External Voltage Regulators - Can they help me on a brownout? 5

[DTGT2002]

Hello folks!

I belong over in the structural forums, but was hoping I might borrow some insight or at least get pointed in a better direction.

For the last 17 years, I have worked with a ranch in Rural Honduras to help provide basic services to an underserved population. Over the years, literacy rates have increased, infant mortality has dropped and the standard of living has been raised.

A number of years ago, electricity reached the area and the mission quit using a generator as the primary power and hooked into the grid.

As things have improved in the area, electrical useage has gone up. Combine that with miles and miles of powerlines run through forests and hillsides and you get some sketchy power conditions.

All of that said, we have experienced significant brownouts at least quarterly for the past two years. The most common victims of these brownout/blackouts are the well pumps and refrigerators. The last event knocked out four desktop computers, a freezer and a two month old submersible pump.

Can anyone shed light on a possible solution? I have been looking into consumer grade voltage regulators to try with the computers. Are external voltage regulators viable for the freezers and refrigerators? How about for the pump?

There are two wells, so we should have two submursible pumps going at any time and we also have two pumps providing air pressure to deliver the water to remote holding tanks. All are wired out of junction boxes currently. The air pumps run off a contactor. Usually the contactor is the first to go. If the brownout period is long, the sub pumps go next. Not good as we are paying around $80 per contactor and as much as $250 when they are not locally sourced.


Anyone have advice to offer or maybe a calling to head south to Honduras for a field trip?

I do appreciate any advice you can offer. If this is the wrong forum or if a more suitable one exists, I do apologize and appreciate any reference to another area available.

Kind regards,

Daniel Toon

 

[davidbeach]

The solution probably depends on the depth and duration of the brown-outs. If of short duration, it may be better to drop the pumps and refrigerators than trying to raise their voltage. If of long duration, it might be best to have a single regulator on the incoming power.

 

[haze10]

I agree. Regulators are basically an automatically stepped transformer tap changer. But there is usually some response time to make the first step, say 5 seconds or so. So a quick brown out would not prevent contactors from tripping off line. If you are talking a relatively small load, consider a motor generator set. Say you have 220V incoming, then have a 220V motor driving a 220V generator. As long as you don't lose frequecny the speed won't change. As voltage goes down on the motor, the amps would go up. But you size the motor to handle that, say something like a 50KW motor driving a 30KW generator. You're overall efficiency will be about 90% so there would be some energy lose. But your output voltage would remain constant all the time, regardless of input voltage.

 

[itsmoked]

I can't see where any 'voltage regulator' is going to help a pathological event. The transmission line is just flat under-sized for the demand. A regulator is going to put substantially more load on an already wavering line.

Options:
1) Time share the line. Requiring certain loads to stay off at certain times.

2) Add some protection. Like dump off a well pump when the voltage drops a certain amount. And then require a time delay (perhaps hours) and a certain higher voltage before allowing reconnection. Do this on anything damageable.

3) Use the generator during peak times.

4) Put the computers on their own UPSs so they can be used thru sort term blackouts. Or dump them and use low power laptops that self UPS and use a fraction of the power anyway.

5) Consider raising the transmission line voltage.

6) If it's a two wire transmission line consider using it as a single wire earth return, only use the two wires as the single wire doubling the power delivery.

7) Add some solar.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Hello Daniel.
What area in Honduras? Can you give me a Google earth or Google map direction?
Do you know the location of the substation which feeds your site?
I no longer have a good contact at ENEE (Empresa Naqtional de Energia Electrica I think it is, the National power grid.)
I am afraid that the incoming voltage will be what it is and any modifications on the grid side of the meter will not be an option.
Are you connected to the ENEE or to a private entrepreneur? You may be experiencing overvoltages as well as undervoltages.

