Nuclear battery

[Bill Sloman]

On Saturday, August 17, 2019 at 6:44:01 PM UTC+10, Martin Brown wrote:

On 16/08/2019 23:36, Rick C wrote:
On Friday, August 16, 2019 at 5:24:04 PM UTC-4, Martin Brown wrote:
On 16/08/2019 21:25, John Larkin wrote:
On Fri, 16 Aug 2019 16:35:51 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

<snip>

I'll wait for the report on what failed before I start talking about
solutions.

It is clear already that the relatively high proportion of renewables at
the time of the first failure during peak evening load meant that there
was much less inertia in the system than with conventional plant. It
also hints that they don't have any spinning reserve at peak load times.

Exactly why the wind farm went offline a minute or so after the gas
plant remains unclear but my instinct is that it was rather too rigid in
its application of the df/dt and delta_f rules. We will eventually find
out after a long investigation and an anodyne whitewash report.

I expect them to bend over in complex contortions to avoid saying that
the UK grid is teetering on the edge of instability (which it is).

If the South Australian example is anything to go by, the UK grid may just lack fast-acting battery powered inverters to catch shut-down transients fast enough.

Once Telsa's 100MW 129MW.hour battery was installed, it took over from whatever had been providing short term phase and voltage control and made about $50 million (most of its purchase price) from selling these services to the grid in its first year.

It also stopped a wave of shut-downs in two adjacent states from knocking anything off-line in South Australia. This happened not all that long after it's installation, and generated a bit of gloating.

This may be the bit of kit that a renewables-heavy grid needs, but hadn't realised that they needed until they saw one working.

--
Bill Sloman, Sydney

 

[Rick C]

On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:

On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was
wrong. I saw in another group that the frequency drop (the trigger
for most of the load shedding) happened some minutes before the gas
plant went offline and that a couple minutes before the wind farm
went offline. So it is not at all clear what was cause and what was
effect.

That is utter bollocks. The raw frequency data for a few sites have been
published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a
five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

Date UTC Hz
20190809 155230 50.003
20190809 155245 49.248
20190809 155300 49.104
20190809 155315 49.23
20190809 155330 49.202
20190809 155345 48.889 <---- Whoops!
20190809 155400 48.914
20190809 155415 49.001
20190809 155430 49.084
20190809 155445 49.273
20190809 155500 49.5
20190809 155515 49.601
20190809 155530 49.676
20190809 155545 49.7
20190809 155600 49.724
20190809 155615 49.761
20190809 155630 49.867
20190809 155645 49.954
20190809 155700 49.958
20190809 155715 49.999
20190809 155730 50.034

It is clear already that the relatively high proportion of renewables at
the time of the first failure during peak evening load meant that there
was much less inertia in the system than with conventional plant. It
also hints that they don't have any spinning reserve at peak load times.

Lol! Again, jumping to conclusions without any evidence. Why do you insist on doing that? Heck, most of the renewables in the UK is wind which clearly does have inertia and can easily be used to stabilize the grid if designed to do that.

Exactly why the wind farm went offline a minute or so after the gas
plant remains unclear but my instinct is that it was rather too rigid in
its application of the df/dt and delta_f rules. We will eventually find
out after a long investigation and an anodyne whitewash report.

Do you realize that makes literally no sense? If it was true that the wind farm applied strict df/dt and delta f rules it would have tripped earlier, not later. The max deviations were all prior to the gas generation going offline i.e. before 16:55.

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209

 

[Bill Sloman]

On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:

On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was
wrong. I saw in another group that the frequency drop (the trigger
for most of the load shedding) happened some minutes before the gas
plant went offline and that a couple minutes before the wind farm
went offline. So it is not at all clear what was cause and what was
effect.

That is utter bollocks. The raw frequency data for a few sites have been
published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a
five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

<snip>

--
Bill Sloman, Sydney

 

[Rick C]

On Saturday, August 17, 2019 at 10:21:34 PM UTC-4, Bill Sloman wrote:

On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was
wrong. I saw in another group that the frequency drop (the trigger
for most of the load shedding) happened some minutes before the gas
plant went offline and that a couple minutes before the wind farm
went offline. So it is not at all clear what was cause and what was
effect.

That is utter bollocks. The raw frequency data for a few sites have been
published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a
five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

But that's not what happened. I don't see any evidence of "increasing deviations". The max deviation was some time before any power shut down. The system was restoring itself and was already to the point of frequency being better than 49.5 Hz before any shut down.

No one has explained the initial deviation and I'm pretty sure I haven't seen anyone say the gas generator went offline as a result of any "deviations". The only report I've seen is that the gas generator went offline because the aggregate power usage dropped below some number. Even then I don't see why they would just shut down the generator output at once rather than reducing it gradually over some minutes so the system could take up the slack. Then the system can make an adjustment and take up the slack with the remaining generation facilities.

It's interesting that no one has mentioned what event could or would have caused the initial frequency deviation.

--

Rick C.

--- Get 1,000 miles of free Supercharging
--- Tesla referral code - https://ts.la/richard11209

 

[Bill Sloman]

On Sunday, August 18, 2019 at 4:48:51 PM UTC+10, Rick C wrote:

On Saturday, August 17, 2019 at 10:21:34 PM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was
wrong. I saw in another group that the frequency drop (the trigger
for most of the load shedding) happened some minutes before the gas
plant went offline and that a couple minutes before the wind farm
went offline. So it is not at all clear what was cause and what was
effect.

That is utter bollocks. The raw frequency data for a few sites have been
published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a
five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute.. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

But that's not what happened. I don't see any evidence of "increasing deviations". The max deviation was some time before any power shut down. The system was restoring itself and was already to the point of frequency being better than 49.5 Hz before any shut down.

