what is insulation resistance test of a transformer?

The insulation resistance test of a transformer measures the effectiveness of its insulation system by determining the resistance between the windings and the ground, as well as between different windings. This test helps identify potential insulation failures, moisture ingress, or deterioration over time. Typically conducted using a megohmmeter, a high voltage is applied to assess the insulation’s ability to withstand electrical stress, ensuring safe and reliable transformer operation.