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 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 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.

In an embodiment a switching device includes at least one stationary contact in a switching chamber containing a gas comprising H.sub.2 and one movable contact in the switching chamber, wherein the switching chamber has a switching chamber wall and a switching chamber base, and wherein the switching chamber at least partially comprises a polymer material configured to release hydrogen when heated.

In an embodiment a switching device includes at least one stationary contact in a switching chamber containing a gas comprising H.sub.2 and one movable contact in the switching chamber, wherein the switching chamber has a switching chamber wall and a switching chamber base, and wherein the switching chamber at least partially comprises a polymer material configured to release hydrogen when heated.

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.

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.