"The system" isn't a single unit in an isolated box. What you are looking at is the sum of the actions of the system at a particular point. That the summed effects of the deviation at that particular point had got the frequency back up to 49.5Hz is not evidence that components parts weren't in trouble.

> No one has explained the initial deviation and I'm pretty sure I haven't seen anyone say the gas generator went offline as a result of any "deviations". The only report I've seen is that the gas generator went offline because the aggregate power usage dropped below some number. Even then I don't see why they would just shut down the generator output at once rather than reducing it gradually over some minutes so the system could take up the slack. Then the system can make an adjustment and take up the slack with the remaining generation facilities.

That sort of control is done by automatic machinery, acting on the conditions at it's connection to the grid, which aren't going to be the conditions at the point where your record was taken.

> It's interesting that no one has mentioned what event could or would have caused the initial frequency deviation.

There are always lightning strikes ... Putting it another way, a utility system with a long history of working with high inertia generators is unlikely to have the kind of distributed monitoring that will let it record fast and localised transients, even if a bunch of the new generators feeding the system can trip out fast enough to react to such events.

--
Bill Sloman, Sydney

 

[Rick C]

On Sunday, August 18, 2019 at 3:38:12 AM UTC-4, Bill Sloman wrote:

On Sunday, August 18, 2019 at 4:48:51 PM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 10:21:34 PM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was
wrong. I saw in another group that the frequency drop (the trigger
for most of the load shedding) happened some minutes before the gas
plant went offline and that a couple minutes before the wind farm
went offline. So it is not at all clear what was cause and what was
effect.

That is utter bollocks. The raw frequency data for a few sites have been
published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a
five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

But that's not what happened. I don't see any evidence of "increasing deviations". The max deviation was some time before any power shut down. The system was restoring itself and was already to the point of frequency being better than 49.5 Hz before any shut down.

"The system" isn't a single unit in an isolated box. What you are looking at is the sum of the actions of the system at a particular point. That the summed effects of the deviation at that particular point had got the frequency back up to 49.5Hz is not evidence that components parts weren't in trouble.

"In trouble"??? What does that mean in technical terms???

You seem to be missing the point that something caused the frequency deviation that led to the observed problems. People are talking as if the generation shut down LED to the problem. In reality it seems to have been a symptom. However, there appears to be no connection between the gas generator shut down (which was done in regards to the total power level, not the frequency glitch) and the initial frequency deviation. Perhaps the wind farm was a result of the frequency deviation that was prior to the gas generator shut down. So there are no clear cause and effect connections between any of these events.

No one has explained the initial deviation and I'm pretty sure I haven't seen anyone say the gas generator went offline as a result of any "deviations". The only report I've seen is that the gas generator went offline because the aggregate power usage dropped below some number. Even then I don't see why they would just shut down the generator output at once rather than reducing it gradually over some minutes so the system could take up the slack. Then the system can make an adjustment and take up the slack with the remaining generation facilities.

That sort of control is done by automatic machinery, acting on the conditions at it's connection to the grid, which aren't going to be the conditions at the point where your record was taken.

So the frequency is not the same at all points? I guess there can be some small phase differences due to the resistive effects of conductors vs. the reactive power draws. But even that won't cause much of a frequency deviation. It would require phase differences exceeding 360 degrees.

It's interesting that no one has mentioned what event could or would have caused the initial frequency deviation.

There are always lightning strikes ... Putting it another way, a utility system with a long history of working with high inertia generators is unlikely to have the kind of distributed monitoring that will let it record fast and localised transients, even if a bunch of the new generators feeding the system can trip out fast enough to react to such events.

Like I said, no one has mentioned any event that could have caused the initial problem. I've not heard anyone talk about lightning impacts at the time of the initial frequency deviation. Have you?

--

Rick C.

--+ Get 1,000 miles of free Supercharging
--+ Tesla referral code - https://ts.la/richard11209

 

[Piglet]

On 17/08/2019 15:48, Rick C wrote:

On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was
wrong. I saw in another group that the frequency drop (the trigger
for most of the load shedding) happened some minutes before the gas
plant went offline and that a couple minutes before the wind farm
went offline. So it is not at all clear what was cause and what was
effect.

That is utter bollocks. The raw frequency data for a few sites have been
published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a
five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

Date UTC Hz
20190809 155230 50.003
20190809 155245 49.248
20190809 155300 49.104
20190809 155315 49.23
20190809 155330 49.202
20190809 155345 48.889 <---- Whoops!
20190809 155400 48.914
20190809 155415 49.001
20190809 155430 49.084
20190809 155445 49.273
20190809 155500 49.5
20190809 155515 49.601
20190809 155530 49.676
20190809 155545 49.7
20190809 155600 49.724
20190809 155615 49.761
20190809 155630 49.867
20190809 155645 49.954
20190809 155700 49.958
20190809 155715 49.999
20190809 155730 50.034


It is clear already that the relatively high proportion of renewables at
the time of the first failure during peak evening load meant that there
was much less inertia in the system than with conventional plant. It
also hints that they don't have any spinning reserve at peak load times.

Lol! Again, jumping to conclusions without any evidence. Why do you insist on doing that? Heck, most of the renewables in the UK is wind which clearly does have inertia and can easily be used to stabilize the grid if designed to do that.


Exactly why the wind farm went offline a minute or so after the gas
plant remains unclear but my instinct is that it was rather too rigid in
its application of the df/dt and delta_f rules. We will eventually find
out after a long investigation and an anodyne whitewash report.

Do you realize that makes literally no sense? If it was true that the wind farm applied strict df/dt and delta f rules it would have tripped earlier, not later. The max deviations were all prior to the gas generation going offline i.e. before 16:55.

