Electricity Forum Intelligent Power Today Magazine Arc Flash Clothing

Transformer Testing & Maintenance


Dielectric Voltage Testing – Standard Methods

There are two standard methods from ASTM International: D877, Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes, and D1816, Standard Test Method for Dielectric Breakdown Voltage of Insulating Oils of Petroleum Origin Using VDE Electrodes. VDE stands...

Harmonic Problems in Power Transformers

Preventing malfunction in power transformers BY ANDY SAGL, Megger Harmonics are another power quality phenomenon that can cause equipment to malfunction. Harmonics are a sinusoidal component of periodic waves that have frequencies that are multiples of the fundamental frequency. Harmonics can cause...

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...

Transformer Testing & Maintenance

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


DGA graphs

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...

A New Approach to High Voltage Insulation System Testing

Speed is the driving force of successful fault prevention. Early detection of insulation deterioration is key for avoiding asset failure, associated unplanned outages, and physical damage to infrastructure. The traditional testing approaches most teams rely on inhibit quick diagnosis of insulation...

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...


Page 1 of 9