New spin on old technology

Lawrence E. Liles

2008-07-02 08:41:47

As a concerned area resident, I would hope that Dominion shows a little more creativity and willingness to embrace newer proven technology in its upcoming design considerations, instead of gross attempts to grab more private property and viewscape disruption.

A newly patented scheme (2004) called Tripole is intended for conversion of existing HVAC (High Voltage Alternating Current) transmission lines to HVDC (High Voltage Direct Current).

Combined with the higher average power possible with a DC transmission line for the same line-to-ground voltage, a Tripole conversion of an existing AC line could allow up to 80 percent more power to be transferred using the same transmission right-of-way, towers, and conductors.

HVDC has been found to be ideal and more economical for bulk energy transfers over long distances, such as being proposed by Dominion Power through our region.

Some HVDC advantages:

• HVDC is inherently more reliable than AC;

• It can carry more power per conductor;

• There is much reduced energy loss per mile compared to HVAC;

• It has lower maintenance costs;

• Direct burial is more feasible through environmentally sensitive areas, and;

• HVDC allows for asynchronous links between distribution regions and provides easier new alternative energy tie-ins.

All this, in turn, can help stabilize the connected AC grids. HVDC is the future of “smart” electrical power transmission.

Nicholas Tesla’s AC won out over Thomas Edison’s DC when our nation adopted its early electrical transmission grid structure. AC’s advantage was found in high voltage transformers that could step up voltages high enough to economically transfer power over long distances.

HVDC technology developed much slower, with the first commercial installation only in 1954 between mainline Sweden and Gotland Island.

Many technical challenges and advances have occurred since that time, until today there are more than 90 HVDC installations around the world. Most are in other countries.

We need assurance that Dominion uses the best technology available today for its desired transmission through our Hallowed Ground. HVDC may be the answer for all parties involved.

Lawrence E. Liles

Marshall