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

1) The insulation layer of current transformers is very thick, and some insulation layers are loosely wrapped with wrinkles between them. In addition, poor vacuum treatment, incomplete immersion, and the formation of gas containing cavities can easily cause partial discharge faults.

2) The size and arrangement of the capacitive screen do not meet the design requirements, and even the discharge capacity of the capacitive screen is low. The capacitive board is not smooth and even misaligned or broken, which damages the voltage equalization characteristics. Therefore, when the electric field strength along the local solid insulation surface reaches a certain value, it will cause partial discharge.

The direct consequence of the partial discharge mentioned above is the cracking of the insulating oil, which generates a large amount of x wax between the insulation layers and increases dielectric loss. This discharge has a cumulative effect, and if it continues to develop, it may exhibit characteristics of arc discharge when analyzing gases in oil.

3) Due to unclean insulation materials or high moisture content, surface discharge may occur on their surface. This situation is more common when the terminal leads discharge along the surface of the solder pad.

4) Loose connections or potential suspension of certain metal components can cause spark discharge, such as loose nuts supporting the primary winding, resulting in floating potential of the shielding aluminum foil of the primary winding, poor contact or poor welding of the final screen lead, and even disconnection, which can lead to such faults.

5) Loose secondary connection clamps, bolts, and nuts, loose end screen grounding nuts, loose ribbon fastening nuts, etc. may increase contact resistance and cause local overheating faults. In addition, improper on-site maintenance and management should also be taken seriously. For example, if a transformer gets wet due to water ingress, it may be related to the manufacturer's sealing structure and sealing materials, but there are also maintenance and management issues. Generally speaking, insufficient vacuum degassing or lack of vacuum drying during maintenance can lead to gas saturation in the oil or high residual bubbles and moisture content in the oil paper insulation. All of these will leave security risks for the equipment.