Page 56 - Energize June 2022

TECHNICAL

Talking transformer testing

Condition monitoring is the frequent collecting, measuring, recording and analysis of the relevant data
regarding an asset’s operation. If we interpret the data correctly, it can give us great insight into the

asset’s condition.

BY CORNÉ DAMES, WEARCHECK

requent monitoring of the asset can result in less TABLE 1: CATEGORIES OF EQUIPMENT
maintenance required or more extended periods without
Fany maintenance required. It is crucial to identify the key
parameters that are needed to give us a complete picture of the
actual status of the transformer and the action we need to take
to ensure the continued reliability of the asset to achieve the
maximum lifetime.

What is the data telling us?
• Has the condition of the unit changed since the last maintenance
period?
• Is it safe to operate the unit?
• Are there signs of deterioration?
• Is it safe to load the unit above the nameplate rating for a
particular period?
• Are we required to implement action to ensure the continued
reliability of the unit?
• How long can we use the unit before we need to consider
replacement?
• Are the identified problems of a recurring nature?

Effective condition monitoring outline
It is vitally important to identify clear goals as part of your strategy.
What do you want to achieve by implementing this condition
monitoring plan? Is it in-service failure prevention? Or maybe life
extension? Maintenance deferral?
By stipulating the outcome and what you want to accomplish, it
would be much easier to identify the required parameters. Health
indexing of assets is becoming a remarkable tool in getting a clearer
picture of the condition of your transformer. Test parameters carry
a numerical value-adding to the total value of the Health Index
Value of the transformer. These parameter weight values were
calculated based on the international standards for mineral oils,
indicating the critical values stipulated in the various standards.

The scope of oil analysis, interpretation of the data, and
critical values
At the beginning of this section, it is essential to state that we deal
with different size transformers in the industry. Transformers are
divided into classes according to the kV ratings of the equipment.
It is up to the reliability or asset manager to use the guidelines for
larger equipment, thereby implementing shorter increment oil
analysis and electrical tests.

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