Measurement methods of low voltage power-line communication channel impedances

The channel characteristics of low voltage power-line as telecommunication line have important influence on communication quality, which include impedance characteristics, attenuation characteristics, noise characteristics and so on[1]. The measurement of input impedances is crucial for power-line communication (PLC) because it´s an essential parameter for transmission characteristic. According to inductive analysis of scientific information at home and abroad, four methods of measuring power-line impedances are summarized in the paper which consist of current probe, resonance, voltammery and ratio. We compare the performance of the four methods in terms of experiment equipment, circuits, steps and frequency range. the result after analyzing show that the Two-current-probe method is a effective method for measurement of power-line impedance, and we make some measurements in the laboratory. The result of measurement reveal that the impedance change with frequency, which will contribute to further study for PLC.