Post on 19-Mar-2020
Leakers . . . What a Mess! Cost Effective Methods for Repairing
Transformer and Circuit Breaker Oil Leaks
Steve Wickman / John Edmon
TDS-Transmission & Distribution Services
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Transformer Leak RepairOil Circuit Breaker Leak RepairSF6 Gas Leak Repairs
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Transformer oil leaks
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Transformer oil leaks
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• Drain and regasket everything?So how do you address your transformer oil leaks?
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So what are your options?Repair Options Advantages Disadvantages
Do nothing • No repair costs • Environmental oil release issues
• Unsightly appearance of equipment
Transformer replacement • New state of the art transformer
• Restart the remaining life cycle
• Labor intensive• Extended outage time• High cost
Regasket/replace leaking components
• Restore transformer gasketingto a like new condition
• Labor intensive• Extended outage time• Typically the high cost option
Online leak seal • Repaired gaskets to like new• Repairs performed with the
transformer in service• Repairs performed in
hours/days• Typically the lower cost option
• Repaired transformer gaskets vs restored to like new condition
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•On line leak seal?
•What is that?
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An alternative oil leak repair technique by means of drilling and injecting sealant compound into the leaking transformer gasket groove on the leaking flange.
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ON-LINE
LEAK SEAL
DRILL & INJECT
REPAIR METHOD
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Drill and inject sealant compound into the leaking transformer gasket groove on the leaking flange.
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Sealant
Drill and inject method on 8-bolt connecting flange
Drill and Inject bushing gasket groove
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Many repairs on the lower end of transformer radiators, and pumps and piping can be performed with the transformer in service.
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Valve could be
leaking from
gasket
Valve could be
leaking from
stem
Cutaway view of flapper valve
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Common 4-Bolt Flapper
Valve Flanges can be repaired by drill and
inject
Leaks on the upper end of radiators and bushing flanges usually require an outage for safe work clearances
but can be performed in one or two days
and there is no wait time prior to restore
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Fabricate a precision clamp of
machined aluminum and utilize the
existing bolts to hold the clamp in place.
External Clamp Technique19
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External clamp
…fabricated from cast aluminum, and finished to precise dimensions to fit the specific component that is leaking.
External Clamps…21
Injecting sealing compound into bushing clamp
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Completed clamp installation23
Access hatches—external clamp24
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• Sealant is of the same durometer as nitrile rubber O-rings and gaskets
• All repairs are made with only one type of sealing compound
• The sealant cures in a matter of hours
• The apparatus can be returned to service immediately after repairs are complete
Properties of sealant material
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If sealant does get into the TR tank or oil filled cavity of a bushing, it will not react with TR oil, nitrogen, or SF6.
Properties of sealant material
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If the repaired component requires disassembly or removal, the cured sealing compound is always soft and pliable. It never hardens.
Properties of sealant material
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Main tank flange with full face gasket
Lid & LTC flange repair method
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Radiator drain valves…
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Cap over a radiator drain plug36
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Radiator fin leaks
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Designed clamp
on radiator fin
leak
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Oil pump bleeder/drain plug
Dresser Couplings
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Clamp over dresser
coupling
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Designed aluminum enclosure over dresser coupling
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NLTC operating shaft and handles
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NLTC shaft packing leak clamp
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CT lead penetrations into main tank
• If leak repair clamps are required in an area that could compromise electrical insulation clearances… a clamp made of non-conducting polyvinyl chloride [PVC] material can be used.
• Typically manufactured from 4 inch thick PVC plate sheets.
PVC Clamps…
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Oil Circuit Breaker Leak Repair
Steve Wickman, PE
TDS-Transmission & Distribution Services
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Circuit Breaker Repair Techniques
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Bushing gasket leaking
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Aluminum clamp installed
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OCB drain valves
SF6 Gas Leak Repairs
Steve Wickman, PE
TDS-Transmission & Distribution Services
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The good stuff...
Higher dielectric strength than air or nitrogenProvides for compactness in the design of equipment
SF6
The bad stuff...
Found to be the most potent greenhouse gas known to dateEmitted into the atmosphere it accumulates in an undegraded state for centuries
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SF6 Leak Detection
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SF6 Leak Detection
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External clamp
Leak Repair Technique on SF6 Apparatus
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External clamp
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External clamp
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External clamp
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External clamp
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External clamp
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External clamp
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Clamp repair concept drawing
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External clamp
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External clamp
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SF6 piping leaks in GCB control cabinet
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SF6 piping leaks
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SF6 piping leaks
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GIS substation leaks
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GIS leaks
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GIS leaks
• Come see us at our booth in the Expo area…
History & development of substation leak seal73
Thank you…
Steve Wickman, PE
TDS-Transmission & Distribution Services
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TRANSMISSION & DISTRIBUTION SERVICES, LLC
28369 DAVIS PARKWAY, SUITE 401
WARRENVILLE, IL 60555
P∙775.586.8300
F∙775.586.1105
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Steve Wickman
630.853.3104
swickman@tdsgroup.biz
John Edmon
775.240.1319
johnedmontds@msn.com
The content of his presentation is the intellectual property ofTDS-Transmission & Distribution Services, LLC. All rightsreserved.
www.tdsleakseal.com
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