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Devaka Cooray
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I live in an area where there is a bunch of sneaky people who illegally use their domestic power line for industrial purposes, like welding and grinding. That sucks up a lot of current in a sudden, causing the transformer to saturate, which results in voltage fluctuation in the whole area. If I look at an incandescent bulb, it appears to slightly flicker in a continuous fashion. When they do their welding stuff, the fluctuation goes deeper making the bulb so dim for about one second per five seconds or something. I'm not sure if you guys are getting a clearer picture of what I mean, so I made this little animation:



This is how bad the power supply here is. I have a large bunch of highly sensitive electronics connected to the line, and I worry that this fluctuation will eventually cause a lot of damage to them. I can even see some signs of damages coming up with this. For example, my LCD monitors get turned off for a second or two, and the air conditioner (it's an inverter-style one) makes a weird sound (the spark kind - not the motor kind) when the level of fluctuation goes up.

I wonder if there could be a way for me to overcome this fluctuation with some sorta electric set up? I have about 6kW of sensitive electronics, but if I can protect at least a load of 2kW, that would be sufficient. I can even knock it down to 300W if there is no better solution.

What if I install a small capacitor bank? Is that something anyone has ever tried for domestic use?
What if I use a little transformer which makes a DC 12V, and then I use another transformer to invert it up to AC? Would a little capacitor attached to the DC line do the trick?

Any better suggestions?
 
Rebecca Norman
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Hi Devaka, I live in a region where the mains supply is like that too. Years ago, we watched as the voltage, normally like 80 so we had a voltage booster to the normal 220, suddenly went up to almost 400. The incandescent bulbs got brighter and brighter and then made a final popping noise and died. Luckily we didn't have any computers plugged in or they would have died. I've heard this can happen when another branch of the wiring in your neighborhood suddenly gets cut. Anyway, it's pretty dangerous and a pain. Do those "surge protectors" actually work at all?

Living at our school, which has off-grid solar electricity, we don't have much fluctuation. I wonder if you could run your mains power through a UPS with a battery and inverter, and the inverter might give you more stable power than the mains. And would help in case of a power outage.

But I'm not an electrical person at all so this is just an uninformed suggestion of something to possibly reearch.
 
Steve Farmer
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You'd need 2.4KW thru your 12V DC to get 2KW after stepping up and inverting.

That's 200A. So a "little capacitor" wouldn't last long. A car battery across the 12V would smooth the power dips and handle 200A in short bursts.
But if you've got sensitive electrical equipment you are going to need quite an expensive sinewave inverter.

You could put your power thru a UPS. Those aren't cheap either but I think will be cheaper than the inverter.
If it's DC equipment you are trying to protect then these already have rectifiers in their power supplies, which provide some basic smoothing. For instance if you are concerned about computer servers, you might be able to switch out a $20 power supply unit and replace it with a $50 unit that provides better protection. Better still use a chassis that has dual redundant power supplies and plug each one into a different phase on your domestic supply.

I'm confused as to what you are trying to protect against. If the power is not surging, only dropping, then what is the risk of damage? Why doesn't the "offender's" domestic supply trip out? Have they illegally modified it in some way? Its worth taking the issue up with your electricity supplier, they may be able to put you on another phase so you won't be affected by one specific problem neighbour. Maybe you already have more than one phase to your house and simply switching to a different outlet in another part of the house will solve this?
 
Devaka Cooray
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Steve Farmer wrote:I'm confused as to what you are trying to protect against. If the power is not surging, only dropping, then what is the risk of damage?

Yes, it's only dropping. I don't know much about the electronics to say what kind of affection it has, but I read that rapid fluctuations are not good for digital electronics. I was told the same when a Panasonic crew came here to do their maintenance stuff on the air conditioner. Could that all be just a myth? But then I think about it, if it doesn't cause any damage, why does the LCD monitors turn off rapidly? And why does the air conditioners making a weird sound when the fluctuation happens?

