A discussion of the power-quality (PQ) aspects of HVDC systems is given, in particular, harmonic aspects. This is followed by a description of the apparatus and their installation as part of an onsite measurement campaign at the Sternö;, classical HVDC station on the SwePol HVDC link. PQ results are presented, including the current and voltage characteristics of the station, converter harmonics, filtered harmonics, noncharacteristic harmonics, switch-on current, and system unbalance.