What are the destructive effects of corona discharge on insulation materials?

Corona discharge is a common electrical phenomenon, particularly in high-voltage equipment. Corona discharge not only affects the performance of electrical equipment but also causes significant damage to insulation materials. This article will discuss in detail the main damaging effects of corona on insulation materials, includingmechanical bombardment, corrosion, and localized overheating.

Content

●Mechanical Bombardment

During corona discharge, a large number ofpositive and negative ions are generated. Under the influence of a strong electric field, these ions are accelerated and bombard the surface of the insulation material at high speeds. Additionally, the collisions between thepositive and negative ionsand air molecules generate secondary ions, which also bombard the insulation material intensely. This continuous mechanical bombardment leads to gradual erosion of the material surface, forming small pits. Over time, these pits expand, potentially resulting in the breakdown of the insulation material. This damage not only affects the mechanical strength of the insulation material but also significantly reduces its insulating properties.

●Corrosive Effects

Corona discharge produces a substantial amount ofozone (O₃) and other strong oxidizing agents. These oxidizers are highly corrosive and cause severe damage to insulation materials, especially organic insulation materials. The strong oxidizing nature of ozone alters the molecular structure of organic insulation materials, leading to a decline in material performance. Furthermore,corona discharge generates nitric oxide (NO), which reacts with moisture in the air to formnitric acid (HNO₃) andnitrous acid (HNO₂). These acidic substances further exacerbate the chemical corrosion of insulation materials. Corrosive effects weaken the mechanical strength of the insulation material and significantly degrade its insulating performance, increasing the risk of electrical equipment failure.

●Localized Overheating

The ion flow generated duringcorona dischargesignificantly increases the current density in localized areas of the insulation material, leading to localized overheating. This localized overheating can causecarbonization of the insulation material, forming conductive paths that result in breakdown. For polymer materials, localized overheating may lead tothermal melting, further reducing theirmechanical and electrical properties. Localized overheating not only damages the internal structure of the insulation material but also poses safety hazards such as fire, severely affecting the safe operation of electrical equipment.

In summary

In summary, the damaging effects of corona discharge on insulation materials are primarily manifested in three aspects:mechanical bombardment, corrosive effects, and localized overheating. These damaging effects not only weaken the mechanical strength and insulating performance of the insulation materials but also increase the risk of equipment failure and safety hazards. Therefore, in the design and operation ofhigh-voltage equipment, effective measures must be taken to control and reduce corona discharge, protect insulation materials, and ensure the reliability and safety of electrical equipment. Through the rational selection of materials and structural design, along with the implementation of appropriateanti-corona measures, the damaging effects of corona on insulation materials can be effectively mitigated, thereby extending the lifespan of electrical equipment.

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