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Anonymous Poster #1

# How To Calculate Cable Inductance and Capacitance Parameters

09/26/2017 5:36 PM

Based on this file from ABB, We can get the capacitance and inductance parameters of a cable
https://library.e.abb.com/public/321b7c021cb73fefc1257a40004c237c/2012%20XLPE%20Users%20Guide_USA.pdf
I'm confused.
- Per page 21
C = Er/59/ln(r0/ri) = 2.5/59/ln(r0/ri); ro seems straight forward from Table 19 column 6 i.e. 2.14, 2.32, ..etc. How to compute ri to get 0.069, 0.079, etc? What is ri value?
- Same for inductance
L = 0.0152+ 0.061*ln(K.S/rc) mH/1000feet;
What is the arrangement in Table 19 to get the inductance? look to columns 11 & 12, What is S spacing factor used here and how the values in 0.224 & 0.122 determined in column 12 [mH/1000feet] without S value?

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#1

### Re: How to calculate cable inductance and capacitance parameters

09/26/2017 6:06 PM

This document shows how the important parameters of coax cable are computed.

http://www.rfcafe.com/references/electrical/coax.htm

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#2

### Re: How To Calculate Cable Inductance And Capacitance Parameters

09/27/2017 12:00 PM

See:

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Julius
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Location: Lubbock, Texas
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#3

### Re: How To Calculate Cable Inductance And Capacitance Parameters

09/27/2017 12:22 PM

The dog ate my homework, did he do yours?

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Join Date: Oct 2012
Location: 100 miles North from the World Center
Posts: 754
#4

### Re: How To Calculate Cable Inductance and Capacitance Parameters

09/27/2017 2:04 PM

Thank you, James. I don’t have a dog but only a big fat cat who never eat a homework.

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Julius
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Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13540
#5

### Re: How To Calculate Cable Inductance and Capacitance Parameters

09/27/2017 2:11 PM

My cat boys are the fattest cats in the neighborhood also, and they are night cats that hang out (up to no good) in the alley, until I get up at 05:00.

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