Stator winding insulation breakdown, short circuit
1: The stator winding is damp. For generators that have been deactivated for a long time or have been repaired for a long time, the insulation resistance should be measured before putting into operation. Those who fail are not allowed to put into operation. The damp generator should be dried.
2: Defects in the winding itself or improper maintenance process, resulting in insulation breakdown or mechanical damage of the winding. The insulation material should be selected according to the specified insulation grade, and the embedded winding and the dipping paint should be strictly in accordance with the process requirements.
3: The winding is overheated. When the insulation is overheated, the insulation performance is lowered, and sometimes the insulation breakdown is quickly caused at a high temperature. Daily inspections should be strengthened to prevent overheating of various parts of the generator and damage the winding insulation.
4: Insulation aging. Generally, the generator runs for 15 to 20 years, and its winding insulation is aging, electrical properties change, and even insulation breakdown. To do the maintenance and preventive test of the generator, if the insulation is found to be unqualified, replace the defective winding insulation or replace the winding in time to prolong the service life of the generator.
5: The inside of the generator enters the metal foreign matter. After repairing the generator, do not leave the metal objects, parts or tools in the stator ;; tie the ligature of the rotor and fasten the end parts so as not to cause centrifugal force. Loose.
6: Excessive voltage breakdown:
1. The line is struck by lightning and the lightning protection is not perfect. Lightning protection facilities should be improved. 2. Misoperation, such as when the load is too high, the generator voltage is raised too high. The generator should be boosted in strict accordance with the operating procedures to prevent misuse. 3. The internal overvoltage of the generator, including the operating overvoltage, arc grounding overvoltage and resonant overvoltage, etc., should strengthen the winding insulation preventive test, and find and eliminate the defects in the stator winding insulation in time.
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