*Pic: The gouge in Basslink … was it caused by Geelong Star … ?
Geelong Star …
An inconvenient truth (Part 2).
A vital statistic for elimination
During all the many debates on the causes for the failure of Basslink there is one conveniently overlooked fact.
A fact, I think, that has been grossly and deliberately understated for what I see as highly questionable political advantage. This all amounts to a gross insult to the integrity of the cable manufacturers.
Much of the expensive time spent by the cable repair ship was just finding the tiny damaged section of Basslink. The worst scenario is when there is no indication on such a long cable where the fault is.
When ships snag a cable and do the right thing, drop their gear and then take a GPS reading, they save a huge expensive search effort.
Similar to outer space technology inner space technology has to be ultra reliable. Bottoms of oceans can be formidable places to reach when things go wrong.
Some internally created faults can be even more difficult to locate especially if they make no external mark. They can be anywhere along the cable and can be impossible find; resulting in the complete loss of the cable.
There is a staggering amount of effort and past knowledge and experience built into these types of cables – for the prevention of self-failure.
There is a whole sophisticated branch of engineering dedicated to these predictions of reliability. In fact during my training, I actually spent one of my practical training periods in a laboratory for life-testing of materials used in large electrical machines.
One common expression of the reliability factor of engineered items is MTBF or Mean Time Between Failures.
A simplified way is to apply the following example to Basslink.
Let’s look at some basic numbers. The design life of the cable is say, 50 years, probably it would be good for 100 years. So how many times would you expect it to fail by itself in a 50-year life lying on an ideal sea bed?
If a practical number exceeded one I would be surprised. So once in fifty years you could expect the undersea portion of the cable to self-fail. Fifty years, that is 18,250 days with a possibility of failure on one day, the cable may fail all by itself. A simple rule of thumb estimate, however that day could be any day in the fifty years.
I spent the majority of my career in the field investigating and repairing problems on major high-tech equipment, some out-of-the-blue and no direct experience on that product.
So how would I cope being flown out to the cable ship and confronted with the faulty section of Basslink on to the deck with little experience in such product?
This is not a laboratory examination just a first field assessment.
The first: “don’t try reinventing the wheel”.
The second: “there is no such thing as an electrical failure; it is always mechanical”.
The third: “electricity always follows the path of least resistance”.
Firstly try to make up for one’s lack of experience by tapping into those who have much practical experience.
I cannot write about this from a direct experience in this instance, as I did not board the cable ship which serviced Basslink.
However, aboard these ships are a team of people whose job it is to lay and repair deep-sea cables on a daily basis. They range from the deckhands to cable splicers and the supervising Engineer or TO. Even the captain might have stories to tell.
When Basslink was pulled from the water it was recovered as a cable that had been traumatized with no sign of any cause. That is there were no anchor chains, weights or the offending ship giving any details, or so the official reports tell us?
In the political scenario of Basslink such a situation is ripe for self-creation and fermentation of, mystery, the hypothetical and the mythical, in the minds of the public.
This by simply ensuring a paucity of information and if the media does get too hot, use of counter-counter-spin, especially on the internet such as Tasmanian Times.
It should not be forgotten that while Basslink was the longest and leading technology cable when first installed and had much publicity, some of it highly controversial political in nature.
However, it is only a cable, in engineering terms a very long non-polarized electrolytic capacitor in basic DC theory.
It is also one of many similar type of VHV DC cables that are commonly used to connect the new phenomenon of offshore wind farms, as well as a number of long distance cables around the world. In the cable-infested northern hemisphere there are many cable breakages per month with a significant number being VHV DC and AC.
In other words these guys on the cable ships deal with similar type cables with similar types of traumas on a regular basis.
However, many of these damaged cables come from the ocean depths, not only bearing their damage they also come with their cause. That can be items left on the sea floor or notification from the offending ship.
So these cable ship teams have a wealth of cause-and-effect knowledge from practical experience.
I have no doubt the team that was responsible for the handling of Basslink’s damaged section would have their own view on what caused the failure of the cable!
However, I am currently unable to tap into such a wealth of experience – unlike Basslink and Hydro engineering personnel.
I can only carry on with information at hand that we have been told or graphically contained in official press photographs.
However, it would not be unreasonable to start from a premise that even before you looked at the damage it was 18,250 to 1 that it was not an internal failure. That is very long odds.
Photographs available indicate there are light mechanical scuffing damage further along the cable from fatal damage point indicating a non-fatal hit at the same time, or at another time.
There is the knowledge of the operational cable controllers overdriving the cable and causing possible heat stress.
From the photographs I have seen the cable lengths north and south for kilometers are buried in about a meter of sand.
These lengths would have very even temperature distribution very similar to a domestic bar heater. So the likely hood of a hotspot developing from external factors on this section of cable is very highly unlikely.
If any external signs of overheating would be indicated by lengths of the cable permanently swelling even slightly.
From the photographs available it looks as though, right up to the blister with a hole the rest of the cable has perfectly circular circumference. Only very close up and simple gauge type inspection would reveal any outward indications of swelling.
From the photograph of the bulge with a hole:
Simply it looks as someone or something had hit the cable with an object resembling a sharp heavy pick.
Mechanically penetrating the armour enough to break the insulation integrity, electricity now takes the new path of least resistance establishing high intensity arc which has a negative resistance allowing an instantaneous extremely high current to flow. The intense heat forming an explosive like high pressure gas bubble ejecting and burning out the cavity made by the penetrating object which would also be burnt.
The now unevenly distributed powerful electrostatic forces across the laminated insulation blow out to form the bulge. The bulge would spread down the cable if not limited by the very fast shutdown of the SCR electronic driver system ashore.
