Wednesday, July 20, 2011

'Thank you's..

I've settled back in at CPIT and getting back in the run of things at the Trades Innovation Institute. I'm getting used to being back now, and finally accepting my ASL is over and had time to reflect on it..

Into it on the 8th March
I'm looking back now and realizing just how amazingly lucky I was, having started this on the 31st January this year (wondering if I was going to see quake damage from September!), and what we've been through here in Christchurch. Not only have I gained a massive amount of experience in Cable Jointing and Line Mechanic work, I've also gained 20Gb of photos and video of the aforementioned work as teaching resources, earthquake damage, and really, captured a part of our history from a 'trades academic' point of view. I feel extremely lucky and privileged to have worked with some of the most heroic individuals I have ever met, who have showed grit and determination in their various tasks to fix the quake-damaged Christchurch distribution network.

The quakes are tapering off (at this stage), and geologists' statistical forecast is looking promising for less quakes and (hopefully) maybe no more M6+ quakes. It's great news, trust me!

I want to make this post about thanking the awesome individuals who helped me at Connetics and other companies too. This has been the greatest work experience of my life, and I hugely appreciate the way that the following people went out of their way for me, instructed, instructed, tolerated and taunted me!

Firstly; Phil Duns, the Connetics Underground Manager. Phil was instrumental in helping me at every turn, and even 'went in to bat for me' when things didn't go to plan. Phil, you're an inspiration, and I hope to repay your kindness eventually.

I'd like to thank the following also from Connetics' Management;
Jono Brent, the CEO who showed awesome leadership during what was clearly a difficult time. John Goodenough, for the general assistance and the 'open office'! Sandy, Wendy, Louisa, Diane, and the Pete Johnson. Thank you all for your help.

Jono and John 'rallying the troops', March 7.
The Cable Jointers:
Steven Bright, thank you so much for the help, instruction, and fun! Robbie Hill, the same! I had a blast with you guys, and I'm forever corrupted!

Steve and Robbie after Steve dinged a big digger.. kidding!

John Hyland; Thanks for telling me about the unusual work! The 'John Hyland system' of using a bike jack is being patented as we speak!

John 'texting' the joint closed.. He has a new brand of arcproof overalls on in this pic..!

Reece, thank you for the instruction and taking photos of me working!

Barry; thank you for letting me know the best jobs to go to, and for sending me off early on the 22nd February. You quite possibly indirectly saved my wife's life.

Karl, Wayne, Ivor, CJ, Scannel, Rex, Ted, Dennis, Terry (the Joint Guru!), Andy, Jeff, Jamie (the famous guy!), and Skid, thanks for all the help and fun guys!

CJ and Scannel flying the flag

Jamie's 'spiking face' and Steve's 'Cheesy grin'.

Ted and Rex ignore the nice view and got down to work..

And our Northland and Auckland mates; Jamie (ma hun!), Clinton, Whari, and Garfield; You and your brothers from the North were our saviours. Thank you, you're awesome. Chur, Bros!

Whari and Alby from Northpower.. That's how we roll!
T and Peachy from Transfield; thank for the laughs!

Thanks also Barry and Conrad from Top Energy, too.

Line Mechanics:
Firstly I want to thank my mate (and brother!) Awesome Peter Boyce.. Thanks for the instruction and help (pre-loaded tool use), fella!
Also Carl (the Chopper King!), Nik, Anton, Danny, Simon (the genius), Hard-case Tim(!), Roger, Ken, Murph, Bevan, James, Jason, Steve and Blair. Thanks all you guys!

Carl surveys the battlefield from his HV tank turret.


Ken is awesome! (Sorry, Pete, but he is too!)

Simon uses his tongue to measure a cable

Test Room:
Jacko, Nigel, Chris, Clive, Steve, Steve Duggan, Nick. Thank you.

I also want to thank Big Jase (Super-tough man-shorts) and Mark the STMS guys, Dave, Dean (BIG is good!), and Rodney (fellow chemical loo fan!) from underground too.

Jase the STMS (Super tough man-shorts) and Tim wearing his helmet!

'Big is good' Dean and Terry 'the jointing guru' spot a UFO.

I would like to thank CPIT for the opportunity to do this ASL also. I will do my utmost to help run courses in Cable Jointing and Line Mechanic work in the future, to train new blood and help fix our broken city.

Finally I want to thank YOU, the reader! I'm over 2000 hits now, and I'm honestly surprised how popular this blog is..! I'll continue to run this, I'm 'in the zone' now, and want to keep contributing to record the recovery of Christchurch.. keep watching!

Cheers

Andrew ;D

...... the story DOES NOT end here.....

Wednesday, July 13, 2011

Weeks 21 and 22 - final weeks of my ASL.

Well, I'm back at CPIT now, and it's been a week of many emotions.. Even though I know I'm a Tutor who is now teaching the future electrical workers who will help rebuild Christchurch, I feel I've abandoned my city.  Packing a shovel and digging, helping with joints, even talking to locals with broken homes, I felt like I was  helping defy these earthquakes that have progressively worsened or ruined life for many of us.

What I don't miss; seeing damage. The central city and towards the east just has so much damage. Seeing all of this gets me down, really. I get this feeling of 'where do you start'? The job of fixing Christchurch seems massive. It will be a long process.

I want to thank so many people for helping me with my Academic Study Leave, what I will do is a new post (next time) and do it then. This post will cover my last two weeks with Connetics.

Soooooo....

Work log:


Monday 20th June: 11kV PILCA-XLPE-PILCA transition joints outside AMI stadium with Steve, Ivor, Dennis and CJ.

The cable joint hole.. took a long time to pump out!

Starting the joint
Tuesday 21st June: Reconnect pole, Lincoln.

The pole in Lincoln to be reconnected
Wednesday 22nd June: Disconnect overhead lines for insulation test, Moncks Spur, and straighten pole, Kingsford St, Dallington.

Danny attaching earths to 11kV cables on Monck's Spur
Poles on Kingsford St, Dallington. 

Thursday 23rd June: Pages Road reattach barge board, Sumner 11kV overhead repair using helicopter.

Love this photo.. the boys about to earth the 11kV circuit.

The helicopter about to lift Carl

Carl working hanging from the helicopter

Friday 24th June: Straighten pole Locksley Ave, light pole New Brighton Road, and pole on Avonside Drive.

Leaning pole at Locksley Ave

Monday 27th June: Install disconnect in 11kV overhead conductors, Birch's Rd, Lincoln.

Ken and Bevan installing a line break

Finished line break


Tuesday 28th June: Grays Road, Chch Airport, install 33kV copper conductors.




Wednesday 29th and Thursday 30th June: 66kV underground-overhead pole connection, Islington substation.

Sealed against the weather; a 66kV pole having  underground-overhead terminations done.

Barry and Terry preparing the 66kV cable for terminating


Friday 1 July: Red Zone: cut and sleeve 11kV PILCA, Gloucester and Colombo Sts.

Robbie and I sleeving off the 11kV PILCA
Steve isolating the cable

Me in front of the destroyed Christ Church Cathedral

Further analysis to come. Now my Academic Study Leave is over, I'm in a 'holding pattern' waiting for the green light to start developing courses for Cable Jointers and Line Mechanics. In the meantime, I'm back in my old role of teaching electricians, students that struggle at high school, and pre-trade electrical theory to current high school students. Next week, thank-yous.



Monday, June 27, 2011

Analysis; Damage to a power network from multiple major earthquakes.

Christchurch has had 3 major, 10 moderate, and around 7000 minor earthquakes and aftershocks at this point in time. The following is a personal account of the damage based on my personal experiences and the different side-effects of earthquakes. 

