×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Power cable failure Intake pumps
2

Power cable failure Intake pumps

Power cable failure Intake pumps

(OP)
Hi all,

Recently we experienced a failure on several 2.4 kV AC feeder cables and control DC cables as a result of a short circuit flash. The feeder cables are supplying power to high horsepower pumps which are used to maintain water level in an intake channel used for Steam Turbine systems. Attached, I included several pictures illustrating the failure and the location where the cables are located.

Several years prior the failure the conduits going to the pumps were revamped, however the contractor introduced several splices on the power and control cables. As a results water/ moisture may have entered the splices and caused the cable failures. Moreover, do to the cables (power and control) been so close to each other, it also damaged a feeder cable from another pump. The short circuit was so intense that it went also through the DC control system (125 VDC) shorting and burning other relays, circuit boards, etc.

I was wondering if the community may provide additional probable causes that may damage a power cable in such matter. Any recommendations to prevent such mishap is also appreciated.

In advance many thanks for your cooperation and support.

Kind regards,

Jairo




RE: Power cable failure Intake pumps

2
The evident layout, workmanship, and maintenance conditions alone indicate that this sort of damage and collateral damage would happen, and will happen again. Shall I really discuss proximity, placement, fireproofing, securing of cables here? Need I point out collapsing vault walls, unbushed, unpacked conduit ends? Is anyone familiar with the forces and movements of cabling when subject to bolted or arcing fault conditions? Even normal environmental thermal movements don't appear to have been properly addressed.

This is not to say such lousy installations are entirely uncommon, but such failures are an expected consequence.

.

(Me,,,wrong? ...aw, just fine-tuning my sarcasm!)

RE: Power cable failure Intake pumps

A costly lesson for some bean-counter somewhere.

Muthu
www.edison.co.in

RE: Power cable failure Intake pumps

(OP)
Hi HCBFlash,

Thanks for your reply. Indeed, the pit is far from been adequate for the purpose of cables. On a short term what would you recommend as a corrective/ preventive measure?
Furthermore, the pit is also used for 125VDC control, not sure if protective devices on the DC system would been able to isolate the faults injected by the AC system.

Kind regards,

Jairo

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources