Cables AC Resistance

Sigh. Do you remember the work of Oliver Heaviside from your formal training? (picture from Wikipedia)

He did a little bit of work on transmission line theory.

rathakrishnan05 What is the voltage rating of your cable?

I can't answer your question directly without consulting a text book. There's not enough motivation for me to do so either and you are probably too busy to do so as well.

The cable vendor is the potential winner in this case and I would recommend that you make him(or her) sing for their supper.

Let the vendor do the work and come up with a technically sound reason for you to select them and to remain "preferred".

My advice does not mean that you shouldn't try to find out for yourself (to either confirm the vendor's advice or to even give them a leg up) or that other CR4 contributors shouldn't offer advice. In my opinion, and experience, delegating the task to the party that has the most to gain is the most efficient course of action.

If the vendor gets it wrong then it is their rap too.

These frequent questions on cabling choices that CR4 happens to draw have always bothered me. To me they always beg the question "Why do you ask?" The wiring and cable selection of a high voltage power distribution should only be decided by someone both formally trained in the transmission line theory of Oliver Heaviside and only by somebody authorized to be making these selections.

As for your business perspective of distributing the responsibility of choice selection to a vendor, I have some serious reservations about that. A vendor certainly should be able to explain their product to a knowledgeable customer. A vendor should also be able to promote the attribute improvements that their product has over a competitor. When the potential customer does not understand the meaning of the product's attributes then the vendor is setting everyone up for failure. Regardless of how well a product can be utilized, if the customer does not understand what the critical attributes are or what they mean, the product can be implemented incorrectly.

Getting back to what I believe is the answer to my question, "Why do you ask?" I am certain that the OP is a student of power distribution. Hopefully they are a student in a formal scholastic program but if not there is certainly nothing wrong in being self taught. Oliver Heaviside was self taught long before telecommunications was a dream. Our OP might be already working somewhere in the power distribution community and are just curious how a proper cable selection is done. If and when our OP returns with any questions that shows that they grasp the introductory concepts of a distributed network I will certainly do my best to explain what is happening. I will not waste my time though on somebody who will not work.

Dear Mr.wareagle,

Thanks for your prompt reply. In the Gulf cable catalog they have mentioned AC resistance, Inductance and Capacitance. Now how can i consider these values for cable sizing. Once again thanks in advance.

Dear Mr.wareagle,

Thanks for your prompt reply. In the attached Gulf cable catalog they have mentioned DC Resistance, AC resistance, Inductance & capacitance values. How we have to consider these inductance and capacitance values in cable sizing calculation.

If the manufacturer stated L and C then that's what they are, not X_L or X_C. BTW you have the latter formula wrong as shown. Please do not ask what it is.

As Standard Guy said, You are likely reading L and C. Not Xl or Xc

To answer your question " How we have to consider these inductance and capacitance values in cable sizing calculation", you don't unless you are concerned about voltage drop. Again what is the voltage rating of the cable.

the voltage ratings are 4.16kV and 480V cables.

Have you consulted the vendor yet?

yes i hav sent mail already.They replied we will consult with technical dept and come back to us.

rathakrishnan05

There is no reason for you to be concerned with Xc. If you cable run is excessive, then you may want to calculate voltage drop using R + jXl. Otherwise you cable selection is base on the amperage rating.

http://www.houwire.com/products/tech...cle310_71.html

http://www.okonite.com/product_catalog/section2/section2-pdfs/2-23.pdf

http://www.superb.org/power/nec%20tables.pdf

Check pages 9 and 10 for 600v cable