The use of a gas as a medium for electrically isolating and/or extinguishing electric arcs, the gas including 1-chloro-2,3,3,3-tetrafluoropropene. Also, an electrical device including a sealed chamber containing electrical components and a gas for electrically isolating and/or extinguishing electric arcs, in which the gas includes 1-chloro-2,3,3,3-tetrafluoropropene. The gas may be only 1-chloro-2,3,3,3-tetrafluoropropene.

An insulating medium for an electric energy transmission device is a fluid at room temperature and atmospheric pressure and has at least the following components ≥50% by volume to ≤98% by volume of synthetic air, and ≥2% by volume to ≤50% by volume of an organic fluorine compound. An electric arc extinguishing medium and a fluid-insulated electric energy transmission device are also provided.

A gas circuit breaker that can reduce deterioration of insulation performance thereof and current breaking performance thereof by the unnecessary gas generated from the arc-extinguishing gas sprayed to the arc is provided. The gas circuit breaker includes a sealed container (8) which arc-extinguishing gas is filled therein, a first fixed contactor (2) which is fixed to the sealed container (8), a second fixed contactor portion (4) which is fixed to the sealed container (8), and a movable contactor portion (3) which moves between the first contactor portion (2) and the second contactor portion (4), and which conducts and breaks current between the first contactor portion (2) and the second contactor portion (4), in which an arc generated between a fixed arc contactor (21) provided to the first fixed contactor portion (2) and a movable arc contactor (31) provided to the movable contactor portion (3) at a time of current breaking action is extinguished by an arc-extinguishing gas being sprayed thereto, and the gas circuit breaker (1) includes a gas chamber (5) to accumulate an unnecessary gas generated from the arc-extinguishing gas sprayed to the arc.

An electrical switching device is provided for interrupting an electrical connection. The device has a switching chamber and two contact pieces being arranged directly in the switching chamber or in an encapsulated housing arranged in the switching chamber and configured to be gas-tight in relation to the switching chamber. The contact pieces are movable relative to each other to bring about a switching action. A fluid insulation medium is also provided, which is arranged in the switching chamber or in a storage volume which can be connected to the switching chamber. The switching chamber or the storage volume has an outlet for letting out the fluid insulation medium. A filter is provided at or adjacent to the outlet, the filter configured to filter gaseous components of the insulation medium, or the reaction products thereof, conducted through the outlet.

A gas-insulated puffer-type switch device for operating inside a sealed gas tight enclosure of an electric power distribution switchgear, the sealed gas tight enclosure being filled with a dielectric gas having a global warming potential lower than that of SF6. The switch device has at least one of improved compactness, minimised electrical stress, maximised heat dissipation and reduced environmental impact.

A high voltage electric switch includes contacts with graphite carbon electrode forming the arc gap. In addition, the carbon contacts are located in a chamber containing at least 60% carbon dioxide (CO2) as a dielectric gas to achieve improved arc interrupting performance. In conventional switches, the metallic contacts introduce metallic vapors into the arc plasma that inhibits the ability of the dielectric gas to interrupt high voltage, high current arcs. As the element carbon is inherently present in CO2 gas, the addition of vapors from the carbon electrodes into the dielectric gas does not significantly interfere with the dielectric arc-interrupting performance of the CO2 dielectric gas.

A medium-voltage or high-voltage electrical device comprising a sealed enclosure in which are located electrical components covered with a solid dielectric layer and a gaseous medium ensuring electrical insulation and/or extinguishing electrical arcs, the gaseous medium comprising heptafluoroisobutyronitrile and a dilution gas, the thickness of the solid dielectric layer being less than 1 mm and being produced from a material comprising a polyepoxide or polyurethane resin optionally containing a filler or aluminum oxide.

A method of distributing an electrically insulating liquefied gas mixture to high-voltage electrical equipment from a storage means containing an insulating gas mixture, including: heating the insulating gas mixture to a temperature such that the contents of the storage means are a homogeneous fluid; and withdrawing the insulating mixture resulting from step a) to fill high-voltage electrical equipment by raising the temperature of the mixture resulting from step a), wherein, during step b), a set value for regulation is applied at variable pressure, calculated in real time based on weighing the storage means, when the change in the set value of pressure is less than 0.2 bar per 1 kg/m.sup.3 of change in density, and then a set value for regulation is applied at constant temperature until the storage means is emptied of its content.

An apparatus for heating an insulation fluid in a medium-voltage or high-voltage switchgear comprises an infrared source which is adapted to emit infrared radiation of at least one wavelength. Thus, at least one vibrational or rotational mode of at least one component of the insulation fluid is excited by absorption of at least a part of the infrared radiation, and condensation of the insulation fluid is efficiently prevented by this direct heating of the insulation fluid. A closed loop temperature regulator is used to heat only when required. A circulator in a heating chamber further provides for a mixing of the insulation fluid, thus preventing steep temperature gradients.

A load-break switch has a housing holding insulation gas at ambient pressure; a first main contact and a second main contact being movable relative to each other in an axial direction of the switch; a first arcing contact and a second arcing contact being movable relative to each other in the axial direction and defining an arcing region where an arc is formed during a current breaking operation, wherein the arcing region is located radially inward from the first main contact; a pressurizing system pressurizing a quenching gas during the current breaking operation; and a nozzle system arranged to blow the pressurized quenching gas onto the arc. The first main contact includes at least one pressure release opening to allow gas flow in a radial outward direction. A total area of the pressure release opening suppresses a reduction of gas flow out of the pressure release opening.