I have been taking it up with the electric company for more than a 5 months now. I gave it up after I realized it simply is not going to work out. From what I heard from the electric company, the offenders are doing that illegally, sucking up power bypassing not only the circuit breaker but also the meter! The electric company even revealed it to me that there are about eight places in our area where people are doing this. For a weird set of reasons, taking it up with the electric company simply doesn't work.

And I did have three UPS devices. All of them work on mechanical relay switches, and when there is a drop of voltage they turn the relays on and off, trying to deliver the optimal voltage. The problem with that is when fluctuation goes on, it happens so rapidly (see the animation I added in my first post in this thread), making the relay switches jiggle like a rap! After about two month, one of my UPS stopped working, giving me an error which says it got a malfunctioning relay. The second UPS has been running for about a little more than a month and suddenly stopped running giving me a "general error". I'm now running on a third UPS and I worry foreseeing it will stop working soon too. Any thoughts on modifying the UPS in a way that I could embed some capacitors somewhere, so the burden would be on the capacitor instead on the relays?

If it's DC equipment you are trying to protect then these already have rectifiers in their power supplies, which provide some basic smoothing.

Thinking about electronics that run on AC, the main things I want to protect are a bunch of LCD monitors and air conditioners. I guess the LCD monitors converts AC to DC internally?? How do you suggest I would protect these equipment anyway?

You'd need 2.4KW thru your 12V DC to get 2KW after stepping up and inverting. That's 200A. So a "little capacitor" wouldn't last long.

Uh oh! How did you obtain the 2.4 kW ?

And if I cut it down to 300W AC, would it be 360W through the DC line? In which case it would be 30A? That still sounds like a lot of current! Does that also mean I need to get a 30A transformer to generate the 12V 30A power it takes?


 
John Polk
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For a weird set of reasons, taking it up with the electric company simply doesn't work. 

Yeah.  "Somebody" is probably receiving a 'gift' for turning a blind eye at the problem.
 
Rufus Laggren
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Maybe first, before spending time "solving" the problem, determine which items are truly in danger. And what type of power problems will actually cause damage. Information might be available from the manufacturers or from knowledgeable repairman (if you can find them near you or on the net). There are forums where engineers talk casually about their problems where you might ask about the actual damage certain equipment is likely to encounter.

To think about a solution, it's important to have a budget. What is it worth to you to "take out insurance" on certain items? This is _the_ controlling factor when trying to solve problems. If you don't have two nickles to rub together that makes things very simple, eliminating a whole lot of options.

It sounds like you have prioritized somewhat, so you know the proper order. Eliminate items which your research says won't be troubled too much by bad power. What's very easy (cheap) to do? Do it. Like unplugging certain items during times when the power is bad. (You have determined what times the power is usually bad, right?)

Batteries are nothing but a really big capacitor. You can place a battery bank between the "grid" and your loads. But you need a very good battery charger, capable of operating _properly_ on the power levels you are experiencing and also of continuously (more or less) charging the batteries you use safely. Poor charging kills batteries very quickly and you will essentially be charging all the time because your want to draw 3000+ watts yourself. That is a particular set of requirements that will dictate what equipment you need.

The load side of the battery bank ("your" side) will need an inverter, again 3000+ watts. This is a safer electrical environment so it will be easier to find. Except that you want to know if you need a good sine wave or whether old school inverters will work. Sine wave inverters cost more.

The batteries will need some kind of maintenance, at the very least weekly checkups but probably much more - especially if you use the standard lead-acid car, lift truck, golf cart batteries, which almost always provide the best bang/buck. Battery installation and maintenance  is NOT something a typical secretary or gardener or child or truck driver can do safely. Because lead-acid batteries contain (potentially large) amounts of acid, produce explosive hydrogen while they charge and hold LARGE energy which, if released all at once by an accidental short, could cause a major explosion. The people handling large batteries (a car battery is large in this context) must know (and understand) what they are doing if you expect to receive the benefits you hope for while remaining safe and healthy.

IOW if you use battery banks, RESPECT battery banks.

