Thread: Big storm and no power in SA

Originally Posted by Simon

Siemens spokesperson is in the news today, quoted as saying gas plant would have tripped also if it had been in the location of the wind farms. Seems to be saying proximity to point of initial failure is a major factor in shut down, not energy source itself.

I am aware turbines will park once wind gets too strong, but frequency / voltage management across the network is not my field.

News!...should come with a disclaimer..."for entertainment purposes only"

Originally Posted by AndyG

So in a Utopian world with Solar, Wind, Tidal and batteries, but no big kick arse fossil turbines and minimal hydro, being where we are, how will the network be synchronized, so we get a nice clean power feed ?

I don't really see this as being a killer of renewables. It requires a more complex solution, but then climate change is a complex problem in itself.

I mean, if we can stick a bunch of satellites up in the sky, and synchronise them close enough within the limits of General Relativity just so we can catch some Pokemon, I'm sure we can get a diverse set of wind generators and so on to talk nice to each other.

I think this is an interesting discussion about it:

https://independentaustralia.net/pol...mo-report,9618

The latest official update is here:
http://www.aemo.com.au/Media-Centre/...e-power-outage

It has a link to the main report. Here is an excerpt:

3.1 Event summary
Immediately prior to the event, SCADA data showed that 883 MW of SA wind generation,8 330 MW of
SA gas generation, and 613 MW of electricity imports via two interconnections with Victoria, in addition
to any generation embedded in the distribution network, were collectively supplying the 1,895 MW of
electricity demand of SA’s 850,000 electricity customers.
Extreme weather conditions resulted in five system faults on the SA transmission system, with three
transmission lines ultimately lost to the power system.9
In response to these faults10, and the resulting six voltage disturbances, there was an unexpected
sustained reduction of 445 MW of wind generation to the north of Adelaide. Analysis of high speed
monitoring data has shown a 39 MW of transient wind power reduction from the normal expected
response of wind farms riding through the voltage disturbances. Increased flows on the main
interconnector (Heywood) with Victoria counteracted this loss of local generation.11 More detail on this
is discussed later in this chapter, specifically Table 4.
This reduction in generation and immediate compensating increase of imports on the Heywood
Interconnector resulted in the activation of Heywood’s automatic Loss of Synchronism protection
mechanism, leading to the ‘tripping’ (disconnection) of the Heywood Interconnector. As a result,
approximately 900 MW of supply from Victoria over the Heywood Interconnector was immediately lost,
and the remaining generation in SA was unable to meet the SA load. The sudden and large deficit of
supply caused the system frequency to collapse more quickly than the Under-Frequency Load
Shedding (UFLS) scheme was able to act, resulting in the SA region Black System.

As a non-expert I'm just trying to cut through the political propaganda, which is strong on both sides, and get a handle on what actually happened and understand what changes are necessary, and probably already happening.
It appears this problem wasn't caused by the intermittent nature of wind power because at the time wind was going gangbusters and was the largest single type of generation source supplying SA, ahead of the interconnectors and gas, so the intermittent argument isn't relevant in this specific case, I think.
The system apparently became unbalanced off the 50 hertz level after the towers went down and some supply was reduced.
It appears the market operator didn't know that some of the wind generators had settings which would cause them to pull out after the second or third incident, while other wind generators had different settings and stayed online. Why didn't the market operator know that?
Also, why didn't the backup generation work, despite having been tested?
It all happened very fast, so it's not surprising this combination of events wasn't anticipated. No doubt lessons will be learned.

I have just had a look at the AEMO 2015 Annual report and this paragraph caught my attention.

It specifically mentions that the SA system wil cope as long as the Heywood interconnector is operational and there is sufficient synchronous generation in SA.
Perhaps there is now not enough synchronous generation.

