Efficient long distance transmission of power

[Hedges]

I keep thinking to build the solar in full series to hopefully come close to 600 volts and use an MPPT at the destination.
I would bury the cable. Might need more solar

That is what I do for my PV, but < 600Voc max (record cold day) is typical 380Vmp under normal conditions.
You might do +/-600V with center grounded to double the voltage. There are 1000V PV systems. Transformerless they might normally be < +/-500V. During power-on testing they do an excursion to having one end grounded, doubling voltage of other end, but wires should handle that briefly.

To get from the 380V typical to near 600V most of the time would require regulation.

 

[rin67630]

I keep thinking to build the solar in full series to hopefully come close to 600 volts and use an MPPT at the destination.
I would bury the cable. Might need more solar

600V DC is a major killer. That is capable of drawing arcs of several feet.
The OP had a hydro-power source, no solar panels.

 

[nonoceb]

If hydrogenerator output 3ph at 48VAC, i think 6 microwave transformer from 220VAC oven and standard triphase 30mA differential can keep safety ok :

3 transformer at the hydro station, wirring in star and neutral grounded, each phase voltage between the neutral point and any one of the line connections is 1/√3 × VL of the line voltage so each transformer primary winding see 27VAC.

Then transformer stepup the voltage with a ratio of 11 so 297VAC on secondary winding, each 3 secondary have to be in star configuration and neutral is grounded to make a 3ph differential 30mA working fine to protect human.

At the end of the line put 3others transformer in reverse way then rectify 3ph AC 48VAC to supply a mppt charger
It's a crazy setup but it's worth a try, hope the primary winding inductance will not too high to take his 700W rated power x 3 = 2100W

Edit : it's not working with oven transformer, because hydroturbine start at 0Hz and go higher than 500Hz, impedance of primary winding will be too high to make an efficient power line. Very difficult but interesting topic!

 

[Warpspeed]

It WILL work with a hydro. At 0Hz the voltage must be zero as well.
At 6Hz the voltage will be one tenth what it is at say 60Hz.
Transformers and loudspeakers work fine over the full audio range, they are certainly not limited to one voltage or one frequency.

There is absolutely no problem running an induction motor, or generator, or a transformer at a much lower or higher frequency, as long as the applied voltage is adjusted in proportion. Variable frequency motor drives work perfectly well at reduced motor speeds, as long as the voltage reduces in proportion to the frequency. What you cannot do is exceed the rated current of any windings.

220v to 2.5Kv is pretty standard, about 11:1 step up.

These transformers often use aluminium wire, and run at a very high flux density, and also have a shunt magnetic air gap. That makes the transformer very lossy at full rated power (2.5Kw) and they are only rated for short term intermittent use in a microwave oven at full rated power.

However, run at only 48v and far less than the original ten amps in the primary, it should work very well at 48v x 11 = 528 volts.
As I remember, the guy that came up with this idea originally, sat his transformers in a metal coffee can full of automatic transmission oil.
That not only greatly improves transformer cooling, it guarantees protection from ingress of moisture, ideal if the whole thing is pretty much out in the open at the hydro end. The extra cooling of the oil should allow at least the original ten amp current rating continuously. In other words, about 500 watts per phase which is double the original posters requirement.

 

[Keith C]

Set up this power system as a SWER system. That's an industry standard that stands for Single Wire Earth Return. That would result in (2) 10AWG lines instead of just one.

 

[Henrysangret]

I have 3 separate systems here off grid. I have a situation where I am setting up a solar only system near our cabin and want to run supplemental power in winter (when we only have rain...) to charge this system from a hydro based system about 800' away. I have a 10AWG UF wire run from the hydro system to the new solar only system. Looking for ideas to run maybe 1000-2000 watts (or more?) over that cable to the new system as efficiently as possible.

I am planning the new solar based system to be 48V nominal

My original idea was to run 120V ac from the remote inverter to a 48V battery charger on the new system. Having trouble finding an efficient 48V charger.
Next idea was to find a 56V AC to DC power supply and run the DC output to a cheap MPPT charge controller, but again, the power supplies seem to all be clustered around max 85% efficiency, added to the MPPT losses and wire losses and well, that leaves a lot to be desired...

Got to be a better way to do this.
Need some other ideas from you folks who are smarter than me.

First, what is the power you are trying to transmit, ac dc and what voltage. If it’s AC you are way ahead of the bar, just highervoltage and lower current. Second, Aliexpress sells a number of voltage converters to run into your into your BMS for charging. Unless this is some sort of experiment but looking for continued operation keep it uncomplicated and simple. I keep reading a lot of really out there suggestions, but do not see any data supporting the recommendations in question.