I need to stress at this point in time, I am NO geologist, seismologist, or network analyst. So some of this information may not be accurate, it's simply based on my logic as an Electrical Tutor! I apologize in advance if I say anything incorrect, and feel free to post anonymous comments (this has been done, already, thank you!) and correct me.

In my opinion there have been four major side-effects of a quake (in Christchurch's case): 
  • Ground shaking 
  • Liquefaction
  • Lateral spread
  • Landslides/building collapse/rockfalls. 
Christchurch did not experience tsunami related to our own quakes at any stage. I will cover each category for some systems in the Christchurch distribution network that were affected, namely:
  • Substations 
  • Overhead lines 
  • Underground cables


Substations:

Ground shaking:
Large cast-iron circuit breakers and large transformers were affected by the shaking. Nothing is exempt from the ground acceleration and the following effects occurred:

Masonry bolts were removed from the concrete foundations by the ground shaking, which affected both circuit breakers and transformers. Also on multiple occasions, oil-filled transformers 'tripped out' due to the 'sloshing' of the internal insulating oil, making the float
switches think the transformer had developed a leak, which causes outages. I am not aware of any circuit breakers 'tripping' due to ground shaking, but it is a possibility.

Seismic bracing behind circuit breakers at Bromley substation 

Seismic bracing at Bromley substation 
During the last two decades, Christchurch's Network owner invested a significant amount of money in seismic strengthening their 270 brick substations which resulted in few sustaining serious damage. See HERE for more information.


Liquefaction:
Christchurch is effectively built on an existing swamp, particularly the eastern areas. The worst-hit example of a substation affected by liquefaction was New Brighton substation, which is approximately 200m from the Avon River. Lateral spread and a high water table were factors here also.


New Brighton substation sunk due to liquefaction


The February magnitude 6.3 quake caused the New Brighton substation to sink approximately 2m into the ground, damaging incoming and outgoing power cables. It also filled the switch room with approximately 700mm deep silt and water. This had to be cleaned out comprehensively and the two 66kV transformers were replaced with a single 66kV transformer fed from a new overhead line.

There were several smaller substation buildings that also sank and 'went out of level', but most appeared to continue operating without issue.

Lateral spread:

New Brighton substation may have been affected by lateral spread, but evidence was sparse to indicate that. As with liquefaction, lateral spread would have affected any substations that were near the Avon River. I'm not sure if that actually occurred at any stage.

Landslide/building collapse/rockfalls:
Sumner substation was hit by a massive boulder and partially disabled by this. It was built below a cliff composed of volcanic rock, some brittle, some boulders. I'm no geologist, so I couldn't describe the type of rock the cliff face was composed of, but the boulder that hit the substation was substantial and did serious damage.

The boulder that destroyed Sumner substation


Inside Sumner substation


Overhead lines:

Ground shaking:
Having seen up to 2.2G of ground acceleration from the magnitude 6.3 quake of February 22nd, Christchurch has seen unprecedented shaking due to an earthquake. Thousands of poles were heavily affected by this shaking and a large number were affected, predominantly by being left on leans, pulling barge boards off houses, straining lines, and damaging pole fittings such as cross arms and insulators. Conductors swung to within arcing distances and proceeded to do so. Also the ground acceleration caused the shafts of insulators to be bent and ties to be broken. 


Leaning poles due to a combination of shaking and liquefaction  in Kingsley St.


Video of using a helicopter to repair broken ties on an 11kV circuit that was inaccessible due to rockfall hazard in Sumner:





Liquefaction:
Many poles were affected by liquefaction, some sinking straight down, some leaning due to liquefaction coming up underneath the pole. 


Installed 3 weeks prior to the June 13 magnitude 6.3 quake, this pole was affected by liquefaction.

The same newly-installed pole.




Lateral spread:
Once again, many poles close to rivers were affected by this in a similar manner to liquefaction. Also, due to the lateral spread, the land sank, causing the water table to rise, which also caused poles to sink.