There used to be available in Honduras small voltage monitors for refrigerators and air conditioners. These plug into the wall outlet and the A/C or refrigerator plugs into the protector.
The devices disconnect the power if the incoming voltage is too high or too low. As I remember they may also provide a minimum time to restart as well to prevent the compressor stalling on high back pressure if it is re-energized to soon following an outage.
Ask at Aceyco, Electrocos, Distribudora Industrial or other major supplier in Tegus' San Pedro Sula or La Ceiba. There will be branches in other locations also.
For laptops and computers A good UPS is a good solution.
At the above mentioned electrical suppliers or refrigeration suppliers you may find voltage monitor relays that will control the contactors on the pumps and inhibit operation when the voltage is outside the set limits.
The ENEE is actually continually upgrading their lines and adding automatic voltage regulators and capacitor banks to improve voltage stability in rural areas. They do have some good engineers in the organization who are working hard to improve service and reliability.
I will probably be in Honduras sometime in the next year but I have no immediate date in mind at this time.
I have had a little first hand experience with voltage problems in Honduras and I hope this helps you.
Yours
Bill

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[waross]

Another option is the wire in voltage monitors sold by refrigeration supply stores. These give good protection for compressors and are available in three phase and single phase. You will probably need to add a contactor to them.
Yours
Bill

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[DTGT2002]

Bill,

The ranch (Rancho El Paraiso) is in Olancho, near San Esteban in the Agalta Valley.

http://www.hoi.org

Here:

http://maps.google.com/maps?f=d&sou...39175&sspn=0.002543,0.003428&ie=UTF8&t=h&z=18

I am the youngest member of the board, am a structural engineer by trade, work on cars as a hobby and as such have been made the mentor for our director of operations.

The Ops director previously instituted a plan for running the pumps during what he perceived to be the lowest useage hours of the day, providing adequate water without taxing the system. This was mainly due to a failed pump due to brownout rather than preplanning.

After reading the initial posts, I was going to ask if a reasonably priced cutoff device might exist. Seem it does and in country!

One next step would be evaluating costs for the units. Surely they are more reasonable than constant repairs.

I have made efforts to shift to laptops from desktops. I am having trouble getting over folks there having been taught that a desktop is more permanent and reliable than a laptop - explicit, first hand proof to the contrary is not adequate. That said, we seem to kill computer equipment from the software side nearly as quickly.

We have tried UPS's before, the frequency of outages has led to fairly rapid deaths of those we have tried. Experience at the office with server grade equipment has shown 1 or 2 deep discharges take good units to their limits. I think loss of power and current work is better than loss of equipment.


Back in the day, we ran the clinic off a solar array donated by the Southern Company. We ran the diesel generator 12 hours a day to keep the fridge coldish and pump some water. We also had a number of propane friges.

Then came the grid. All our problems solved! It was ok when we were the main user in our area.

I'll have folks look into the voltage monitors. We should also look into the control for the pumps. There is more equipment in the panel than just the contactor, but I have not built a good enough diagram to get any outside opinions.

I collected dimensional data on our structures a while back. Now I need to add circuit diagragms and desired loads to see what we can do. Finances used to limit who had what, electronics wise. I'll bet we have more TV's and DVD players around than anyone could ever guess.

Thanks for all your help!

I am open to additional solutions and suggestions!


Thanks!

Daniel

 

[waross]

It's a small small world. I did some work at Maderas Tucan some years ago. I think that's about 4 miles from your ranch.
There was a gringo millwright married to a girl in the little village across the road from the Maderas Tucan turn-off. His name was Herb. He's a good man if you can use him at the ranch. (If he is still in the area).
The sub station feeding that area is probably in Juticalpa. The line (34.5/19.9 kV primary as I remember) runs about 30 miles to Gualaco. Three phases and a neutral were carried from Gualaco to the mill near you (Maderas Tucan). Two phases and a neutral were carried on north to and past San Esteban. There is a lot of load and a few small mills and at least one small dairy running on open delta. The voltage control is back in Juticalpa and the main load is in Gualaco as I understand. The voltage is set to minimize complaints from Gualaco. North of that, the tail wags the dog. Even though we had three phases at Maderas Tucan, the voltage unbalances and phase shifts induced by the voltage drop on the neutral caused us a lot of trouble.

Back to your problems:
Consider lightning arrestors on your service. Some of your failures particularly the computers may have been from lightning rather than from low voltage.
I wish I could recommend specific devices but I am afraid that it would be pointless. You have to go shopping and decide if the devices available in stock are suitable. Next month they may be sold out with none on order but there may be some similar devices on the shelf across the street.
If you can list the equipment (including ratings, approximate is better than nothing) we can probably help you assemble a protection package.
itsmoked has some good ideas and combined with suggestions as to what is doable in your location he will be a valuable resource person.
We're waiting to see your equipment list.
Yours
Bill

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

This is what EngTips is about, Bill!

