More Main Line Questions

[farmerjo]

Putting up another house next to old one,get by with power at the moment but fear for communication between the two with appliances.

Before going to the PEA i just want to clarify a couple of things.

Can someone identify in  pictures

Is this 3 phase power to my meter consisting of 2 x 50sq and 1 x 25sq cables?

Does anyone know what the silver device is at the bottom of transformer pole?

Thanks.

 

 

  

[KhunBENQ]

It's not 3-phase power.

Ordinary transformer (45 kVA?) for one phase plus neutral.

Also only two wires for the high voltage on top.

 

I don't know what the device left of the meter is for.

I see similar devices here. Something to monitor/raise alarm?

Bet someone knows or take a closeup picture.

[sometimewoodworker]

1 hour ago, KhunBENQ said:

I don't know what the device left of the meter is for.

I see similar devices here. Something to monitor/raise alarm?

 Bet someone knows or take a closeup picture.

It has a daylight sensor on the bottom so is likely to be the power supply for the street light.

[farmerjo]

So in the top picture on top left the two top lines are the 50sq cables for single phase power to meter.

What is the 3rd 25sq cable for?

The 4th small one is my fibre optic for internet.

[Crossy]

44 minutes ago, farmerjo said:

What is the 3rd 25sq cable for

 

Switched hot for the street lighting?

 

Only two 25kV lines, so no possibility of 3-phase, hope that transformer is big enough.

[carlyai]

So in the top picture on top left the two top lines are the 50sq cables for single phase power to meter.
What is the 3rd 25sq cable for?
The 4th small one is my fibre optic for internet.

As a rough guess it's the feed going up the pole to another donga out to the right.

Sent from my SM-J700F using Tapatalk

[farmerjo]

6 minutes ago, Crossy said:

 

Switched hot for the street lighting?

Thanks guys,the street lighting makes sense.

Okay so in my thinking besides going from 25sq to 50sq from meter to house(600 metres) to help with voltage drop.

The PEA would have to bring the main overhead line down my road and place a transformer at my gate 

for any real improvement?. 

[Crossy]

5 minutes ago, farmerjo said:

Thanks guys,the street lighting makes sense.

Okay so in my thinking besides going from 25sq to 50sq from meter to house(600 metres) to help with voltage drop.

The PEA would have to bring the main overhead line down my road and place a transformer at my gate 

for any real improvement?. 

 

A 600m run is a loooong way at 220V. The Doncaster Cables calculator suggests 150mm² for 45A and 5% drop.

 

Running tall poles and a local transformer is the best answer, but it's going to cost $$$ ????

 

Really fat aluminium cable, say 185mm² (about 22mm overall outside diameter), would be cheaper and easier as you wouldn't need new poles.

 

[farmerjo]

47 minutes ago, Crossy said:

 

A 600m run is a loooong way at 220V. The Doncaster Cables calculator suggests 150mm² for 45A and 5% drop.

 

Running tall poles and a local transformer is the best answer, but it's going to cost $$$ ????

 

Really fat aluminium cable, say 185mm² (about 22mm overall outside diameter), would be cheaper and easier as you wouldn't need new poles.

 

Thanks Crossy

Looks like a dogs breakfast to sort. 

I've included a diagram to show where the cables go after transformer(30KVA)

I think the cable is standard PEA cable 50sq?

There are roughly 80 households feeding off the routes.

So is this the 2 options.

Extend main line(the 2 x 25kva lines)old transformer to here and new transformer.(dotted line)

All the pre exsisting routes stay on old transformer and new one for me and further expansion in the future.

Or i just replace my meter to house run from 25sq to 185sq and still maybe incur voltage drop from there 550 metre run from transformer.

Other options?

Roughly talking with PEA serviceman before he was talking about 100K for 30 KVA transformer.

Hope i haven't confused things to much.

 

 

[farmerjo]

On 5/20/2019 at 2:38 PM, Crossy said:

 

Switched hot for the street lighting?

 

Only two 25kV lines, so no possibility of 3-phase, hope that transformer is big enough.

One last question if i may as i'm mechanical not electrical especially high voltage.

You say hope transformer is big enough.

Would the PEA know what size transformer is actually needed for village and allowing for future growth if the current 30KVA is under the pump.

Say i helped change that 30KVA to a 50KVA,would that be a long term solution or would there be a cut off point where the two main 25 KVA would have to be upgraded eventually.   

[Crossy]

PEA would have used their "standard" small village transformer when they installed. There was likely some headroom but they wouldn't see the investment in a well oversized unit as money well spent.