The benefit of inertia from still spinning rotors to frequency stability
only happens if there is still an electrical connection and field magnet
- that is lost if breakers trip and disconnect.

I wonder if the reason the gas powered station timing shows it
disconnected *after* the frequency droop is because the disconnect time
you are looking at is some human-determined officially-deemed disconnect
time and not the actual, earlier, time the breakers actuated?

Alternatively, one report I saw wrote that the wind farm was supplying
800MW when it disconnected and the gas plant was smaller at 730MW so it
could have been the smaller gas plant was not able to make up the power
loss and then dropped out?

piglet

 

[Piglet]

On 18/08/2019 08:57, Rick C wrote:

Like I said, no one has mentioned any event that could have caused the initial problem. I've not heard anyone talk about lightning impacts at the time of the initial frequency deviation. Have you?

Yes, many reports have talked about a lightning strike shutting down one
of the generators - where they have differed is that some say the wind
farm was struck and others say the gas plant!

piglet

 

[Bill Sloman]

On Sunday, August 18, 2019 at 5:57:58 PM UTC+10, Rick C wrote:

On Sunday, August 18, 2019 at 3:38:12 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 4:48:51 PM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 10:21:34 PM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was wrong. I saw in another group that the frequency drop (the trigger for most of the load shedding) happened some minutes before the gas plant went offline and that a couple minutes before the wind farmwent offline. So it is not at all clear what was cause and what was effect.

That is utter bollocks. The raw frequency data for a few sites have been published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

But that's not what happened. I don't see any evidence of "increasing deviations". The max deviation was some time before any power shut down. The system was restoring itself and was already to the point of frequency being better than 49.5 Hz before any shut down.

"The system" isn't a single unit in an isolated box. What you are looking at is the sum of the actions of the system at a particular point. That the summed effects of the deviation at that particular point had got the frequency back up to 49.5Hz is not evidence that components parts weren't in trouble.

"In trouble"??? What does that mean in technical terms???

Not delivering the current into the grid that it should have at that instant. How else could a generator be in trouble?

> You seem to be missing the point that something caused the frequency deviation that led to the observed problems. People are talking as if the generation shut down LED to the problem. In reality it seems to have been a symptom.

Actually,a consequence.

> However, there appears to be no connection between the gas generator shut down (which was done in regards to the total power level, not the frequency glitch) and the initial frequency deviation. Perhaps the wind farm was a result of the frequency deviation that was prior to the gas generator shut down. So there are no clear cause and effect connections between any of these events.

Maybe nothing obvious. Sadly, causes and effects work these things out for themselves inside the system, and aren't under any obligation to post messages about what is actually going on.

No one has explained the initial deviation and I'm pretty sure I haven't seen anyone say the gas generator went offline as a result of any "deviations". The only report I've seen is that the gas generator went offline because the aggregate power usage dropped below some number. Even then I don't see why they would just shut down the generator output at once rather than reducing it gradually over some minutes so the system could take up the slack. Then the system can make an adjustment and take up the slack with the remaining generation facilities.

That sort of control is done by automatic machinery, acting on the conditions at it's connection to the grid, which aren't going to be the conditions at the point where your record was taken.

So the frequency is not the same at all points?

Signals take time to propagate. Grid connections aren't designed as constant impedance transmission lines.

> I guess there can be some small phase differences due to the resistive effects of conductors vs. the reactive power draws. But even that won't cause much of a frequency deviation. It would require phase differences exceeding 360 degrees.

Frequency is the integral of phase. What's going through the grid is current. Look at the current for long enough, and you can extract a frequency. If the grid is shutting down at the time, this probably isn't worth doing.

> > > It's interesting that no one has mentioned what event could or would have caused the initial frequency deviation.

They've probably got enough sense not to shoot their mouths off until they have got all the data together and gone through it.

There are always lightning strikes ... Putting it another way, a utility system with a long history of working with high inertia generators is unlikely to have the kind of distributed monitoring that will let it record fast and localised transients, even if a bunch of the new generators feeding the system can trip out fast enough to react to such events.

Like I said, no one has mentioned any event that could have caused the initial problem. I've not heard anyone talk about lightning impacts at the time of the initial frequency deviation. Have you?

No. But that's one place that hard-to-predict transients can come from.

--
Bill Sloman, Sydney

 

[John Doe]

Piotr Wyderski <peter.pan@neverland.mil> wrote:

Not terribly innovative on its own, but given the DIY aspect and
price, it can be a viable "eternal" auxiliary power supply for
some hi-rel devices:

In case anybody doesn't already know... NASA depends on nuclear
batteries for its deep space probes.

 

[Sjouke Burry]

On 19.08.19 0:30, John Doe wrote:

Piotr Wyderski <peter.pan@neverland.mil> wrote:

Not terribly innovative on its own, but given the DIY aspect and
price, it can be a viable "eternal" auxiliary power supply for
some hi-rel devices:

In case anybody doesn't already know... NASA depends on nuclear
batteries for its deep space probes.

Not a battery, but a reactor, a big block of radioactive stuff,
surrounded by
a few thousand thermocouples.
The heat from the core is converted to electricity.

So, a generator instead of a battery.

 

[Rick C]

On Sunday, August 18, 2019 at 10:23:54 AM UTC-4, Bill Sloman wrote:

On Sunday, August 18, 2019 at 5:57:58 PM UTC+10, Rick C wrote:
On Sunday, August 18, 2019 at 3:38:12 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 4:48:51 PM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 10:21:34 PM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was wrong. I saw in another group that the frequency drop (the trigger for most of the load shedding) happened some minutes before the gas plant went offline and that a couple minutes before the wind farmwent offline. So it is not at all clear what was cause and what was effect.

That is utter bollocks. The raw frequency data for a few sites have been published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

But that's not what happened. I don't see any evidence of "increasing deviations". The max deviation was some time before any power shut down. The system was restoring itself and was already to the point of frequency being better than 49.5 Hz before any shut down.

"The system" isn't a single unit in an isolated box. What you are looking at is the sum of the actions of the system at a particular point. That the summed effects of the deviation at that particular point had got the frequency back up to 49.5Hz is not evidence that components parts weren't in trouble.

"In trouble"??? What does that mean in technical terms???

Not delivering the current into the grid that it should have at that instant. How else could a generator be in trouble?

You tell me, it was your statement. Instead of being snarky about it, why not just be clear.

If the generator was "in trouble", then the grid would have been dropping frequency. The issue is that the grid frequency dropped for no explained reason, then when it was recovering and within spec, meaning most of the grid was producing more power than was drawn two facilities went offline. One supposedly because the total power of the grid dropped below some figure and the other, two minutes later, dropped off for no explained reason.

When you talk about being "in trouble", what "components parts" are you referring to?

You seem to be missing the point that something caused the frequency deviation that led to the observed problems. People are talking as if the generation shut down LED to the problem. In reality it seems to have been a symptom.

Actually,a consequence.

First, that is not demonstrated as yet. No evidence has been provided. The one shutdown was claimed to have been because of normal, expected operation having nothing to do with the frequency deviation. The other has not been explained at all.

However, there appears to be no connection between the gas generator shut down (which was done in regards to the total power level, not the frequency glitch) and the initial frequency deviation. Perhaps the wind farm was a result of the frequency deviation that was prior to the gas generator shut down. So there are no clear cause and effect connections between any of these events.

Maybe nothing obvious. Sadly, causes and effects work these things out for themselves inside the system, and aren't under any obligation to post messages about what is actually going on.

Ah, you mean it is all a mystery? Yes, let's get Columbo on the job!

No one has explained the initial deviation and I'm pretty sure I haven't seen anyone say the gas generator went offline as a result of any "deviations". The only report I've seen is that the gas generator went offline because the aggregate power usage dropped below some number. Even then I don't see why they would just shut down the generator output at once rather than reducing it gradually over some minutes so the system could take up the slack. Then the system can make an adjustment and take up the slack with the remaining generation facilities.

That sort of control is done by automatic machinery, acting on the conditions at it's connection to the grid, which aren't going to be the conditions at the point where your record was taken.

So the frequency is not the same at all points?

Signals take time to propagate. Grid connections aren't designed as constant impedance transmission lines.

So how many microseconds, millseconds??? Seconds perhaps? Lol. If any part of the system gets behind in frequency by the amounts mentioned by any significant fraction of a second, the current will be flowing back into generators and loads will receive zero power.
Even at 50 Hz 10 ms is 180 degrees out of phase. At 49.5 Hz that only takes 1 second.

I guess there can be some small phase differences due to the resistive effects of conductors vs. the reactive power draws. But even that won't cause much of a frequency deviation. It would require phase differences exceeding 360 degrees.

Frequency is the integral of phase. What's going through the grid is current. Look at the current for long enough, and you can extract a frequency. If the grid is shutting down at the time, this probably isn't worth doing.

It's interesting that no one has mentioned what event could or would have caused the initial frequency deviation.

They've probably got enough sense not to shoot their mouths off until they have got all the data together and gone through it.

You mean because they don't yet know. Yep.

There are always lightning strikes ... Putting it another way, a utility system with a long history of working with high inertia generators is unlikely to have the kind of distributed monitoring that will let it record fast and localised transients, even if a bunch of the new generators feeding the system can trip out fast enough to react to such events.

Like I said, no one has mentioned any event that could have caused the initial problem. I've not heard anyone talk about lightning impacts at the time of the initial frequency deviation. Have you?

No. But that's one place that hard-to-predict transients can come from.

They don't happen invisibly. Lightning strikes are not very subtle.

--

Rick C.

+-- Get 1,000 miles of free Supercharging
+-- Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Sunday, August 18, 2019 at 6:16:03 AM UTC-4, piglet wrote:

On 18/08/2019 08:57, Rick C wrote:

Like I said, no one has mentioned any event that could have caused the initial problem. I've not heard anyone talk about lightning impacts at the time of the initial frequency deviation. Have you?


Yes, many reports have talked about a lightning strike shutting down one
of the generators - where they have differed is that some say the wind
farm was struck and others say the gas plant!

Clearly then the lightning report is highly reliable.

--

Rick C.

-++ Get 1,000 miles of free Supercharging
-++ Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Sunday, August 18, 2019 at 6:09:59 AM UTC-4, piglet wrote:

On 17/08/2019 15:48, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was
wrong. I saw in another group that the frequency drop (the trigger
for most of the load shedding) happened some minutes before the gas
plant went offline and that a couple minutes before the wind farm
went offline. So it is not at all clear what was cause and what was
effect.

That is utter bollocks. The raw frequency data for a few sites have been
published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a
five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

Date UTC Hz
20190809 155230 50.003
20190809 155245 49.248
20190809 155300 49.104
20190809 155315 49.23
20190809 155330 49.202
20190809 155345 48.889 <---- Whoops!
20190809 155400 48.914
20190809 155415 49.001
20190809 155430 49.084
20190809 155445 49.273
20190809 155500 49.5
20190809 155515 49.601
20190809 155530 49.676
20190809 155545 49.7
20190809 155600 49.724
20190809 155615 49.761
20190809 155630 49.867
20190809 155645 49.954
20190809 155700 49.958
20190809 155715 49.999
20190809 155730 50.034


It is clear already that the relatively high proportion of renewables at
the time of the first failure during peak evening load meant that there
was much less inertia in the system than with conventional plant. It
also hints that they don't have any spinning reserve at peak load times.

Lol! Again, jumping to conclusions without any evidence. Why do you insist on doing that? Heck, most of the renewables in the UK is wind which clearly does have inertia and can easily be used to stabilize the grid if designed to do that.


Exactly why the wind farm went offline a minute or so after the gas
plant remains unclear but my instinct is that it was rather too rigid in
its application of the df/dt and delta_f rules. We will eventually find
out after a long investigation and an anodyne whitewash report.

Do you realize that makes literally no sense? If it was true that the wind farm applied strict df/dt and delta f rules it would have tripped earlier, not later. The max deviations were all prior to the gas generation going offline i.e. before 16:55.


The benefit of inertia from still spinning rotors to frequency stability
only happens if there is still an electrical connection and field magnet
- that is lost if breakers trip and disconnect.

I wonder if the reason the gas powered station timing shows it
disconnected *after* the frequency droop is because the disconnect time
you are looking at is some human-determined officially-deemed disconnect
time and not the actual, earlier, time the breakers actuated?

Alternatively, one report I saw wrote that the wind farm was supplying
800MW when it disconnected and the gas plant was smaller at 730MW so it
could have been the smaller gas plant was not able to make up the power
loss and then dropped out?

You should read the facts. I have no reason to believe the timestamp of the gas generator shutdown was recorded by a human rather than automatically. It seems very unlikely. The claim was the gas generator was "shut down" automatically because the total grid usage dropped below some amount. This is rather the opposite of load shedding, generation shedding. I can't understand why they would drop it all at once rather than reducing it gradually so the system could adjust. It seems hard on both ends, the generation and the grid.

--

Rick C.

-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209

 

On Mon, 19 Aug 2019 01:41:06 +0200, Sjouke Burry
<burrynulnulfour@ppllaanneett.nnll> wrote:

On 19.08.19 0:30, John Doe wrote:
Piotr Wyderski <peter.pan@neverland.mil> wrote:

Not terribly innovative on its own, but given the DIY aspect and
price, it can be a viable "eternal" auxiliary power supply for
some hi-rel devices:

In case anybody doesn't already know... NASA depends on nuclear
batteries for its deep space probes.

Not a battery, but a reactor, a big block of radioactive stuff,
surrounded by
a few thousand thermocouples.
The heat from the core is converted to electricity.

So, a generator instead of a battery.

NASA is not using reactors, just RTGs,
https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator
in which a high concentration of an isotope with a half life in the
order of years or decades spontaneously decay. heating up the
thermocouples. The radiation decay during decades, thus Voyagers have
less and less power available today. The RTG is most radioactive
during launch, so a launch failure can be harmful. The Apollo 13 RTG
flew around the moon before re-entering.

The Soviets also had true UO2 nuclear reactors in orbit
https://en.wikipedia.org/wiki/TOPAZ_nuclear_reactor
to power radarsats. The chain reaction was activated once in orbit,
before that it was quite harmless.

Some of the systems that was intended to put the reactor into a
graveyard orbit after use failed and the reactor crashed into the
atmosphere. The best known case was the Kosmos that spread out
radioactive debris into Canada.

 

[Tom Gardner]

On 19/08/19 04:41, Rick C wrote:

On Sunday, August 18, 2019 at 10:23:54 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 5:57:58 PM UTC+10, Rick C wrote:

Maybe nothing obvious. Sadly, causes and effects work these things out for
themselves inside the system, and aren't under any obligation to post
messages about what is actually going on.

Ah, you mean it is all a mystery? Yes, let's get Columbo on the job!

You are being silly, and not doing yourself credit.

They've probably got enough sense not to shoot their mouths off until they
have got all the data together and gone through it.

You mean because they don't yet know. Yep.

You are being silly, and not doing yourself credit.

Like I said, no one has mentioned any event that could have caused the
initial problem. I've not heard anyone talk about lightning impacts at
the time of the initial frequency deviation. Have you?

No. But that's one place that hard-to-predict transients can come from.

They don't happen invisibly. Lightning strikes are not very subtle.

You are being silly, and not doing yourself credit.

 

[Bill Sloman]

On Monday, August 19, 2019 at 1:41:15 PM UTC+10, Rick C wrote:

On Sunday, August 18, 2019 at 10:23:54 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 5:57:58 PM UTC+10, Rick C wrote:
On Sunday, August 18, 2019 at 3:38:12 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 4:48:51 PM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 10:21:34 PM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was wrong. I saw in another group that the frequency drop (the trigger for most of the load shedding) happened some minutes before the gas plant went offline and that a couple minutes before the wind farmwent offline. So it is not at all clear what was cause and what was effect.

That is utter bollocks. The raw frequency data for a few sites have been published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

But that's not what happened. I don't see any evidence of "increasing deviations". The max deviation was some time before any power shut down. The system was restoring itself and was already to the point of frequency being better than 49.5 Hz before any shut down.

"The system" isn't a single unit in an isolated box. What you are looking at is the sum of the actions of the system at a particular point. That the summed effects of the deviation at that particular point had got the frequency back up to 49.5Hz is not evidence that components parts weren't in trouble.

"In trouble"??? What does that mean in technical terms???

Not delivering the current into the grid that it should have at that instant. How else could a generator be in trouble?

You tell me, it was your statement. Instead of being snarky about it, why not just be clear.

I thought it was clear.

> If the generator was "in trouble", then the grid would have been dropping frequency.

That might be one kind of trouble.

