How is a transformer Megger test conducted?

To conduct a transformer Megger test, first ensure that the transformer is de-energized and isolated from the electrical network to avoid any risks. Connect the Megger test leads to the winding terminals of the transformer. Set the Megger device to the desired test voltage, typically between 250V to 5kV depending on the voltage rating of the transformer. Activate the Megger to apply the test voltage while observing the insulation resistance reading on the device. Hold the test for a specified duration, usually around 60 seconds, to obtain a stable reading. After completing the test, discharge any residual voltage from the transformer windings to ensure safety. Record the insulation resistance values to assess the condition of the transformer insulation. Regularly testing with a Megger helps to identify potential insulation failures and ensures the reliability of the transformer in operation. Remember to test a transformer periodically as part of a comprehensive maintenance program.