Giving way at uncontrolled intersections

[Franco Cozzo]

Originally Posted by roKWiz

Why is there still such things as domestic overhead powerlines.
Didn't these go out when someone knew how to operate a ditchwitch, our little town doesn't have many.

Agree completely, should be a retrofit program to put them all under ground.

They were promising that here since the ash Wednesday bushfires with the power lines near Woodend, 40 years later they're still above ground and every time it rains or gets windy they have dramas and cause region wide power outages.

[Itsme]

Originally Posted by Franco Cozzo

Agree completely, should be a retrofit program to put them all under ground.

They were promising that here since the ash Wednesday bushfires with the power lines near Woodend, 40 years later they're still above ground and every time it rains or gets windy they have dramas and cause region wide power outages.

You will not see existing overhead power lines going underground, no one will pay for it.

[Franco Cozzo]

Originally Posted by Itsme

You will not see existing overhead power lines going underground, no one will pay for it.

Well now we privatised all the poles and wires in our 'gold plating' exercise, of course not,

If it was still government owned then you could put pressure on them.

[Itsme]

Originally Posted by Franco Cozzo

Well now we privatised all the poles and wires in our 'gold plating' exercise, of course not,

If it was still government owned then you could put pressure on them.

Privatisation happened just on 30 years ago, the "If's 'went out the door a long time ago.

[Dr Smith]

Originally Posted by roKWiz

Why is there still such things as domestic overhead powerlines.
Didn't these go out when someone knew how to operate a ditchwitch, our little town doesn't have many.

Because privatised assets owned by corporates don't operate that way....once again Governments getting done over by business during asset sales with no conditions in the purchase contracts for such things....and ironically in the Power industry the term "gold plating" of assets gets thrown around where the electricity distributor can spend their money upgrading assets when not necessarily needed however pass on the "cost' of such upgrades to power retailers and ultimately us the public...with not much oversite.

[FoxtrotGolfXray 5.0]

Originally Posted by Citroënbender

Daringly, to return to topic - are the outages so bad as possibly suggested yesterday evening?

My comments were primarily based upon Loy Yang A losing all four units. That, IIRC, is an unprecedented event for them (outside of commission testing), and I was working on the basis that it would take them days, if not a week or more, to get all four units back on line.

As of this morning, all four units are back online. A pretty massive effort to have them back less than 48 hours after the trip.

Originally Posted by whynot

That the faults bumped off major power stations nearby is no surprise. But one will have to wait for the engineering report to understand if it was transient stability, over frequency (due to lack of load) or under frequency (too much load dumped on them) that caused the generators to trip. All said, nice work by the plant operators to get back two units that evening - on a power station not designed for TTHL.

My understanding is that Loy Yang A is designed for TTHL. The problem in this event was that the boilers tripped before the turbines, I believe.

Hence my scepticism that they'd have all four units back on line in the time frame they did.

If anyone wants a good insight into the details of the events, this website provides some good data and interpretation.

https://wattclarity.com.au/

From a personal perspective, we lost power at my house at about 4:30pm (about the time the storm front hit town) and were without power for around 18 hours. Parts of town were also out, whilst some still had power. It also seems as though power was restored in stages, as my mum, who lives up the other end of town from me, lost power at the same time as I did, but had her power restored later that night.

We also lost all telecomms a couple of hours after power went out. I assume that is because tower back-up systems also ran out of juice. That was restored mid morning yesterday, around the same time as power was restored.

Some of my work colleagues who live around Yarram, Boolara, Mirboo North, are still without power and have indicated it will take some time to have it restored simply because of the amount of tress and wires down, etc.

[whynot]

Originally Posted by FoxtrotGolfXray 5.0

As of this morning, all four units are back online. A pretty massive effort to have them back less than 48 hours after the trip.

My understanding is that Loy Yang A is designed for TTHL. The problem in this event was that the boilers tripped before the turbines, I believe.

My mistake on Loy Yang not being designed for TTHL. I am getting my power stations mixed up. I have been there once in a professional capacity and it is an amazing site.

Regardless, designed for TTHL (or not), boiler trips are bad news. The crew on site did well to return the plant to service so quick.

