Current practicing engineers use a number of modern diagnostic techniques to assess the insulation condition of aged transformers. These techniques are categorized into electrical and chemical analysis.

Electrical analysis such as:

Partial discharge (PD) analysis

Dielectric breakdown voltage measurement

Return voltage measurement

Time domain polarization measurement

Frequency domain polarization measurement

Chemical analysis such as:

Moisture analysis in transformer oil by Karl Fischer titration

Dissolved gas analysis (DGA)

Degree of polymerisation (DP) measurement

Furan analysis by high performance liquid chromatography (HPLC)

Recently, furan analysis has become more popular in the field of transformer insulation strength assessment and transformer remnant life estimation related research. ASTM D5837 is the current widely accepted standard test method of furan measurement as published by American Society for Testing and Materials (ASTM). This test is reliable and accurate in identifying and measuring the concentration of furfural derivatives in transformer oil. However, the test performed under this standard has a few disadvantageous as summarized below:

The test is time consuming and laborious.

Professional skills are required to perform the test because of its complexity.

Test equipment and apparatus are expensive.

Increases the cost of asset management as electrical utilities company employs oil analysis companies to perform the furan analysis.

Delays in getting test result due to possibility of large number of test samples from other companies in the queue.