Fast Current Limiting with Virtual Synchronous Generators

Installations of renewable energy systems like photovoltaic arrays and wind power generators are increasing in number. Problems may occur when such systems get installed on weak grids. Other than in major power distribution grids can sudden load changes endanger a stable operation of such systems. This is due to the high internal impedance of weak grids. The installation of virtual synchronous generators (VSG) stabilizes local grids. It absorbs the transients and existing current harmonics and also improves the power quality by compensating reactive components. Combined with fast current limitation, fault ride through (FRT) events are now possible, even with very fast switching inverters and their low inductance.