Wind Turbine Far away from Input

Jayboy

Hi Chaps

I hope everyone is well. Just want to start off by saying thanks to everyone on this forum and the forum facility itself. Its truly a marvel of information and the true description of what the internet is all about. Well done to everyone.

Straight of the bat: I am looking into a 3000W Turbine for my off grid home. My first challenge is cable runs. The best spot for the Turbine is about 250m from my cottage.
In your guys opinion what is the best way to transport the power over this distance.

My initial thoughts would be to step up the voltage for the long cable run and then step it down again on the other side.
I am looking to use a HY 3000W 48V. I got no clue how if my idea is possible and how the controller would fit into this setup.

How do the guys usually get it right to have their wind Turbines a larger distance away from the input?
Thanks everyone.
Jay

BB.

Re: Wind Turbine Far away from Input

Welcome to the forum Jay!

From your accent, I would guess you are in South Africa? If so--Don't you have a lot of sun light (on average)? (here is a quick overview of South African insolation data--PDF download presentation). Would solar panels work for you?

Anyway, your question... Sending 3kW at 48 volts for 250 meters is difficult... Using a US based (AWG) voltage drop calculator (you should find one that can help you with metric wire sizes) (3,000 watts / 48 volts = 62.5 amps; 3% max voltage drop would be 48*0.03=1.44 volt max recommended)(note, this is just a quick back of the envelope calculation):

• ~825 feet @ 1.44 volt drop => 2x500 kcmil copper wire in parallel (each direction) or one ~500 mm² cable each way

Got to assume that is pretty expensive. A pair of 500 mcm/kcmil cables would be ~$20 USD per foot (round trip =? 2*825feet * $20 per foot = $33,000 just for cabling).

So, just to show that simply attaching a 48 volt turbine to charge a 48 volt battery bank at 3kW over 250 meters is not the cheapest way to go...

There are MPPT charge controllers designed to connect between a wind turbine and the battery bank... And, depending on the turbine, the MPPT controller may be able to get the operating voltage upwards of 100 VDC (allow the alternator to run at a higher voltage/lower current--can be much more efficient).

If you can run the turbine at 100 VDC, that would cut the current by 1/2 and allow the voltage drop to double (and stay at 3% maximum)... That would cut the $33k USD price to 1/4 the amount of copper. Midnite Solar makes a Wind Turbine compatible turbine controller (a variation of their MPPT solar charge controller). They also have a forum (and visit here), and are very good at answering questions.

You have other choices... Your wind turbine's alternator is a three phase unit--It is possible that you could use a transformer to up the transmission voltage to >600 VAC and then drop it down back at your building site to the rectifier (this would take 4-6 smallish transformers--but would need to know the RPM/Frequency of the wind turbine--transformers become less efficient at lower frequencies--so I don't know if anyone has ever done this or not).

Another choice, put your battery bank and charge controller at the base of the wind turbine tower, and send 230 VAC @ 3kW to your home.

• 3,000 watts / 230 VAC = 13 amps
• voltage drop calculator: 6.9 volt drop max, 825 feet, 13 amps => 4 AWG @ 6.4 volt drop or ~$1 per foot (~21 mm²)

So, while you may not want to have your main inverter/battery bank at the wind turbine, depending on your power needs, it may be a cost effective solution to run power to your home (or even run an AC battery charger for your local/home battery bank).

Another possibility, you setup your home power system (battery bank Off Grid AC Inverter, solar/generator battery charging, etc.). And set up a Grid Tied inverter for your wind turbine. Connect the GT inverter output to your Off Grid TSW inverter (3kW or larger).

Many (some/all/most/a few?) TSW off grid inverters can actually be "back driven" by a Grid Tied Inverter. The OG inverter sets the 230 VAC 60 Hz "local grid power". The GT inverter will supply what ever energy it can. The OG inverter will either make up the difference, or if the load is less than the GT inverter's output, the OG inverter will "reverse" power transfer direction and actually charge the battery bank. It is pretty slick.

This is not a "simple" setup, and there are many issues you have to resolve (will your OG inverter "run backwards" and charge the battery bank; what happens when the battery bank is full--Will you have a dump controller on the DC battery bank or will you have a OG inverter that "shifts" the 50 Hz to 51 Hz which shuts down the GT inverter--which then needs to "shut down" the wind turbine, etc....).

