AVR/GENSET

[carlyai]

Now that I have been up coutry for some months, I think I need to look at some form of voltage regulation on my incoming supply, and also a gen set when the supply fails.

Context: I have planned to have a 3 phase input to my consumer box (had a lot of feedback and got some great answers in a different post with this forum), the house roof tiles are nearly going on, so I thought I might try to add AVR to start with or to leave a space in the consumer box for AVR if possible. The three phase incoming supply is run to 3 seperate breaker sets, each protected by a residual current device (as discussed before in another post).

I would need 3 seperate AVRs for my set up i think. I think I may need this as sometimes when we have electrical storms near our area the voltage drops and the fans slow and everything seems to 'groan'. Are there consumer type AVR's that I could fit in my set up, ie in my consumer unit, or are they too large and I would need to locate them somewhere else? Any suggestions?

Also, because we don't want to go into Mukdahan to pick up supplies weekly, I plan on having a freezer in the house. When the incoming power fails for extended periods I would like to have alternate power available. At the monent ( because I have given my builder enough headaches with the electrics), I just thought I may be able to by a manual switch that I can throw that will disconnect the 3 incoming phases and then connect to 1 phase that supples the freezer, some lights and fans. From the forum it seems that the Chinese brand gen sets are a bit noisy, so was thinking a honda of the correct VA to supply my alternate power.

In the future I would like to set up the gen set correctly with ideas expressed in the forum on auto stop etc, but at the moment just want to plan for AVRs and switch for back up power.

Does this sound OK? Or should I just have a gen set outside with a cable to the freezer?

[thomasteve]

Definitely won't fit in the consumer unit !! as they are larger than an old desktop PC - there's a picture of one in another thread.

[carlyai]

OK thanks. Thought they may be large, but we're building a large consumer box outside, so still might be able to put them in it if i let the builder know.

Sorry, can't find the avr picture thread, any clues as to where it is?

[Carib]

OK thanks. Thought they may be large, but we're building a large consumer box outside, so still might be able to put them in it if i let the builder know.

Sorry, can't find the avr picture thread, any clues as to where it is?

Here is one

http://www.thaivisa.com/forum/topic/671566-voltage-drop-solved/

[Carib]

And here is an already archived but interesting topic about generators.

http://www.thaivisa.com/forum/topic/309747-Generators-Thailand/

[IMHO]

First off, you can get 3-phase AVR's, so you can get by with a single unit. As noted by thomassteve, these things are *huge* though - my single phase 20kva one is actually around 2x the size of a desktop PC and weighs around 80KG (not a misprint).

As for the genset setup, here's what I'd suggest:

3 phase mains > 3 phase stabilizer > phase 1 > Transfer switch/genset > Consumer Unit A

.......................................................... phase 2 > Consumer Unit B

.......................................................... phase 3 > Consumer Unit C

Your 'critial' appliances would then be wired into CU A, so they are genset backed.

Also, if your mains supply is susceptible to only having 1 or 2 phases go down, another possible solution is to have 3x power outlets for the freezer - one from each CU/phase - so you can plug it into a phase that still works.

[carlyai]

Great, thank you for these threads. Just on the 'voltage drop solved' thread, any idea of the 'low volts cut off ' circuit diagram or suppliers in thailand.

IMHO can you give me a link to a transfer switch as am not sure what to ask for or exactly what it looks like, if i buy one.

Thanks for your help. I looked around (not enough obviously) and searched AVR in the search area but did not find these threads that answer my questions, in the future how do i find relevant threads without asking and taking people's time?

[Crossy]

For undervolt relays we have a couple of these http://www.gencontrol.co.uk/single-phase-voltage-control-relay-zhrv5-02-a220.html I did get them from the UK, but probably available from your local wholesaler.

Gencontrol also do automatic transfer switches and (if you're a bit handy) the bits to make your own (much cheaper). Their shipping rates to Thailand, at least for smaller items, are very reasonable.

If you don't mind manual transfer your local wholesaler should have suitable rotary switches.

Have a look at this thread for some DIY ideas for keeping the cost down http://www.thaivisa.com/forum/topic/671221-build-a-low-cost-semi-automatic-generator-transfer-switch/

For your freezer, if you follow IMHO's idea of having 3 outlets on different phases, knock up something like this with 220V relays and you don't have to worry which phase is on.

That's the poor man's version, without undervolt relays the relays tend to stay on even if the supply is very low, rich man's version coming soon.

EDIT Rich man's version, much more expensive as it uses 3 undervolt relays, but would be more reliable if long term low voltage is an issue.

EDIT 2 Actually, you could save some money by omitting the leftmost undervolt relay (K1) and connecting K4 as in the poor man's version.

[Crossy]

Forum sponsor Genset is worth a PM, his website is here http://www.generatorsolutions.org/

Sadly Genset has not been online for 12 months, I suspect far to busy with his 'real' job.

[carlyai]

Thanks Crossy.

Am I correct in thinking that when the voltage on any/all of the phases dips and my avr starts to hum away and draw more current to keep up the 220v, I'll be taking current away from my single phase 5A meter neibours. So that every time they hear my back of house start to hum and their fan stops turning, eventually they will figure it out that the Big Buffalo Falang is causing us problems and they might start throwing rocks at the chickens.