Renewable energy integration in the NEM continued to be
an important topic of discussion for both government and
industry. AEMO conducted our first study, in association
with transmission business ElectraNet, into the impact of
renewable energy integration on power system security and
reliability. The report looked specifically at South Australia
(SA), as it has the highest wind and solar PV generator
penetration of any NEM region. It concluded the SA power
system can operate securely and reliably with a high
percentage of wind and PV generation, as long as the
Heywood Interconnector linking SA and Victoria is
operational, and sufficient synchronous generation is
connected and operating on the SA power system. AEMO
will continue to consult with industry and further investigate
options to provide both short-term and longer-term
solutions to support higher levels of wind and PV
generation in SA.
The increase of wind and solar PV energy generation as a
proportion of the total generation mix is not isolated to SA.
The 2015 Electricity Statement of Opportunities (ESOO)
reported industry has announced approximately
4,500 megawatts (MW) of generation capacity to be
withdrawn over the next 10 years, with only wind and solar
generation projects committed at this stage for the
next decade.
Message from the Chief Executive Officer
4 |

Yes, that is interesting. Thanks.
I also found this paragraph in the body of the report I linked to above:

The most well known characteristic of wind power, variation of output with wind strength (often termed ?intermittency?), was not a material factor in the events of 28 September 2016.

So I think, using the official terminology, there was a 'non-credible' combination of events involved in the SA situation.

Not meaning to be smarmy but I articulated that a while back.

AEMO failed to classify the loss of wind and the subsequent and resultant loss of the interconnector as credible. Had they not failed in that regard, they would have scheduled more thermal baseload to run.

And that is what the new market regulation, ordered by the SA governent, will do.

The intermittency of wind supply is not the central issue here. It is the non-existence of inertia in wind generation that, in this instance, that was the straw that broke the camel's back.

Originally Posted by DiscoMick

I think this is an interesting discussion about it:

https://independentaustralia.net/pol...mo-report,9618

The latest official update is here:
Update to preliminary operating incident report into the South Australian state-wide power outage

It has a link to the main report. Here is an excerpt:

3.1 Event summary
Immediately prior to the event, SCADA data showed that 883 MW of SA wind generation,8 330 MW of
SA gas generation, and 613 MW of electricity imports via two interconnections with Victoria, in addition
to any generation embedded in the distribution network, were collectively supplying the 1,895 MW of
electricity demand of SA's 850,000 electricity customers.
Extreme weather conditions resulted in five system faults on the SA transmission system, with three
transmission lines ultimately lost to the power system.9
In response to these faults10, and the resulting six voltage disturbances, there was an unexpected
sustained reduction of 445 MW of wind generation to the north of Adelaide. Analysis of high speed
monitoring data has shown a 39 MW of transient wind power reduction from the normal expected
response of wind farms riding through the voltage disturbances. Increased flows on the main
interconnector (Heywood) with Victoria counteracted this loss of local generation.11 More detail on this
is discussed later in this chapter, specifically Table 4.
This reduction in generation and immediate compensating increase of imports on the Heywood
Interconnector resulted in the activation of Heywood's automatic Loss of Synchronism protection
mechanism, leading to the 'tripping? (disconnection) of the Heywood Interconnector. As a result,
approximately 900 MW of supply from Victoria over the Heywood Interconnector was immediately lost,
and the remaining generation in SA was unable to meet the SA load. The sudden and large deficit of
supply caused the system frequency to collapse more quickly than the Under-Frequency Load
Shedding (UFLS) scheme was able to act, resulting in the SA region Black System.

As a non-expert I'm just trying to cut through the political propaganda, which is strong on both sides, and get a handle on what actually happened and understand what changes are necessary, and probably already happening.
It appears this problem wasn't caused by the intermittent nature of wind power because at the time wind was going gangbusters and was the largest single type of generation source supplying SA, ahead of the interconnectors and gas, so the intermittent argument isn't relevant in this specific case, I think.
The system apparently became unbalanced off the 50 hertz level after the towers went down and some supply was reduced.
It appears the market operator didn't know that some of the wind generators had settings which would cause them to pull out after the second or third incident, while other wind generators had different settings and stayed online. Why didn't the market operator know that?
Also, why didn't the backup generation work, despite having been tested?
It all happened very fast, so it's not surprising this combination of events wasn't anticipated. No doubt lessons will be learned.

That interpretation is exactly how I read your attached extract of the report.

I get paid to edit or interpret reports from time to time and the wording of the extract has been very carefully put together, as it should be, to get to the root cause of the problem.

I'm not pro this or that re: renewables at a state level, but I have done a lot of work on solving problems (material or conceptual). I've learnt that the only way something will start to be solved is by recognising the root cause.

If there are two sides ignoring this fact and just taking pot shots at each other the problem just becomes an expensive, festering wound.

DL

And I really enjoy reading all the erudite posts in this thread........ for example I never knew that the whole grid had to be synchronised at 50Hz.

DL