EN
800kV transformer bushings for ±800kV UHV substations in Ningxia
Dec.15.2025
As the core energy hub of China's "West-to-East Power Transmission" northern channel, Ningxia's UHV substations undertake the key function of new energy integration and cross-regional transmission. Relying on over 60 years of R&D and manufacturing experience in high-voltage bushings, Nanjing Electric, Ltd. customized and supplied 800kV transformer bushings for ±800kV UHV substations in Ningxia. Verified by long-term operation, these bushings have become the "core heart components" ensuring regional power grid stability, demonstrating the mature reliability of China's UHV equipment.
Targeting Ningxia's harsh environment with arid climate, large temperature difference (extreme temperature difference up to 40℃) and frequent sandstorms, Nanjing Electric conducted special technical upgrades for these bushings: adopting "ceramic-epoxy resin composite insulation structure" instead of traditional pure ceramic design, controlling the dielectric loss factor (tanδ) below 0.003, which is 50% lower than the national standard requirement; innovatively developing "gradient umbrella skirt + silicone rubber anti-pollution coating", increasing the pollution flashover voltage by 60%, and completely solving the insulation hidden danger caused by sandstorm contamination. With a rated current of 4000A and a short-time withstand current peak value of over 63kA, all bushings have passed the dual standard certification of GB/T 4109-2021 and IEC 60137:2017, with key performance indicators superior to international similar products.
Since commissioning, these bushings have been operating stably for over 5 years at core nodes such as Ningxia Lingzhou Converter Station and Yinchuan East Substation. They have withstood 37 extreme sandstorm weather events and 12 power grid load shocks, with a zero failure rate. Their stable operation not only supports the Ningxia-Hunan ±800kV UHV project to achieve the design goal of "transmitting 36 billion kWh of green electricity annually", but also increases Ningxia's new energy grid connection and accommodation rate to over 96%. It reduces the annual external thermal power import by more than 10 million tons, providing key equipment support for the construction of the northwest clean energy base.