Very Low Frequency Grid Oscillations


Thread Starter



I work for a TSO, and we are experiencing very low (0.06Hz) oscillations of our grid frequency (50Hz) - the grid frequency signal very often looks like it is ringing in a fairly undamped way, with an oscillation amplitude of about 20-30mHz. Recently it grew quite large - 0.4Hz peak-peak swing, persisting for several minutes. I am wondering if anyone might be able to explain the mechanism behind this oscillation? It is not an inter-area oscillation - I suspect it is a governor mode of some sort. I also believe that our system frequency is quite poorly regulated - system stiffness was 300-400MW/Hz when the big oscillation occurred - lots of machines (e.g. wind turbines) are not regulating.

Thanks in advance for any light anyone can shed on this!

there is strong evidence that low-frequency grid-oscillations are related to the connection of large, kVAr starved, wind-Farm Induction-Generators.

A good start would be to search Control.Com Archives, as well as the Internet, fr, "Power System Stabilizers."

Phil Corso