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Transformer Testing & Maintenance


Conductive Glues

Electrically conductive pastes in high-voltage transformers BY LISA RINALDO, Prohm-tect As with other components of North American infrastructure such as wastewater and stormwater systems, much of the continent’s electrical grid faces long-term problems. Aging facilities, rising energy...

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...

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...

Transformer Testing & Maintenance

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 measurement noise, not the transformer. Conventional methods assign limits to each of the gases to detect and assess abnormal gas formation. Formerly it...

Related Articles


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...

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....

transformer repair

Radiator Fin(s) Leak Repair

Radiator fins are notorious for leaking at various locations. One of which is where the fins are attached (welded) to the horizontal bottom-run header. Measurements are taken so a weir box can be installed to cover the fin(s) that are leaking. It is preferred the weir box will cover above the...


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