33KV vertical Line Post Composite Insulator

Studies have shown that the heating of insulators consists of three parts:
One is the heating caused by the polarization effect excited by the dielectric under the action of the power frequency voltage;
The second is the internal penetrating leakage current heating;
The third is surface creepage leakage current heating.
When the insulator is in good operating condition, its heat generation is mainly the first item; when the performance of the porcelain insulator is deteriorated, or the porcelain part is cracked, or the surface of the porcelain plate is dirty, the leakage current of the second or third item will increase, and the heat generation will increase. cause the temperature of the insulator to rise. At present, it is believed that there are three main reasons for the deterioration of insulators: improper control of the manufacturing process, internal defects and the influence of changes in the operating environment.
Due to the process and formula in the manufacturing process, it is easy to form micro-cracks and hygroscopic pores in the ceramics, which may cause unbalanced internal stress. The local stress concentration will increase the micro-cracks, and the water will penetrate into the porcelain body through the cracks and through holes in the gas phase, and the hygroscopic pores provide a space for water molecules to stand. The water undergoes a stress-induced chemical reaction with the glass phase, which induces the slow propagation of cracks. Under the condition of power frequency voltage, water molecules rub against each other in the process of turning polarization, and the heat generated in the area of intense molecular motion will cause a significant temperature rise locally in the insulator.
Basic Information
In power systems, rod-shaped porcelain post insulators are widely used in busbars and disconnectors. In the long-term operation process, the comprehensive action of mechanical, thermal, electrical, environmental and other factors will inevitably cause various physical and chemical changes in insulator porcelain, which will cause electrical properties and mechanical strength to increase with the increase of operating time. Gradually decline, and the characteristics of heat generation, discharge, and light emission will appear simultaneously with the performance decline process.