Quasi Twenty Four-Pulse Operation of HVDC Series Tapping Stations

In the literature the concept of "independent" operation has been proposed to reduce the reactive power requirement of a series tap, provided that the tap consists of, at least, two (or two sets of) bridges in series. Alternatively, the overall magnitudes of certain characteristic harmonics may be reduced. In this paper, a new firing angle algorithm is presented, which, when used with two (or two sets of) series-connected bridges, enables reduced generation of certain characteristic harmonics. It is studied in the context of a classical application, which is termed as "quasi twenty four-pulse" (Q 24-P) operation. The idea not only is feasible but also has other potentially important applications.