Just to back up what you are saying, there is a SARS document on the AEMC web site that discusses some of the challenges with system restarting. It is a good read.

https://www.aemc.gov.au/sites/defaul...21-%282%29.PDF

We are certainly in an age where there are a lot of clueless folk, with little engineering understanding, in key positions demanding changes in the grid with little understanding of the consequences. Sigh ...

[Terraplainin']

Originally Posted by whynot

We are certainly in an age where there are a lot of clueless folk, with little engineering understanding, in key positions demanding changes in the grid with little understanding of the consequences.

This should be printed, in 40 point bold, in every newspaper in the land.

[chinamonty]

Originally Posted by roKWiz

Why is there still such things as domestic overhead powerlines.
Didn't these go out when someone knew how to operate a ditchwitch, our little town doesn't have many.

The main problem has been the transmission lines rather than local connections. I am in Dandenong and my power and phone were only out for two hours.

[whynot]

Originally Posted by roKWiz

Why is there still such things as domestic overhead powerlines.
Didn't these go out when someone knew how to operate a ditchwitch, our little town doesn't have many.

It is really expensive to retro fit.

On a green field site (e.g. a new housing estate), the cost differential isn't so bad. Last time I saw actual costs (about +10 years ago), it was around $4k per lot for underground in a new housing estate and about $1.5 per lot for overhead in a new housing estate. Some local councils insist on undergrounding in new estates. Others, chasing population growth, don't.

Undergrounding an old overhead network can get very expensive. Rule of thumb is about six times the cost to completely redo overhead for the low voltage and 11/22kV distribution network.

But the costs don't stop there. A spot on the ground has to be found for the local distribution transformer. If there isn't enough space on the footpath, then it requires buying or compulsory acquiring about 15m2 off someone's front garden. This makes people very shirty. Next, all the houses with an overhead connection have to be converted to an underground connection. This means digging up lawns, cutting (or tunnel boring) driveways, etc. A certain (albeit small) percentage will have their water mains / sewerage / NBN / gas accidently cut in the process. Figure $5K for the average job.

When it gets to higher voltages (like 66kV and above), long underground transmission lines have other unwanted technical characterises. The short version is they are highly capacitive and cause unwanted voltage swings and transients on the network. (Even underground transmission cables around town can cause issues.) Cost of underground transmission can be up to 16 times that of overhead transmission. It is usually only cost effective to underground transmission in heavy urban areas where it would be impossible to run a new overhead transmission line.

Some other unexpected engineering issues can pop up as well. For example, underground cables don't like trees. Underground cables require some moisture in the soil, so that the soil wicks away heat loss in the cables. Obviously, trees require soil moisture to live, and during droughts, they will aggressively go chasing soil moisture. This dries out the soil near the underground cable, and dry sandy soil is more like a thermal blanket. The heat becomes trapped around the cable, which drives more moisture away. Cables run hotter and this shortens the cable asset life (under good conditions should be between 80-100 years).

There is also technology change on the horizon to consider as well. It costs considerable money per household to go from overhead to underground. Effectively, the asset owner gets a massive loan and pays it back over the next 40 years.

The cost of undergrounding is borne by everyone, regardless whether they can afford the cost or not, and regardless whether they want the extra reliability or not.

So, there is this ongoing discussion inside the electricity industry. Instead of forcing customers, should we leave it to the customer to make their own decision on reliability? Or even should we go as far as disconnecting the grid at the fringes of the network and leave it to the customer to install their own power supply.

Consider the cost of, say, a 5kW solar PV system, a 13kWh Tesla Powerwall, and a Tesla gateway is around $25k installed. The Tesla Powerwall and Gateway effectively gives the customer 13kWh UPS level resilience. And the 5kW solar PV gives them a chance to recharge the next day.

Or an alternative solution, about $7K installed, one can get a 6kW standby generator with auto-start and auto-changeover.

One final point, there are a lot of Australian based technical papers on the web that discuss the pros and cons of undergrounding, and the cost to the community. Worth having a read through them.

[Citroënbender]

Another great read - thank you!

[chinamonty]

Originally Posted by whynot

It is really expensive to retro fit.

