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Utility Transformers



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...

Utility Transformers

Transformer testing and failure analysis

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. Common events or conditions that can lead to a transformer failure include lightning or switching impulses, sustained overvoltage, short circuits on the electric system, overloading, overheating, dielectric breakdown of the insulating oil due...

Related Articles


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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Power Transformers Health Check

Power transformers are static electric machines used to step-up or step-down voltage in electric power applications. The capital cost of a power transformer in the range of 100MVA can be $1M or more and by the time it is under operation, the price is increased. The average age of installed large...


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