5.4.Measurement of Tangent (tan δ)

5.4.Measurement of Tangent (tan δ) of Dielectric Loss Angle of Winding with the bushing： Upon the measurement of the high-voltage winding of the transformer, the neutral point and the three phases of the high-voltage winding should be short-circuited and the branch of the low-voltage winding should be short-circuited and grounded; upon the measurement of the low-voltage winding of the transformer, the three phases of the tested branch low-voltage winding should be short-circuited, the untested branch of the low-voltage winding, the three phases of the high-voltage winding and the neutral should be short-circuited and grounded. Use the output voltage of 10 kV to measure the dielectric loss of the high-voltage winding; the high-voltage winding should be grounded and the low-voltage should be short-circuited. Use the output voltage of 10 kV to measure the dielectric loss of the low-voltage winding; Use the output voltage of 10 kV to test the overall grounding dielectric loss of the transformer.