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What, nothing on the power disruption?

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What, nothing on the power disruption?

Old 10th Aug 2019, 16:16
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What, nothing on the power disruption?

Although power wasnt lost for that long, the impact on the rail system seemed to be enduring. Agree it poses questions about the resilience of power generation and distribution, but why isn't the press questioning the separate resilience of the rail system.
I read that Thameslink trains were at a stand and it required a technician to get to each train to allow restart. Is that right? Seems a fundamental resiliency issue right there.
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Old 10th Aug 2019, 16:28
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Too many people using electric cars and power gobbling 'smart' phones drawing too much from the system?
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Old 10th Aug 2019, 16:47
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Seems to have been caused by unplanned generator shut downs that were supposed to be designed to protect the generators in the event of a fault.

The fault in this case may have been a series of lightning strikes that took out sections of the grid for longer than they should have done as surge arrestors operated. At least one region has reported that they had multiple generator shutdowns caused by a prolonged frequency dip (the recorded dip was pretty grim, down below 49.4 Hz for maybe 20 to 30 seconds at around 16.50 yesterday afternoon), and that this prolonged frequency dip may have been caused by one or more delayed auto reclosing events (auto reclose normally happens within about 1s or so). At least one big wind farm went off line (to protect itself) when the grid frequency dropped right off the scale (wind was providing about 50% of our power this morning). When the grid has unplanned generator shut downs it load sheds to protect remaining generators that are still on line. If it didn't do this, then the resulting frequency dip would cause a cascade failure, where more and more generators shut down to protect themselves from overload.
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Old 10th Aug 2019, 16:59
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Was surprised to see reports of torches/phones being required in locations where I would have expected back up/battery lighting to come on automatically.
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Old 10th Aug 2019, 17:01
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There appears to be very little slack in the system.
Imports from France,Netherlands and Scotland are necessary.
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Old 10th Aug 2019, 17:05
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Not only is there not much slack in the system, but there's also less and less spinning reserve. I have a suspicion that with more and more DC interconnects, both from abroad and from wind and solar generation, the grid may be losing stability. There's a lot to be said for having power stations that are spinning and can provide frequency resilience when there's a dip. DC to AC conversion units can't do this, they seem to respond within ms to any change in grid frequency.
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Old 10th Aug 2019, 17:48
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Probably down to power companies taking the cheapest route and instead of converting viable coal powered stations to gas, they demolished them thus reducing the redundancy in the system to address these issues. And it's not going to get any better soon.
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Old 10th Aug 2019, 17:59
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Originally Posted by VP959 View Post
... caused by a prolonged frequency dip (the recorded dip was pretty grim, down below 49.4 Hz for maybe 20 to 30 seconds at around 16.50 yesterday afternoon), and that this prolonged frequency dip may have been caused by one or more delayed auto reclosing events (auto reclose normally happens within about 1s or so)
... and there was me hearing only the other day that the price for FFR-type services has dropped so low that nobody much is bothering to sign up to them any more ...
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Old 10th Aug 2019, 18:04
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Originally Posted by Gertrude the Wombat View Post
... and there was me hearing only the other day that the price for FFR-type services has dropped so low that nobody much is bothering to sign up to them any more ...
Almost certainly a contributory factor, perhaps. Without sufficient FFR resource grid stability will just get poorer and poorer. There's a lot to be said for big, heavy, spinning stuff when it comes to maintaining stability.
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Old 10th Aug 2019, 19:21
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FFR ? Any views on trains needing a technician to be ported in? Is this true?
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Old 10th Aug 2019, 20:03
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FFR (fast frequency response) and related markets are deals where the owner of an "asset" (generator or battery that can be switched on quickly, or consumer of electricity that can be switched off quickly) does a deal with the grid whereby they are paid for the asset to sit there doing nothing, but if the frequency drops below a certain threshold the asset kicks in to increase grid supply or decrease consumption.

Now, people want to be paid for keeping large chunks of capital kit sitting around doing nothing, and if they don't get paid enough (eg if they can make more money actually running the generator and selling the electricity) they won't bid for the contracts. And if there isn't much kit providing FFR then when the frequency drops there might not be enough kit on standby to maintain the frequency.
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Old 10th Aug 2019, 20:43
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Milud, I refer you to my previous statement.......

The price of electricity.
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Old 10th Aug 2019, 21:17
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Ah, thanks. Now, about the trains? No wonder Thameslink was stuffed if a technician had to visit every single train. If true, somebody missed this on the risk register/ catastrophe plan.
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Old 10th Aug 2019, 21:40
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Re. the trains/technicians, it is true for the Hitachi IETs that only a company tech can reset etc. It is part of the contractual agreement signed by the DaFT. Go figure, as our cousins might say.
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Old 10th Aug 2019, 21:43
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The passenger seats on them are bloody awful too. More uncomfortable than a church pew.
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Old 10th Aug 2019, 21:52
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Re the trains; yet another notch in Mr. Failing's belt!
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Old 10th Aug 2019, 22:20
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Re the trains - the entire fleet of 700 and 717 class units (those out in service that is) shut themselves down to protect themselves because of the frequency dip. If the dip was minor and short lived then the units just powered down and only needed a reset once power was restored. Those subject to a more severe and prolonged dip shut down totally and went into 'lockdown' mode, necessitating a 'man with laptop' to come and reset them manually.
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Old 10th Aug 2019, 22:28
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Thatís an accurate summary but itís unacceptable for a short outage to shut down such a large part of the network with passengers sealed without ventilation for hours. We need to seriously look at resilience.
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Old 10th Aug 2019, 22:59
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Originally Posted by ShotOne View Post
We need to seriously look at resilience.
You can have as much resilience as you like.

But the amount of resilience people say they want and the amount they actually vote to pay for aren't always the same.
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Old 11th Aug 2019, 00:30
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Absolutely agree, Gertrude. BAís outrageous outsourced IT shambles another example. But itís not just money; why design and certify trains which are immobilised for hours by a short power outage?
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