ENG PHYS

Single Conductor Energy Transmission

Presented by Yan Duan

October 18th 2013

ENG PHYSBackground

Conventional way to transmit energy at a long distance:

Closed circuit is always required.

A “new” way to transmit energy, with only one single wire.

ENG PHYSMotivation Tesla’s Work

Not that “new”: back to 100 years ago, the ingenious scientist/engineer (Eng Phys) N. Tesla was already able to implement a resonance circuit, thus to use only a single wire, energy could be transferred from station 1 to station 2.

ENG PHYSQualitative Explanation

By choosing suitable values of capacitors and inductors, the displacement current in the single wire could form a standing wave, thus a resonant wave, with a phase difference of 90 degrees between displacement current and voltage. That is with a standing wave, the long-distance divided two parts of the "circuit" could be regarded as simply integrated, thus the energy can be transmitted.

ENG PHYSThree Goals

Primary – Provide a qualitative explanation with some simple math models

Secondary goal – Obtain a reliable quantitative description of the phenomenon, hopefully to provide a whole set of math models that make sense

Stretch goal – Build a small scale single wire transmission line system if the investigation in the first term was going well.

ENG PHYSThree Goals

Primary – Provide a qualitative explanation with some simple math models

Secondary goal – Obtain a reliable quantitative description of the phenomenon, hopefully to provide a whole set of math models that make sense

Stretch goal – Build a small scale single wire transmission line system if the investigation in the first term was going well.

ENG PHYSPlan: outline

The literature resources I could rely on is rather limited now, the original Tesla’s work is still not published yet, and most of the materials online were merely about qualitative description of this phenomenon. Probably I’ll start from basic EM theories (Maxwell equation, etc…), based on the qualitative explanation above, hopefully move further a bit every week and keep revising math models.

ENG PHYSPlan: progress so far…

A small break through

ENG PHYSexplanation

On the two sides there’re two LC resonance circuit. Below it’s a wave guide with two perfect conductors on its

tow ends, from EM theories we know that perfect conductors implies total reflection, if the length of the single wire is well-chosen (n times the half of wavelength of EM wave), then as we add up the incident and reflected wave there would be a steady standing wave vibrating on the line, thus to induce AC currents on the right LC circuit .

ENG PHYSNext Step: Simulation

Thanks to Dr. Jie Chen’s group, I’m able to use Comsol Multiphysics to simulate the circuit above.

ENG PHYSCost

Since this project only involves theoretical work so far, and the simulation software is fortunately provided by research group I worked for during the Summer, thus so far the predicted cost is almost zero.

If the investigation and simulation goes well, in the near future we’ll probably try a small scale experiment, but that really depends….(length of the wire, 20km?!!)

ENG PHYSPrediction of success

Different from conventional equivalent circuit analysis in power engineering, modeling of transmission line is handled by theories of electrodynamics, which indeed provide a rather different view of the entire model: a wave guide carrying radio-frequency EM waves!

ENG PHYSReference

Analog Signal Processing Problems cnx.org Kharchenko K.P. Short-Wave Horn Antennas without Visual

Walls. Moscow: RadioSoft, 2003 Strebkov D.S., Nekrasov A.I. Resonant Methods for Electric

Power Transmission. Moscow: VIESH, 2004 “Introduction to electrodynamics”, Griffith “Power system design” 5th edition, pearson press.