The Tan Delta test, also known as the Dissipation Factor or Loss Angle test, was performed on the Circuit Breaker and Current Transformer to assess the dielectric strength. The main purpose of the Tan Delta test is to ensure safe and reliable operation of the transformer and associated equipment by assessing the insulation quality.
Tan Delta (tan δ) is a measure of insulation quality. It can measure dielectric losses (energy lost as heat) in the insulation when an AC voltage is applied.
When an AC voltage of 10 kV was applied through the tan delta tester, the current through the insulation had two components:
Capacitive Current (Ic): The ideal current that leads the voltage by 90°. Resistive Current (Ir): The component due to imperfections or moisture in the insulation, in phase with the voltage.
Here is the formula for the phase angle (δ) between the total current and pure capacitive current: Tan delta= Ir/Ic.
A small tan δ indicates good, healthy insulation (mostly capacitive), while a high tan δ indicates poor insulation (due to leakage current or moisture).
The standard Dissipation Factor (D&F) value should be less than 0.5%, and the results should be within the satisfactory range, 0.225% and 0.335%.
The connection setup of the CB and CT with the testing device is shown in the attached pictures.
We have different models of tan delta tester, which has different functions. Through the different connections, you can measure the Tan Delta (tan δ) for different test objects. If you want to learn more about the test method or function of tan delta tester, please contact us any time.