> The issue is that the grid frequency dropped for no explained reason, then when it was recovering and within spec, meaning most of the grid was producing more power than was drawn two facilities went offline. One supposedly because the total power of the grid dropped below some figure and the other, two minutes later, dropped off for no explained reason.

"Explained reasons" are what you find in detailed reports, written by people who have spent time poring over all the information available.

You can complain that these reports should appear faster, but that doesn't get us anywhere.

> When you talk about being "in trouble", what "components parts" are you referring to?

How would I know? The whole discussion has been restricted to what you could see at a downstream output.

You seem to be missing the point that something caused the frequency deviation that led to the observed problems. People are talking as if the generation shut down LED to the problem. In reality it seems to have been a symptom.

Actually,a consequence.

First, that is not demonstrated as yet.

There was stuff going on on the grid before the shut-downs happen. This may be just a coincidence, but this seems rather unlikely. the one thing you can rely on about causes is that they precede effects.

No evidence has been provided. The one shutdown was claimed to have been because of normal, expected operation having nothing to do with the frequency deviation. The other has not been explained at all.

However, there appears to be no connection between the gas generator shut down (which was done in regards to the total power level, not the frequency glitch) and the initial frequency deviation. Perhaps the wind farm was a result of the frequency deviation that was prior to the gas generator shut down. So there are no clear cause and effect connections between any of these events.

Maybe nothing obvious. Sadly, causes and effects work these things out for themselves inside the system, and aren't under any obligation to post messages about what is actually going on.

Ah, you mean it is all a mystery? Yes, let's get Columbo on the job!

Columbo wasn't trained in investigating that kind of mystery. The industry has its own trouble-shooters and data analysts,and they may eventually work out what was going on. They may not tell the general public about it.

No one has explained the initial deviation and I'm pretty sure I haven't seen anyone say the gas generator went offline as a result of any "deviations". The only report I've seen is that the gas generator went offline because the aggregate power usage dropped below some number. Even then I don't see why they would just shut down the generator output at once rather than reducing it gradually over some minutes so the system could take up the slack. Then the system can make an adjustment and take up the slack with the remaining generation facilities.

That sort of control is done by automatic machinery, acting on the conditions at it's connection to the grid, which aren't going to be the conditions at the point where your record was taken.

So the frequency is not the same at all points?

Signals take time to propagate. Grid connections aren't designed as constant impedance transmission lines.

So how many microseconds, millseconds??? Seconds perhaps? Lol. If any part of the system gets behind in frequency by the amounts mentioned by any significant fraction of a second, the current will be flowing back into generators and loads will receive zero power.

Miles of wire have inductance. Thinking in term of propagation delays probably isn't useful.

> Even at 50 Hz 10 ms is 180 degrees out of phase. At 49.5 Hz that only takes 1 second.

The utility generators try to keep in the current being propagated as close to 50Hz as they can. When the grid gets perturbed the current stop looking like nice pure sine waves. The fact that the current deviates from a pure 50Hz sine is clear evidence of a problem, but doesn't necessarily tell you much about the nature of the problem.

I guess there can be some small phase differences due to the resistive effects of conductors vs. the reactive power draws. But even that won't cause much of a frequency deviation. It would require phase differences exceeding 360 degrees.

Frequency is the integral of phase. What's going through the grid is current. Look at the current for long enough, and you can extract a frequency. If the grid is shutting down at the time, this probably isn't worth doing.

It's interesting that no one has mentioned what event could or would have caused the initial frequency deviation.

They've probably got enough sense not to shoot their mouths off until they have got all the data together and gone through it.

You mean because they don't yet know. Yep.

There are always lightning strikes ... Putting it another way, a utility system with a long history of working with high inertia generators is unlikely to have the kind of distributed monitoring that will let it record fast and localised transients, even if a bunch of the new generators feeding the system can trip out fast enough to react to such events.

Like I said, no one has mentioned any event that could have caused the initial problem. I've not heard anyone talk about lightning impacts at the time of the initial frequency deviation. Have you?

No. But that's one place that hard-to-predict transients can come from.

They don't happen invisibly. Lightning strikes are not very subtle.

If you are close to where they hit the ground.

--
Bill Sloman, Sydney

 

[Rick C]

On Monday, August 19, 2019 at 4:45:20 AM UTC-4, Bill Sloman wrote:

On Monday, August 19, 2019 at 1:41:15 PM UTC+10, Rick C wrote:
On Sunday, August 18, 2019 at 10:23:54 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 5:57:58 PM UTC+10, Rick C wrote:
On Sunday, August 18, 2019 at 3:38:12 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 4:48:51 PM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 10:21:34 PM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was wrong. I saw in another group that the frequency drop (the trigger for most of the load shedding) happened some minutes before the gas plant went offline and that a couple minutes before the wind farmwent offline. So it is not at all clear what was cause and what was effect.

That is utter bollocks. The raw frequency data for a few sites have been published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

But that's not what happened. I don't see any evidence of "increasing deviations". The max deviation was some time before any power shut down. The system was restoring itself and was already to the point of frequency being better than 49.5 Hz before any shut down.

"The system" isn't a single unit in an isolated box. What you are looking at is the sum of the actions of the system at a particular point. That the summed effects of the deviation at that particular point had got the frequency back up to 49.5Hz is not evidence that components parts weren't in trouble.

"In trouble"??? What does that mean in technical terms???

Not delivering the current into the grid that it should have at that instant. How else could a generator be in trouble?

You tell me, it was your statement. Instead of being snarky about it, why not just be clear.

I thought it was clear.

If the generator was "in trouble", then the grid would have been dropping frequency.

That might be one kind of trouble.

The issue is that the grid frequency dropped for no explained reason, then when it was recovering and within spec, meaning most of the grid was producing more power than was drawn two facilities went offline. One supposedly because the total power of the grid dropped below some figure and the other, two minutes later, dropped off for no explained reason.

