What are the common faults of Power Current Transformer

1) The insulation of the Power Current Transformer is very thick, and some insulation wraps are loose, and there are wrinkles between the insulating layers. In addition, the vacuum treatment is poor, and the impregnation is not complete to form a gas-containing cavity, which is easy to cause partial discharge failure.

2) The size and arrangement of the capacitive screen do not meet the design requirements, so at least the capacitive screen should be placed. The capacitor plate is not lubricated and flat, and even misaligned or broken, which destroys the pressure equalization characteristics. Therefore, when the electric field strength along the surface of part of the solid insulation reaches a certain value, a partial discharge will be formed.

The direct result of the above partial discharge is to crack the insulating oil, generate a large amount of x wax between the insulating layers, and increase the dielectric loss. This kind of discharge has a cumulative effect, and if it continues, the analysis of gas in the oil may show the characteristics of arc discharge.

3) Because the insulating material is not clean or has high moisture content, creeping discharge may occur on its surface. This situation is more common when a terminal lead discharges along the surface of the pad.

4) Some loose connections or potential suspension of metal parts will cause spark discharge, such as the loosening of the primary winding support nut, forming the potential suspension of the primary winding shielding aluminum foil, poor contact or welding of the final screen lead, and even wire breakage, which will cause such failures.

5)-Loose connection splints, bolts and nuts, loose grounding nuts on the bottom screen, loose tap fastening nuts, etc., may increase the contact resistance and cause some overheating failures. In addition, improper on-site maintenance and management should also cause attention. For example, the dampness of the transformer may be related to the sealing structure and sealing material of the manufacturer, but there are also maintenance and management issues. Generally speaking, the on-site vacuum degassing is not sufficient or vacuum drying is not performed during maintenance, which causes the dissolved gas in the oil to be easily saturated or the residual bubbles and high moisture content in the oil-paper insulation. All of these will leave hidden safety hazards to the equipment.