Feasibility of C(3)F(7)CN/CO(2) gas mixtures in high-voltage DC GIL: a review on recent advances

• Main Authors: Youping Tu, Geng Chen, Cong Wang, Yuming Shao, Yujing Tong, Chuanyang Li, Guoming Ma, Tohid Shahsavarian
• Format: Article
• Language: English
• Published: Wiley 2020-05-01
• Series: High Voltage
• Subjects: gas insulated transmission lines; flashover; gas mixtures; gaseous insulation; reviews; carbon compounds; thermal stresses; surface flashover performance; gas stability; gas-insulated transmission line; gas-solid interface; gas environment; eco-friendly dc gas insulation equipment; high-voltage dc gil; eco-friendly insulating gas; gas-insulated equipment; gas gap breakdown; review; renewable energy resources; offshore wind power plant; dc transmission; insulation properties; lightning impulse voltage; decomposition characteristics; electrical stresses; charge accumulation characteristics; dc voltage stress; c(3)f(7)cn-co(2)
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/hve.2020.0083

With the rise of renewable energy resources, especially offshore wind power plant, the DC transmission concept has attracted more and more attention. The selection of eco-friendly insulating gas, as most critical insulating part of gas-insulated equipment is top priority for developing highly reliable system. Moreover, it is acknowledged that eco-friendly C(3)F(7)CN/CO(2) gas mixtures have become a potential alternative to SF(6) gas due to its excellent performance. This study reviews the basic physical properties of C(3)F(7)CN gas/gas mixtures and insulation properties including the gas gap breakdown and surface flashover performance at DC, as well as lightning impulse voltage. Investigation about the gas stability is presented, including the compatibility of gas with solid materials in gas-insulated transmission line (GIL), and the decomposition characteristics under long-term electrical and thermal stresses. The important progress on the charge accumulation characteristics of gas–solid interface in the novel gas environment under DC voltage stress is analysed. Finally, the key issues that need to be paid attention to and further followed through regarding the application of this novel gas in GIL are summarised and put forward. This study hopefully can provide a complete reference for the development of eco-friendly DC gas insulation equipment with C(3)F(7)CN/CO(2) gas mixtures.