"Explained reasons" are what you find in detailed reports, written by people who have spent time poring over all the information available.

You can complain that these reports should appear faster, but that doesn't get us anywhere.

I'm not complaining about the reports. I'm complaining about people acting like they already have the reports... and the answers.

When you talk about being "in trouble", what "components parts" are you referring to?

How would I know? The whole discussion has been restricted to what you could see at a downstream output.

Exactly, yet it doesn't keep you from speculating.

You seem to be missing the point that something caused the frequency deviation that led to the observed problems. People are talking as if the generation shut down LED to the problem. In reality it seems to have been a symptom.

Actually,a consequence.

First, that is not demonstrated as yet.

There was stuff going on on the grid before the shut-downs happen. This may be just a coincidence, but this seems rather unlikely. the one thing you can rely on about causes is that they precede effects.

No evidence has been provided. The one shutdown was claimed to have been because of normal, expected operation having nothing to do with the frequency deviation. The other has not been explained at all.

However, there appears to be no connection between the gas generator shut down (which was done in regards to the total power level, not the frequency glitch) and the initial frequency deviation. Perhaps the wind farm was a result of the frequency deviation that was prior to the gas generator shut down. So there are no clear cause and effect connections between any of these events.

Maybe nothing obvious. Sadly, causes and effects work these things out for themselves inside the system, and aren't under any obligation to post messages about what is actually going on.

Ah, you mean it is all a mystery? Yes, let's get Columbo on the job!

Columbo wasn't trained in investigating that kind of mystery. The industry has its own trouble-shooters and data analysts,and they may eventually work out what was going on. They may not tell the general public about it.

I believe these sorts of reports are generally public.

No one has explained the initial deviation and I'm pretty sure I haven't seen anyone say the gas generator went offline as a result of any "deviations". The only report I've seen is that the gas generator went offline because the aggregate power usage dropped below some number. Even then I don't see why they would just shut down the generator output at once rather than reducing it gradually over some minutes so the system could take up the slack. Then the system can make an adjustment and take up the slack with the remaining generation facilities.

That sort of control is done by automatic machinery, acting on the conditions at it's connection to the grid, which aren't going to be the conditions at the point where your record was taken.

So the frequency is not the same at all points?

Signals take time to propagate. Grid connections aren't designed as constant impedance transmission lines.

So how many microseconds, millseconds??? Seconds perhaps? Lol. If any part of the system gets behind in frequency by the amounts mentioned by any significant fraction of a second, the current will be flowing back into generators and loads will receive zero power.

Miles of wire have inductance. Thinking in term of propagation delays probably isn't useful.

Of course it is. That's one factor in the grid that we have at least some information on. The delays can't allow excessive phase differences. Waving hands about "inductance, inductance" is of no value since no one has suggested any way it would have been a factor other than to muddy the waters to some unknown degree.

Even at 50 Hz 10 ms is 180 degrees out of phase. At 49.5 Hz that only takes 1 second.

The utility generators try to keep in the current being propagated as close to 50Hz as they can. When the grid gets perturbed the current stop looking like nice pure sine waves. The fact that the current deviates from a pure 50Hz sine is clear evidence of a problem, but doesn't necessarily tell you much about the nature of the problem.

The issue is that the power *did* lose frequency and it was minutes before any of the generators shut down or any of the loads were reported to have gone off line. Talking about non-sinusoidal currents is not of much value. You seem to toss a lot of turds into the punch bowl without actually making any effort to explain anything.

I guess there can be some small phase differences due to the resistive effects of conductors vs. the reactive power draws. But even that won't cause much of a frequency deviation. It would require phase differences exceeding 360 degrees.

Frequency is the integral of phase. What's going through the grid is current. Look at the current for long enough, and you can extract a frequency. If the grid is shutting down at the time, this probably isn't worth doing.

It's interesting that no one has mentioned what event could or would have caused the initial frequency deviation.

They've probably got enough sense not to shoot their mouths off until they have got all the data together and gone through it.

You mean because they don't yet know. Yep.

There are always lightning strikes ... Putting it another way, a utility system with a long history of working with high inertia generators is unlikely to have the kind of distributed monitoring that will let it record fast and localised transients, even if a bunch of the new generators feeding the system can trip out fast enough to react to such events.

Like I said, no one has mentioned any event that could have caused the initial problem. I've not heard anyone talk about lightning impacts at the time of the initial frequency deviation. Have you?

No. But that's one place that hard-to-predict transients can come from.

They don't happen invisibly. Lightning strikes are not very subtle.

If you are close to where they hit the ground.

I guess it's like horseshoes and hand grenades, close counts too.

--

Rick C.

++- Get 1,000 miles of free Supercharging
++- Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Monday, August 19, 2019 at 2:21:07 AM UTC-4, Tom Gardner wrote:

On 19/08/19 04:41, Rick C wrote:
On Sunday, August 18, 2019 at 10:23:54 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 5:57:58 PM UTC+10, Rick C wrote:

Maybe nothing obvious. Sadly, causes and effects work these things out for
themselves inside the system, and aren't under any obligation to post
messages about what is actually going on.

Ah, you mean it is all a mystery? Yes, let's get Columbo on the job!

You are being silly, and not doing yourself credit.



They've probably got enough sense not to shoot their mouths off until they
have got all the data together and gone through it.

You mean because they don't yet know. Yep.

You are being silly, and not doing yourself credit.


Like I said, no one has mentioned any event that could have caused the
initial problem. I've not heard anyone talk about lightning impacts at
the time of the initial frequency deviation. Have you?

No. But that's one place that hard-to-predict transients can come from.

