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Electrical 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...

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...

Power Utility Replaces Aging Transformers with Customized, Drop-in Units

As aging transformers at generation facilities near end-of-life cycles, a number of potentially dangerous events can come into play when it comes to aging transformers – in addition to untimely power outages and costly repairs. Because many transformers are exposed to dust and high operating...

Electrical Transformers

Transformer Diagnostic Testing

Transformer diagnostic testing: standards to diagnose equipment with Sweep Frequency Response analysis

BY VOLNEY NARANJO, Megger

Sweep Frequency Response Analysis (SFRA) has become a powerful tool in advanced power transformer assessments and probably one of the main and first tools used to diagnose troubled transformers or as a regular maintenance test. In addition to being able to detect problems related to the mechanical or electrical integrity of the transformer, the results can be compared to...

Related Articles


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...

electrical transformer

New options for insulation systems in power transformers

Introduction The development of new insulation materials has been critical in the evolution of the design of power transformers. Insulation systems for liquid filled power transformers are a combination of materials that are aimed to provide the required electrical, mechanical, thermal properties...

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...


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