Rapid response averts power failure

Paul Boughton

Specialist expertise and a rapid response from Furmanitethe speciality services company geared to maximising asset uptimeenabled a fault at a main supply grid station to be repaired within 24 hours – ensuring uninterrupted electricity supply – where a similar fault had previously taken several weeks to rectify.

Switchgear on a 33KV busbar chamber at a Scottish Power Grid substation north of Glasgow had been damaged when the chamber casting (manufactured from aluminium alloy and filled with hot bitumen compound) suffered severe distortion following an internal flashover. Two 3–4 inch vertical cracks and a 1⁄4 inch hole in the casing had resulted.

While depending on the alternative busbar systema failure would have left up to 40 000 customers at risk of losing their electricity supply.

Furmaniteknown for its specialist on-site leak sealing expertisewas called in to helpand undertook an on-site assessment of the damage and operating conditions to select the most suitable method and materials for an in-situ repair.

The cracks were contaminated with bitumenso an in-situ welded repair had been ruled out.

The recommended solution was an innovative epoxy putty repairdesigned to accommodate the operating requirements for the chamber which is filled with hot bitumen compound at around 140°C.

The solution was readily acceptedwith Furmanite’s technicians on-site to undertake the repair within 24 hoursthe day after the order was received.

The surface of the casing was prepared using aluminium desoutter and roughing toolsworking carefully directly on and around the defects.

A range of fast-curing epoxy putties were then appliedcombined with reinforcing layers for extra structural strength.

The applied repair fully rectified the damagesealing both the cracks and the holewith a design life of some 10 years.

ScottishPower PowerSystems senior project engineer Ken Hamilton pointed out: “This fault was very similar to one which occurred at another site nearly four years ago.
“On that occasion the repair required us to carry out continuous 24-hour working to dismantle the fractured casting. This was then transported to Manchester where a specialist welding company completed a repair.

“The casting was then returned to site and re-assembled before re-filling three chambers with a total of three-quarters of a tonne of hot bitumen compound.“

He continued: “It was a very big job and took many weeks to complete before the network was finally restored to normal. On this occasionthanks to Furmanite’s prompt responsethe repairs were completed over the weekend. This allowed us to complete all our work and restore the switchgear to normal service just over a week later.”
Furmanite sales manager Jim Russell added: “We’re geared to helping our customers maximise asset uptime.

“This is typical of the service we offerapplying our technologyexperience and expertise to provide a solution to meet the customer’s needs.”

MeanwhileFurmanitein conjunction with ExelonCaldon and Sargent & Lundyengineeredhas designedmanufactured and fitted a complexmulti-part enclosure clampat Exelon Peach Bottom Atomic Power Station PennsylvaniaUSA. It was tested to extreme tolerances and safely installed while the unit remained on-linebut at a lower power level.

For more informationplease visit www.furmanite.com

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