Although a good battery system (you're essentially creating a very large UPS) might easily run $10k-$20k, if you get a real understanding of how they work, clarify and reduce your actual needs vv. loads, time of day, etc, you can probably set something up for far less $$.

But still you will need much study and time spent planning and working. So maybe serious effort spent finding out if/what you actually _must_ do per paragraph 1 above is your best bet right now. Also consider how much it will cost to just replace things as they break. That is also a solution.

And, of course, if your work benefits somebody very important at (or to) the power company then problems that take you down might become the power company's problems... Sometimes social engineering is more affective than the technical kind.

And in the end it might be best to just buy a good generator.

Rufus

 
Seva Tokarev
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My grandfather in USSR in 1960s had Autotransformer for that very purpose.
As far as I understand, since then more advanced Voltage_regulators became available.
 
Devaka Cooray
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Rufus Laggren wrote:Maybe first, before spending time "solving" the problem, determine which items are truly in danger. And what type of power problems will actually cause damage. Information might be available from the manufacturers or from knowledgeable repairman (if you can find them near you or on the net). There are forums where engineers talk casually about their problems where you might ask about the actual damage certain equipment is likely to encounter.

Relay-operated UPS are sure to be in danger - it broke two of them I had within a span of five months. I'll try to contact the manufacturers of these computers. But what I noticed is when I say 'fluctuation' most people tend to picture of surges or a slow and smooth drop of voltage. Is there a better technical term to describe the situation as just as shown in my animation?

Oh and are laptops generally in danger?

It sounds like the heavy load of 3kW is never going to work out for a sane solution. What if we knock it down to 300W? Or maybe say 250W? I do have a UPS which says it supports up to 750W. Instead of a car battery it runs on two small 12V 12Ah batteries. The only problem with this UPS is it doesn't seem to do the AC->DC->AC 'invert' thing when the grid power is on. Instead, there's a relay switch that directs the grid power directly to the load. It only switches to the battery power when there is no grid power. With a load of 300W, the batteries only last for a little more than an hour, so it's not a thing I can use out of the box as a workaround. The fluctuation here starts at about 7am everyday and continues up to 8pm.

I like the idea that the UPS is seemingly doing a good job at protecting its battery - preventing overcharge and overload. Any thoughts as to hack into the UPS and make it work as an inverter, at the same time smoothing up the voltage with support of its battery (use the battery as a capacitor) or with something like that voltage regulator thing Seva mentioned?
 
João Carneiro
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We used to have "voltage stabilizers" for TV's about 25 years ago. It was the only way as power distribution was messy. Don't have a clue where to get one these day's.

Undervoltage is as serious as overvoltage. Bulbs glow dimmer, but electronics enters dangerous states. Modern electronics have developed the concept of "brown out" that simply handles these situations, but there is a disrruption in the normal working of the device.

About UPS damage, be sure to get a nice managed UPS, and specify some histeresys on the event of loosing the defined input tension. So make it go "on battery" for at least a couple of minutes on these events. That should take care of the relay malfunction.

Capacitor banks could help filtering out some ripple and electrical noise, but i guess if you're using an UPS already you don't need them.

If i had this problem, i would get a nice voltage stabilizer for my premium electronics: TV, routers, computers. Change my lamps to led lights with nice power ratings, like this one that can go from 85 to 265V in input voltage.(around here voltage is rated at 230V).

Now that i think of it, i got a modern oven and a washer that would really suffer from such conditions... so there could be more devices to protect...

I would also make a formal complaint to the utility company as they are bound to maintain certaint operational parameters on the power grid. And of course, get a nice, knowleageable electrician to keep them in line.

 
Devaka Cooray
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João Carneiro wrote:If i had this problem, i would get a nice voltage stabilizer for my premium electronic

Are there voltage stabilizers that work without relays or some other mechanical/moving parts? How would I find one of those?

João Carneiro wrote:I would also make a formal complaint to the utility company as they are bound

I did. And it simply didn't work out for some utterly weird reasons.

