Novel Composite Insulator

Just a wild guess: They don't work worth beans.

How would matters be different if electromagnetism followed Dexter's Right-Hand Rule?

Suggest you review patent 3,963,858 since embedded magnets are not mentioned. The embedded conductive spheroids have a specific function which may reduce flash-over caused by surface contamination.

Embedded magnets will have little or no effect on increasing the flash-over threshold. Once an arc HAS formed, a large magnetic field will exert a cross product force on the arc current and can be very effective in blowing out the arc.

This link shows that magnetic arc blowout is a quite old and well understood process.

You are absolutely right. AFTER the flash over occurs magnetic field - very little can be done. But here again - I have been studying - pre-flashover and post arc phenomena on the net. I think OP has a point which cannot be ignored.

Kindly look up patent 4,010,316 by Jolly et al High voltage insulator having magnets elements to prevent flash over dated 1st March 1977. In 1977 there were no composites and hence magnetic strength though large wall thickness should be lower. This raises many other questions on patenting system in US!!! Can you patent an idea which does not work?

What is the effect of magnetic field - pre & post flash over? Obviously arc starts with small leakage current which then multiplies fast and becomes a arc later. If at this initial stage - creep distance can be artificially magnified by presence of magnetic field - objective has been achieved!!! In fact why can't magnetic field influence even dry path length as well as creep path length!!!!

"Mystery creates wonder and wonder is the basis of man's desire to understand." -- Neil Armstrong

The US Patent Office has supposedly stopped granting patents on unworkable devices (perpetual motion machines, over-unity generators, etc.), but I have seen a few laughable duds slip through the reviewers net.

Can you provide an example of a new composite material, suitable for high voltage insulator construction, which was not available in 1977?

Cross product arc force is proportional to current flow. Tiny leakage currents experiences tiny net forces. Creep distance is along path of physical surface of insulator. I don't see how the magnetic field can lengthen this path and have any significant effect prior to arc formation.

This second patent expects the magnets to ASSIST in blowing out smaller partial arcs between the conducting spheroids of the first patent. These incomplete arcs theoretically clean the contaminants off the insulator which theoretically helps prevent a complete flash-over.

Yes, there are some plausible effects described in these patents which may actually have practical applications. Feel free to join with OP to develop these concepts into beneficial products.

I think the main reasons are as follows.

1) The effect is too small to be economically viable compared to a standard composite insulator.

When the conductor the insulator is supporting carries an electric current a magnetic field is produced around that conductor. What happens when the current varies or is low (as would be the case in a real world power transmission and distribution network).

2) The cost is too high to be economically viable compared to a standard composite insulator.

And finally

3) The added disadvantages out way the disadvantages compared to a standard composite insulator.

Even if it did work, adding magnetic material adds weight to the insulator AND reduces strength. These are to be avoided!

Additionally there is a reason the insulator uses a fibreglass rod, not just for strength but also to prevent internal breakdown and flash over which would occur if you filled the middle of an insulator with what is effectively a conductor. Internal flash over is an insulator failure mode, not just external flash over on the outside.

There may be some papers available on the internet concerning studies undertaken to assess the viability of adding magnetic material. If you can find some post us a link, I would be interested in seeing them, as I have never seen an actual insulator product or heard of a current insulator manufacturer test program incorporating magnetic material in this way.

Replying to point 3 first. Of course no one will think of putting magnets in the central fiberglass rod. One could think of a pattern in the shim - somewhat as below

Red dots denoting say N and blue dots denoting South poles. Pattern, density etc could be debated. If it helps cut string length and hence cost- it will answer point 1 and 2 in your post. Once the concept is accepted, additional changes can be made to the composite insulators.

You are right that on small leakage currents effects will be smaller- but we should look at the time this leakage becomes an avalanche.

I think I understand what you are saying but orientating and fitting thin magnets into the shed (or shim as you call them) mold is going to be a serious engineering cost as opposed to say just adding an extra shed to increase the insulators voltage breakdown rating, or leaving it as it is.

I work with production engineering and I just cannot see how adding magnets to lose a shed or two (+ reduced fibreglass rod length) is going to be more cost effective (even if it worked flawlessly AND all costs for mold modification, machining, laboratory testing, certification, marketing of new design, etc were totally ignored).

With regards to "will it actually work", "is it a viable alternative" and "whats the long-term life performance", that is an entirely different matter!

I would be interested in any links you may be able to find on research and development on the subject (relating to composite insulators).

The only place the magnet could be is on the end of the insulator. If the magnet is located anywhere else it shortens the flash-over distance to it's new location. Having the magnet at some mid-point will create a new corona spot that leads to flash over because the magnet changes the electrical voltage field intensity along the length of the insulator. Magnetic and electrical voltage fields are two different things.

