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Transformer Testing & Maintenance


Power Transformer Failures

Electric utilities maximize utilization of their assets, while maintaining reliability. Power transformers are typically reliable, but have been known to fail suddenly and/or prematurely. Transformer failures are both costly and can leave customers dissatisfied, harming the reputation of a utility....


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 Testing & Maintenance

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 the impact of these unwanted differential currents. Electricity Today Magazine and ABB will focus on how to improve transformer protection by using the symmetrical component techniques to stabilize differential protection schemes without sacrificing the speed and...

Related Articles


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...

Normalized Energy Intensity chart

Advancements in Dissolved Gas Analysis: NEI & Gassing Events

One of the most important steps when looking at DGA data is to decide whether the data support the existence of a fault that is actively breaking down the insulation before you try to use a triangle, pentagon, or gas ratio method to identify a fault type. Otherwise, you are diagnosing random...

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...

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...


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