On a green field site (e.g. a new housing estate), the cost differential isn't so bad. Last time I saw actual costs (about +10 years ago), it was around $4k per lot for underground in a new housing estate and about $1.5 per lot for overhead in a new housing estate. Some local councils insist on undergrounding in new estates. Others, chasing population growth, don't.

Undergrounding an old overhead network can get very expensive. Rule of thumb is about six times the cost to completely redo overhead for the low voltage and 11/22kV distribution network.

But the costs don't stop there. A spot on the ground has to be found for the local distribution transformer. If there isn't enough space on the footpath, then it requires buying or compulsory acquiring about 15m2 off someone's front garden. This makes people very shirty. Next, all the houses with an overhead connection have to be converted to an underground connection. This means digging up lawns, cutting (or tunnel boring) driveways, etc. A certain (albeit small) percentage will have their water mains / sewerage / NBN / gas accidently cut in the process. Figure $5K for the average job.

When it gets to higher voltages (like 66kV and above), long underground transmission lines have other unwanted technical characterises. The short version is they are highly capacitive and cause unwanted voltage swings and transients on the network. (Even underground transmission cables around town can cause issues.) Cost of underground transmission can be up to 16 times that of overhead transmission. It is usually only cost effective to underground transmission in heavy urban areas where it would be impossible to run a new overhead transmission line.

Some other unexpected engineering issues can pop up as well. For example, underground cables don't like trees. Underground cables require some moisture in the soil, so that the soil wicks away heat loss in the cables. Obviously, trees require soil moisture to live, and during droughts, they will aggressively go chasing soil moisture. This dries out the soil near the underground cable, and dry sandy soil is more like a thermal blanket. The heat becomes trapped around the cable, which drives more moisture away. Cables run hotter and this shortens the cable asset life (under good conditions should be between 80-100 years).

There is also technology change on the horizon to consider as well. It costs considerable money per household to go from overhead to underground. Effectively, the asset owner gets a massive loan and pays it back over the next 40 years.

The cost of undergrounding is borne by everyone, regardless whether they can afford the cost or not, and regardless whether they want the extra reliability or not.

So, there is this ongoing discussion inside the electricity industry. Instead of forcing customers, should we leave it to the customer to make their own decision on reliability? Or even should we go as far as disconnecting the grid at the fringes of the network and leave it to the customer to install their own power supply.

Consider the cost of, say, a 5kW solar PV system, a 13kWh Tesla Powerwall, and a Tesla gateway is around $25k installed. The Tesla Powerwall and Gateway effectively gives the customer 13kWh UPS level resilience. And the 5kW solar PV gives them a chance to recharge the next day.

Or an alternative solution, about $7K installed, one can get a 6kW standby generator with auto-start and auto-changeover.

One final point, there are a lot of Australian based technical papers on the web that discuss the pros and cons of undergrounding, and the cost to the community. Worth having a read through them.

As well as the cost being between 10 and 20 times the cost of overhead transmission the thing that everyone misses in discussions about putting high voltage underground is the cost of the thousands of signs they would have to put in telling you not to dig (same as they do with gas).
You also need to have geologically secure land when burying cables - look at what happened in Christchurch from the earthquake. Fortunately this is less of an issue for Victoria and other Australian States.

[roKWiz]

Eerr, my key word was domestic street poles, don't think I mentioned the large overhead transmission wires between substations.

After the 2009 bushfires caused by poorly maintained crappy wooden poles falling over into bushland, (where there was no large trees) we had the power companies agreed (well forced to by an inquiry) to start installing most domestic services underground at around the same time NBN was digging up the towns here.
It was also around the same time the $ydney to Melbourne pipeline was being repositioned and upgraded along with ARTC butcher of the rail line.
And this is through mountainous and granite belt country.

As stated before this town is one of the earliest settled inland towns in Vic and most of the power is underground, not that I use it.

These companies agreed to do this stuff, then usually throw their hands in the air and say its all to hard, just like the country telecommunication fiasco inquiry we had after several deaths from no cell service.
Still NOT fixed.




Dear greedy (poor) power companies, stop gambling on the stock market and get out and actually upgrade the network. Yes we know how much profit you made in the last couple of years and its time to re invest in the grids capacity and safety.

