Instances of system frequency outside the normal operating band
How common is it that mainland frequency deviates outside the NOFB (normal operating frequency band)?
How common is it that mainland frequency deviates outside the NOFB (normal operating frequency band)?
On Tuesday the 19th of August between 11:45 and 12:20 there was a significant frequency deviation on the mainland.
An initial review of payment and cost outcomes of the first 44 days of financial operation of the FPP arrangements.
In reviewing system frequency on the 16th of June, 2025, we observed a drop that reached below the NOFB.
At 16:01 on April 10, 2025, a system frequency dip was observed from the Global-Roam frequency logger.
High speed frequency measurements provide a deeper understanding of how the system responded to the unplanned 500kV line outage.
It was captured by a keen eyed reader, that the distribution of mainland grid frequency in recent times now exhibits cat ears.
In this overview, we take a longitudinal look back at how frequency has changed over the years.