The performance evaluation of glass insulation materials involves the national standard GB/T 8411 series, of which GB/T 8411.2-2008 specifies the test methods, and GB/T 8411.3-2009 specifies the material properties. This series of standards has been modified to adopt the international standard IEC 60672 series.
Insulation resistance is a key performance indicator for measuring its insulation condition. It is typically measured using a 5000V megohmmeter. For newly installed insulators, the insulation resistance should be greater than or equal to 500MΩ, while for insulators in operation, it should be greater than or equal to 300MΩ.
Glass insulators have high surface mechanical strength, and their electrical strength generally remains stable throughout operation. Furthermore, their aging process is slower than that of porcelain insulators. The self-breakage rate of glass insulators is an important indicator of product quality and one of the quality criteria for evaluating power transmission projects. Because damage is easily detected during line inspections, and the remaining portion still maintains sufficient mechanical strength, periodic preventative live-line tests on glass insulators during operation can be eliminated.
When measuring insulation resistance, attention should be paid to the influence of environmental factors. Increased temperature will lead to a decrease in insulation resistance, and increased humidity will cause moisture to be absorbed on the insulation surface to form a water film, increasing the surface leakage current and causing a significant decrease in insulation resistance. Therefore, measurements should be suspended when the humidity is high.
