What are these transformer looking things I have been seeing?

[Naithi]

Hi.
I have seen these transformer like things on the higher voltage powerlines when I go to regional areas in NSW and I was wondering what they are? I can't remember seeing them where I come from (Central Coast NSW)
They couldn't be transformers because they are not connected to any other wires.
Would love any insights.

I am just a science teacher who loves to learn what he sees

 

[westward10]

Even though in Australia I suspect @Julie. may have an idea.

 

[Julie.]

No idea actually, not something I have come across.

Lots of guesses of course!

Could be a load break switch plus surge arrestors

 

[Naithi]

Thanks for your help anyway. I can't seem to be able to upload any more pics, which might be able to show it better. this is the only one it would let me.

 

[Julie.]

Surprisingly one of my old colleagues is on shift tonight in Western Australia (Western Power), I sent him a message and he thinks it may be an SF6 load break switch by insulect (it's an Australian make).

Cannot believe he answered so quickly, he must be bored in the control room!

Gas-Insulated Load Break Switches — Insulect

Insulect’s fully enclosed, pole mounted SF6 load break switches are used extensively throughout distribution networks and are designed to be maintenance free with a long service life. Available in 12kV, 24 kV and 36kV Voltage rating with load/load break current ratings of 400 and 630 amps Faul

insulect.com

 

[Naithi]

Surprisingly one of my old colleagues is on shift tonight in Western Australia (Western Power), I sent him a message and he thinks it may be an SF6 load break switch by insulect (it's an Australian make).

Cannot believe he answered so quickly, he must be bored in the control room!

Gas-Insulated Load Break Switches — Insulect

Insulect’s fully enclosed, pole mounted SF6 load break switches are used extensively throughout distribution networks and are designed to be maintenance free with a long service life. Available in 12kV, 24 kV and 36kV Voltage rating with load/load break current ratings of 400 and 630 amps Faul

insulect.com

Oh wow! Thanks for that. I had a quick look, but it is really late here… I’ll read and process it in the morning.. ha ha..
Thanks so much for that!

 

[Naithi]

Surprisingly one of my old colleagues is on shift tonight in Western Australia (Western Power), I sent him a message and he thinks it may be an SF6 load break switch by insulect (it's an Australian make).

Cannot believe he answered so quickly, he must be bored in the control room!

Gas-Insulated Load Break Switches — Insulect

Insulect’s fully enclosed, pole mounted SF6 load break switches are used extensively throughout distribution networks and are designed to be maintenance free with a long service life. Available in 12kV, 24 kV and 36kV Voltage rating with load/load break current ratings of 400 and 630 amps Faul

insulect.com

Thanks for that Julie. I am just back from holidays, and have a bit of a chance to reflect on all the things i saw.
So basically they are used to open the circuit to perform maintenance, etc?
Is the SF6 used so that the electricity doesn't arc between connections? I actually already knew that SF6 is an important electrical insulator.

 

[ElectroChem]

Thanks for that Julie. I am just back from holidays, and have a bit of a chance to reflect on all the things i saw.
So basically they are used to open the circuit to perform maintenance, etc?
Is the SF6 used so that the electricity doesn't arc between connections? I actually already knew that SF6 is an important electrical insulator.

SF6 is used to reduce the size of the equipment. That looks like a 33kv line, maybe an 11kv. An air-break switch at that voltage would need much larger separations so would either be out in the open and subject to weather/birds etc. or much bulkier if enclosed.

 

[Julie.]

Thanks for that Julie. I am just back from holidays, and have a bit of a chance to reflect on all the things i saw.
So basically they are used to open the circuit to perform maintenance, etc?
Is the SF6 used so that the electricity doesn't arc between connections? I actually already knew that SF6 is an important electrical insulator.

Yes, they are basically a switch just for routine switching, so open for maintenance, general stuff etc, if there happens to be a fault on the line it can close safely, but cannot open or disconnect in the case of a fault. - it's the closest thing to a light switch! You open and close as you need to but in the event of a fault it isn't the light switch that opens, it's the breaker upstream (in your main panel at home)

SF6 is used as it's both a better insulator than air, but also quenches the arc better than air.

Traditionally high and medium voltage switchgear tended to be oil filled - however although there are some advantages, the resulting explosion in the event something goes wrong internally is a huge bleve - this fireball can be very destructive so the trend is away from oil to SF6, or vacuum equipment.

 

[Naithi]

SF6 is used to reduce the size of the equipment. That looks like a 33kv line, maybe an 11kv. An air-break switch at that voltage would need much larger separations so would either be out in the open and subject to weather/birds etc. or much bulkier if enclosed.

Makes sense. Thanks for your reply

 

[Naithi]

Yes, they are basically a switch just for routine switching, so open for maintenance, general stuff etc, if there happens to be a fault on the line it can close safely, but cannot open or disconnect in the case of a fault. - it's the closest thing to a light switch! You open and close as you need to but in the event of a fault it isn't the light switch that opens, it's the breaker upstream (in your main panel at home)

SF6 is used as it's both a better insulator than air, but also quenches the arc better than air.

Traditionally high and medium voltage switchgear tended to be oil filled - however although there are some advantages, the resulting explosion in the event something goes wrong internally is a huge bleve - this fireball can be very destructive so the trend is away from oil to SF6, or vacuum equipment.

Interesting about the oil. Thanks for your reply.
Thank you so much for discussing this with me.