 
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Devaka Cooray
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Looking at each of these voltage regulators, none of them seems to have mentioned any little clue as to how they work. Do they operate on relays? Do they respond quick enough?

I found a relay-less voltage regulator here in a local shop, but it turns out they use servo motors instead of relays. I think that would be much slower to respond and prone to get broken sooner than a relay-operated voltage regulator.

Based on the discussion on this thread so far, I can think of two possibilities:

1) Find a voltage regulator that does not operate on relays or mechanical/moving parts. Maybe something that operates on capacitors? Or some sorta transistors? A combination? Do we have a technical name for this kinda voltage regulators?

2) A little(?) DIY project trying to modify an inverter, UPS, or a regulator.

Any thoughts on any of these possibilities?
 
João Carneiro
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Devaka, there are many useful contributions on this thread. Wise words have been spoken.

Please do understand that you can get things off the shelf that offer diferent solutions to diferent problems. But diferent things will be present on diferent shelfs around the world. Maybe your problem can be solved with a simple voltage regulator, maybe not. Maybe you can solve it using a managed UPS and configuring it properly. But it could be in such way that your input is so dirty/unstable that you have to resort to turn it to DC and back to clean sine AC...

There are also other considerations on energy efficiency, because energy transformations have an energetic price, so there is loss at every step of the way, this can make your electricity bills increase.

DIY at this level is cool for people who know what they are doing. VERY EXPENSIVE errors can occour... even to people that know what they are doing.

But consider your budget and options. You may even get to realize that since you are investing you can go offgrid with just a bit more...
 
Devaka Cooray
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Considering the potential loss in case of a worst case, which includes the cost of appliances and more importantly the data stored within them (of course I do keep backup's, but....), I think I would be okay with a bit heavy budget.

Going offgrid is fine, except the batteries in my UPS wouldn't last that long (as the fluctuation usually happens all the way from 7am to 8pm ). Maybe running on an inverter-style generator would be a handy solution?
 
João Carneiro
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Devaka Cooray wrote:Considering the potential loss in case of a worst case, which includes the cost of appliances and more importantly the data stored within them (of course I do keep backup's, but....), I think I would be okay with a bit heavy budget.

Going offgrid is fine, except the batteries in my UPS wouldn't last that long (as the fluctuation usually happens all the way from 7am to 8pm ). Maybe running on an inverter-style generator would be a handy solution?


how much power are we talking about?
 
Devaka Cooray
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I think 2kW is an overkill. Eliminating the less-wanted devices, it would be about 300W.
 
Wyatt Barnes
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I am not familiar with particulars but a UPS would be the way to go from what I have picked up over the years talking to computer people who operated with unstable grids around the world. Solves all short term problems and will protect the device from damage by shutting down if the problem persists past its ability to maintain voltage. I was offered one a couple of years ago but had no use for it since my grid is very stable. I did just meet a software geek who has a pile of sensitive hardware running most of the time and she has seven individual UPSs running all of the time.
 
João Carneiro
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So if you have the budget, get an online UPS. At that power rating it shouldn't be really expensive.

An online(double conversion) UPS, keeps things going on battery power, when the grid power is present, it continuously charges/feeds the battery's circuitry, when it goes out, it runs on battery until depletion.

The catch: there is a continuous power loss, that defines the efficiency of the UPS. That is the real silent cost of this solution...

 
João Carneiro
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And if you want a cheaper & safe DIY approach, get a quality relay, with a superior switching rating, if possible with the same pinout. Grab a soldering iron, and replace it your broken UPS...

I am curious though on how long it would handle the abuse and become in need to be replaced again. Guess it would really depend on the picking.

With the proper tools you could even repair the relay itself...

Are you into this sort of thing or just want a solution off the shelf?
 
Hank Roberts
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If you want to buy off-the-shelf hardware, look for a "power conditioner" or "line conditioner"

If you want to build your own, search the same terms.

I see "In Sri Lanka the standard voltage is 230 V. The standard frequency is 50 Hz."

So look locally.
 
