The transformer winding deformation test is an important means to detect whether there is mechanical deformation or displacement of transformer winding. There are usually two test methods to do: frequency response analysis (FRA) or short-circuit impedance method.
Frequency Response Analysis (FRA)
Principle: By injecting signals of different frequencies into the transformer winding, the response curve is measured and the mechanical state of the winding is analyzed.
Steps: Select the test frequency range (usually 10 Hz to 2 MHz).
The high-voltage and low-voltage windings were tested respectively, and the frequency response curves were recorded.
Compare historical data or factory data to determine whether there is deformation.
Advantages: High sensitivity, can detect small deformation.
Short-circuit impedance method
Principle: By measuring the change of transformer short-circuit impedance, determine whether there is displacement or deformation of the winding.
Steps: The rated current is applied to the low voltage side to measure the short circuit impedance of the high voltage side.
Impedance changes were analyzed by comparing historical data.
Advantages: Easy to operate, suitable for field testing