Calculating the impedance profile of the AC network at a HVDC link via modulation of the inverter's firing angle signal

Knowledge of the characteristics of the AC network impedance at a high voltage direct current (HVDC) link is of vital importance to the operation of the link. The purpose of this thesis was to develop a method to accurately determine the AC network impedance characteristics at a HVDC link. Impedance profiling was achieved by measuring the current entering the AC network and the voltage of the AC bus bar while modulating the HVDC inverter's firing angle signal. Specific impedance profiling techniques were tested using various network impedances and DC current orders. In addition, the ride-through capability of a HVDC link with a modulated firing angle was examined.; The AC network impedance at a HVDC link can be quickly identified over a wide frequency band via multiple frequency modulation of the converter's firing angle signal. The optimum time for impedance profiling is when the DC current order is set at a low value. (Abstract shortened by UMI.)...