What are the Processes and Causes of Insulation Aging?

Insulation aging is a common issue in the operation of electrical equipment, which affects the performance and lifespan of the devices. The main causes of insulation aging can be attributed to thermal, electrical, mechanical stress, and environmental factors. Below is a brief analysis of the aging processes and specific causes:

Content

●Thermal Aging  

During the operation of electrical equipment, insulation materials generate a significant amount of heat due to energy loss. Prolonged exposure to high temperatures leads to the oxidation and thermal decomposition of insulation materials, gradually reducing their mechanical strength. Under these high-temperature conditions, the insulation becomes brittle, resulting in cracking and delamination, which weakens its load-bearing capacity and eventually causes failure. Thermal aging is a cumulative process— the higher the temperature, the faster the aging occurs.

● Electrical Aging  

Electrical aging is caused by the prolonged exposure of insulation materials to electric fields. Gaps, cracks, or bubbles in the insulation material can easily lead to partial discharge under high voltage. Partial discharges not only erode the insulation material but also cause oxidation and puncturing, which reduces the thickness of the insulation layer and eventually leads to insulation breakdown. Additionally, if there are conductive particles or foreign substances within the insulation, electrical aging can accelerate, rapidly diminishing the insulation’s effectiveness.

●Mechanical Stress Aging  

Mechanical stress aging occurs as a result of thermal and mechanical stresses applied to insulation materials over time. Temperature fluctuations during equipment operation cause the materials to expand and contract, creating thermal stress. Repeated thermal cycling can lead to the formation of cracks and delamination on the surface of the insulation. These cracks create gaps that exacerbate electrical aging. Moreover, mechanical vibrations can fatigue the materials, accelerating the aging process.

●Environmental Aging  

Environmental factors such as humidity, dust, and harmful gases also contribute to insulation aging. A humid environment can cause the insulation material to absorb moisture, reducing its insulating properties and leading to surface leakage currents or creepage. Dust and contaminants can further promote partial discharge or localized electrical stress, increasing the risk of insulation failure.

In summary

Insulation aging results from a combination of thermal, electrical, mechanical, and environmental factors. Heat accelerates material degradation, electric fields cause partial discharge and breakdown, mechanical stress weakens material structures, and environmental conditions reduce insulation performance. Understanding these causes and implementing preventive maintenance measures can extend the lifespan of electrical equipment and ensure safe operation.

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