Page 57 - Energize June 2022

TECHNICAL

The maintenance engineer or manager needs to determine All steps involved in sample taking must adhere to quality
what type of testing would benefit him in identifying problem control procedures, including the container that is used, the
areas within his fleet. Some of the analysis has been identified as sampling kit, the taking of the sample, the marking of the sample,
to routine type tests. Still, there is an extensive range of tests that the closing of the sample, the storage and handling of the sample,
can assist in identifying specific problem criteria within the system, and then the delivery of the sample to the laboratory. If the sample
which might not be clear through the typical day-to-day analysis identification and sample data are handwritten, the human factor
usually performed. can lead to incorrect interpretation of the data. The label should
be attached to the container to ensure no mix-ups in sample
Oil sampling identification. Ensure that the label is completed in neat, easy-to-
The taking of the oil sample is one of the most crucial and critical read handwriting.
influencers in the analysis outcome. If a sample is not taken to The label should be waterproof, and the pen used to write
the prescribed procedure, then there is a significant possibility on the label should be oil- and water-resistant. Otherwise, some
that the analysis performed, and the results acquired, are of no data might be lost, making it extremely difficult for the laboratory
use. Care should be taken to ensure quality control procedures personnel to complete the report or allocate the sample to a
are applied in each step of the sampling process as set out by specific transformer.
international standards.
A good quality sample taken by applying the correct procedure Test types
is essential. A sample can be contaminated by various factors, all This section describes the various types of tests to be conducted to
of which can influence the outcome of the results in a negative determine the transformer’s condition, the critical values, and the
manner. recommended actions in each case:

TABLE 2: TESTS FOR IN-SERVICE MINERAL INSULATING OILS

energize | June 2022 | 55