While there are hundreds of different porcelain insulator manufacturers scattered across the globe, those who produce toughened glass cap & pin discs number barely over a dozen. The reason for this discrepancy is certainly not a function of customer preference since glass and porcelain strings have traditionally had a roughly similar market share on overhead lines worldwide. Indeed, many countries, including France, Spain and Italy, have grids dominated by glass.
China – with the world’s largest power network – also sees an important role for glass strings on transmission lines and has the largest number of glass insulator plants of any country. INMR visits Sichuan YiBin Global Group – a glass insulator manufacturer based in central Sichuan Province.
“The quality of an insulator is one of the keys to guaranteeing the reliability of a power system,” observes SYGG’s Deputy General Manager. “And achieving a consistently high quality depends on several factors including the right production technology, the latest equipment and skilled workers. “It was with these targets in mind,” he adds, “that we decided to invest some RMB 280 million (circa USD 40 million) with the goal of establishing a world-class production line for glass insulator discs here in Chengdu. This investment was then supported by our Group’s more than 20 years of relevant glass manufacturing experience.” According to the Deputy GM, this process is ongoing as an additional RMB 40million was invested in R&D just over the past year to introduce new, very high strength insulator designs.
Indeed, the technical manager reports that SYGG has several R&D projects underway, including a triple shed design as well as glass shells pre-coated in the factory with RTV silicone. “Our target,” he states, “is to research all insulator designs up to 300 kN and 500 kV. With this range, we know we can cover the large majority of needs worldwide.”
The annual domestic market for glass insulators in China is estimated at about 20 million discs and reflects a fairly stable market in recent years.
The annual domestic market for glass insulators in China is estimated at about 20 million discs and reflects a fairly stable market situation over the past several years. This volume is predominantly for AC, with about 7-8 percent for DC – a higher level than in the past. Moreover, because of the number of major DC projects now being planned by China’s State Grid, the local market for DC insulators is expected to continue to grow rapidly.