Small-Signal Stability and SCR Enhancement of Offshore WPPs with Synchronous Condensers

Abstract: Synchronous condensers (SCs) have been reported to improve the overall stability and short-circuit power of a power system. SCs are also being integrated into offshore wind power plants (WPPs) for the same reason. This paper, investigates the effect of synchronous condensers on an offshore wind power plant with grid-following (GFL) and grid-forming (GFM) converter controls. Primarily, the effect of synchronous condensers can be two-fold: (1) overall stability enhancement of the WPP by providing reactive power support, (2) contribution to the effective short circuit ratio (SCR) of the WPP by fault current support. Therefore, this paper focuses on studies concerning these effects on an aggregated model of a WPP connected to the grid. To that end, a state-space model of the test system is developed for small-signal stability assessment and the synchronous condenser's effect on its stability. In addition, a mathematical explanation of SCR enhancement with synchronous condenser is provided and is verified with time-domain electromagnetic transient simulations.