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[jfpe]

It really is a small world! I am enjoying a layover in North Carolina, just returning home from installing (small) off grid solar systems for a handfull of rural schools in Honduras.

Cheers,
John

 

[waross]

Too true, Gunnar. I was thinking that myself.
What part of Honduras were you working in John?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[waross]

Here is a link showing both the ranch Daniel is assisting and the mill where I worked.

http://maps.google.com/maps?f=d&source=s_d&saddr=15.097276,-85.840044&daddr=15.096987,-85.879511

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jfpe]

We were working around San Antonio del Norte in the La Paz district. We installed 240W PV systems along with lights, a TV, and a DVD player in 3 remote schools. 240W doesn't sound like much, but when you are startig from zero...

-John

 

[DTGT2002]

My first effort in Honduras (when I was 13) was part of a group finishing an installation at a remote clinic, 6 hours up logging roads in the mountains. An earlier group installed the solar panels and wired the clinic. We installed the batteries, inverter and a rigged up hardware cloth shield over the panels (regardless of country, kids must throw rocks at glass).

The system was sufficient to run a small frige for vaccines and two three light bulbs. These bulbs were the first electric lights many in the village has ever seen.

I remember that first night, with eyes lining every window to see what made the lights inside.

The system lasted over 10 years, I believe without a battery change until the clinic was annexed by an adjacent municipality and later abandoned. We hope to get it back online soon.

It is a small world.

I will get moving on my research and data.

It can be a challenge getting info, with me in Georgia and the sketchy internet down there.

Anyone have experience with internet connections and improvement to the same in rural areas. We currently use a satellite based solution. The nearest cell tower doesn't have a strong enough signal to make it a good alternative. Perhaps a local cell signal repeater? Or is that just one more load on my already bad electric lines?


Thanks and I really appreciate the thoughts and feedback.

You guys will likely guide a lot of effort on my next trip.


Daniel

 

[waross]

Here is a sample listing of mostly plugin Refrigerator protectors. Most of the electrical wholesalers in Honduras will have a similar device available. Try for one with a time delay as well as voltage protection.

http://www.alibaba.com/showroom/refrigerator-voltage-protector.html

For the protection of pumps refrigeration protectors similar to these are available at most refrigeration supply houses in Honduras.
Note also the surge suppressor.

http://www.icmcontrols.com/products/category.php?cat_pk=37

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[DTGT2002]

Thanks!

I am looking at those and will have our folks in country check out some stores on the weekend.

I will probably buy this:

http://www.p3international.com/products/p4480.html#

Novel to have the measurements, and the undervoltage protection circuits should be similar to its cheaper cousins that seem to only be available in markets outside the U.S.

I'm trying to refresh my brain on wiring and circuits to better grasp the pump wiring, but the ICM Controls link seems spot on for our needs and affordable.

It is very nice to have a community such as this to discuss challenges such as these and find solutions.

We might manage to fix the whole world one of these days.

Thanks!

Daniel

 

[waross]

Thanks for the feedback.
The

http://www.p3international.com/products/p4480.html#

looks nice but it brings up a few concerns.
I can't download the instructions. The brochure mentions under-voltage protection with no details. The protectors that I suggested have a restart timer which is very important for refrigeration equipment. The timer is a very important part of the protection which you don't want to trade off less important features. I suggest that you verify that this device has the timed restart feature. This would normally be a delay of 3 to 5 minutes before turning on.
The other thing to be aware of is information overload. The local people, when faced with a wealth of power information that they don't understand, may feel that they have to respond in some way. It can get interesting!
But, that said, one of those meters as a test meter for your own use may be an excellent addition to your tool kit.
I had a thought on your UPS issues that I forgot to post.
My thought is that the UPS should be used only to effect an orderly and immediate shut down of the computers and printers. If the local folk continue to use the computers until the UPS chokes, they may just as well put a bullet into it. Quicker and kinder.
To that end, have I mentioned the time I was visiting a computer shop in La Ceiba. The manager pointed to a computer on the bench and commented that;
"The hard drive's shot."
The rest of the story.
The computer belonged to a security company and a couple of the guards were practicing fast draws in the office with their pistols. A gun went off and the hard drive died of a gunshot wound.
If the folk don't want laptops, turn the computers off when the power fails.
Good luck and stay in touch.
When is your next trip scheduled?

Bill
--------------------
"Why not the best?"
Jimmy Carter