The impact of variable renewable energy (VRE) on the power system stability – the renaissance of synchronous condensers

The energy transition, i.e. the strategic change from fossil fuels to renewable energy sources, entails a fundamental transformation of the transmission and distribution grids. The electric power system is in transition which shifts from a rotating mass-dominated system to a power converter-dominated system. Without the appropriate measures, this will have a negative impact on power system stability. This report describes the implications of the transformation of the electric power system o n voltage stability and frequency stability, it compares Synchronous Condensers (SynCon), SVCs (static VAR compensation) and static synchronous compensators (STATCOM) with regard to the different grid needs. SynCons, which have been used for reactive power compensation since the early 20th century, and have been replaced by other technologies in the meantime, are experiencing a renaissance in transmission and distribution grids [1].