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Transformer Monitoring



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...

Transformer Monitoring

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...

Related Articles


hydrocarbon gas emission

Advancements in Dissolved Gas Analysis: Risk Assessment

In general, the purpose of periodic screening with DGA for power transformers is risk assessment. Is any transformer likely to fail in service? If so, how severe is the problem? Previous articles in this series have described ways to improve DGA interpretation. In this article we provide a glimpse...

hydrocarbon gas emission

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...

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...


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