2019/08/22

UK NG power outage 2019-08-09 - [2]

An interim report [Interim Report into the Low Frequency Demand Disconnection (LFDD) following Generator Trips and Frequency Excursion on 9 Aug 2019] has been made by the National Grid concerning the events leading to the power outage. The documents tend to disappears here is the frequency/time plot from the document:


Of interest is the fact that after the initial failures at Hornsea and one of the turbines at Little Barford the system begins to recover. Then another 2 of the Little Barford generators is manually removed because of steam overpressure.
It is at this point the system crashes out and load is shed.


2019/08/17

UK power outage August 2019

Suggestions have been made that adding  wind energy to the UK national grid has increased the frequency variability.

By looking at the Gridwatch data for frequency it is possible to see the frequency variation at a 5 minute sample rate.

I have plotted the  frequency for 2012 to 2019 looking at the rolling
 [50 minute max]-[50 minute min]
data.

This shows an insignificant change over the 7 years:


However looking at frequency deviations above 0.5Hz there were none before 2005 but 6 after 2005.

Also looking at the overall plot there appears to have been an improvement in frequency stability at March 2014. If this is true then the plot does show a worsening of frequency stability from 2014 until about 2017

Since 2017 there has been insignificant change.


2019/08/16

Arctic Sea Ice 2019-08-15

Latest update
Still shows a likely 2019 minimum of around 4.1 million km2
But unlikely to be below 2012 minimum



2019/08/10

UK NG power outage on 2019-08-09

Some interesting stuff from gridwatch.

Claim from the National Grid is that power outage caused by Little Barford and Hornsea wind disconnecting from grid.

In May 2008 similar happened:
htTps://www.ofgem.gov.uk/ofgem-publications/41426/nationalgrid-systemeventsof27mayfordswg16july.pdf
except 2 stations (Longannet and Sizewell)  tripped which gave a loss of 1582MW and then other back up systems failed.
the outage ended after 7 hours


Little Barford Power Station is a 740 MWe gas-fired power station
Hornsea Wind Farm maximum is 1.2GW
1.5 GW maximum lost according to gridwatch and they have learned nothing since 2008.

and of course even more people affected


What is interesting is that Gridwatch shows that the frequency dropped nearly 20 minutes before the two stations went offline. Grid watch is updated every 5 minutes so should have shown a intantataneos frequency and power loss.
 The frequency changes as a result of overload on the grid.

Did the stations drop because of frequency drop or did the frequency drop because the stations went offline? Or is it a reporting issue?

If the fast reserve cannot handle 1.8GW going offline simultaneously how do they expect to handle Hinkley C  with 2 reactors of 1.6GW?

PS
Many suggest that the variability of the wind is to be blamed. But if you look at the power levels during that day there was adequate capacity.
There was 8GW of spare CCGT power at the time of the outage. There was a demand 2.8GW below peak of the previous day. There was no drop or increase in wind strength. Simply put a gas power station tripped and a fault occurred on the transmission lines from the wind farm causing 0.9GW loss of supply.



2019/08/05

Arctic Sea Ice 2019-08-05

Arctic Sea Ice Extent from ADS


Data is lining up to be a normal reduction in extent (i.e. not an exceptional loss like 2012).

This would give a 2019 minimum of around 4.1 million kmif rate of loss is maintained