Inspection of insulating paper in transformer

Insulation products will affect the insulation effect due to various parameters, and there are many factors affecting these parameters. We need to have a certain understanding in order to control them properly and avoid reducing the use effect. Today we'll look at six factors that affect the electrical strength of insulating paper in transformer.

(1) Sample thickness. When the insulation material is very thin, the breakdown voltage is proportional to the thickness, that is, the electrical strength is independent of the thickness. When the insulation thickness increases, it will be difficult to dissipate heat and appear impurities and bubbles, etc., thus reducing the electrical strength.

(2) Temperature. Electrical strength decreases when the temperature is higher than the normal room temperature.

(3) Humidity. No water or moisture inside of the insulation material. Otherwise the electrical strength will be reduced.

(4) Voltage acting time. The voltage strength of most materials is related to the voltage acting time. The longer the time, the lower the voltage.

In the test, if the voltage intensity is high, the rate of pressure rise will be faster. If the voltage action time is long, the stepwise or slow pressure rise can reflect the defects such as thermal effect and air gap in the material better. Therefore, the general test method does not adopt pulse boost method, but adopts continuous boost method.

(5) Mechanical damage. Mechanical damage to insulating materials will reduce the electrical strength, so we should try to avoid damage during processing and manufacturing.

(6) Electrode. Generally speaking, large electrode area will cause breakdown voltage drop. weaknesses will be easily found for large area. In addition, the electrode should be smooth and not uneven, in order to reduce the voltage affecting the accuracy of the test results.

The above are several factors that affect the electrical strength of insulating paper in transformer. We should reasonably control various factors at daily use to make it give full play to its maximum value.