On the basis of analyzing the structural characteristics of low-voltage power distribution network, the input impedance of out-door low-voltage distribution network is measured and analyzed. Taking a university laboratory and a residential neighborhood as representative, the input impedance of the low-voltage distribution network within the frequency band from 1MHz to 30MHz is measured. The results show that the input impedance is varied from construction of the distribution network, frequency and load property. For the entire frequency band, the input impedance varies from tens to hundreds of ohms to the difference of frequency, especially within 1MHz to 10MHz. In the frequency range from 20MHz to 30MHz, the input impedance changes more smoothly, at about 100 to 200 ohms. The load property has evident influence on power network impedance and the power network impedance is time varying to a certain extent. The simulated environment of low-voltage distribution circuit is established in the laboratory, and the input impedance is also measured. The test results are consistent with the characteristics of the previous environment.