Apr 2020
Electricity Transmission
Long Term Stability Testing of Alternative Gases 2: C5F10O
Apr 2020
Apr 2021
National Grid Electricity Transmission
Gordon Wilson (box.ngetinnovation@nationalgrid.com)
Click here to send a question to the contact.
Network Innovation Allowance
ET - Transition to low carbon future, ET - New technologies and commercial evolution, ET - Safety and health and environment
Environmental and Substations
Sulphur hexafluoride gas, SF6, is unique in its electrical and thermal performance. However, its Global Warming Potential, GWP, is very high at around 23900, compared with CO2 which has a GWP of one. Such negative impact on the environment led to the designation of the gas as a “Kyoto Gas”. In the UK, it is estimated that SF6 contributes 0.2% of the annual greenhouse emissions.
In recent years, new gas molecules and mixtures of gases have been considered and tested. A number of candidates have been particularly studied, these include dry air, N2 or CO2, polyfluorinated gases especially Trifluoroiodomethane (CF3I), Perfluorinated Ketones, Octafluorotetra-hydrofuran, Hydrofluoroolefins (HFOs), and Fluoronitriles.
This proposal is to extend the work being conducted on the stability of Novec™ 4710 and its mixtures under project NGTO002 to Novec™ 5110 (C5F10O) and its mixtures. Similar techniques, as developed for the Novec 4710™ gas mixtures project, will be adopted here.
The aim of this work is to gain a better understanding of the recently proposed alternative gases (C5F10O or Novec™ 5110) gas mixtures to replace SF6 gas. It will also enable obtaining a better understanding of the health and safety implications when using the newly proposed alternative gas mixtures, through by-products analysis. Moreover, it will allow the assessment of the stability of the new gas mixtures and their impact on surrounding equipment.
The objectives of this work are to:
  • quantify the impact of electrical discharges and flashover on the dielectric properties of the gas mixtures
  • measure the by-products of the gas mixtures following flashover
  • determine the impact of the gas mixtures and their by-products on surrounding materials.
  • develop an indicator of gas mixture degradation and estimate long term stability.