What are the main factors that affect the insulation resistance of electrical equipment?

The factors affecting the insulation resistance of electrical equipment are as follows:

(1) humidity. When the relative humidity of air increases, insulation absorbs more water due to capillary action, and the electrical conductivity increases and the insulation resistance decreases. Practice has proved that the insulation resistance measured in foggy days and rainy days is obviously lower than that in sunny days.

(2) temperature. The insulation resistance of general insulators decreases with the increase of temperature. The first reason is that the temperature rises and the ion movement in the insulator accelerates; The moisture in the insulator and insulator is relaxed, and under the action of external electric field, water molecules extend along the fiber material in a slender velvet shape, which increases its conductivity; Salts and acidic substances contained in insulators will be dissolved by water, which will also increase the conductivity and reduce the insulation resistance. The change of insulation resistance varies with different insulation materials, and the hygroscopic material changes the most with temperature.

Because temperature has a great influence on insulation resistance, and it is difficult to measure at the same temperature every time, in order to compare the measurement results, the measurement results are generally converted into the same temperature.