voltage drop due to high consumption?

[notrub]

We have been exchanging ideas about AVR units.  Rather, some of you have been helping me to understand that they exist and what they do.  Thank you.  We have getting between 145 and, this AM 175, volts arriving at our house.  There are a number of households along this same wire (that runs along our lane) who are having the same problem.  Uncle, who works at the PEA is writing a letter stating this fact to his boss and listing 6 households suffering from low voltage.  They might install a transformer or other device or do something to raise the volts supplied.  What, I don't know.

 

One fellow, up the road from us (closer to the main power lines) uses a lot of electricity with 6 or more AC units running all day and more other devices too.  Can his high use of electricity cause our voltage to drop at our home further down the line?  He is considering putting in 3 phase and Uncle is now saying that once he does (and stops drawing off the line in the lane) our voltage will go back up to 220.  Is this true?

 

The PEA has extended the line beside our house several KM to provide service for farmers a bit out of town.  They have not installed any transformers or other equipment as part of this line extension.  These farmers at the end have low voltage too and cannot use their well pumps.

 

I don't really believe the story about one household using all the volts, like water in a pipe, and so we don't get the full 220 as a consequence.

 

As usual, thank you for any comments you may have.

[sometimewoodworker]

3 minutes ago, notrub said:

One fellow, up the road from us (closer to the main power lines) uses a lot of electricity with 6 or more AC units running all day and more other devices too.  Can his high use of electricity cause our voltage to drop at our home further down the line? 

It certainly can

 

3 minutes ago, notrub said:

He is considering putting in 3 phase and Uncle is now saying that once he does (and stops drawing off the line in the lane) our voltage will go back up to 220.  Is this true?

Probably no as your line voltage is extremely low, but you could get lucky and the PEA may switch you to a different phase.

[Crossy]

A big consumer on the same line will certainly pull your supply down.

 

Is your 145-175V constant or does it actually achieve something sensible at times (middle of the night)?

 

If the big user goes 3-phase his load should split to 30% on each phase and reduce the drop, you may or may not then achieve 220V.

 

Having someone inside PEA is certainly an advantage.

 

[sometimewoodworker]

24 minutes ago, notrub said:

I don't really believe the story about one household using all the volts, like water in a pipe, and so we don't get the full 220 as a consequence.

You are partly correct also partly wrong.

 

One household will not be getting 220v while others get less. But when the load is high enough (it doesn't take very much) it will pull the voltage down for all the users. On my supply each 20A load pulls the voltage down 10V so I can potentially pull the line voltage down by 50V, and there are others on this phase.

Edited July 20, 2019 by sometimewoodworker

[farmerjo]

We are on the end of a line,during night with a couple of a/c's going we can drop to 175 volts.

Most times with light loads we achieve 220 volts.

We have a manual step up transformer dedicated for the bore pump,during the heat of the day,even if i set it to 300 volts it drops to 150 volts and won't start the pump some days.

I have other issues with distance from transformer and cable size from meter to house.

Trying to get a resolution with PEA on their side before spending on my side but taking longer than expected.

We have a little 1kva generator in the meantime as handy if power down or out and you want to run the water pump for a cold shower or keep the tele,internet,drinking water cooler and some fans going. 

Edited July 20, 2019 by farmerjo

[tjo o tjim]

@FarmerJoeThe AVR route is likely your best solution if you get 220V at times.  I would expect that PEA won’t do much for 175V periodically.  145V from the OP is much more serious and shows a real problem.

[xtrnuno41]

Probably old system, from a time where not many people had power consuming devices . like  airco's.

Now it changed, there are more on the line (you said they extended the cable) and more power consumption in devices.

Engineers should recalculate due to modern times and fix the installation now.

IN old times it was enough maybe, but now it fails.

New transformer or seperate transformers for every house and maybe adjust cables, bigger diameter.

The higher the voltage, the less power loss you have. Thats why they transport electricity up to millions of volts in some cases. YEs, we have power cables from one country to another with these voltages.

THen bring it back down to lower voltage by transformers, eventually  220 volts in houses.

 

I dont know how all is connected in the place where you are, if there is a city or village with way more connections all consuming more then in the older days.

If they calculated in old times with almost no power consumption and it grew in time, the installation is not working anymore and many people will suffer from power loss. If they acted right, as it should have been, they anticipated on this and keep the installation in right conditions and renew it. Guess they didnt do, as maintenance and updating costs money. ALready seen in Thailand , maintenance and/or renewing has not the highest priority. 

 

Also cables, which material it is, pure copper cables or a compound one?

Compound is cheaper but not better, copper is best economically if you can afford. 

 

Now and then you read here about people being electrocuted, this is due to unsafety house

switch board with big sized fuses, no ground , no rcbo's (or so).

Devices working on 220 volt can break up or even dont work at all, as the power is too low.

When it is always "on" (like a fridge) , it can switch to work and stop again auto by changing power inlet. It can finally break up, long run or short run.   

Never under estimate electricity, you cant see it, but it can kill you !! ALways be aware, it can also overload a device an start a fire.

 

Electricity is like water in the pipe. 

IF everyone just uses a little water, little side pipes and pump capacity calculated on that, it will work. The one in the beginning of the pipe does have the most advantage, but capacity of pump is right calculated and others can also profit.

IF one decides to have more pipes or bigger ones and use it,  he will use more and drains the pipe, so others cant have anymore, the flow for others, get less. When you are in the beginning of the pipe, you have the most advantage. The pump is too little for the amount asked. 

[farmerjo]

5 hours ago, tjo o tjim said:

@FarmerJoeThe AVR route is likely your best solution if you get 220V at times.  I would expect that PEA won’t do much for 175V periodically.  145V from the OP is much more serious and shows a real problem.

