how to conduct tan delta test of transformer?

To conduct a tan delta test on a transformer, first ensure the transformer is de-energized and properly grounded. Connect the test equipment, typically a tan delta measuring device, to the transformer’s bushings. Apply a voltage, usually at the rated frequency, and gradually increase it to the test level. Measure the capacitance and the power factor (tan delta) at various voltage levels. Analyze the results to assess insulation condition and detect potential issues. Always follow safety protocols during testing.