Observation of a under frequency event - 49,84 Hz on 03.04.2019
On the evening of 03.04.2019, another underfrequency event occurred, similar to the event on 10 January 2019. At the moment it is not possible to determine the exact cause, but the grid frequency dropped to 49.84 Hz at 21:02:30 CEST, outside the normal range. In the European grid, the nominal frequency is 50 Hz, with a controller deadband of +/- 10 mHz. Thus, there is no frequency control within this insensitivity range of 49.99 Hz to 50.01 Hz.
Similar to the previous disturbance in January, the frequency dropped below the 50 Hz at the change of hours. Unlike the disturbance in January, we have not yet been able to identify a cause and are still evaluating the event. So far, it can be said that all our measuring stations have not recorded any significant local differences, so the cause cannot yet be localised. The strength of the manifestation was equally distributed at all stations, with a measured frequency of 49.84 Hz, i.e. -160 mHz deviation from 50 Hz nominal frequency.
For comparison, an averaged representation of the grid frequency in the UCTE grid at 21:00. The plot shows the grid frequency averaged over different time periods, with the underfrequency in April 2019 (green AVG line) standing out in particular:
