Tuesday, May 17, 2011

Weeks 14 & 15 - Subs department - Brookside, Hororata, Greendale Substations, Test Room

Well, I've finished with lines in the interim until later this month. In the meantime I'm going to be spending some time in 'Subs' and the 'Test room' Departments.

Work log:


Monday 2 May: SUBS; Brookside and Hororata Substations; repair design fault with approved manufacturer's rewire.

Brookside substation


Switchgear at Brookside substation

Hororata Substation. The windows broken in the 4 September 2010 quake have been covered with wood.

Tuesday 3 May: Wire control unit in workshop.

Wednesday 4 May: Greendale Substation; Move and permanently wire communications unit.

Greendale substation.. yes, it's practically on the fault line.
Control units inside the substation
Evidence of the explosion that occurred at the back of a circuit breaker during the M7.1 earthquake.

Substation yard gates... do they line up?!!

Thursday 5 May: TEST ROOM; Isolate and earth faulty 11kV cables, Opawa Rd bridge and near AMI stadium. Also reconnect 11kV supply cable, Cannon Hill Crescent.

Australian cable jointers helping fix our broken network

Uppermost cable is earthquake damaged steel and lead armoured 11kV  HDPE cable. Lower is replacement XLPE.


Damaged 11kV PILCA cable marked pink for jointers
Friday: 6 May: Sheath test 66kV cable between Papanui and McFaddens Rd Substations. Find fault on Orchard Rd and Bridge St lighting circuits.

McFaddens Rd Substation 66kV transformer building

Nigel from the Test Room earthing a 66kV circuit prior to the sheath test
Monday 9th May: Red Zone 66kV sheath test and Bankside LV underground cable fault.

Inside the Red Zone near Victoria Square.. Which building is 'wrong'?

The same jointers (Shaun Baker and Barry Kelly) that got Dallington Substation reconnected repair the Addington-Armagh 66kV Oil-filled cable

The Armagh "inside" substation

Robbie and Steve dig for a low-voltage (LV) cable after the fault has been found with the 'thumper'.

Nigel replaces pole fuses 

Tuesday 10th May: Find faulty 11kV cable between Beach Road substation and New Brighton substation using TDR and 'thumper'.

Connetics and Delta (Otago) vehicles at Beach Rd sub

The TDR (time domain reflectometer) in action

Peter from Delta using listening equipment for 'thumping'

Marking the faulty cable after 'thumping'

Wednesday 11th May: Red Zone test 11kV cable.

The CTV elevator shaft and stairwell is demolished.
A Madras St sub. Left is the gap where a church was.

Thursday 12th May: Ferry Road LV cable fault find and repair.

LV fault found using 'thumper'

Existing joint torn apart by earthquake.

Friday 13th May: Isolate/Test/Join/Test/Energize 11kV XLPE cable Shands Road.



Analysis: Subs and Test room departments

Subs are electrical fitters, which is the supply equivalent of industrial electricians, of which I am one. The work the subs workers do is very familiar to me and I felt quite at home in their workshop and on-job with them. However, the point of my ASL is not to be in my 'comfort zone', and to throw myself at the unfamiliar and learn it, so educationwise, it was, however, not hugely beneficial for me to spend too much time in subs, so I limited that to just three days.


The Test Room, however, is a whole new ballgame for me. The workers in the test room are the network 'fault finders', 'isolators', 'energizers', and almost direct the repair of the network. Faults in underground and overhead cables are found using complex pieces of equipment acting upon order sheets from network owner Orion.
There are two ways the Test Room operate; faults and scheduled maintenance.

Faults are identified by the network controller in the control room or rung in by the public. Orion will then use a Network Operator to identify the fault or faulty circuit. Often the supply to consumers can be maintained by 'ring circuits' or 'backfeeding'.
Once the faulty circuit is identified, the Operator will disconnect the circuit by operating circuit breakers or removing fuses or links.

The Orion 'Operating order' sheet

The job is then passed on to the Test Room for fault diagnosis and identification. The faulty cable is tested, and once the fault location identified, the cable is earthed.
This is where the picture becomes complete. A 'dig up' crew carefully exposes the faulty cable, cable jointers 'spike' the cable, and then repair the cable. The Test Room then test the cable once the jointers are clear, and if the cable is found to be without fault, the circuit is possibly re-energized, if Orion require it to be.

'Scheduled maintenance' is very similar, except a fault does not need to be found. Usually it involves a cable movement or connection change, once again involving the Cable Jointers.

My time in the Test Room completes a cycle of learning for me, I now have full understanding of the process involved in repairing a damaged cable. It would not be appropriate for me to endeavour into the very flash toys the Test Room employ to fault find cables with, as my focus at Connetics really is Cable Jointing and Line Mechanic work.

Analysis: Line Mechanic Vehicles


Line Mechanics have a large scope of work to cover; wooden poles, metal poles, reinforced concrete poles, and towers (pylons) must all be worked upon. A Line Mechanics' truck must be fully equipped for any eventuality as they sometimes work very far afield. There are two trucks used:

'HIAB' Truck

The 'HIAB' or 'crane' truck
The 'HIAB' truck is so named from one of the first models of transportable hydraulic crane trucks; Hydrauliska Industri AB, which is a Finnish manufacturer of loader cranes, demountable container handlers, forestry cranes, truck-mounted forklifts and tail lifts. See HERE.


The HIAB truck is predominantly used for pole handling and live line work. It's powerful yet compact when packed away crane is ideal for Line Mechanics' use. With plenty of cargo space on the back, and room for compartments in the side, it is a fully mobile workshop and crane. 


A skilled crane operator can make a job far, far easier and less time consuming than a less experienced operator. Dual controls, one set either side of the rear of the truck enable ease of operation.


In addition to the hydraulic crane, there are hydraulic stability legs to prevent the truck capsizing under crane loads. 


Another clever addition the HIAB truck has is a fully insulated 'line holder'. This device holds conductors up in the air when doing live line jobs as a temporary 'pole'. 


The 'line holder'
 
The HIAB being the 'pole'
Tool and equipment compartments

Spare part compartments and even a jug and toastie maker!

Fuel and chainsaw

The deck
There are many other uses for a HIAB truck, these are just a simple overview.



'Bucket Truck' or 'Cherry Picker'

The 'Bucket truck' or 'cherry picker'

The 'bucket truck' is a vehicle primarily used for line mechanic access to poles and overhead network systems. It has a hydraulic telescoping arm, the last section being made of an insulating material for safety.

The bucket can legally be used as a work platform and line mechanics must wear harnesses (as when up poles as well) and be anchored inside the bucket as part of safe operating procedure. Dual controls, one set inside the bucket and one set on the truck deck allow for easy operation. Stability legs are also used on the bucket truck. Connetics bucket truck buckets are rated at 200kg total weight.


The 'bucket truck' tool compartments

'Going hard' on the 66kV Bromley-Dallington install in the buckets

Safety harness
It's a long way up; this is not a job for people with a fear of heights!

Between the two vehicles, the Line Mechanic must be competent in:

  • Driving a HT (Heavy trade) vehicle (licence required)
  • Operating a HIAB hydraulic crane (licence required)
  • Operating a bucket truck (licence required)
  • 'Hot stick' or 'Glove and barrier' rating if working on live lines


I realise that my ASL, which was initially to gain experience in the supply industry in Cable Jointing and Line Mechanic work, has grown to actually being a recording of history. My Picasa account will have all my earthquake related photos. I'm more than happy to make them public. Institutions must make reference to CPIT if you choose to use them please.

I would like to extend a greeting to ETITO viewers, too, from the newsletter. Feel free to ask questions!

From Bedford Row, where I was when the M6.3 quake hit, with the Hotel Grand Chancellor leaning ominously behind.

