The specialized production ofpartial discharge testersfor UHV power can help many power workers conduct various power tests more conveniently.

Power transformers mainly use oil paper barrier insulation, which is composed of electrical paper and insulating oil. Due to the complex structure and uneven insulation of large transformers. When there are internal defects such as improper design, high local field strength, poor process or external factors, partial discharge will inevitably occur in transformers and gradually develop, ultimately causing transformer damage. Partial discharge inside power transformers mainly occurs in the following situations:

(1) The oil paper isolation insulation in the middle of the winding breaks through the oil passage;

(2) Fault in the oil passage at the end of the winding;

(3) The oil gap between the insulated wire and the electrical paper (lead insulation, lap insulation, phase insulation) is broken down;

(4) The vertical insulation oil passage between coils (between turns and between cakes) has malfunctioned;

(5) Discharge of branches such as insulation cardboard shells;

(6) Creepage of other solid insulation materials;

(7) Discharge of other metal foreign objects infiltrating the insulation layer.

Therefore, for transformers that leave the factory, partial discharge tests are required in the following situations:

(1) Before the new transformer is put into operation, a partial discharge test should be conducted to check whether there is insulation damage during transportation and installation after the transformer leaves the factory.

(2) Conduct partial discharge tests on transformers that have undergone major repairs or modifications to assess their insulation condition after repair.

(3) Further qualitative diagnosis should be conducted on transformers suspected of having insulation faults during operation, such as abnormal situations related to insulation, such as discharge faults in oil and gas chromatographs.

(4) As a preventive testing project or online testing content, monitor the insulation condition of transformers during operation.