SMA has the Sunny Island inverter/charger family which supports similar setups (power sharing on the 230 VAC 50 Hz "local grid"). They may be able to help you with the wind portion.

Anyway--Those are the three or so options I see for your setup.

Personally, I am not a fan of small wind. Turbines are not that reliable--and wind itself is not as reliable/predictable as sun.

Towers are expensive to install. Turbines should be (in general) >20 meters minimum above the ground and any near by up wind obstructions.

Anyway--if you have good sun and can install it much closer to your home--Solar electric panels may end up being a less expensive solution.

Your thoughts/requirements?

-Bill

Jayboy

Re: Wind Turbine Far away from Input

Hi Bill

Thanks so much for the reply and the detailed explanation.
I know how much time and effort goes into typing one of these. So thank you.

I am South African! I was hoping my IP address from my ISP gave this away and not my accent. I will have to go read midsummer night dream again to try and make it less noticeable.

Regarding the Turbine: The 3000W comes in a 110 and 220V flavor as-well.
Let me try and explain what I am trying to achieve- The word Try to explain is important here as all these things are fairly new to me.
I appreciate your responses greatly as this gives me a better direction and helps to zone in on what is all going to be required from this setup.

My ideal setup would be:

Incorporate an Inverter in my home that can receive two power inputs at the same time. This being Wind Turbine and Grid Power.
The Wind Turbine would actively offset my Power usage from the grid and the makeup of the power required comes from the Grid.

In south Africa it is not legal to sell or send power back to the grid. So an inverter that could provide two input sources (grid and wind Turbine) to actively and contentiously offset my grid usage would be ideal!

Questions:
1) This offsetting inverter does it exist? If I am not mistaken a Victron Energy Multiplus has this function?
2) If this inverter does exist does it prefer DC or AC on the renewable input side?
3) I have a feeling the SMA windyboy is the one required for what I am trying to achieve? It feels a very complicated setup that required a lot of planing,

In a nutshell. Could I control my 3000W Wind Turbine with something like a SMA windy boy- connect it to an inverter that could offset my Grid usage with power from the Wind Turbine.

Thanks

BB.

Re: Wind Turbine Far away from Input

It depends... First, yes, it was your IP address (we moderators use it to help answer questions in a way that is appropriate for the location of the person asking questions when the location was not supplied).

Second, Horizontal Axis Wind Turbines (HAWT) can very easily over-speed to destruction if they are not constantly loaded (by an electrical load) or otherwise controlled (brake, short across the windings, feathering the blades, furling from the wind, etc.). A good turbine should have two or more ways of shutting down in case of failure.

So--Here here you have a devices (HAWT) that wants to be constantly loaded (electronic load, battery bank, feeding a grid, etc.). and you want to ability to throttle its output relative to local power usage such that you don't back feed the grid.

It is actually a fairly complex control issue (reducing alternator output without over speeding, or adding a variable load bank so to keep the power output to the grid a zero amps maximum)... Don't know of anyone that has such a system--but I am not an expert. There appear to be some solar GT inverters that may offer the ability in Europe--or at least possibly in the near future. But that is different--no worry about controlling the HAWT RPM.

Another issue is that with pure GT systems (no battery bank, just a power source, GT inverter, and "the utility grid"), we actually use the grid as a giant (and cheap) AC Battery that only costs us ~$6 per month service charge (plus any net power we may use).

If you don't use the grid as a battery, and you don't have a local battery bank/or opportunity loads (for example, water pumping for irrigation/refilling pond is a handy opportunity load), you may have 2-3kW of wind power and only 100-400 watts of local AC load--No storage means that power is "thrown away".

And, local storage (battery bank+electronic stuff) is not cheap--For example, in the US (real rough numbers):

• $0.10-$0.20 per kWH utility power
• $0.15 to $0.30 per kWH for Grid Tied solar (solar panels+GT inverter with net metering)
• $0.45-$0.75 per kWH for Hybrid Inverter (GT operation when grid is up; Off grid when utility is down--Hybrid inverter+battery bank+DC charging sources)
• $1.00-$2.00 per kWH for pure Off Grid power (OG Inverter+battery bank+charge controller+DC power sources)

I would highly suggest, before you purchase any hardware, that you design on paper and list the material/components you will need to build/install/maintain your system. Then take all that capital+maintenance costs (batteries 5-15 years depending; inverters/charge controller/etc. 10+ year life) and divide it by the estimated 20 years kWH you will be able to use--And get your $/kWH pricing.

