Feasibility study of AC- and DC-side active filters for HVDC converter terminals

The authors evaluate the technical and economic feasibility for active filtering of DC-side voltage harmonics and the AC-side current harmonics produced by a HVDC (high voltage direct current) converter. The following designs for the active filter concepts are compared with the existing AC-side and DC-side passive filters used at the Dickinson terminal of the CU HVDC transmission line project: the DC-side active filter consisting of a capacitor coupled current injection source to neutralize the 12th, 24th, and the 36th harmonics actively and the AC-side active filter designed to provide the same fundamental frequency-reactive VARs as the existing passive filters. Controlled currents are injected to filter the 11th and the 13th harmonic current actively. A cost comparison is made between these active filter designs and the cost of the existing passive filter supplied by the United Power Association