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Anonymous Poster #1

# Compute Sequence Impedance for A Cable Tray

09/30/2017 2:48 PM

I have 3 runs of 500MCM cables in a tray. I need to compute the sequence impedance. I have cable parameters but the cable arrangement is not symmetrical i.e. I need to model the geometric. Do you have a suggestion?

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Guru

Join Date: Oct 2008
Posts: 40715
#1

### Re: Compute Sequence Impedance for A Cable Tray

09/30/2017 4:02 PM
Guru

Join Date: May 2007
Location: Annapolis, Maryland
Posts: 4388
#2

### Re: Compute Sequence Impedance for A Cable Tray

09/30/2017 10:55 PM

You're in luck if this is homework because as a student you can use the ATPDraw program royalty-free for non-commercial use.

http://www.ece.mtu.edu/atp/ATPDraw/ATPDraw.html

And then there are lecture notes about using ATPDraw to find the sequence impedances.

http://www.ece.mtu.edu/faculty/bamork/ee5200_F10/LineConstantsHKH.pdf

We would need to know more about the asymmetry to model it.

Active Contributor

Join Date: Sep 2017
Location: Russia, Moscow
Posts: 23
#3

### Re: Compute Sequence Impedance for A Cable Tray

10/02/2017 2:25 AM

If I understood correctly, then you are searching Symmetrical Components.

The positive phase-sequence resistance equals negative sequence impedance.

Need more information. What is the voltage? Are cables 1-phase or 3 or 4?

Guru

Join Date: Oct 2012
Location: 100 miles North from the World Center
Posts: 772
#4

### Re: Compute Sequence Impedance for A Cable Tray

10/22/2017 10:17 AM

The each single core cable current could be different [unbalanced]:

See:

A CABLE CONFIGURATION TECHNIQUE FOR THE BALANCE OF CURRENT DISTRIBUTION IN PARALLEL CABLES

http://jmst.ntou.edu.tw/marine/18-2/290-297.pdf

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Julius
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