F-Gas Free Switchgear - A real Alternative to SF6 Gas Insulated Switchgear

Sulfur hexafluoride (SF
6
) is widely used in electrical switchgear equipment at both medium and high voltage, due to its excellent insulation and arc quenching properties and thus ensures a safe and reliable power distribution in the networks. In medium voltage gas-insulated switchgears (GIS) SF
6
, gas is predominantly used as an insulating medium as well as interrupting medium for load-break switching applications. However, SF
6
, has a Global Warming Potential (GWP) of 25200 times higher than CO
2
, it is considered as one of the strongest greenhouse gases. And when emitted into the atmosphere, often during decommissioning of the switchgear, SF
6
gas stays in atmosphere for up to 3200 years and contribute to Global Warming. Various fluorinated gas (F-Gas) regulatory bodies like European Commission, California Air Resources Board (CARB) call for alternatives to SF
6
, gas for both insulation and switching behavior of the switchgear. This led to various alternatives currently available in the market from different manufacturers. Each of them has different characteristics and handling needs when compared with today’s SF
6
.1.Natural Origin Gases - Mixture of N
2
, O
2
, CO
2
2.C5-FK (Fluoroketone C5F10O) mixed withN
2
, O
2
, CO
2
3.C4-FN (Fluoronitrile C4F7N) mixed with N
2
, O
2
, CO
2
Many third-party institutions have done their individual analysis of these alternatives and published their technical brochures. In this paper, a summary of these analyses is presented with additional experiences from F-gas-free solution where “Natural Origin Gases (NOG)” alternative is used. It covers different aspects like environmental, health and safety, gas stability and gas handling which are important for evaluation of switchgear solutions over the entire lifecycle. It is also discussed how the proven vacuum technology is used along with NOG in order to replace SF
6
, as an interrupting medium in load break switch applications instead of using other F-Gas alternatives.