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Transformer Testing & Maintenance


Insulation Resistance Test

Insulation Resistance (IR) test, often called Megger test, is more than 100 years old and assumed to be a very straightforward test. During my inspection and testing work in the past 15 years in Canada, US, and internationally, I have seen different practices of performing and interpretation of IR...

Designing A Safe & Reliable Transformer Maintenance Program

The critical importance of power to every aspect of our world cannot be over-exaggerated. It must be generated and distributed effectively to end users, and any disruption in that process means loss of operations, money, and in extreme cases, life. Therefore, the reliability of power creation and...

The Dissolved Gas Analysis Toolkit

Dissolved gas analysis: addressing the challenges of collecting samples BY DONAL SKELLY, GE’s Digital Energy business Dissolved gas analysis (DGA) is a technique for identifying and quantifying the gas formed in oil-filled electrical equipment because of either the natural aging of oil and paper...

Transformer Testing & Maintenance

transformer repair

Radiator Fin(s) Leak Repair

Radiator fins are notorious for leaking at various locations. One of which is where the fins are attached (welded) to the horizontal bottom-run header. Measurements are taken so a weir box can be installed to cover the fin(s) that are leaking. It is preferred the weir box will cover above the leaking area about 6".
This 6” cover will allow for urethane (poured into weir box) to adhere to the drier part of the fin(s) to assist with the sealing process. After pour, the technician will mark the outside of the weir box at the location(s) where the original leak was. This incase further work may be required for a better seal. After the urethane is poured and let to cure (usually overnight) the job is inspected to determined seal effectiveness. In the event we still have some leakage; whether the following day or later, an additional procedure may be performed. If leaking, the weir box is fabricated out of 11ga galvanized sheet metal which is thick enough for completing a 1/16" NPT. The technician will decide where (usually where it's been marked) and how many 1/16" D&T’s (drill & taps) are required. Once additional d&t's are completed, injection valves installed, then a special 2-part sealant (must be approved from a dielectric and DGA standpoint) will be injected. The thought is: now that there is cured urethane above the original leak(s) and we have marked the weir box for injecting close to that spot, we have created a bridging barrier for our sealant to back up against (so as not to extrude out the top of the weir box).

Related Articles


The Dissolved Gas Analysis Toolkit

Dissolved gas analysis: addressing the challenges of collecting samples BY DONAL SKELLY, GE’s Digital Energy business Dissolved gas analysis (DGA) is a technique for identifying and quantifying the gas formed in oil-filled electrical equipment because of either the natural aging of oil and paper...

Zensol new instrument for OLTC testing

According to CIGRE A2.34, the dynamic resistance measurement or DRM (OFFLINE) is a test that offers diagnostics for several diverter or selector switch malfunctions such as: contact problems, broken springs, broken transition resistors, poor contact pressure, inadequate transition time, momentary...

FERC Complaint Targets Duke, PJM Transmission Planning

A coalition of large energy consumers and ratepayer advocates has filed a complaint with the Federal Energy Regulatory Commission (FERC), urging the agency to prohibit transmission owners from independently planning "local" transmission projects exceeding 100 kilovolts (kV). The coalition argues...


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