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Electrical Transformers

Industry and Education

As we see the electrical industry advance it is obvious the demographics will be challenged. The infrastructure investment needs of the electrical and renewable energy grid will reach the $billions$ over the next 15-20 years with expensive, complex and specialized training and education needs. ...

Utility Transformers

How to Improve Transformer Protection

Using symmetrical components for fault discrimination in differential protection BY IMRAN RIZVI, ABB Inc. Classical differential protection schemes are subject to ghost differential currents due to current transformer (CT) saturation and magnetization currents. Several methods are used to counter...

Transformer Monitoring

Protection of Electrical Power Transformers

INTRODUCTIONIn most large electrical systems, generators and power transformers are the two most expensive pieces of equipment. In addition to the capital cost of purchase, these two key devices are also the most critical to continuous and reliable operation of the system.Consider, for example, the...

Transformer Testing & Maintenance

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...

Dielectric Fluids

Advancements in Dissolved Gas Analysis: Investigating Failure Cases

IntroductionDissolved gas analysis (DGA) provides the early warning radar view of a transformer fleet with a non-intrusive screening process for early identification of problematic transformers. Suspicious transformers can be subjected to more invasive and costly physical testing to determine the...

Transformer Protection

Prevent Transformer Shutdown

Power transformers seldom shutdown; however, if a shutdown occurs, the effects would be immediate and devastating to utility operations. According to “An Analysis of Transformer Failures” by William H. Bartley, P.E., on behalf of the Hartford Steam Boiler Inspection and Insurance Company, the...

Power Transformers

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).

Power Transformers Articles