Wideband impedance dynamic measurement method and system of LCC-HVDC system

The invention provides a broadband impedance dynamic measurement method and system of an LCC-HVDC system. The method comprises the steps of obtaining measurement data of a synchronous phasor measurement device in an LCC-HVDC converter station; constructing a broadband impedance calculation model, inputting the measurement data into the model, calculating to obtain an impedance amplitude and a phase angle of the LCC-HVDC converter station side in a broadband domain, and fitting to generate a broadband impedance measurement curve at an initial moment; determining the change rate of direct current transmission power according to the voltage data and the current data, and determining the time step length of broadband impedance measurement; and according to the discriminant relationship between the change rate of the direct current transmission power and the time step length, adaptively adjusting the moment of acquiring the measurement data, and dynamically refreshing and fitting to generate a broadband impedance