This building sank more than the pole did, ripping the termination bracket off the roof of the building.


Landslide/building collapse/rockfalls:
Poles above and below cliffs were affected by rockfalls and landsliding. Poles were hit by debris below, as well as their associated lines. This damaged poles by outright destroying the pole to breaking insulators and crossarms.


The Sumner boulder that fell on a pole.


The pole with the boulder on it.




Underground cables:


Ground shaking:
Two of the four types of dynamic force that travel underground during a large earthquake can be seen below.




A static description of waves is shown HERE.


As anybody can imagine, these massive forces can affect subterranean infrastructure systems, such as power cables, telecommunication cables, water pipes and waste pipes to name a few. In Christchurch all the aforementioned systems were affected by the quakes, power cables being in the firing line.


A minimum of four major 66kV underground cables were damaged, two beyond repair. The sheer ground acceleration ruptured the concrete the cables were embedded in in multiple locations, mostly where the liquefaction was at its worst. The other two cables had faults that were able to be repaired.



Partially completed 66kV XLPE repair joint


In the centre of the picture is a faulted 11kV PILCA cable, above is the concrete in which the one of the heavily damaged 66kV oil-filled cables can be partially seen.


3-in-a-row; three PILCA 11kV cables all bent and faulted.


Other cables were damaged also, approximately 800 underground cable faults occurred from the February quake. 11kV paper insulated lead covered armoured (PILCA) cables were bent into Z and S shapes, causing the insulation to fail on them. Other faults included previous faults pulling apart and terminations being removed from protective devices. Cables that transitioned up poles were bent by the pole swaying during the quake.


Liquefaction:
The makeup of the swampy soil in the eastern areas of Christchurch seemed to allow cables to be damaged as stated above, but the actual liquefaction process of water bubbling to the surface of soil did not affect cables as the shaking did. Liquefaction rather made travel impossible in some cases and created large potholes that vehicles fell into. The higher water table involved pumping out joint holes before work, which in some cases took hours.


An abandoned joint hole, this particular joint incomplete as several faults were found on the same cable.


Lateral spread:
Lateral spread caused cables to fault next to bridges that the cables passed under, and also caused joints to tear apart near rivers. Also cracks that appeared in land on hillside suburbs tore T-joints, other joints and terminations apart. 


Originally straight; this <still functioning> LV XLPE cable has been bent by lateral spreading.

Steve from Connetics showing the bent cable.


An 11kV XLPE joint torn apart by lateral spread.


A LV joint torn apart by lateral spread.



Landslide/building collapse/rockfalls:

I'm not aware of any faults due to these effects, however I understand many kiosks were damaged by falling buildings in the Christchurch CBD 'Red Zone' and the Lyttelton town centre.

Solutions:

Substations:
The circuit breakers inside Bromley substation were reinforced with steel braces to prevent further shaking and destabilizing. New Brighton substation was relocated to Rawhiti Domain, where there was little liquefaction and lateral spread. Sumner substation, I'm not entirely sure, but I think it was bypassed. 



Overhead lines:
Due to the ease of fault finding and maintenance, overhead lines were rapidly repaired. Severe unstable poles were immediately repaired, and ongoing pole straightening is continuing.



Underground cables:
Approximately 800 underground cable faults were repaired. Test Technicians and Cable jointers from all over New Zealand and Australia were employed to assist with the mammoth diagnosis and repair effort. Specialist 66kV jointers were bought in to repair oil-filled and XLPE insulated cables. The irreparable 66kV cables were replaced with temporary 66kV overhead lines, to keep the power supply running through winter until such time as a window of opportunity to replace the faulty cables exists.




See HERE for my blog post regarding the Bromley-Dallington 66kV overhead install.
See HERE for my blog post regarding the New Brighton-Rawhiti 66kV overhead install.