[whynot]

Originally Posted by roKWiz

Eerr, my key word was domestic street poles, don't think I mentioned the large overhead transmission wires between substations.

I gave examples from distribution through to transmission.

Domestic street poles include low voltage (240/415V), the medium voltage network (11,000 volts or 22,000 volts as the case may be), and occasionally the sub-transmission voltages (33,000 volts).

Back in the 1990's, I project coordinated one overhead to underground project as part of a beautification works in conjunction with Main Roads. What an awful mess that was. The result looked great (still does). But, along the way were shirty business owners (digging up their footpath), one crew accidently taking out a 2,400 pair Telstra cable (no phones for some for a week), other services not on their assigned alignment resulting in re-design and re-approvals, complaints about where we located a certain 11kV/415v padmounts, high-voltage switching constraints, complaints about the traffic jams when we had a lane closed, cost overruns due to poor estimating, etc, etc. I was drowning in paperwork and please explains.

After that, I made sure that I made myself scarce when similar projects were handed out.

Originally Posted by roKWiz

After the 2009 bushfires caused by poorly maintained crappy wooden poles falling over into bushland, (where there was no large trees) we had the power companies agreed (well forced to by an inquiry) to start installing most domestic services underground at around the same time NBN was digging up the towns here.

Let us look at this in a bit more detail, using the Royal Commission as a reference.

http://royalcommission.vic.gov.au/Co...used-Fire.html

First, in the 2009 bushfire failed electricity assets caused five of the 11 major fires. Not all of them.

Second, since 1997 an average of 4,800 fire starts have occurred each year on private property in the SP AusNet distribution area. Of all these fires, SP AusNet assets had been associated with 52.8 fire starts (1.1 per cent) each year.

Bulk undergrounding of the network is not going to remove even a majority of the ignition sources for bush fires.

Third, the fires at Kilmore East fire (which killed 119 people), Coleraine fire, and Horsham fires were all caused by electrical faults on SWER lines.

Just a small digression about SWER lines. SWER stands for Single Wire Earth Return. SWER is installed where it is uneconomic to install normal three-phase power. It is built as cheaply as possible to extend the fringe of the electricity network. Even done on the cheap, SWER is so un-economic to install that the system we have today was funded by government policy in the 1950’s through to the 1980’s. Funded basically by charging city electricity consumers a surcharge to subsidise country consumers. Even so, the government had to stop the practice when it was costing (in 1980 dollars) over $100,000 to extend the SWER network.

Just to give an idea of the expense involved in the 2020’s, recently Essential Energy (NSW) was granted a special exemption to remove the SWER lines and replace it with a SAPS (Stand Alone Power System) for just one property. The reason for the exemption was that a like for like replacement of the SWER with a new SWER line to this isolated property was going to cost over $1M. It was cheaper to put in a SAPS. But because a SAPS is a “generator” and Essential Energy (as a distributer) cannot by law hold a generator licence, they had to get an exemption. More about SAPS is https://www.essentialenergy.com.au/o...-power-systems



Since the Royal Commission there have been further research into other ways to prevent SWER lines causing bushfires. Specifically, the Powerline Bushfire Safety Taskforce. They have a full report available here and is worth the read. https://www.esv.vic.gov.au/sites/def..._30Sep2011.pdf

Originally Posted by roKWiz

These companies agreed to do this stuff, then usually throw their hands in the air and say its all to hard, just like the country telecommunication fiasco inquiry we had after several deaths from no cell service.
Still NOT fixed.

In defence of the power companies, they just cannot go spending money on the network. Every dollar spent has to be pre-approved so that they are not “gold plating” the network. In Victoria’s jurisdiction this is the Essential Services Commission (ESC).

