Working function of composite insulator

Unlike porcelain and glass insulators, the biggest problem of composite insulators is material aging. Electric field, climate, environmental condition and mechanical load are the main aging factors.

 

The electric field is chosen by the material, length and geometry of the insulator. In order to reduce the effect of the electric field around the end attachment, the composite insulators of the 230kV and above grade lines of foreign countries adopt the equalizing ring.

 

In the monotonous climate, the end electric field does not produce corona discharge, but if the insulator appears fouling phenomenon. The work of rain, dew and fog will make the dirt layer humidification and the conductive leakage current leakage current, attack, the conductive layer (a monotone monotone band) arc and a high-temperature Wen Gao electric field. The arc discharge is not eliminated, and the discharge intensity and duration are closely related to the material, climate and pollution degree of the umbrella skirt.

 

The composite insulator exposed after a few years may appear discoloration, powder and cracking in the outdoors, this is due to the discharge level, ultraviolet radiation, pollution accumulation caused by chemical changes constitute the insulator surface material, this phenomenon has also exacerbated the deterioration of discharge frequency. In mechanical strength, generally use the material creep tendency causes the mandrel, the mechanical strength of composite insulators to accept the load over time also tends to decrease, reduce amplitude depends on the load and duration.

 

Advance of composite insulator life, in addition to planning and technical level of production, the selection of materials is crucial. The key to planning composite insulators is to reduce the surface discharge frequency caused by contamination.