Transformer Oil Diagnostics | EA Technology
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Transformer Oil Diagnostics

Transformer oil holds critical information on the condition of the transformer from thermal and electrical faults to contamination and degradation of the oil. Without monitoring, these conditions can take a toll on the life of a transformer.

Transformer oil analysis provides a highly accurate indication of the internal condition of a transformer. Diagnostic tests offer insights into:

  • Abnormal electrical or thermal activity
  • Effects of transformer aging, including the condition of paper insulation – the primary indicator of potential transformer failure
  • Information on the condition of the transformer and where it is in its lifecycle based on the transformer health index
  • Cost-effective and efficient maintenance planning, refurbishment and replacement

Key benefits of Transformer Oil Analysis

  • Assesses the internal condition of the transformer
  • Helps calculate the probability of failure and end-of-life
  • Identifies degradation before it leads to failure
  • It is essential for effective maintenance and replacement strategies
  • Allows testing to be done at low cost
  • Offers excellent return on investment

Oil Diagnostic tests:

EA Technology offers a wide range of analytical specification tests, coupled with expert interpretation and reporting systems. Typical testing on transformer units includes:


Analysis  Standard
Dissolved Gas Analysis (DGA)  IEC 60567
Moisture IEC 60814
Acidity  IEC 62021
Breakdown Voltage Strength  IEC 60247
Furan Analysis (Paper Insulation Assessment) IEC 61196
PCB Analysis IEC 61619
Dissipation Factor (Power Factor) 

IEC 60247

Interfacial Tension (IFT) ASTM D971
Density (Specific Gravity) ASTM D1524
Colour & Appearance ASTM D1500

EA Technology can also offer an additional range of bespoke testing such as:

Analysis  Standard
Corrosive Sulphur  IEC 62535
DBDS IEC 62697
Inhibitor Content (% DBPC) IEC 60666

These tests allow EA Technology to build up a bespoke testing programme that aims to meet all the specific requirements of our clients.

For more information on our diagnostic tests follow the links below.

Health Index Assessment for Transformers – Moving Towards a Condition Based Strategy

EA Technology has extensive experience of working with owners and operators of high voltage equipment to understand degradation and failure processes. One aspect of this work has been the development of Health Indices.

Health Indices for high voltage equipment combine relevant information on assets to derive a single number that gives an indication of overall degradation and proximity to end-of-life.

Health Index and Transformer Oil Analysis (Advanced Assessment)

By combining the oil analysis results with detailed background information, on-site survey results and unrivalled sector experience, EA Technology can produce a full Health Index assessment for each transformer. This information can then be used to make strategic investment decisions regarding repair, refurbishment and replacement programmes.

Transformer oil analysis can help in identifying which transformers could benefit from life extension measures and alert operators to potential problems before they lead to failure.

By moving from a time-based maintenance and replacement programme to a condition-based strategy, you can bring considerable cost and efficiency savings, while also increasing the reliability of supplies.

The Transformer Health Index Assessment Includes the Following Key Areas:

  • DGA, Oil Quality and FFA analysis
  • Current Health Index and probability of failure
  • Ten-year future Health Index and probability of failure
  • Years to End-of-Life (EOL) assessment
  • Graphical depiction of Health Indexes for the transformer population
  • Full written report of transformer details, results, discussion and recommendations
  • Inclusion of on-site survey results, Partial Discharge Survey, Thermographic Survey and more

Download an example report on the link below.


Oil Diagnostic Suites for Transformer Oil Diagnostics:

The above standard testing is offered in specific diagnostic suites designed to provide the maximum condition information on the transformers. The standard test suites are designed for individual samples to deliver a routine set of oil analysis at low cost.

The health index suites are designed to provide maximum information on the oil analysis results, interpretation and integration into asset management techniques.

Contact us to find out how we can help you with your oil diagnostics and analysis.

Jonathan Lewin
Head of Analytical – EA Technology

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