They don't happen invisibly. Lightning strikes are not very subtle.

You are being silly, and not doing yourself credit.

Lol! Pot - kettle! Beetlejuice, Beetlejuice, Beetlejuice...

I especially like the fact that you trimmed all of my argument away. That is akin to lying...

Liar, liar, pants on fire!

--

Rick C.

+-+ Get 1,000 miles of free Supercharging
+-+ Tesla referral code - https://ts.la/richard11209

 

[Bill Sloman]

On Monday, August 19, 2019 at 10:17:00 PM UTC+10, Rick C wrote:

On Monday, August 19, 2019 at 4:45:20 AM UTC-4, Bill Sloman wrote:
On Monday, August 19, 2019 at 1:41:15 PM UTC+10, Rick C wrote:
On Sunday, August 18, 2019 at 10:23:54 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 5:57:58 PM UTC+10, Rick C wrote:
On Sunday, August 18, 2019 at 3:38:12 AM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 4:48:51 PM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 10:21:34 PM UTC-4, Bill Sloman wrote:
On Sunday, August 18, 2019 at 12:48:50 AM UTC+10, Rick C wrote:
On Saturday, August 17, 2019 at 4:44:01 AM UTC-4, Martin Brown wrote:
On 16/08/2019 23:36, Rick C wrote:

They still have not released enough information to say what was wrong. I saw in another group that the frequency drop (the trigger for most of the load shedding) happened some minutes before the gas plant went offline and that a couple minutes before the wind farmwent offline. So it is not at all clear what was cause and what was effect.

That is utter bollocks. The raw frequency data for a few sites have been published online with timestamps that match that event see for example:

https://groups.google.com/forum/#!search/%22Manchester$20$232%22$20power$20cut/uk.d-i-y/n0CaxawZRR4/-d6gHUIECwAJ

The frequency (and voltage) dip and load shedding was all over inside a five minute period and then bounced back. 16:52:44 - 16:57:00

Don't know about "utter bollocks"...

You mention 16:52 and yet the shutdowns occurred after 16:55. I think you are verifying my claim. If you look at the data you linked to, it also shows maximum frequency deviation prior to 16:55. West Midlands shows frequencies below 49.5 as early as 16:52:44.

Here is the data I saw on 15 second measurements rather than 1 minute. By 16:55 the frequency is back to 49.5 Hz.

The frequency deviations are the "event". The shutdowns are consequences of the event. Feed the wrong kind of transient into a system, and you get increasing deviations until something trips out. The deviations can swing from positive to negative in the process.

But that's not what happened. I don't see any evidence of "increasing deviations". The max deviation was some time before any power shut down. The system was restoring itself and was already to the point of frequency being better than 49.5 Hz before any shut down.

"The system" isn't a single unit in an isolated box. What you are looking at is the sum of the actions of the system at a particular point.. That the summed effects of the deviation at that particular point had got the frequency back up to 49.5Hz is not evidence that components parts weren't in trouble.

"In trouble"??? What does that mean in technical terms???

Not delivering the current into the grid that it should have at that instant. How else could a generator be in trouble?

You tell me, it was your statement. Instead of being snarky about it, why not just be clear.

I thought it was clear.

If the generator was "in trouble", then the grid would have been dropping frequency.

That might be one kind of trouble.

The issue is that the grid frequency dropped for no explained reason, then when it was recovering and within spec, meaning most of the grid was producing more power than was drawn two facilities went offline. One supposedly because the total power of the grid dropped below some figure and the other, two minutes later, dropped off for no explained reason.

"Explained reasons" are what you find in detailed reports, written by people who have spent time poring over all the information available.

You can complain that these reports should appear faster, but that doesn't get us anywhere.

I'm not complaining about the reports. I'm complaining about people acting like they already have the reports... and the answers.

So you are slapping yourself on the wrist.

When you talk about being "in trouble", what "components parts" are you referring to?

How would I know? The whole discussion has been restricted to what you could see at a downstream output.

Exactly, yet it doesn't keep you from speculating.

About the only speculation I've allowed myself was the proposition that a lightning strike might have had a part in the event.

You seem to be missing the point that something caused the frequency deviation that led to the observed problems. People are talking as if the generation shut down LED to the problem. In reality it seems to have been a symptom.

Actually,a consequence.

First, that is not demonstrated as yet.

There was stuff going on on the grid before the shut-downs happen. This may be just a coincidence, but this seems rather unlikely. the one thing you can rely on about causes is that they precede effects.

No evidence has been provided.

You posted a list of voltage and frequency observations. That isn't much evidence, but it is something.

The one shutdown was claimed to have been because of normal, expected operation having nothing to do with the frequency deviation. The other has not been explained at all.

However, there appears to be no connection between the gas generator shut down (which was done in regards to the total power level, not the frequency glitch) and the initial frequency deviation. Perhaps the wind farm was a result of the frequency deviation that was prior to the gas generator shut down. So there are no clear cause and effect connections between any of these events.

Maybe nothing obvious. Sadly, causes and effects work these things out for themselves inside the system, and aren't under any obligation to post messages about what is actually going on.

Ah, you mean it is all a mystery? Yes, let's get Columbo on the job!

Columbo wasn't trained in investigating that kind of mystery. The industry has its own trouble-shooters and data analysts,and they may eventually work out what was going on. They may not tell the general public about it.

I believe these sorts of reports are generally public.

Eventually. In some form or other.

<snip>

They don't happen invisibly. Lightning strikes are not very subtle.

If you are close to where they hit the ground.

I guess it's like horseshoes and hand grenades, close counts too.

Being close enough to a human observer is one thing. Being close enough to a power line or sub-station is something else.

--
Bill Sloman, Sydney