Isolated phase busducts maintenance

[npower0073]

Dear all. On site, a CCPP 400MW nominal output and IPB manufactured by EGE. We are in the process of making maintenance contract with a contractor. I know tht somethings to be done is leak test with pressurized air, insulation test, inspection of bars, paint checks tightness of bolts, and so on. DO you know any company near Greece or in Europe general to provide such services?

 

[ScottyUK]

Gordon Kitto Welding are successors to the part of the Balfour Beatty Power Construction business which dealt with IPB construction. They went though a period trading as Emform a few years ago. They definitely support UK field service, but I'm not sure about mainland Europe. Link below.

http://www.gordonkitto.co.uk/

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[npower0073]

From the AS BUILT manuals i saw that i have mainly to do the following:
Check tightness of connections
Check insulators
make insulation test
make air leakage test
Check for any ingress of dust or dirt

 

[electricpete]

I was going to suggest to check the insulators. Of course the porcelain of the insulators. But what may not be so obvious is that some buses (like at our plant!) are suspended from above by insulators rather than supported from below by insulators. The insulator has lead molded between the base and th einside of the porcelain, and it tends to creep under tension. If you examine the base of the insulators you can see subtle differences in the dimensions (up to 1/4" in our case) as the insulator slowly pulls off of the base.

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[burnt2x]

Know what bolts are being used also. If you had been doing bolt tighness testing for some time, embrittlement on bolts might require you some relacement bolts. It is best to do IR thermal pics on the system prior to specifying to contractors. Make sure the sytem load is noted when taking IR thermal capture so that you can narrow down which bolted joints are your priorities.
My $0.02.

 

[npower0073]

On the external piping of the busduct there are several flanges with bolted connections to the pipe. I guess that these flanges are for inspection reasons. Is that right?

 

[ScottyUK]

Depending on the design of the IPB (and depending on what you mean) these could be access points to the insulators which support the bar or access points to joints, bends, or tees in the bar. Any chance of a photo?


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If we learn from our mistakes I'm getting a great education!

 

[GTstartup]

Since you mention insulation test, I recommend and AC hipot test. A DC or "megger" test is basically a waste of time

 

[ScottyUK]

Partial discharge will pick up much more and detect it before it goes terminal. PD test is especially good with resin insulators. It's arguably more expensive to do but compared to the time and effort to repair a damaged IPB the additional cost is negligible.


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If we learn from our mistakes I'm getting a great education!