This is kind of understandable, the amount of data would be huge. When faults happen though, recordings are automatically made available.
Some of these measurements can have surprisingly high frequency sampling, even though the grid itself feels "slow".
Depends on the fault. Without dedicated measurement in place it's still a lot of (literal) legwork to install current and voltage loggers.
> Some of these measurements can have surprisingly high frequency sampling, even though the grid itself feels "slow".
Sure. But especially in a world dominated by more and more solar and wind, where something like a cloud passing by can easily shed hundreds of kilowatts in a matter of seconds, the grid needs much, much more data across the board and everywhere - and much, much more battery storage, both centralized at substations and decentralized in people's basements.