In the US, other than grid tied solar (which can be equal to or even less than utility power costs in some cases), any sort of Wind/Solar Hybrid or Off Grid power system (including battery bank) will almost always cost way more than the price of utility power.

In many countries, people do build a "UPS" (uninterruptable power supply) systems for their home because they have many afternoon blackouts (AC Battery charger, Battery Bank, and AC inverter + AC Transfer switch) to give them power for ~6-8 hours a day... And you can add wind or solar panels to such a system to reduce utility power costs (in the US, it is actually illegal to install an off grid power system to reduce your utility power bill without paying the utilty a "stranding charge" because you left the grid without their permission, and they have contracts/infrastructure to supply power to your home for the next 20-40 years which they want paid back).

In the end--My first advise is to measure your loads (with something like a Kill-a-Watt meter in 230 VAC 50 Hz for your region???) and practice extreme conservation (turn off stuff that uses power in standby, laptop vs desktop computer, CFL or LED lighting, efficient new refrigerators, heating/cooling systems, insulation, shading against summer sun, windows to collect heat in winter, lots of insulation and double pane windows, etc.). In general, it is almost always cheaper and a better investment to do conservation than to generate power.

If you are still interested in GT mode Wind Turbine supporting AC Inverters that don't feed power to the grid--There are a few people with more knowledge than I that will probably chime in here too.

-Bill

ChrisOlson

Re: Wind Turbine Far away from Input

Jayboy wrote: »

Straight of the bat: I am looking into a 3000W Turbine for my off grid home. My first challenge is cable runs. The best spot for the Turbine is about 250m from my cottage.
In your guys opinion what is the best way to transport the power over this distance.

One of my turbines is roughly 1/4 mile (~400 meters) from the utility room. While cut-in is 60 volts (MPPT turbine on a 24 volt system), it's typical operating voltage is 60-142. At 3,200 watts output at the turbine generator there is only 21 amps input to the controller and 2.72 kVA real output to the battery bank. It is rectified at the tower base and the underground wire run is DC, which has more efficient power transmission over distance than AC does. I used AWG 2 aluminum wire for the underground run and the losses are very, very low.

That turbine generates, on average, 7-8 kWh per day on a 90 foot tower.

Frankly, I don't think the HY 3000W turbine makes a very good off-grid wind power system. I've never seen too many Chinese built turbines that actually hold up for the long run.
--
Chris

keyturbocars

Re: Wind Turbine Far away from Input

ChrisOlson wrote: »

Frankly, I don't think the HY 3000W turbine makes a very good off-grid wind power system. I've never seen too many Chinese built turbines that actually hold up for the long run.
--
Chris

I think that Chris is absolutely right about most Chinese wind turbines; however, I think the HY wind turbines are different. I'd owned my HY-2000 for about 2 years now and it has been absolutely perfect. No problems whatsoever. I did get rid of the factory controller and went with a Classic though, so I don't know how the original controller would hold up long term. The wind turbine itself has been outstanding. Even on a short tower, it produces good power when the wind blows around here. I live in a canyon and the lay of the land allows this to work on a short tower. Most people could not have a turbine up only around 40 feet and make good power. It works in my case, but I don't recommend it for most people.

ChrisOlson

Re: Wind Turbine Far away from Input

keyturbocars wrote: »

I think that Chris is absolutely right about most Chinese wind turbines; however, I think the HY wind turbines are different.

Actually, they're all pretty much the same. Most of them get installed on short towers. But if you put one on a 80-90 foot tower in clean laminar wind where it gets pushed right to its limit for days at a time like mine do, the stators in them won't hold up and you end up with a buzz bomb on the tower. They depend on reactance limiting in the core for their light stator windings to protect them from over-current. But with no mechanical furling (either side furling or variable pitch blades) they burn up.

I got bits and pieces of various Chinese turbines, including at least one HYenergy one, in my shop. All had various failures ranging from slip rings to stators to bearings failing and ripping the core apart to broken blades. Any turbine that only depends on stator braking to control it in high winds is a failure waiting to happen.

