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Insulating Fluid Analysis


Insulating fluid analysis is a proven loss prevention technique which should be part of any preventive maintenance program.

Caneland Sunset 2a (Large)
IMG_3831a (Large)
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IMG_3825a (Large)

Protecting Transformers and Other Fluid Filled Electrical Equipment

Fluid monitoring and analysis is the key to electrical equipment reliability, performance and longevity.

Protect Your Investment

Insulating fluid analysis is a proven loss prevention technique, and a key component of any preventive maintenance program. Oil sampling is the most effective and cost efficient test that can be performed on electrical equipment, since the majority of the testing is done online, with no power interruption. It has been estimated that transformer fluids contain approximately 70% of the diagnostic information available for transformers. Sampling provides a means to check the condition of the oil and how it compares to industry averages. For in-service transformers, sampling and testing the oil provides a method to determine the condition of the solid and liquid insulation systems, as well as the operating condition of the unit, without opening or de-energizing the transformer.

Early Detection

Early detection is key to preventing unscheduled outages. Understanding transformer condition on the basis of fluid analysis can prevent transformer failure. Electrical insulating oil and cellulosic insulation breaks down under abnormal thermal or electrical stress. The results of these stresses are the appearance of volatile and non-volatile gases, known as fault gases. Gas analysis technique identifies fault gases, and relates their quantity, generation rate and relevant ratios to type and severity of fault.

Typical Problems Detected

  • Thermal degradation

  • Arcing

  • Partial discharge

  • Degradation of paper insulation

Our Standard Test Package

  • Dissolved Gas Analysis (DGA), ASTM Standard D-3612

  • Moisture Content, ASTM Standard D-1533B

  • Interfacial Tension, ASTM Standard D-971

  • Acid Number, ASTM Standard D-974

  • Color Number, ASTM Standard D-1500

  • Visual Examination, ASTM Standard D-1524

  • Dielectric Strength, ASTM Standard D-1816 @ 1mm

  • Power Factor, ASTM Standard D-924

Additional Testing

  • Furan, ASTM Standard D-5837

  • PCB Testing, GC - MS/MS Method

  • Metals, ASTM D-5185

  • Particle Count, Laser Technique

Condition Assessment

It is recommended that DGA be performed annually with results compared from year to year. The value of our analysis increases once lifetime trending is made available.

In addition to DGA, the oil quality is also evaluated. In order for the insulating fluid to perform optimally it should meet certain criteria/test limits. No one technique will be able to accurately assess the transformer condition: they are all used together to provide a good evaluation. Being able to distinguish small changes in the fluid quality is important because once the oil is contaminated (oxidized, excessive water, sludge, etc) it is more difficult to successfully reclaim the oil. Once in the paper insulation system these contaminants are difficult to remove and ultimately reduce the life of the transformer.

Computerized Analysis and Reporting

The laboratory results are uploaded into our analyzing software (Delta X Research Transformer Oil Analyst™ software – TOA4). TOA4 provides state-of-the-art computerized interpretation of insulating fluid test results. With this software, we are able to quickly process test data and identify abnormal results so that decisive action can be taken to correct problems and prevent avoidable equipment failure. A written report detailing findings, recommendations and corrective actions is also provided.


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