Impedance test device of low-voltage electric power carrier channel

The invention provides an impedance test device of a low-voltage electric power carrier channel, belonging to the power grid carrier communication field, which solves the problems of the existing method for measuring carrier channel impedance that the frequency characteristics of a high-frequency transformer and a resonant circuit affect the accuracy of the measuring value of a carrier, only the impedance modulus can be measured but the impedance phase can not be measured owing to limited carrier measuring frequency points. In the invention, a starting carrier control terminal of an embedded signal acquisition and processing system is connected with a signal control terminal of a DDS (direct digital synthesis) carrier signal source, testing input-output terminals of the embedded signal acquisition and processing system are connected with testing input-output terminals of a free coordinate axis vector test unit; the DDS carrier signal source, a high-frequency power amplifier and a primary side of a high-frequency transformer are sequentially connected; a load resistor R is connected in series between the high-frequency power amplifier and the primary side of the high-frequency transformer; a secondary side output terminal of the high-frequency transformer is connected with an input terminal of a coupling unit of a detuned circuit; and an output terminal of the coupling unit of the detuned circuit is connected with two tested low-voltage power lines.