Grid Problem

Wouldn't effect the coast at all. The logistics of what you propose would not be cost effective. The wire was designed as a conductor with minimum losses. The voltage need to get enough current to pass thru to heat it up would mean the design of new equipment to obtain that voltage. the insulator that retains the wires on the tower would have to be re-engineered to the new voltage. Test studies would have to be done to determine the damage done to the conductor. How it may shorten its life and cost of replacement. Towers may need to be replaced to keep the increased potential voltage from arcing.

I'm appalled! Why has no one mentioned that the customers' equipment connected to the power lines would suffer catastrophic damage by spiking the voltage high enough to cause ice to melt! Incredibly dumb idea . . .

Actualy there is no need to increase the voltage, just the current. Simply connect a suitable resistor across the conductors at the fartheset end of the feeder and watch the whole thing get warm and toasty just before the weakest connection melts and falls out. The heat will most likely concentrate at the poorest connection and other parts will not even get warm before all the fuses blow.

A rabbit brained scheme if I ever heard one! It's not significant enough to rate the title "hare".

Have FUN!
TT3

If you just sent voltage spike down the line and if the load stayed the same, wouldn't the current in the transmission line decrease? Afterall, that's why they transmit power over long distances at extremely high voltages to get the current down isn't it?

Travis

Did you consider the flash overs adn the insulator damages due to the spike ? What is the spike! current required to heat the conductor to the melting point of ice ? Not practical wven of i put surge protectors at the recieving transformer level. Also the surge protectors at the towers will bypass the spikes if they cross a limit and if I remove them, what protects my lines from lightining strikes ?

So it would be easier to design a wire with a semi con builty into it for this application? I wasn't saying that u need to keep the wire red hot just above 32 deg. that isn't alot to maintain. Besides There are spikes all the time already. Just how big of one would we need to keep the wire 32 deg. Im trying to prevent ice buildup not melt it.

omberdonk; if you were to put a low power factor load at the receiving end of the line, i would think that would warm the lines, should be better than a spike. perry

I have heard of them surging high voltage lines with a current pulse to cause them to mechanically pulse and throw off built up ice. I don't know if this is real but there would be issues with safety if there were people who happened to be underneath a line when it dropped a big chunk of ice.

What is the power requirement for heating a grid a few hundred miles long ? and with the very low resistance of the transmission lines what will be the current? even the lightening surge (being of microsecond duration) may not be able to generate the required heat to warm it up. Then the ice being insulator, you need enough heat to keep it warm till it freezes back since the molten water will form a liquid around inside the ice cylinder.

The surge created vibration too is not practical to break the ice. May be the better method is live with it if you can not avoid it.

In TRIZ philosophy we can better think about using the ice rather than avoid it

What is the problem with ice ?

a) The weight

b) Insulation disc - insulation failure.

Provide some extra strength to the lines for this purpose (may be already being done)

Re design the insulator so that ice do not accumulate.

Now the conductor is having an extra cross-section (ice/ water being conductive) of course not in pure form but with todays clean atmosphere, sufficient additives are there for it to conduct.

Now we can utilize the grid to carry more power by re-routing the transmissions.

advantage

a) Power transmission

b) The skin effect (assuming AC transmission) may melt the ice from outer surface onwards and not from core

the circle may be periodically altered to cover previously dead arms (switched off for the over loading).

If necessary some wireless remote sensors (infra red) may monitor the temperatures.

Just a idle thought

oops this guest was me missed the login for nth time

You can warm up the wires by simply reducing the transformers ratio at both ends of the transmission line for a short time.

By reducing the voltage to 75% of normal, the load current will increase to 133% and the conduction losses to 178%. That might be enough to melt the ice.

This can only be applied to high voltage transmission lines as you need switchable transformers at both ends. The increase in production capacity to run this operation would not be more than a few percent or could be compensated by shedding some of the load if over-capacity is not available.

I can't believe I did not think of dropping the voltage to increase the current. It is an even better idea than adding resistance at the end of the line. The losses would be much less this way.

To be honest, I was thinking more about branch circuits than main transmission lines. This is still a good idea for the main lines though and could actually work if the transformers at the ends of the line are capable of handling the voltage change required and the higher current involved.

Have FUN!

TT3

This is routinely done by northern utilities on susceptible transmission lines but it is done by increasing the phase current both to prevent ice formation on the conductors and to control ice shedding in the event of ice formation.

Transmission, sub-transmission and distribution circuit current is not static under normal operating conditions. It is dynamic in response to circuit loading. In some cases the loading profile may be more or less cyclic if, for example, a large foundry with several electric furnaces has a regular scheduled time over which the furnaces are operating. Those kinds of routine significant loads would be factored into a utility's line capacity and loading considerations.

I would suggest that one of the major reasons that spikes are not used is the possibility that birds roosting on the lines would be injured. You know these environmentalists would be up in arms if any of our feathered freinds were injured or killed. As a matter of fact, birds roosting on the lines is another reason for line breakage. Birds don't weigh much, but when there are literally hundreds of them sitting together on a power line, the weight is considerable.

I responded to a forum similar to this several years ago but the question was exactly that, birds causing line breakage. I suggested a small tracer wire be installed close to the power wire and connected to an earth ground. When the birds landed on the line, the close proximity of the ground wire to the power wire would be enough to cause an arc much like those bug zappers that are in use.

When I posted that, you would have thought that I suggested killing babies!! The response was overwhelming. I was chastized continually for several days from people all over the world. I had prefaced my response with a tongue-in-cheek comment, but that didn't diminish the effect. Scratch the idea of anything that might harm the birds.