power transmission

[masudasim]

Hi

We need to specify a cable for carrying power as well as data to approximately 10 Km distance. For data transmission over such long distances we have selected single mode fibre.

For power transmission we have to select conductors of proper gauge, transmission type like AC or DC, no of conductors to compensate voltage drops, AC/DC voltage levels etc.On the basis of these parameters we have to select proper AC-DC and DC-DC converters on both side.

The maximum total power needed at ouput(i.e. at 10Km) is less than 1 KW.Actually we need multiple voltage outputs (at different powers) at the end like +/-12V,+/-5V,+/-3.3V,+/-24V etc but net power is less than 1KW.

Theoreticaly we have done some calculations but from practical (real world) point of view can any one kindly suggest us appropriate # of conductors, conductors AWG, transmission type, Voltage level for transmission etc for our application? One constraint we have on receiving side (i.e. 10 Km) is that of size.We have a limited size box in which we have to accomodate all AC-DC or DC-DC or both converters.

 

[waross]

I would first calculate the losses when transmitting power at a voltage in the range of 600 Volts to 1000 Volts. Cable for higher voltages gets even more expensive.
Another option is to use undersized (for voltage drop, not ampacity)cable and put good regulation on the receiving end. At only 1000 Watts, paying for the losses in a smaller cable may be cheaper than a larger cable.

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

 

[electricuwe]

Depending on the space available at the receiving end select a suitable DC/DC-converter first. For the power range under consideration 300..400 V input DC/DC with quite small space requirements will be available, usually used as building blocks of modular SMPS-power supplies fed from 230 V mains via a PFC.

If you have more space choosing 750..1500 V DC and buying a DC/DC designed as auxilliary power-suppy for light railway application might be a good choice. In this case you will need less cross section for the cable.

If you go for line frequency AC you will need a quite bulky transformer.

 

[itsmoked]

Sounds like you should consider radio and solar as compared to your present solution.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jghrist]

What is your power source? You may be able to transmit the power at the available voltage and avoid a transformation at the beginning. Transmission at your desired output voltage will result in too much voltage drop. You need a higher voltage, at least 480V. There's no sense in converting to dc at the source because you'll have to convert to a lower voltage at the end anyway and converting to a lower voltage is a lot cheaper with ac.