The Fenno-Skan HVDC link commissioning

The commissioning of the Fenno-Skan HVDC link between Finland and Sweden, with the longest submarine DC cable in the world, is described. The main pre-commissioning activities, important for an efficient commissioning, are discussed together with time schedules and suitable organisation forms. The procedures to test special control features, such as subsynchronous oscillation (SSO) damping control are presented. The full scale network interaction tests which are an important part of the commissioning are also discussed. These tests succeeded very well and provided a lot of information about the system behaviour for future operation and planning purposes