Power Transformer Failures

how does the transformer work

A transformer is an electrical device used to convert voltage. using the principle of induction of electromagnetic fields according to Faraday's law
Looking at the alternating current form, the primary side (Vp) creates a magnetic flux (green line) that crosses the secondary winding causing inductance. Generate voltage on the secondary winding.

power transformer (Oil Insulation Type: Oil Immersed)

Most of the power transformers are of the oil insulated type. It utilizes oil for insulation and to reduce the temperature of the windings. which will have characteristics and differences from dry transformers

1. Faults within the transformer (Internal Failures) and methods for detecting faults
The occurrence of a fault within the transformer is what affects the transformer itself. and should detect abnormalities as soon as possible which different types of tests Anomalies can be predicted and estimated according to each testing technique.

2. Faults from external sources (External Failures) and abnormal detection methods
The occurrence of malfunctions from external sources is uncontrollable. An effective solution is There must be a good design of protective equipment and covering all abnormalities.

Example “Proactive Transformer Fault Analysis”
There is a transformer that is more than 50 years old, not sure if it will work normally or not.
How should we proceed?
The answer is that we should do 4 things as follows.

1. Let the oil lab analyze whether there is a lot of loose paper or not.
Check Furan Test*
*Furan Test – see the paper molecules that have come loose in the oil

2. Stop the transformer power supply to cut a sample of kraft paper to measure DP test* to compare with Furan.
Look at the DP value for strength. maintain the shape of the insulator
*DP test – degree of polymerization Look at the strength of the paper fibers.

3. Measure other additional values such as Breakdown Voltage and Loss Power Factor Test.

4. Make a Financial Model to compare investments