The very first thing to notice is the massive deviation in frequency when the tower went down and brought on these a number of journeys – leaping to 50.53Hz in a matter of seconds, exterior of the traditional containment bend, simply earlier than 1639AEST on Saturday, November 12.
The truth that the tour was rapidly arrested after which fell is probably going largely because of the fast response of the massive batteries, notably the unique Tesla Large Battery on the Hornsdale Energy Reserve, which can have contributed round 100MW to the difficulty, together with some inertia, and on the smaller Dalrymple North battery.
A few of the huge gasoline turbines additionally responded, however not as rapidly, and the contribution of the batteries is vital as a result of if the frequency response had gone a lot additional, there would have been one other threat of tripping extra wind farms and creating greater issues within the grid.
(The third huge battery within the state, at Lake Bonney, discovered itself on the opposite aspect of the grid separation, so contributed to the other frequency tour in Victoria, in inexperienced within the graph above).
The official line from AEMO is barely that the batteries did what was anticipated of them, which is identical commentary that AEMO made from the identical equipment performed a giant function in earlier separation.
The attraction of the massive batteries is that they act as a type of “shock absorber” for the grid, and are so fast and correct that NSW desires the most important of all of them, with the 700MW and 1680MWh Waratah Tremendous Battery to be constructed on the central coast earlier than the closure of the large Eraring coal generator.
After the South Australia occasion, the 2 batteries – Hornsdale and Dalrymple – had been placed on “maintain” for the subsequent week – principally at a mid level that left them poised to answer any journeys of generator or load, though they had been in a position to answer minor frequency modifications throughout the week.
The opposite attention-grabbing side of AEMO’s interim report is the efforts to regulate the output of rooftop photo voltaic, which is an remoted South Australia grid is taken into account the key wild card, just because it’s able to assembly most if not all of home demand, and depart AEMO with treasured few levers to regulate in one other emergency.
Every day, AEMO instructed the native community homeowners to keep up demand ranges of between 714MW and 855MW, relying on system constraints. It’s greatest problem got here on Thursday, November 17, when greater than 1600MW of distributed photo voltaic manufacturing was predicted.
That meant shutting off as much as 410MW of distributed, however principally rooftop, photo voltaic every day for as much as 10 hours, although a mixture of inverter indicators and voltage controls. That helped hold the biggest credible contingency inside safe limits.
AEMO took different measures, similar to shuffling its pack of gasoline turbines – dialling them right down to minimal ranges and selecting smaller machines over greater ones – to make sure that any journey didn’t trigger an enormous distributed photo voltaic “shake-off” that would have brought on extra issues for the system.
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