Here's the final report on the blackout from ENTSO-E:
https://www.entsoe.eu/publications/blackout/28-april-2025-ib...
From the summary on the page:
> The investigation concludes that the blackout resulted from a combination of many interacting factors, including oscillations, gaps in voltage and reactive power control, differences in voltage regulation practices, rapid output reductions and generator disconnections in Spain, and uneven stabilisation capabilities. These factors led to fast increases of voltage and cascading generation disconnections in Spain, resulting in the blackout in continental Spain and Portugal.
It even models scenarios where they double and triple the available inertia to see if it would have had any effect:
> The above analyses indicate that, even under the assumption of perfect execution of defence plan actions, neither these measures nor additional inertia would have been sufficient to prevent system collapse.
Here's the US regulation from 2016:
> As a result, all newly interconnecting non-synchronous generators will be required to provide reactive power
https://www.ferc.gov/sites/default/files/2020-06/RM16-1-000....
https://www.entsoe.eu/publications/blackout/28-april-2025-ib...
From the summary on the page:
> The investigation concludes that the blackout resulted from a combination of many interacting factors, including oscillations, gaps in voltage and reactive power control, differences in voltage regulation practices, rapid output reductions and generator disconnections in Spain, and uneven stabilisation capabilities. These factors led to fast increases of voltage and cascading generation disconnections in Spain, resulting in the blackout in continental Spain and Portugal.
It even models scenarios where they double and triple the available inertia to see if it would have had any effect:
> The above analyses indicate that, even under the assumption of perfect execution of defence plan actions, neither these measures nor additional inertia would have been sufficient to prevent system collapse.
Here's the US regulation from 2016:
> As a result, all newly interconnecting non-synchronous generators will be required to provide reactive power
https://www.ferc.gov/sites/default/files/2020-06/RM16-1-000....