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Electrical Transformers


Advantages of Headspace Hydrogen Monitoring for Network Transformers

INTRODUCTION The utilization of online dissolved gas analysis monitoring has proven to be one of the most effective predictors of overall transformer health and condition. Monitoring can vary greatly from nine gas to single gas systems to best suit the customers application when considering...

Dielectric Fluids


Advancements in Dissolved Gas Analysis: Data Quality

IntroductionThere is more to DGA interpretation than comparing the latest gas concentrations to limits in a table or plotting them in a triangle or pentagon to identify the apparent fault type. We have found that the whole DGA history of a transformer must be considered when interpreting its most...

Transformer Protection


Case Study: Rapid Changes in Bushing Health

IntroductionContinuous online monitoring of bushings provides real-time information which can result in the early detection of a possible failure. Challenge: A Major AlarmA prominent U.S. utility was looking for a way to improve system reliability for their 138kV assets. They researched and...

Transformer Monitoring


Transformer Testing & Maintenance


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...

Utility Transformers


Advancements in Dissolved Gas Analysis: Accounting for Gas Loss

Dissolved gas analysis (DGA) in transformers is a very successful periodic screening method to identify transformers that may be having problems. It is a symptom-based assessment of health, rather than a condition-based assessment. That is because the gases themselves do not cause failure, but are...

Power Transformers

Sweep Frequency Response Analysis

Sweep frequency response analysis: Reliable demagnetization of transformer cores

BY MARKUS PÜTTER, MICHAEL RÄDLER, BORIS UNTERER, OMICRON electronics GmbH

Whenever a power or distribution transformer is isolated from the power system, it is very probable that residual magnetism remains in the core due to the phase shift. However, residual magnetism also occurs when performing winding resistance tests. Since manufacturers use these measurements in their routine testing and these tests are typically performed for on-site condition...

Power Transformers Articles