 

[nonoceb]

Set up this power system as a SWER system. That's an industry standard that stands for Single Wire Earth Return. That would result in (2) 10AWG lines instead of just one.

Output 21A over double 800' awg10 (0.4Ohms) give a voltage drop of 8.4V so you can transmit 830W from 48VDC with efficiency of 83%.
Easy and welcome corrosion in grounded electrode

For dangerous high voltage It 's seem impossible to protect human from electrical shock hazard with Single Wire Earth Return and at high voltage like 500VAC it's better to play with power lines fully isolated from ground.

The high voltage is the good way to make transmission really efficient but It's pretty hard to find stepup fully isoled converter with mppt algorithm.
Maybe using an 2000W high frequency induction heating device to drive a small hf tranformer can made the AC high voltage at 50-300khz then at the end an other hf transformer to stepdown the voltage to real mppt controller (because induction heater side cannot make regulation).
An high frequency induction heating is specially made to drive a transformer so ...

 

[Warpspeed]

If its ac, just use transformers at each end and step up the voltage.

If its dc, use a 60Hz inverter located at the hydro, and use transformers at each end.

 

[Stewfish]

I have 3 separate systems here off grid. I have a situation where I am setting up a solar only system near our cabin and want to run supplemental power in winter (when we only have rain...) to charge this system from a hydro based system about 800' away. I have a 10AWG UF wire run from the hydro system to the new solar only system. Looking for ideas to run maybe 1000-2000 watts (or more?) over that cable to the new system as efficiently as possible.

I am planning the new solar based system to be 48V nominal

My original idea was to run 120V ac from the remote inverter to a 48V battery charger on the new system. Having trouble finding an efficient 48V charger.
Next idea was to find a 56V AC to DC power supply and run the DC output to a cheap MPPT charge controller, but again, the power supplies seem to all be clustered around max 85% efficiency, added to the MPPT losses and wire losses and well, that leaves a lot to be desired...

Got to be a better way to do this.
Need some other ideas from you folks who are smarter than me.

At 800ft the southwire voltage drop calculator says thats a 20.99% voltage drop using 10 guage wire. A couple thoughts come to mind.

Power companies run like 14,000 volts to tranformers and then from the transformer you will get 600v to houses for only a short distance away.

They use aluminum in the air for cooling and costs. Run your lines in the air with ceramic isolators on the poles.

I think I remember at 900ft 120v drops to like 110v using 2guage wire. The cheapest wire you will find is mobile home connection wire. If I remember correctly its 2 guage and 4 strands. If you are just doing single phase connect two strands to have two pairs to get double the thickness... kind of. It was $500 at Lowes for $500 ft. For 4 conductors. Use thenlarge splices that bolt onto the wires and adhesive lined heat shrink and use 3m 5200 over that heat shrink. Don't forget dielectric gease inside also. You have to look for the lowest price and some Lowes were cheaper than others. Home depot was more expensive. Costs have gone up over the last year though.

Feed a few batteries at the hydro. Get a european 240v MPP inverter to run off a couple batteries. American 240v is not really 240v its just two legs of 120v split phase so get a European inverter. MPP has an alibaba page and you can buy directly from Taiwan like I did. Then you could use a smaller wire size and get a step down converter with a range of 240 volts down to 120v. You will get half the voltage drop at 10.5% for 240v.

Use a ram water pump to feed the water at 1:7 run to rise ratio to a tank/pond put the hydro at the pond next to your house, then use the water to feed your property or swimming pond/waterfall.

A ram pump with high starting pressure from a stream would do great at getting water up a hill. Start with 10 inch pipe in the stream and work down to a 1 inch ramp pump to get high psi. Maybe have a pond that fills all day and a waste gate that opens when you get home at night to create power and fill batteries when solar is not being produced. Even a solar pump could fill the pond all day. Have the pond drain to a second pond, that flow can also have a ram pump send water back up to the top pond and the over flow goes to the second pond.

FYI a washing machine on its' side has the longest lasting wet to dry seal you will find. Remove the washing machine motor and put your alternator on the shaft, remove the drum inside and put the water wheel on that side of the shaft. Now you have an alternator that wont get wet and corrode. There is a washing machine hydro guy on youtube.

 

[curiouscarbon]

FYI a washing machine on its' side has the longest lasting wet to dry seal you will find. Remove the washing machine motor and put your alternator on the shaft, remove the drum inside and put the water wheel on that side of the shaft. Now you have an alternator that wont get wet and corrode. There is a washing machine hydro guy on youtube.

thanks now i simply have to look this up.

COTS principle hacking is rad!

 

[Stewfish]

thanks now i simply have to look this up.

COTS principle hacking is rad!

Watch his vids on how he gets the water down stream with psi, etc