Causes And Signs Of Increased Distortion In The Electric Field Around Insulators
During routine inspections of high-voltage transmission lines, abnormal discharge traces are frequently found on the surface of insulators. This phenomenon usually stems from changes in the physical environment, disrupting the previously uniform potential energy balance. When water droplets, dust, or metal particles are deposited on the surface, the electric field around the suspension type insulator is distorted more severely, which directly affects the reliability of the power grid operation.
Common Factors Leading to Electric Field Imbalance
Changes in the electric field environment are not without cause. Based on field experience and simulations, the following situations are often the culprits inducing distortion:
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Accumulated dirt and moisture: Salt and industrial dust can form a conductive layer in humid air.
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Damage at hardware connections: Displacement of the equalizing ring or corrosion of hardware can alter the structural boundaries.
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Internal insulation defects: Aging of the core rod or the presence of air gaps can cause a sudden increase in internal electric field strength.
The specific impact of increased distortion on insulation performance
As the electric field around composite tension insulator becomes more distorted, the equipment will experience a series of chain reactions. This change is not limited to the physical surface but also touches upon the chemical stability of the insulating material.
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Increased Corona Discharge Frequency: The electric field concentrates in a narrow area, accelerating air ionization. This high-frequency micro-discharge generates ozone, chemically corroding the synthetic material skirts and leaving irreparable carbonized channels.
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Risk of Localized Surface Flashover: Once the distorted field strength exceeds the air breakdown strength, current will leap along the contamination path. At this point, although the creepage distance of the high voltage transmission line insulators remains physically unchanged, its electrical performance has been significantly reduced.
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Accelerated Hardware Lifespan Decline: Long-term uneven field strength leads to accumulated thermal effects. Under abnormal potential gradients, the mechanical strength of hardware accessories may be damaged, even inducing brittle fracture.
Identification Details in On-Site Monitoring:
Inspectors can observe obvious luminous points using an ultraviolet imager. These densely packed areas of light are a direct reflection of the intensified distortion of the electric field around overhead power line insulators. For tension insulator circuits of different voltage levels, observing the discharge intensity at the edge of the fittings is an important basis for judging their health status.