 

What will happen is the load will continue increasing until the transformer can't cope and people start complaining about low power, at which point PEA may do something. By that time a small jump to 50kVA wouldn't be worth the effort, so adding a third line to the 25kV, installing a 100kVA transformer and re-jigging the village distribution system to be 3-phase would be the route.

 

As to your problem. How much of an issue is volt-drop currently? You can get some idea where the drop is occuring with a decent load (water heater). Measure the voltage at your incoming breaker, turn on the heater, measure the voltage again. Then do the same measurment at your meter (get someone in the house to turn on the heater). You can then see just how much of the drop is occurring in your 600m run and determine if just replacing that run with a fatter wire (or doubling up on the existing ones) will be worth the effort.

 

A thought. Adding another pair to your 600m run (so 4 wires total) would have the advantage that, should 3-phase become available in future, you already have the necessary wires to the houses.

[farmerjo]

3 hours ago, Crossy said:

PEA would have used their "standard" small village transformer when they installed. There was likely some headroom but they wouldn't see the investment in a well oversized unit as money well spent.

 

What will happen is the load will continue increasing until the transformer can't cope and people start complaining about low power, at which point PEA may do something. By that time a small jump to 50kVA wouldn't be worth the effort, so adding a third line to the 25kV, installing a 100kVA transformer and re-jigging the village distribution system to be 3-phase would be the route.

 

As to your problem. How much of an issue is volt-drop currently? You can get some idea where the drop is occuring with a decent load (water heater). Measure the voltage at your incoming breaker, turn on the heater, measure the voltage again. Then do the same measurment at your meter (get someone in the house to turn on the heater). You can then see just how much of the drop is occurring in your 600m run and determine if just replacing that run with a fatter wire (or doubling up on the existing ones) will be worth the effort.

 

A thought. Adding another pair to your 600m run (so 4 wires total) would have the advantage that, should 3-phase become available in future, you already have the necessary wires to the houses.

For run of the mill power we can get by ok if we stagger using appliances.

Like now with house construction,only fans,fridges tv and internet while welding machines are being used,after working hours we can pump water from bore then start 2 inverter air cons,outside lights and water heater at half dial(1800 watts)

Now  the PEA worked on the transformer the variac is working fine for the bore pump,they did a test at meter with variac on and off and the volt drop was only 6 volts.(tap set at 4 out of 10 on variac dial)

Have not done one for normal usage ie hot water.

The new(small) house will have 1 hot water,tv,3 fans,5 lights and possibly a air con if the qcon bricks aren't cooling enough. 

When the new place is up and running i will monitor and if so do as you suggested and double up the cable size as i have more than half the spare cable already.A neighbour between me and my meter has applied for a grant so the main low voltage may end up as close as 300 metres to house but there's a sticking point there as they want to use my poles but i want them back(private made concrete) so i'm not a libility on that section of line so can't see it happening in the short term.

When we moved here there was only 10 houses(that's why i was allowed such a long cable run) but a couple of years ago they made us our own village so progress is moving quickly.

Thankyou for advising about double cable and not to throw good money after bad with the PEA.

That will have to be a community effort to get the 3 phase here. 

 

[carlyai]

Farmerjo wrote: 'possibly a air con if the qcon bricks aren't cooling enough.'

My shed is built from 10 cm QCon blocks and insulated roof, but it still gets hot inside. I think you plan for an aircon, and if you don't need it, no worries. Better to go over than under in your plans.

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[farmerjo]

Ok one last last question????

I've decided to shift a couple of power poles away from the new build so will have to lengthen the power cables an extra few meters.

I have read a lot of you guys are using AVR's for incoming voltage regulation.

I have this step up transformer i use purely for the bore pump(off the mains),we turn the dial to number 4 and it stabilises the power enough to start the pump.

My question is can i move  and connect this to the main lines coming in before the breakers and just leave it set on a setting say 4 and leave it running 24 hours a day.There is a small fan in the top which i could see  failing after time.

Every appliance could benefit from it,ac's,hot water(ok?) microwave,etc rather than just the bore pump.

Is it worth a trial?

Do other people use this type of setup?

 

 

   

 

[farmerjo]

Ok disregard last post.

Will leave as is.

Found an old closed topic from 2009.Took some readings on step up transformer on bore pump.

And as mentioned in there the supply voltage would be to high to leave on all the time.

 

 

 

[farmerjo]

Called into local PEA on way back from town today to ask if it was ok to run 2 extra cables from meter to house to increase cable size and lessen volt drop.

They basically said it would not make any difference.

The good news is he was straight on the phone to the bigger office and according to him there coming out next week to install another transformer as part of the planned upgrade.

So we will go from there....

[TheMysteriousMrTesla]

Do let us know how you get on. These things are all good fun ????