4 ms·

how much battery storage at what point in the system would have prevented this blackout?

jhayward 7y ago
Answering that question would take a detailed analysis which I am not aware of. It would be less than the instant load of the Eaton Socon - Wymondley transmission circuit that was struck by lightning. It is basically a question of providing just enough frequency support, for long enough, for the remainder of the grid to respond to the frequency drop. In other words, let the frequency sag a bit so generators respond but not so much that they disconnect. I think there's also some control system error implied in the wind farm's drop as I read the article. That perhaps shouldn't have happened at all and was an un-analyzed state that will be corrected.
- generatorguy 7y ago
  >> but that battery in South Australia is only 100MW and the grid lost over 1400 MW >I hear this kind of misconception fairly often and so it is worth noting that you don't need 1400 MW of battery to protect from this event. I would be interested in any papers or literature that have led you to this conclusion. as soon as (generation - load) <> 0 the frequency is going to change. If you lose 200MW of generation and have 100MW of batteries that are configured with 0 or very small amount of droop they see some small change in frequency and crank out 100MW to try and stop it from falling further. Then they are maxed out, there is still 100MW of imbalance for conventional generation with governors to take up, which they will as the frequency falls as if the trip had only been 100MW in the first place. How is this not a 1:1 relationship, 100 MW of batteries displace 100MW of lost generation? For this event in the UK in particular it appears the issue is that the large windfarm, and 500MW of small embedded or distributed generation are en masse improperly configured or by nature are not able to ride through any small transient wobble in frequency. TFA didn't show us what voltage these plants saw. Although a 200MW steam turbine also tripped due to the same lightning/transmission line trip event, so clearly it was subjected to something that exceeded instantaneous thresholds and had to trip immediately. And then that steam turbine tripping caused the gas turbines at the same plant to trip which indicates there are some design or operational issues at that plant. Also is 20s reclose time for a transmission line standard? I've only configured distribution line reclosers but it was more on the order of 1s for the first reclose and maybe 7s for the second?

Answering that question would take a detailed analysis which I am not aware of. It would be less than the instant load of the Eaton Socon - Wymondley transmission circuit that was struck by lightning. It is basically a question of providing just enough frequency support, for long enough, for the remainder of the grid to respond to the frequency drop. In other words, let the frequency sag a bit so generators respond but not so much that they disconnect. I think there's also some control system error implied in the wind farm's drop as I read the article. That perhaps shouldn't have happened at all and was an un-analyzed state that will be corrected.

generatorguy 7y ago
>> but that battery in South Australia is only 100MW and the grid lost over 1400 MW >I hear this kind of misconception fairly often and so it is worth noting that you don't need 1400 MW of battery to protect from this event. I would be interested in any papers or literature that have led you to this conclusion. as soon as (generation - load) <> 0 the frequency is going to change. If you lose 200MW of generation and have 100MW of batteries that are configured with 0 or very small amount of droop they see some small change in frequency and crank out 100MW to try and stop it from falling further. Then they are maxed out, there is still 100MW of imbalance for conventional generation with governors to take up, which they will as the frequency falls as if the trip had only been 100MW in the first place. How is this not a 1:1 relationship, 100 MW of batteries displace 100MW of lost generation? For this event in the UK in particular it appears the issue is that the large windfarm, and 500MW of small embedded or distributed generation are en masse improperly configured or by nature are not able to ride through any small transient wobble in frequency. TFA didn't show us what voltage these plants saw. Although a 200MW steam turbine also tripped due to the same lightning/transmission line trip event, so clearly it was subjected to something that exceeded instantaneous thresholds and had to trip immediately. And then that steam turbine tripping caused the gas turbines at the same plant to trip which indicates there are some design or operational issues at that plant. Also is 20s reclose time for a transmission line standard? I've only configured distribution line reclosers but it was more on the order of 1s for the first reclose and maybe 7s for the second?