The internal structure of SCB18 dry-type transformer is mostly charged and discharged in some oil gaps, oil wedges, gas gaps, metal composite metal conductors with floating potential differences, metal conductor inclination angles and solid insulation layer surfaces. The following analysis is performed on the partial discharge pulse of SCB18 dry-type transformer:

Our manufacturers have mastered the waveform characteristics of partial discharge in SCB18 dry-type transformer, which is of great practical significance to the partial discharge test of SCB18 dry-type transformer with the current value pulse method as the basic concept: first, it can broaden the accurate measurement frequency range, and select the detection technology according to pulse charge and discharge to improve its anti-interference mode; Secondly, the SCB18 dry-type transformer partial discharge monitoring system can be promoted offline or online, including the placement of sensors and the characteristics of working frequency, and the selection of accurate measurement frequency segments of the system. Moreover, it also has important practical value for the internal charging and discharging machine vision of SCB18 dry-type transformer. The structure of the insulation layer in the SCB18 dry-type transformer is easy to cause partial discharge due to the concentration of the electric field, and there are four types of structures that are easy to cause partial discharge.

When two and a half wires of the same wire are parallel to each other and vertical, their higher magnetic field strength appears on the surface of the wire at the distance between the two wires. In the same environment, the two wires intersect vertically, and the magnetic field strength is higher than that planned by the normal perpendicular plane, which is higher than 10%. The transformer grounding wire at the head of the high-voltage rotor winding is against the box wall and the rotor winding of other transformers, which are all areas where the concentration of electric fields is easy to cause partial discharge. The spacing of the tip insulation, the angle of the tip discharge ring, and the thickness of the insulating tube).

The surface layer of the metal electrode presented in the highlighted metal electrode SCB18 dry-type transformer, such as the welding of the inner wall of the fuel tank and the welding scar adhering to it; inclination burrs from wire soldering; screw caps for tap power switches; The edge of the multi-pole core column and the burrs generated in the cutting of the iron solution chip will also cause the concentration of the electric field, which will increase exponentially.

In the insulation layer system of SCB18 dry-type transformer, compared with paper and thick cardboard, the dielectric constant of the oil is reduced, and the breakdown field strength of the oil is low, which determines that part of the insulation layer of the dry-tested SCB18 dry-type transformer is the oil gap. The residue will cause the electric field in the oil to cause rugged changes, and the residue of metal composite materials or floating water droplets will expand the strength of the higher magnetic field in the surrounding oil to about 3 times of the original.