Ryan Tollmann
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João Carneiro wrote:Devaka, there are many useful contributions on this thread. Wise words have been spoken.

Please do understand that you can get things off the shelf that offer diferent solutions to diferent problems. But diferent things will be present on diferent shelfs around the world. Maybe your problem can be solved with a simple voltage regulator, maybe not. Maybe you can solve it using a managed UPS and configuring it properly. But it could be in such way that your input is so dirty/unstable that you have to resort to turn it to DC and back to clean sine AC...

There are also other considerations on energy efficiency, because energy transformations have an energetic price, so there is loss at every step of the way, this can make your electricity bills increase.

DIY at this level is cool for people who know what they are doing. VERY EXPENSIVE errors can occour... even to people that know what they are doing.

But consider your budget and options. You may even get to realize that since you are investing you can go offgrid with just a bit more.
.


I agree, I think you should look into setting up a solar system with some fed/state rebates to zero out the cost...MLsolar in California deals in used solar panels...I got ( 8 ) 6.5 volt 3? Amp panels for 20$ each( 10 yrs old)...for my RV wired in series and parrelel for 13 volt ? Amps more then enough for my 81$ Wal-Mart marine 109amp hr batteries..they even sold me the 50' wiring and 30 amp charge controller for a total of 200$... ebay sells full-sine 5000w/10000watt inverters for about 300-500$ ... depending on the maker...though they can go as high as several thousand... but remember you may on some states get a 100% rebate... In  NJ some people were getting 110% rebate.

 
Devaka Cooray
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João Carneiro wrote:An online(double conversion) UPS, keeps things going on battery power, when the grid power is present, it continuously charges/feeds the battery's circuitry, when it goes out, it runs on battery until depletion.

Wow! That sounds like what exactly I was looking for!  Thanks João!
I need to see where I can buy one from.

João Carneiro wrote:Are you into this sort of thing or just want a solution off the shelf?

I've been into that sorta things about 12 years back. Then lost the interest somehow . For now, I'd definitely be looking for a quick and off-the-shelf solution.

Hank Roberts wrote:If you want to buy off-the-shelf hardware, look for a "power conditioner" or "line conditioner".

Wow! That too sound like what I was looking for. I used to have the sense that line conditioners only work at very low voltages. Hmm, I'll need to do a bit of research between online UPS and power conditioners in the local market here.

Oh, and welcome to permies, Hank!


Ryan,

Solar sounds like a good off grid solution too. But then the problem would be the maintenance of the battery. Maybe that 'charge controller' would take care of things like over charge and over discharge prevention??
 
Andrew Lyke
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I realize that Amazon isn't the solution for Sri Lanka (or I assume so), but here's a system made in China that would seem to address your problem:
https://www.amazon.com/Simran-AR-3000-3000-Watt-Stabilizer-Transformer/dp/B000E636BU/ref=pd_sim_23_5?ie=UTF8&psc=1&refRID=5H56X9T2CRSF61B983R2

I tried searching on the product name (/Simran-AR-3000-3000-Watt-Stabilizer-Transformer), but it only came up in Amazon for me. Perhaps you could find a direct link to the product availability in your area.

Cheers!
Andy
 
Ryan Tollmann
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"
Ryan,

Solar sounds like a good off grid solution too. But then the problem would be the maintenance of the battery. Maybe that 'charge controller' would take care of things like over charge and over discharge prevention??"

Yeah charge controllers are for that very purpose, I have an swm charge controller. There are pros and and cons to both types.  but I've seen elaborate systems that don't use a batterty bank as storage, instead they use hho generator to convert solar electricity into gas and store the gas separately as hydrogen and oxygen then burn it in a generator setup....but my budject so far doesn't allow me that luxury.  Working on a small weedwacker moter to run hho gasfor a generator head but that's backburner (pun intended) to my project to use hho for a replacement in propane campstoves/heaters etc.  When I have finished with the proof of concept projects I'll upgrade to a solar hho factory to produce and store hho for all my rv needs eventually even driving.
 
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