So I should install an avr, so that I don't brown out any of my electrical gear, but have to know somehow when I am going to cause neibours problems so that I can turn off my gear.

Hope that makes sense. Must be an under voltage buzzar or something that can be set. I want to protect my gear but not at the expense of unhappy neibours.

[Crossy]

Yes, the AVR will pull more Amps from the supply to maintain the output voltage, you can't get more power out than you put in.

They do hum, but not loud enough that the neighbours will hear

You don't need to AVR everything, lights don't need it (if you don't mind the occasional flicker), water heaters don't need it either. So if you can split your loading (easier on a new install) you can get away with a smaller unit.

We have a baby (2kVA) AVR which does the technology and inside lights (all low energy, they don't need the AVR but we also have a big UPS on the same circuit).

The aircon is not on the AVR but does have a low-voltage cutout (one of the units I linked to) so that they get switched off if the voltage goes below 190V or over 240V, we can survive on fans during the brown outs (I don't run the genset at night so the UPS keeps the fans going).

[IMHO]

Thanks Crossy.

Am I correct in thinking that when the voltage on any/all of the phases dips and my avr starts to hum away and draw more current to keep up the 220v, I'll be taking current away from my single phase 5A meter neibours. So that every time they hear my back of house start to hum and their fan stops turning, eventually they will figure it out that the Big Buffalo Falang is causing us problems and they might start throwing rocks at the chickens.

So I should install an avr, so that I don't brown out any of my electrical gear, but have to know somehow when I am going to cause neibours problems so that I can turn off my gear.

Hope that makes sense. Must be an under voltage buzzar or something that can be set. I want to protect my gear but not at the expense of unhappy neibours.

If your neighbours have 5/15 meters, they don't have anything that draws enough current for voltage drop to really effect them - at most they might have a small 3-3.5kW heater and the water temp out of that varies wildly with the inlet temp anyway... And which blows their fuse/breaker everything someone turns on the microwave at the same time

Pretty sure they are all already quite used to the lights flickering - you didn't create the voltage drop problem after all

[carlyai]

Sorry internet trouble. Thanks for that. I tried to get onto Kelenor.com from a link the forum gave me, the link works but they didn't reply to my email. I supose I'm looking at a 6kva 3 phase avr if I go that way.

Kelenor has a 6 KVA for B13920. Does anyone know if they have suppliers in Pattaya or Bangkok? I've got to go down tomorrow and sort out something on Monday at the port. (TIP: If for some reason you decide to buy a gas log fire from china, don't mention the 'remote' as they want B24000 for input duty, remote was the key word I think meaning 'luxury goods').

If I can just wander a bit, the Thai electrical system seems very robust and judging from all those phases strung up on bamboo poles around the place, it needs to be. I live about 20 km from Kuchinari, and there must be a power sub station somewhere around there but havn't seen one, so I would guess a main sub station is in Kalasin, only a guess. Would I be correct in thinking that if I put my dark glasses on and shorted a phase (bang active and nuetral together), and kept it shorted that nothing would happen, as far as that phase 'tripping out', for a while. Every storm they must get lots of near short of s/c on their power lines, and if the reasonable quick s/c caused the sub station to 'trip' then the system wouldn't work too well.

I know of a place in Australia where they had a lot of power trouble with bats getting strung across a phase, so they would, hit the power up two or three times, and if it was a bat this would normally fix the problem. Bad luck if it was your grandmother across the phase.

How do they manage the power in remote Thailand without it tripping out all the time?

[IMHO]

Sorry internet trouble. Thanks for that. I tried to get onto Kelenor.com from a link the forum gave me, the link works but they didn't reply to my email. I supose I'm looking at a 6kva 3 phase avr if I go that way.

Kelenor has a 6 KVA for B13920. Does anyone know if they have suppliers in Pattaya or Bangkok? I've got to go down tomorrow and sort out something on Monday at the port. (TIP: If for some reason you decide to buy a gas log fire from china, don't mention the 'remote' as they want B24000 for input duty, remote was the key word I think meaning 'luxury goods').

If I can just wander a bit, the Thai electrical system seems very robust and judging from all those phases strung up on bamboo poles around the place, it needs to be. I live about 20 km from Kuchinari, and there must be a power sub station somewhere around there but havn't seen one, so I would guess a main sub station is in Kalasin, only a guess. Would I be correct in thinking that if I put my dark glasses on and shorted a phase (bang active and nuetral together), and kept it shorted that nothing would happen, as far as that phase 'tripping out', for a while. Every storm they must get lots of near short of s/c on their power lines, and if the reasonable quick s/c caused the sub station to 'trip' then the system wouldn't work too well.

I know of a place in Australia where they had a lot of power trouble with bats getting strung across a phase, so they would, hit the power up two or three times, and if it was a bat this would normally fix the problem. Bad luck if it was your grandmother across the phase.

How do they manage the power in remote Thailand without it tripping out all the time?

Mains cables in TH are insulated.. not sure about AU.