Thanks tjo o tjim.

A few questions in regard to the AVR

As i get 220 volts to say 2000 watts usage before drop off.(assumption)most of the time.

I could upgrade my meter to home line from 25 to 50mm aluminium which according to calcs would give and extra 17 volts at 8000 watts giving 199 volts at approx 25,000 baht for materials and labour.

Left at 25mm aluminium  8000 watts the volts would drop to 182 volts.

I would see more than that in actual 8000 watt usage if i could ever get to that.

I've read the bigger the AVR the less they have to work.(?)

So if the safest and most reliable way was to purchase a 30kva single phase unit i don't mind the extra expense between a 20 and 30 kva unit.

The problem is i need an outdoor unit as my main cable goes off to 5 different 63amp breakers.

1 kitchen/sala

2 inside old house

3 bore pump at old house with 2 a/c's direct off that line.

4 shed

5 new house

My meter is a 15/45

 

So what options would be best to take.

-Deal with PEA to help with my meter side problems

-Involve a company like CBC to come and install there Full intelligent transmission system

-Just upgrade my cable size and live with lower volts but more wattage

-Try and find an outdoor 30 kva AVR and install locally. 

 

Thanks for replies,my patience is wearing thin with the PEA.

 

[GalaxyMan]

I get the same thing here in Samui with regularity. The voltage drops about half for up to 3-4 hours, usually during the day. Fans will almost turn, lights won't work, etc. The 30K I spent to have a 5.5kvh generator installed has been money well spent.

[Crossy]

21 minutes ago, farmerjo said:

So what options would be best to take.

-Deal with PEA to help with my meter side problems

-Involve a company like CBC to come and install there Full intelligent transmission system

-Just upgrade my cable size and live with lower volts but more wattage

-Try and find an outdoor 30 kva AVR and install locally. 

 

Fixing the supply is always the best option. But I fully understand the PEA patience issue.

 

I would upgrade the cable first, every volt you can get at the end of the run is a volt that you don't have to create with your AVR.

 

You'll likely end up building an outdoor enclosure (shed) for the AVR. I've not seen any truly outdoor units.

 

I wouldn't go larger than double your maximum anticipated load, losses also increase with the size of the AVR.

 

[tjo o tjim]

29 minutes ago, farmerjo said:

Thanks tjo o tjim.

A few questions in regard to the AVR

You need to look at the big picture to know where your money is best spent— how big is the PEA transformer, how long are the lines from the transformer to your meter, how many customers on the line, and how long is your run from the meter to home?

 

If the transformer itself is badly overloaded, replacing your feed from the meter isn’t going to do much.  If the transformer looks ok, and most of the voltage drop is along the PEA lines then that becomes the most economical place to upgrade.

 

Do you have any idea what your maximum current is when you hit 175V?  If you are above about 50A, then upgrading your line downstream of the meter would make sense. 

 

As for AVR models, @Crossy is the expert.

[millymoopoo]

The primary factors effecting voltage drop are:
Load.

Distance.

And cable thickness/quality.

If you are at the end of long run from the transformer on a thin wire with many houses connected to it, you're going to get rather sever voltage drop.

Upgrading the service to a thicker cable will help, as will moving some of the houses over to a different phase.

Installing a new transformer closer would be the best and most expensive solution.

[Odin Norway]

I had the same problem being 300 meter from the main line. PEA use 25mm alu cable into most meters and that should be good enough.Unless you want to pull 100 amp or more. I installed a AVR from global on 75 amp.That took care of my problem easy for less then 20k.Before I got it I changed a lot of lightbulbs.Power-supplies and fans don't like low voltage either.

[emptypockets]

7 hours ago, farmerjo said:

Thanks tjo o tjim.

A few questions in regard to the AVR

As i get 220 volts to say 2000 watts usage before drop off.(assumption)most of the time.

I could upgrade my meter to home line from 25 to 50mm aluminium which according to calcs would give and extra 17 volts at 8000 watts giving 199 volts at approx 25,000 baht for materials and labour.

Left at 25mm aluminium  8000 watts the volts would drop to 182 volts.

I would see more than that in actual 8000 watt usage if i could ever get to that.

I've read the bigger the AVR the less they have to work.(?)

So if the safest and most reliable way was to purchase a 30kva single phase unit i don't mind the extra expense between a 20 and 30 kva unit.

The problem is i need an outdoor unit as my main cable goes off to 5 different 63amp breakers.

1 kitchen/sala

2 inside old house

3 bore pump at old house with 2 a/c's direct off that line.

4 shed

5 new house

My meter is a 15/45

 

So what options would be best to take.

-Deal with PEA to help with my meter side problems

-Involve a company like CBC to come and install there Full intelligent transmission system

-Just upgrade my cable size and live with lower volts but more wattage

-Try and find an outdoor 30 kva AVR and install locally. 

 

Thanks for replies,my patience is wearing thin with the PEA.

 

Deal with PEA initially.  You can't get something for nothing. 

[wilailuk]

"Deal with PEA"??

 

I gave up, they demanded signed letters from the whole Moo Baan that we wanted more power, the puu yai baan didn´t want to organize that work, kikiat I guess, so I bought a cheap manual voltage regulator (4.500 THB) - and I go out at night from 19 to 23.00, where the power is really low, and turn it up a few notches if needed.. wonderful life in bannok.. always something to do! 

Edited July 20, 2019 by wilailuk

[Crossy]

Doncaster Cables have a handy volt-drop / cable size calculator http://www.doncastercables.com/technical-help/

 

Note that this is intended for copper cable, if you want to use the much cheaper aluminium cable you need to go one size larger than the calculator indicates.

[farmerjo]

http://www.cbcinter.co.th/voltage-drop-calculation-online/

 

This is another good one.