Selection of DC modulation input signals and modulation modes based on data filter and disturbance energy analysis

DC modulation (DCM) can significantly improve the transient stability of AC/DC hybrid systems, and the modulation effect is obviously influenced by different DCM input signals and modulation modes. In this paper, a method is proposed to select DCM signals at different monitoring points. Power fluctuations of the pre-selected monitoring points are gathered when faults occur on a particular AC line, then a certain data filter method is used to select the most efficient DCM signal for power fluctuation suppression. The magnitude of the power fluctuations are compared by using disturbance energy analysis. Thus the monitoring site which is mostly involved when fault occur on the particular AC line can be finally selected. The above method is verified in a practical power system via PSD-BPA program. With the selected DCM input signal at proper monitoring site, different modulation modes are compared also. The digital simulation shows the validity, flexibility and convenience of the proposed method.