Recent Development of Two Alternative Gases to SF6 for High Voltage Electrical Power Applications

Abstract

For many years, SF6 has been the preferred dielectric medium in electrical power applications, particularly in high voltage gas-insulated equipment. However, with the recognition that SF6 has an extremely long atmospheric lifetime and very high global warming potential, governments have pursued emission reductions from gas-filled equipment. The electrical power industry has responded to this environmental challenge applying SF6-free technologies to an expanding range of applications which have traditionally used SF6, including gas-insulated switchgear, gas-insulated circuit breakers and gas-insulated lines or bus bars. Some of these SF6-free solutions include gas mixtures containing fluorinated compounds that have low climate impact, among them, a fluoronitrile and a fluoroketone developed as 3M™ Novec™ 4710 Insulating Gas and 3M™ Novec™ 5110 Insulating Gas, respectively. Both fluoronitrile and fluoroketone mixtures are successfully used in gas-insulated equipment currently operating on the grid where they reduce greenhouse gas emissions by more than 99% versus SF6. This paper reviews these leading components of alternative-gas mixtures with updates on the performance, safety and environmental profiles in electrical power applications.

Trifluoromethyl Fluorosulfonate (CF3OSO2F) and Trifluoromethoxy Sulfur Pentafluoride (CF3OSF5) – Two Gaseous Sulfur(VI) Compounds with Insulating Properties

“…[5] However, this phase out proved challenging, as the industrially favored properties of SF 6 are also the reason for its exceptionally long atmospheric lifetime of about 3200 years and the resulting global warming potential (GWP) of around 23900 over a 100 year period. [6][7][8] The high GWP value is based on the lifetime in the environment and on the ability to absorb IR irradiation. The absorption cross section for fluorinated molecules is often relatively high.…”

Consistent Calculation from Particle Composition to Arc Simulation for Arc Ignition Process in Polymer Ablated Arcs

“…Due to the situation of F-gases regulation represented by sulfur hexa uoride (SF6), development of more effective arc extinguishing technique is required in power circuit breakers [1,2]. Controlling ablation from solid materials in nozzles can be of great interest and key role, as is searching for alternative gas with high arc-extinguishing capabilities.…”

Monitoring, Detection and Locating of Transient Earth Fault Using Zero-Sequence Current and Cable Screen Earthing Current in Medium Voltage Cable and Mixed Feeders

“…Moreover, the installation of sensors in depths of the network is often difficult since new types of MV switchgear often require de-energization before the sensor is installed. De-energization is required because of the safety reasons and in case of gas insulated switchgears, the insulation gas SF6 has to be extracted before the installation of the sensors because of high global warning potential [16]. Moreover, the method is limited to the single segment underground cable line, which is rarely found in the real distribution system network.…”