Wednesday, May 4, 2011

Week 13 - Pole straightening, live line work, Bromley Substation

Apologies, I'm a week late with this post.. I attended a conference at CPIT for Trades Innovation Institute staff. I presented with my colleague Rob Mattson at this conference and we were very well received.

Previous weeks' log:

Monday 18th April: Lift and repair liquefaction-sunken pole Netley Place, Aranui.

Pole lifted

Carl and James restraining cables

Tuesday 19th April: Live line switch pole replacement 11kV, Hoskyns Road, West Melton (see analysis).

Nik and Andre in action in full glove-and-barrier kit

Wednesday 20th April: Live line switch pole replacement 11kV, West Coast Road, SH73, Darfield (see analysis).

Lines being held temporarily whilst pole is erected.

Thursday 21st April: Fill large circuit breaker terminal block with bichemical insulator, Transpower Bromley Substation.

Above Steve is bracing to secure the large cast-iron circuit breakers in case of future earthquakes. These multi-tonne machines ripped their floor restraining bolts out during the magnitude 6.3 Christchurch earthquake. 
One of the circuit breakers.
Analysis: Live line work


The possibility exists with overhead where the power cannot be de-energized. Line mechanics gain qualifications to work in these situations, two I know of are 'hot stick' and 'glove and barrier'. I have not yet witnessed 'hot stick', but I have seen 'glove and barrier' on two occasions, one at West Melton and one at Darfield. Both were 11kV and both were replacing poles with old style switching equipment with new style switching equipment.

Removal of existing pole:


'Glove and barrier' involves the use of high-voltage rated gloves, gauntlets on the line mechanics, and the use of large insulating sheets clipped to all live parts of the lines and pole. The live lines are disconnected from the pole and associated insulators whilst being held in place using a large fully-insulated extension arm attached to the HIAB crane on one vehicle. A cherry picker vehicle allows the line mechanics to work on the lines. A point of note is the last extension of the cherry picker truck before the bucket is fully insulated. All vehicles are bonded to earth and together as part of the process.

The existing pole to be replaced
The new pole (minus switchgear) to go in.

Insulators being attached

The last extension of the cherry picker 

Cherry picker bucket ready with insulated pads and clips

Earthed vehicle
Full safety harness

The boys with HV glove and arm protectors

A 'link stick' and lugall winch hold the conductors aerially using strops to prevent any chance of the live conductors dropping and contacting the ground, causing short circuits and potential 'step voltage', which could kill people near the downed conductor.

The conductors held aloft temporarily by a fully insulated extension arm on the HIAB crane

The new pole being erected. The existing pole is held vertically by a crane and cut off at the base, then carefully lowered. The underground section is excavated and a new hole for the new pole is dug.

Installing the pole


Straightening the pole

Insulating covers being attached

Crimping conductors

Insulators removed



Switch operation demonstrated by me above..

The finished product. Note restraining wire in the ground, pole identifying number, and reflector for oncoming traffic.

This process was quite difficult to photograph, as the whole point of glove and barrier is to put a barrier up, which blocks electricity and photographers!

Pedagogy:

I should point out that different electrical companies use different 'glove and barrier', and 'hot stick' procedures, and Connetics' procedures may be different to other companies' ones. This I will be taking into account when teaching. However, these procedures all contain heavy safety elements and common sense, which simply saves lives.

Consultation with electricity supply companies may enable a 'live line teaching procedure' template to be designed that will satisfy the needs of all workers. It would be a 'best practice' procedure and would have to be accepted as a training tool to be used by CPIT to train lines companies' workers.

This process could also apply to cable jointing, as seen earlier in my blog. Cable jointing relies on a 'recipe' of instruction to complete different types of joints, and an error in sequence in completing a joint can be a $1500 mistake, which is why the ability to follow procedural instruction is crucial in the electricity supply industry, and demands significant teaching focus.

Anything can be achieved with excellent safe procedures, must see video see HERE.

My time in lines is over (temporarily), I'm off to the Substations Department until later in May, when I will go back to Lines to see helicopters running lines near Lake Coleridge.

My camera in action!