Local discharge phenomenon, mainly refers to the high-voltage electrical equipment. According to the statistics of the power grid, partial discharge is an important reason for the final insulation breakdown of high-voltage electrical equipment, and it is also an important indicator of insulation deterioration. The insulation of power equipment occurs in a local range under a sufficiently strong electric field. This discharge is limited to the local short insulation (bridge) connection between conductors without forming a conductive channel. Each local discharge will have some effects on the insulation medium, the slight local discharge has little influence on the insulation of power equipment, and the insulation strength decreases slowly; while the strong local discharge will make the insulation strength decrease quickly. This is an important factor that damages the insulation of high-voltage power equipment. Therefore, when designing the insulation of high-voltage power equipment, it is necessary to allow no strong local discharge in the insulation structure under the action of long-term working voltage. The monitoring of the equipment in operation should be strengthened. When the local discharge exceeds a certain degree, the equipment should be withdrawn from operation for maintenance or replacement. In a solid dielectric with a gas or liquid, this part of the gas or liquid starts discharging when the local field strength of the breakdown field strength reaches its breakdown field strength. Partial discharge is generally due to the insulator interior or insulation Caused by the particularly concentrated local and concentrated surface electric field. Usually this discharge appears as a pulse of duration less than 1 μ s. When the insulation discharges locally, it will affect the insulation life. Every discharge, high energy electron or accelerate the impact of the electron, especially long-term local discharge can cause a variety of forms of physical effects and chemical reaction, such as charged particles on the bubble wall, may break insulation bonds and cracking, destroy the molecular structure of insulation, insulation deterioration, accelerate the insulation damage process.