Glass Insulators: The "Safety Guards" of Power Transmission
In modern power systems, insulators are core components that ensure the safe and stable operation of transmission lines. Just like bridges connecting conductors and transmission towers, they undertake the dual functions of mechanical support and electrical insulation. Among various types of insulators, glass insulators have become the preferred equipment in high-voltage and ultra-high-voltage transmission fields due to their excellent comprehensive performance. They are widely applied in domestic power grid construction and projects along the "Belt and Road", playing an irreplaceable role as the "safety guards" of energy transmission.
Glass insulators are made of high borosilicate glass as the base material, with added oxides to adjust their performance, through a series of processes including high-temperature melting, compression molding, and tempering. Structurally, they consist of glass parts, steel caps, and steel feet, which are firmly fixed together by cement adhesive. The three parts work in coordination to ensure both mechanical strength and reliable insulation performance. The most distinctive advantage of glass insulators is their "zero-value self-explosion" characteristic. When the insulation performance degrades or internal defects exist, the insulators will automatically break due to the release of residual stress, forming obvious fault signs. Maintenance personnel can quickly find and replace the faulty insulators through visual inspection without checking each one individually, which greatly reduces maintenance costs and improves the safety of power grid operation.
In addition, glass insulators have excellent electrical and mechanical properties. Their typical volume resistivity can reach more than 1×10¹⁴Ω·cm, and the power frequency breakdown strength is not less than 30kV/mm, which can effectively prevent electric leakage. They also have outstanding weather resistance, being able to operate stably without cracks under temperature cycles from -40℃ to +80℃, and can resist ultraviolet radiation, acid-base corrosion. Their electrical and mechanical performance degrades slightly after long-term operation, with a service life of more than 40 years. Moreover, broken glass can be 100% recycled and remelted for reuse, which is in line with the green development needs under the "double carbon" goal.
Their application scenarios cover the entire power transmission link, focusing on three core areas. Firstly, in ultra-high-voltage projects, as the preferred insulation equipment, they support the construction of key projects such as Qinghai-Henan and Baihetan-Jiangsu in China. Secondly, in new energy grid connection, they are suitable for the access of distributed energy such as wind power and photovoltaic power, and their penetration rate in complex environments such as the northwest of China is higher than that of ceramic insulators. Thirdly, in the renovation of old power grids, they undertake a large number of replacement needs with high cost performance. At the same time, the export of glass insulators continues to grow. In 2025, China's glass insulator export volume reached 980 million US dollars, with a year-on-year increase, mainly flowing to Southeast Asia, the Middle East and other regions.