Electrical aging is that the insulating materials and insulating structures in electrical equipment are subject to the action of electric fields during operation. Under the long-term effect of electrical stress as the main aging factor, performance irreversibly changes until failure. This aging not only exists in the insulation of electrical equipment in high-voltage and ultra-high-voltage power systems, but also occurs in electronic devices with high working electric field strength. Insulation of electrical equipment is mostly made of high-molecular insulation materials，which is sensitive to electrical aging.

Electrical aging can be roughly divided into two categories: discharge aging and ineffective electrical aging. Discharge aging is the main form of electrical aging. The reason why the insulating material will age under the discharge is due to heat, combustion, ultraviolet rays, active products (electron 6, oxygen 0, nitrogen N, active nitrogen molecule N, oxygen molecule 02, nitrogen molecule cation N, oxygen molecule Cation 02 and products 03, N02, HN02, etc.). which factor plays a dominant role depends on the discharge conditions, which are the magnitude of the discharge intensity and the environment.

The discharge intensity is related to the type of discharge. In the case of corona discharge, the intensity is low; in the arc discharge, the intensity is high; and in the spark discharge, the intensity is in between. Environmental factors are mainly the presence of oxygen, moisture, pollution, air gaps, etc. Like the intensity of discharge, the degree of aging varies greatly between aerobic and anaerobic; the existence of air gaps in dendritic aging makes dendritic aging develop rapidly, while electrical trace is closely related to environmental pollution factors. Non-discharge aging is caused by the heat generated by the current flowing through the insulating material under the action of the electric field, which results in thermal breakdown of the material; the thermal effect of the current flowing through the surface of the material causes localized carbonation channels on the surface of the material. ; Under the action of DC voltage, the material is aged by electrochemical action or space charge.