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Power-User

Join Date: Mar 2009
Posts: 126

Arc Flash at Cable Termination

01/28/2017 11:57 PM

Hi All,

In our 22Kv power distribution system which consists of 10 units of transformer step down from 22/.415Kv the system already in service for 25years (1992). However we are encounted numerous of arc flash at out going from ABB SACE HA2 GIS switch gear.

Cable termination kit brand : Raychem ,

Cable type : PILC

By the way yearly we have conduction partial discharge method inspections ,however not detected any sign of arc flash.

Need technical advise fro all electrical guru

Thank you

aikhh

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Guru

Join Date: Mar 2007
Location: at the beach in Florida
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#1

Re: arc flash at cable termination

01/29/2017 12:14 AM

What portion of your equipment is original? Have transformers and capacity been added over the years?...and if so has the safety equipment been upgraded as well? Who is advising you? Do experienced electricians control the system or are they new?

http://www.abb.com/product/ap/db0003db004279/B11201F3920BE1ECC1257AAD003C8877.aspx

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Guru
United Kingdom - Member - New Member

Join Date: Aug 2010
Location: Resting under the Major Oak
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#2

Re: arc flash at cable termination

01/29/2017 6:27 AM

It would help if you told us where the flashover occurs. Is the cable shielded? Has stress relief been used? Etc.......

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Associate

Join Date: Sep 2016
Location: Madrid, SPAIN
Posts: 45
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#3

Re: Arc Flash at Cable Termination

01/30/2017 1:27 AM

Electric Arcs usually happen because of some sort of inductance. Assuming that your system is properly designed, you must have some sort of parasitic inductance.

Change all power cables by shielded power cables in the affected area.

If you cannot afford it, then wait for it to break. It will not last long.

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Guru

Join Date: Feb 2013
Posts: 1272
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#4

Re: Arc Flash at Cable Termination

01/30/2017 5:38 AM

I have doubts that this is in fact arcing in the traditional sense, as people know it here. I highly suspect tracking on the heatshrink tubing and possibly the stress cones to earth being too close a proximity to one another and possibly earth.

Where is the arcing occurring? Around the cores at the stress cone tops? At the crutch seal? Elsewhere? Is this singe core PILC or 3 cord PILC?

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Guru
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Join Date: Sep 2006
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#5

Re: Arc Flash at Cable Termination

01/30/2017 3:46 PM

Is this a failure in the cables or solid dielectric insulation components, if so have you checked the failures are not due to Electrical Treeing?

Electrical_treeing

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Guru

Join Date: Feb 2013
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#6
In reply to #5

Re: Arc Flash at Cable Termination

01/30/2017 4:11 PM

Just to save some confusion, PILC (Paper Insulated Lead Covered or Lead Cable), Oil or grease filled. Drained or mass impregnated, so there should be no treeing. Treeing normally occurs on solid dielectrics such as XLPE, PVC, EPDM (plastic type insulations and not craft paper types).

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Guru
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#7
In reply to #6

Re: Arc Flash at Cable Termination

01/30/2017 4:38 PM

It was unclear to me if the failures were actually in the PILC cables or something else related to them nearby.

'at' to me could have implied some sort of solid dielectric termination kit or bushing could perhaps be the cause and not the cable itself.

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Guru

Join Date: Feb 2013
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#8
In reply to #7

Re: Arc Flash at Cable Termination

01/30/2017 4:45 PM

Ok, I took it at the termination as he stated Raychem, which I also assume to be a heatshrink term. He needs to offer up detail or a photo.

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Guru

Join Date: Dec 2010
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#9

Re: Arc Flash at Cable Termination

02/02/2017 11:12 AM
  1. When do arc flashes occur? When opening ABB breaker? When other breakers operate in 22 kV system? During Lightning storms? Or at other event....
  2. Are the faults just on one phase?
  3. Where is damage? In switchgear? In cable?
  4. Who repaired damage? Same person each time?
  5. What protection relays operate?
  6. Any pictures of damage?

CR4 can only work on what you write.

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Guru

Join Date: Feb 2013
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#10
In reply to #9

Re: Arc Flash at Cable Termination

02/02/2017 11:55 AM

I doubt we will hear any feedback on this. Dirty terms and insulation breakdown no doubt.

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Guru

Join Date: Apr 2007
Posts: 543
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#11

Re: Arc Flash at Cable Termination

02/08/2017 11:26 PM

Please send us the photo at what point the arc flase occure. You have encounted numerous of arc flash at out going from ABB SACE HA2 GIS switch gear but does not specify at which location. It is at the VCB or at the termination kit?

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