Reading from the Royal Commissions report is interesting …

In 2004 and 2005 Powercor presented compelling submissions to the Essential Services Commission, seeking revenue to place power lines in high-risk bushfire areas underground. Powercor referred to the fact that ‘undergrounding to protect against bushfire has been identified as an area of concern for customers in rural and semi-rural areas’ and noted that its service territory contained some of the most bushfire-prone land in the world. It also pointed out that, even when steps were taken that went beyond the action required by the Line Clearance Code, contact between vegetation and power lines could occur.65

Powercor presented evidence suggesting that customers were willing to pay for the placement of power lines underground and that the economic benefits were material. It pointed out, however, that, although it would incur undergrounding costs, it would not capture all the benefits, including those delivered to the entire community. Powercor argued:

Each year ‘disaster-level’ bushfires (where the total insurance costs of the event are more than $10 million) cost Australia an average of $77 million … overhead electrical assets can result in the ignition of a number of fires each year due simply to the existence of an energy source exposed to natural elements …

It is difficult to accurately quantify the benefits associated with undergrounding to prevent fire hazards as the value of the benefit will vary depending upon location. Powercor Australia is not aware of any study that has been able to readily value the benefits associated with reducing fire hazard, including those prepared by other regulators. The difficulty in quantifying the benefits does not mean those benefits are not material.

Powercor Australia believes the [Essential Services] Commission has an obligation to investigate the benefits associated with undergrounding to reduce fire danger both from a stand point of ensuring it meets its own objectives, but also from a societal perspective given the benefits from undergrounding largely accrue to the community as a whole.66

Mr Ken Gardner was the head of the state safety regulator, Energy Safe Victoria, when Powercor made the submission to the Essential Services Commission. He told the Bushfires Royal Commission that ESV did not make submissions supporting or opposing Powercor’s submission. Despite ESV knowing of Powercor’s submission, it appears there was no consultation between ESV and the ESC before the ESC’s rejection of the submission.67

The ESC put forward a number of reasons for rejecting Powercor’s submission, among them the following:

• The distribution businesses had failed to quantify the benefit or reveal the amount and network type to be undergrounded.68

• The costs of undergrounding should be paid by the customer.69

• The regulatory framework’s incentive-based nature would ensure undergrounding where the benefits outweigh the costs.70

• The Victorian State Government Powerline Relocation Scheme funded up to half the undergrounding cost when a community benefit would result, and this was a more appropriate mechanism for obtaining revenue where there was community benefit.71

The ESC’s assertion that undergrounding costs should be paid by the customer ignores the fact that many of the benefits of undergrounding—in particular, the reduction in bushfire risk—accrue to the entire community. The ESC’s approach also ignores the fact that those benefits, including the saving of lives, are less amenable to measurement in financial terms.

Accordingly, the ESC’s argument that distributors would use underground cabling where the overall benefits outweighed the costs is flawed. The Australian Energy Regulator’s Mr Chris Pattas, General Manager of the Network Regulation South Branch, agreed that a distribution business might target reliability in high-density areas because if it misses reliability targets in those areas it will be penalised more heavily than it would be for missing targets in low-density areas. The areas of highest risk of bushfire are, however, areas of low-density population, and Mr Pattas could not point to any incentive for a distribution business to focus on reliability in low-density areas. Similarly, Mr Fearon of Energy Safe Victoria stated that the ‘current generation’ of incentive arrangements go to average performance and that SWER lines are low-priority reliability targets.72

Finally, the Commission notes that the ESC’s reliance on the Powerline Relocation Scheme was misplaced. The scheme concerns the undergrounding of power lines in areas where there is high pedestrian or vehicular activity or where environmental or cultural factors justify such placement. Most projects under the scheme are for distances of between 100 and 400 metres, and the scheme is expressly not concerned with reducing bushfire risk. The Commission would welcome a scheme that is directed at undergrounding for the purpose of reducing bushfire risk.73

So, the greedy power companies have previously applied for approval to spend money underground the network in targeted locations to reduce bush fire risk, and this approval was declined by the Victorian Government.

Originally Posted by roKWiz

Dear greedy (poor) power companies, stop gambling on the stock market and get out and actually upgrade the network. Yes we know how much profit you made in the last couple of years and its time to re invest in the grids capacity and safety.

Yeah, I get it that in Victoria the power lines are owned by private companies.

But here in Queensland, both the distribution companies (Energex and Ergon) and the transmission company (Powerlink) are owned by the Queensland Government. Even government owned power companies are not undertaking widespread undergrounding projects.

[Franco Cozzo]

Interesting, I'm in Powercor region, maybe thats why near Woodend is still poles and wires fiasco that shits the bed every time there's a gentle breeze.