Ann: Change in substantial holding-NXT.AX, page-39

Report from NXT website re recent power interruptions in South Australia

Nextdc : Vigilance is key in our highly interconnected world

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10/04/2016 | 02:44am EDT

The complete shutdown on Wednesday 28 September of the South Australian electricity grid seems to have triggered a small amount of variability in the Victorian and New South Wales power supplies. At the same time the grid in SA went offline, an minor ripple in grid power was simultaneously picked up by both our M1 Melbourne and S1 Sydney data centres - demonstrating the vital need to pre-empt potential threats to our increasingly interconnected critical infrastructure.
'At about 4:18pm AEST on Wednesday the uninterruptible power systems in both our S1 and M1 data centres elected to kick in to ensure stable power supply to the entire facility,' said COO Simon Cooper. 'Although none of the multiple grid feeds failed, our systems in both sites saw sufficient variability to make that decision automatically.'
The Diesel Rotary Uninterruptible Power Supply (DRUPS) systems used at M1 and S1 are designed and manufactured by the globally renowned German manufacturer Piller. Their role is to monitor the grid and to bridge the gap between grid failure and generator start-up when required. If mains power is lost or is considered by NEXTDC's systems to be under stress, the rotary UPS flywheel ensures high quality power continues to be available until the multiple diesel generators take over.
The South Australian Premier was reported to say that powerful wind gusts and thunderstorms smashed 22 electricity transmission stations near Port Augusta at 3.48pm local time Wednesday 28 September (4:18pm AEST), which triggered a safety shutdown also impacting the Murraylink electricity transmission interconnector with Victoria.
Simon commented, 'Of course neither of our sites are anywhere near South Australia, not to mention them being roughly 750km apart from each other. That said, I am not a strong believer in coincidence.'
'We do know that the South Australian, Victorian and New South Wales transmission grids are interconnected, all for good reason. But 1.5 million people suddenly dropping off a grid is a massive and unusual event,' Simon continued. 'As far as I am aware there were no end-user consequences within the Victorian or New South Wales networks, but it was extremely reassuring to see our systems notice that ripple in our pond and pre-empt that possibility, exactly as they are designed to do.'

Regards
Westwind