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Originally Posted by Citroënbender
Daringly, to return to topic - are the outages so bad as possibly suggested yesterday evening?
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From a distance of two states away, I am sort of struggling to comprehend the damage on both the distribution and transmission levels for the recorded wind speeds.
Because 500kV transmission towers are backbone infrastructure, particularly for such a sensitive customer as a smelter, they are built like brick dunnies. These were built in the old SECV days, before privatisation, when engineers were old and conservative. I haven't got access to the design specifications, but at a guess, 160 kph wind gust minimum is the design rating. Add in an engineering safety factor on top of that, and they shouldn't topple in winds below 180-200 kph.
So, either there is; a design flaw that has been there since the 1980's, a wind gust (micro burst) up around 180 kph, poor maintenance, or the lines has picked up debris (like roofing iron) that has turned it into a sail. Or all of the above.
That the faults bumped off major power stations nearby is no surprise. But one will have to wait for the engineering report to understand if it was transient stability, over frequency (due to lack of load) or under frequency (too much load dumped on them) that caused the generators to trip. All said, nice work by the plant operators to get back two units that evening - on a power station not designed for TTHL.
The level of power outages on the distribution network is a surprise as well. Looking through the BoM observations, there are a few sites around Melbourne that peaked at 106 kph. But most sites are only around 80 kph gusts. From a distance, the only conclusion that I can draw is that the greenies have been actively harassing the power companies for the last few years not to cut trees near powerlines.
(This sort of happens once every 10 - 15 years. Greenies create a stink in the local media. Next, the local media run sob stories - with some teary do-gooder - about some endangered pigeon in the tree in their front yard. Electricity company avoids bad publicity by not cutting tree due to community objections. Greenies hail it as a societal victory over evil electricity company. Works for everyone, right up until the next storm drags down a monster gum tree into the electricity lines that supply the local hospital / supermarket / telco site / pub. People wake up to themselves, and tree trimming resumes.)
If Victoria is really going for an all electricity future (i.e. no gas for heating & cooking, and EV for transport), then the government of the day needs to understand exactly how critical a highly resilient the electricity grid has to be. That means lot of redundancy (and transmission lines) across the state. It also means a superbly maintained distribution network - including trees being kept clear of powerlines.