The main problem with wind power for off-grid is this - people put up a 7 or 8 foot diameter turbine on a 30 or 40 foot tower and then it don't make enough power to be useful (Bergey XL.1 Noisemaker - another Chinese turbine). Or they fall for sales pitches like a 5 blade rotor (HY-3000) makes 60% more power in low winds than a 3 blade, when there is no power in low winds to begin with. And then wind power gets a bad rap with many people saying it don't work or it's not worthwhile. Well ..... duh.
--
Chris

keyturbocars

Re: Wind Turbine Far away from Input

Chris,

I hope this doesn't come across as arguing, because I sure don't like to argue with people. I haven't owned every Chinese wind turbine so I can't say for sure how they ALL perform. I suspect that you haven't owned them all either, so it's hard to say that "they are all the same". Generally, I do NOT trust Chinese wind turbines. I've only owned 2 and the first Chinese wind turbine burned up in winds of only around 30mph - just like you are describing.

But, the fact is that my HY-2000 has been different. This is not just an opinion. It's a verified fact. I have 2 years or real world data. True, it's only seen peak winds of around 60mph. I don't know how it would behave in higher winds. We've had winds of around 100mph here before, but I didn't have a wind turbine at the time, so I don't know what would have happened. Over the past couple years, it has operated flawlessly in high winds 30-50mph for a couple days at a time. I suspect if the stator was going to burn out, it would have done so a long time ago. Again, I don't know how the original controller would have held up. I switched to the Midnite Classic because I liked the MPPT concept and wanted to try it. Glad that I did. I've seen 5kW peak output out of my HY-2000 "2kW" wind turbine. My experience has been that my HY-2000 wind turbine has outperformed all the published data given by the factory.

Now, I can't speak intelligently about any of the other HY wind turbines from personal experience, because I haven't owned them. I do know that there is another member on here (David) that has 3 HY-3000 wind turbines and last I heard they were working well. Again, I haven't owned all the HY turbines. I can only speak factually about my HY-2000. With that being said, you said that you have a failed HY turbine in your shop. I'd be very interested in hearing more about that. Which model it was and what went wrong with it?

I agree that a mechanical braking system would offer greater peace of mind. My HY-2000 does brake itself at a certain RPM (equates to winds of around 42mph or so) when the blades are designed to aerodynamically stall. The blades are designed to twist at a certain point and this slows the turbine. I can tell you that it works. When the winds get that high, you can hear the blades braking because the sounds dramatically changes. In any case, I don't like to spin my turbine that high, so I have my Classic programmed to slow the turbine electromagnetically. In addition, as much as I like power, I have my Classic programmed to keep peak power closer to 4kW. I am interested in longevity. Like I said, I've seen power peak past 5,000 watts around 50mph wind, but I just decided to tune it back and not push the limits of the Classic 150 too much. I'm more interested in long term reliability than short term power gain.

Anyway, personally I would not lump the HY-2000 in with all the other junk wind turbines coming out of China. For those that are reading this, most of you have probably seen this information that I posted on here a long time ago. For some that might not, here is some of my experience: http://www.rc-trucks.org/home-wind-turbine.htm

I haven't been on here as much in recent time. Life is very busy, and my wind turbine and solar system operate flawlessly so I don't even think about them much anymore. That's the way that I like it.

Ed

PS. My signature is very outdated. Now, I've got an XW6048 inverter, a Morningstar TS-MPPT-45 controlling 2.1kW of solar. New Concorde Lifeline 48V bank with 600ah capacity. I don't live off grid, so mine is just for emergency backup power and really mostly as a "hobby", I suppose.

ChrisOlson

Re: Wind Turbine Far away from Input

Ed, I'm glad you like your wind turbine.

I got a HY-1000 that I got on "trade" (meaning - it's junk, please get it out of here) when I installed a new wind turbine after it had failed. The windings are burned up in it.

I do professional off-grid wind power installations. I've seen and worked with 'em all - including the classics like the old Whirlwind and Whisper turbines built by Elliot Bayley in Duluth, MN (before he sold them out to Southwest Windpower), Jacobs, and Winco Winchargers.
--
Chris