Iberien Peninsular Blackout

No one wants to blame net zero as the root cause

To be fair lots of things have changed over the years - we no longer have Central Electricity Generating Board whose primary task was to generate sufficient electricity for the nation, rather now we have a loose collection of private generators whose primary responsibility (as with any commercial company) is to create wealth for their shareholders. Load profiles have changed - we have much less heavy industry with large spinning motors that run constantly all day, but more commercial and domestic loads which are naturally more erratic. The nature of loads has changed across the board too - a lot of simple resistive loads have disappeared (filament lighting, resistive heating) and many motors now have electronic drives. Millions of small transformers in all sorts of things have been replaced by SMPSUs. Unlike traditional loads most electronic controls will respond to a reduced voltage by increasing the current demand - so no longer present such a simple load to the grid and traditional regulation methods (e.g. voltage reductions) not longer work as they did. Then there are new kinds of loads like EVs and domestic heat pumps. Also the changes to inverters for generators (esp. wind and solar). Some of that may indeed have been driven by "net zero" but a lot is also done for other reasons - other politics (privatisation and moving away from coal due to 1980s economic policies, or later policies to reduce dependencies on imported fuels (e.g. Russian gas)), just economics in general as the new technology is cheaper to run, or just "progress" in general. Life brings changes, some changes work out for the better, others don't. As ever, finding problems and fixing them is the life blood for engineers.

   - Andy.

Hello Sergio:

It appears that the UK Power system is working on a knife edge. No one wants to blame net zero as the root cause

 The only advice I heard yesterday on a Guardian podcast, is that every UK family needs to have a 72 hour protection Kit to adequately cover black out conditions.

It should be noted that here is Florida everyone is advised to have a hurricane kit consisting of flashlights, water, cash, full tank of gas, canned food, battery powered radio, small LP burner, dry cookies ,medical kit , etc etc. The state government also has special tax free days on these items just before the start of the season (which Is June 1, 2025),

Peter Brooks

Palm Bay

I wonder what happened last week with power outages at Standstead Airport and then the next day on large parts of London Underground

lyledunn said:

It might be taken for granted but electricity is badly missed when gone! 

For some, it might be like the end of the world!

GB are already at 1 cycle per second squared. The standard changed after the 2019 frequency excursion, to reduce cascade tripping. At the same time, we extended the requirement to ride through voltage dips, again to reduce cascade tripping 

I saw a report (when web searching about the issue) that the Irish grid is moving to 1Hz/s to accommodate the 'flexibility' renewables (my word choice .

Sergio Fernandez said:

Frequency is crucial to any grid.

I suspect that it's not as crucial as people think. Rather it's a statement about how some parts of the electrical network were designed and configured.

Way back in the UK past we had the 3-day week caused by a miners strike which meant that the frequency was allowed to be 'way-off', apparently to the point that electric clocks could be 10 minutes away of true time (during the loaded day), and that the grid than ran fast overnight to catch up.

I do remember when working at NEI Parsons (c1979) that V/f was a concern for transformer saturation.

(I was looking at designed a digital converter to monitor the generator voltage for control purposes needing multiple readings per cycle via a 3ph->6ph transformer, a 6 phase rectifier, a voltage to frequency converter and counter per part cycle - It implicitly produced a V/f reading!, and a 1/f reading)

We have become locked in to that way of thinking, forgetting all the newer converter based transmission tech that doesn't care in the same way.

I'm glad you found it interesting

you're absolutely right, there was a loss of embedded generation, which led to the rules being changed to try to keep them spinning

Thanks for that Dave. Digging though that and its references, it does look like it was more "interesting" than previously reported.

of Hornsea 1, one report says:

3.21. We have found that the wind farm’s onshore control system operated as expected
when the system voltage dipped concurrently with the lightning strike. The offshore
wind turbine controllers, however, reacted incorrectly to voltage fluctuations on the
offshore network following the fault. This caused an instability between the onshore
control system and the individual wind turbines. The instability triggered two
modules to automatically shut down.

which seems to suggest that while the shore side did behave correctly according to the grid codes, the offshore (and/or connection) bit didn't.

There was also a loss of distributed generation:

2.4.6. The level of power loss (or increase in net demand on the electricity system)
caused the frequency of the electricity system to fall at a rate of change of
frequency (RoCoF) above 0.125Hz/s. Some distributed generators operating
under legacy Distribution Code requirements have loss of mains protection
mechanisms triggered by RoCoF set at this rate. As a result, an estimated 350-
430MW of distributed generation tripped off unnecessarily, based on
information provided by the ESO19.

- Andy.

A few points that seem to come out of this while we wait for more official information.

1) Is frequency still a useful measure of grid stability and safety with the ever increasing amount of invertor connected generation and load.?

2) What could replace frequency as a control measure?

3) Overloads and trip outs will always occur. How can the spread be better controlled? How can the recovery be improved?

4) Can the inertia and frequency control of a rotating generator be replaced by an inverter? A rotating generator with electromagnetic or fuse overload protection and transformer coupling can take significant short term overloads, maybe a factor of 3 for 10 seconds. This would require a significantly overrated and more expensive inverter system.

5) Is transient stability also a problem to be addressed by inverter connected devices. I started looking at my old uni. text book, Electric Power Systems by B.M. Weedy but decided my maths is no longer up to it.