The magnet would have to try to simulate a corona ring to spread the electrical field out, aluminum corona rings are always used for corosion resistance, usually all non-ceramic insulators over 138kV have corona rings, ceramic and glass over 220kV to 345kV have corona rings, depending upon conditions.

Although corona can happen below 10 volts with the right conditions, and arcing at battery voltages.

Jack of All Trades was saying this after a fashion.

This is indeed an excellent idea. With composites occupying important field in the field of Engineering I am sure your idea will be thought over by some for carrying out research and finding a solution.

Lot more thought has gone into this idea- after visit to the best High voltage test lab and in consultation with one off the best composite manufacturers. Basically- I found kind of a reluctance to to try and make a few attempts. Attitude is"Why should I do anything- when I ma satisfied with the yield and there are no market driven forces to develop anything new. Existing insulators meet IEC requirements (which itself is written based on available technology". Hence there was a need to actively participate in this blog. I am fully aware of the aluminum corona ring placements etc etc."

"The ultimate measure of a man is not where he stands in moments of comfort but where he stands at times of challenge and discovery." -- Martin Luther King, Jr.

This concept is actually used for certain high-voltage low vacuum applications. Called "Magnetic Insulation", the technique can increase the flashover potential of an insulator (or a conductor) within a low vacuum. The magnetic (B) field should be perpendicular to the applied electric (E) field (i.e., parallel to the insulator surface). The technique typically uses DC fields of ~ 0.1 - 2T or pulsed B fields self-generated by large pulsed currents flowing through cylindrically-symmetric conductors. The idea is to force any free electrons (or secondary electrons from collisions) in the insuating gap to follow circular or spiral trajectories that return them to the emitting conductor or insulator surface rather than allowing them to make it to the opposite conductor. The technique works very well for certain ultra-high pulsed power applications such as pulsed accelerators, pulsed microwave devices, or other pulsed power systems.

Unfortunately, this is a rather exotic technique, and it only works for insulators or conductors immersed within a relatively high vacuum. So, Magnetic insulation will not work in air or SF6 at atmospheric pressure due to the very short mean free paths and lifetimes for free electrons.

Following is a very technical paper that describes using Magnetically Insulated Transmission Lines (MITL's) for handling very high voltages in very confined spaces. This particular application for Magnetic Insulation is used in the Sandia Z Machine:

http://www.sandia.gov/pulsedpower/prog_cap/pub_papers/Z_MITLs_120401.pdf

Thank you very much for this elaborate, technical explanation. I have just downloaded the article - link given by you. It seems to be useful at first glace. Will revert- if there are doubts.

"Diligence is the mother of good fortune." -- Miguel de Cervantes

Thank you very much. On CR 4 it is one of those rare responses which gave satisfactory scientifically supported explanation.

Why one has been looking fro a new approach is - India is looking for upgrading its transmission line from existing 400 KV to 1000 KV (1MV). What puzzled me was the technology for 11 KV to even 1MV for making composite insulator is almost same - except for adding more shims or adding some aluminum corona rings. It is specifically targeted at 1MV insulator market. I am associated with company making magnets in India and will be keen to support any composite insulator manufacturer who is willing to take up the development seriously. Well, if this helps to get competitive advantage at lower voltages like 25KV, there is another bigger market to explore.

The method we used in starters and contactors many years ago was to have very thick coils each side of the contacts wired in series with the contacts, so as the contacts "break" and an arc forms, the current that is passing through the arc now "blows out" the arc!!!

Simple and effective and no need for magnets.......

I am sure that someone here, more up to date than I, can explain this far far better....

Yes, I do have a pdf file titled" Magnetic blow-out circuit breakers" - Electricity -100 years ago. It does use permanent magnets. This was one of the appears which prompted me to pursue the idea further.

Sometimes what's old and didn't work (except as a marketing tool) keeps coming back to waste time.

"I believe we are masters of our lives - we hold all the cards and it is up to us to use them right." Vesna Vulovic - survived 33,000ft fall

This is your individual perception. Did you that for GPS or Global positioning system - which every talks about fitting in his vehicle and even guided missiles work on it- the mathematical analysis was developed almost in 1970 or earlier? Do you know that in GPS signal to noise ratio is less than one- which means there is more noise than signal? No one could imagine its mathematical application when it was developed !!!!!!!! Keep such comments to your self.

This forum is strictly for technical discussion- don't have to make such comments

"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

If you ask a question, you may appear like a fool for a moment, but if you don't, you may remain a fool for ever.

"The way to get started is to quit talking and begin doing." -- Walt Disney

LOL!

We already know that MSDIVEKAR and a2x=z are one and the same. INCOGNITO sounds suspiciously like a third clone. (Just curious.)

Could well be true!!