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nawas
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Join Date: May 2007
Location: Abu Dhabi
Posts: 11

Flashover - Medium Voltage Switch Gear Panel

06/15/2015 4:27 AM

Dear Engineers

We are facing frequent flashover in our Medium Voltage switch gear panel ( Panel details :- SRP - SRUP Make : ABB ) . We noticed from the incident all its happening between the Cable compartment and Busbar area.

The way of explosion we cannot confirm what is the reason and also we noticed one of the VT ( voltage transformer ) Grounded in the primary side but no any Physical damage in the VT , Cable terminal badly damaged .

I am Just wondering if anybody else has come across this problem & if so how did you resolve it and also share your experience with SRP panels .
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RAMConsult
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Engineering Fields - Power Engineering - New Member

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#1

Re: Flashover -Medium Voltage Switch Gear Panel

06/15/2015 9:49 AM

If your cable terminal is badly damaged then you should be examining the other terminations to be sure that they are correctly installed. You should also look for evidence of some type of contact between the cable and a creature. Check the insulation integrity of everything in the cubicle while it is de-energized.

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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#2

Re: Flashover -Medium Voltage Switch Gear Panel

06/15/2015 5:05 PM

It is supposed to be a medium voltage switchgear panel, not a rodent cooker!

Contact the panel manufacturer for advice, if necessary purchasing a call-out. Do it by telephone. Do it today.

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jack of all trades
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New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

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#3

Re: Flashover - Medium Voltage Switch Gear Panel

06/15/2015 9:02 PM

Contact the manufacturer immediately, the panel may not be fit for purpose or installed correctly for the environment it is in.

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satnat.2008
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Join Date: Oct 2011
Posts: 34
#4

Re: Flashover - Medium Voltage Switch Gear Panel

06/16/2015 12:51 AM

Is your system an ungrounded system .

If so , then your grounded PT will increase the capacitance in other two healthy phases . ie In an ungrounded system ,a single phase ground fault will increase the rated voltage by 1.732 times in other two healthier phase . which will lead to arching fault . These kind of fault will not remain for a longer time . however if the same is not isolated then it will lead to collateral damage .

Is it helpful .. give your feedback ...
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SHOCKHISCAN
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Join Date: Nov 2007
Location: Eastern Arizona mountains on Route 666 about a mile from God's country
Posts: 1676
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#5

Re: Flashover - Medium Voltage Switch Gear Panel

06/16/2015 10:10 AM

New problem? Or old reoccurring one?

Possible causes:

Incorrect cable termination(s)? (Shielded, or non-shielded? Are the insulation layers stripped back the correct distance and installed properly?)

Improper cable termination? (Loose connections, oxidized surfaces,?)

Incorrect cable or lug size for application? (Too small to carry the load.)

Ambient contaminants present? (Acid?, Moisture?, Oxygen enriched? ?)

Are the cable drain conductors correctly terminated as per the OEM specifications?

Is the spacing correct on the cables throughout the area(s)?

Are all of the drains and grounds properly secured so that there is no contact between the cable insulation and/or conductor shields?

Is the cable and/or buss bar insulation intact and properly installed?

Was a CT open circuited due to a failed ammeter or improper maintenance procedure?

If connected to a VFD; Is the drive going into regeneration for too long a period of time with no means of discharging the voltage induced by the collapsing field when power is removed or drive is stopped?

We have multiple ABB MV panels and they work very well if maintained properly.

Hope this helps.

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roykav
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Join Date: Dec 2011
Posts: 96
Good Answers: 2
#6

Re: Flashover - Medium Voltage Switch Gear Panel

06/20/2015 2:34 PM

usually primary of VT will not be grounded, only secondary will be grounded.
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jack of all trades (1); PWSlack (1); RAMConsult (1); roykav (1); satnat.2008 (1); SHOCKHISCAN (1)

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