Dielectric Loss Test Diagram Working Principle:
Power is input to the operation box, which has overcurrent automatic trip and zero-position interlock device to prevent sudden voltage application. The voltage is regulated by an auto-transformer and then input to the primary winding of the test transformer. According to the principle of electromagnetic induction, the secondary (high-voltage) winding obtains a voltage amplitude proportional to the turns ratio with the primary winding - power frequency high voltage. This power frequency high voltage can be rectified by a high-voltage silicon stack and filtered by a stabilizing capacitor to obtain DC high voltage, whose amplitude is twice the effective value of the power frequency high voltage.
Precautions:
1. When conducting high-voltage tests, at least 2 or more personnel must participate, with clear division of labor and mutual communication methods. A dedicated person should supervise the site safety and observe the test status of the test object;
2. The transformer and control box should be reliably grounded;
3. During the test, the voltage increase speed should not be too fast, and sudden full voltage energization or de-energization is absolutely not allowed;
4. During the voltage increase or withstand voltage test, if any of the following abnormal conditions are found, the voltage should be immediately reduced, and the power should be cut off to stop the test. After identifying the cause, the test can be resumed. ① The voltmeter pointer swings significantly; ② A smell of insulation burning or smoke is detected; ③ Abnormal sounds are heard inside the test object.
5. During the test, if the test object is short-circuited or breaks down, the overcurrent relay in the control box will operate. At this time, return the voltage regulator to zero, cut off the power, and then the test object can be removed.
