AGE Testing - Part 2

In Part 1, we learned that AGE is an additive in some perchloroethylene fluids, where it functions as an acid scavenger. The AGE test is appropriate for samples from former Askarel-filled transformers that were retrofilled with perchloroethylene fluid.

The actual AGE test determines the concentration of the AGE additive that is in the fluid. The test is performed by first adding a small amount of hydrochloric acid to a measured amount of the perchloroethylene fluid sample and letting it sit for a specific amount of time so that any AGE in the sample will react with (neutralize) at least some of the acid. After the test, the amount of acid remaining is measured, giving an indication of the concentration of AGE in the sample. This result is compared to three calibration standards that are also run with the same procedure: a blank, a 1000 ppm AGE standard, and a 2000 ppm AGE standard. The response of the sample is compared with the response of the three standards to determine the concentration of AGE in the sample.

The amount of sample needed for the test is fairly small – only about 5 mL. The test results are reported in custom letter format, giving the AGE concentration in ppm (parts per million), together with recommendations. S. D. Myers, Inc. guidelines regarding AGE content are as follows:

>1500 ppm AGE is Acceptable (2000 to 2500 ppm is optimum)

>1000 ppm, but ≤1500 ppm AGE is Questionable

≤1000 ppm AGE is Unacceptable

If ≤1500 ppm, but >0 ppm, AGE content should be replenished.

If AGE content is completely depleted, the transformer should be considered unreliable and should be replaced.

If a transformer requires AGE acid scavenger replenishment, it is important that this maintenance be done in order to prevent irreversible damage to the metals in the transformer from the build up of acids. If AGE acid scavenger is not added, acids will eventually form, due to the breakdown of the fluid, and attack the metals in the transformer (such as the braised joints where the leads come out of the windings), making the transformer unreliable.

In summary:

• AGE is an additive in some perchloroethylene fluids, where it functions as an acid scavenger.
• The AGE test is appropriate for samples from former Askarel-filled transformers that were retrofilled with perchloroethylene fluid.
• If a transformer requires AGE acid scavenger replenishment, it is important that this maintenance be done in order to prevent irreversible damage to the metals in the transformer from the build up of acids.
• The AGE test is not appropriate for samples from Wecosol-filled transformers, since Wecosol was a Westinghouse original-equipment fluid that did not contain AGE acid scavenger.
• Retrofilled transformers,filled with perchloroethylene fluid that was not intended to be the final retrofill fluid, should be considered unreliable and should be replaced.

1. If transformers filled with a permanent perchloroethylene fluid such as System 50 Fluid, Perclene, or TransClene are found to have their AGE content completely diminished, they should be considered unreliable and should be replaced.