In other words consistent with fatal external mechanical trauma.
However that does not mean that it was, as we have no physical cause … for example boat anchor or ship notification to back it up.
However, the statistical possibility is about 18,250 to 1 in favour of external mechanical trauma.
Therefore, it would not be unreasonable to call this a Hit and Run situation for immediate investigation purpose, pending further evidence to the contrary.
This evidence would have to come later from a “forensic examination” of the cable at a laboratory as carried out by Basslink-appointed laboratories in UK. In effect by default the laboratory would be looking for the type of fault or condition in the cable which would make up the factor of ONE in 18,250 of possible cable failure.
In other words trying to find a genuine reason for eliminating the straight forward external mechanical trauma theory.
The much belated report, when officially released, did not show any reason why the cable should have failed internally.
All it said was it could have been caused by either external or internal event.
Thereby eliminating a whole host of internal problems. Including permanent effects from overdriving the cable.
Mostly this class of faults is for long academic papers. Basically they describe small changes in the physical structure of the cable over time and operating conditions including signs of excessive temperature damage. They normally go on to influence the design of the next generation of cables or the manufacturing protocols.
These are also a family of problems. I have no doubt Hydro describes the “modeling” for the Tasmanian Government’s legal action.
Thus the original official forensic report effectively increased the actual odds that it was an external mechanical trauma event by a significant amount.
Let us just say it has eliminated the chances of internal failure by a factor of ten.
It is now 180,250 to 1, that the cause was “external mechanical trauma”. Interesting odds. My guess the real total figure is higher rather than lower.
Basslink is a major piece of infrastructure to Australia, one which Tasmania’s electrical power security was heavily dependent on at the time of failure.
As such it warrants investigation transparency similar to, air, train and other civil disasters; perhaps the mostly closely related is the South Australian power shut down now two years ago.
All the articles I have written on the Basslink saga – http://oldtt.pixelkey.biz/index.php?/article/basslink-dracula-in-charge-of-the-blood-bank/ ; http://oldtt.pixelkey.biz/index.php?/article/what-is-your-view-on-what-caused-the-basslink-failure/ ; http://oldtt.pixelkey.biz/index.php?/article/basslink-the-very-secretive-state-government-/ ; http://oldtt.pixelkey.biz/index.php?/article/is-a-door-flying-open-on-/ ; http://oldtt.pixelkey.biz/index.php?/article/likely-cause-of-basslink-failure-is-the-geelong-star/ – I have tried to logically (with a technological basis) show that the current Tasmanian Governments and associated entities public actions on this matter are seriously flawed.
I cannot absolutely, on the data available, prove that Geelong Star did cause fatal damage to Basslink but I believe I have reduced the odds that it did to very small.
However, there was an article in Tasmanian Times by Clive Stott on 21 January 2017, link below:
What is of most interest is comment #9 and I quote:
“I’ve got a mate who knows someone who worked on Geelong Star reckons they were in the area on the day and has a copy of part of the ships log.”
Whilst again it is not proof, unless positively confirmed, it is another “smoking gun” of a different kind.
One of the major anomalies of this saga despite having, three police forces, Tasmanian, Victorian and Federal plus the Federal Maritime Authorities to release any known data on the Geelong Star or obtain data by Maritime Law.
Very little if anything has been made publicly available of their involvement in this saga, in fact to me these entities have washed their hands of the whole affair.
Yet I understand in Australian territorial waters Geelong Star would have committed a maritime offence by not notifying authorities and disclosing her position – even if it was delayed at the time because she actually was not aware of striking the cable.
It does appear from the outset of the Basslink saga all entities involved have directed a large – desperate – effort and publicity on the least likely causes of cable failure and currently have been totally unsuccessful in doing so.
They relentlessly continue to do so in what I think may end up as a farcical civil court case which I can only think has two purposes … firstly to put what appears to be a “natural” end to this saga.
Secondly and more importantly sink from public minds that the real cause was most likely “fatal external mechanical trauma” with strong links to the Geelong Star.
It does appear from the outset of the Basslink saga on the Tasmanian Government, Basslink and Hydro have been the only story presenters of an involved and highly controlled publicity spin, with vicious active counter-spin to those that challenge their presentation, of the least likely causes of cable failure. To date this has been without technical substantiation.
Yet, I understand in Australian territorial waters Geelong Star would have committed a maritime offence by not notifying authorities and disclosing her position even, at the time, it was delayed because she actually was not aware of striking the cable.
One of the major anomalies of this saga – despite having three police forces Tasmanian, Victorian and Federal plus the Federal Maritime Authorities; there has been no acknowledgement of any involvement by these entities in this saga or release any known data on the Geelong Star or obtain data by Maritime Law.
In fact to me these entities have washed their hands of the whole affair.
The Tasmanian Government and Basslink continue in what I believe may end up as a farcical civil court case which I can only think has two purposes.
Firstly to put what appears to the public to be a natural end to this saga but secondly perhaps, more importantly, sink forever from public minds that the real cause was most likely “fatal external mechanical trauma” with strong links to the Geelong Star.
I believe one must ask the question “”in whose interest”” is this one-sided policy.
*Bio of Kelvin Jones: Technically trained and qualified in the UK by a major electrical engineering manufacturing company in Power Engineering with Switch and Protection specialisation, moving on to defence electronics, commissioning RADAR and development of underwater weapons. TV transmission, field work and commissioning work on industrial electronics and HVAC carrier protection. Research in cellular and fibre optics communications. Field work on scientific, bio, and medical instrumentation with extensive work on Medical Imaging particularly CT scanners and Nuclear imaging. Mature age universty studies in computer science and Technology with emphasis on the viability of renewable energy technology on legacy power grids.