Abstract: Disclosed is a station or distribution surge arrester of the type comprising a single column of varistors stacked one upon the other and centrally arranged in a cylindrical chamber provided in a casing made of an insulating material. A plurality of movable props, made of a material which is both insulating and non-elastic, are used for holding the varistors in column form centrally in the chamber, even if the varistors break diametrically as is often the case during a severe thermal shock. By holding the varistors permanently at the center of the chamber, the props ensure the non-obstruction of several vertical passages around the column, which passages allow an arc created within the surge arrester to move freely toward a pressure limiting diaphragm during failure of the latter and, thereby, reduce explosion risks to a minimum.

Abstract: An enclosure for electric device, in particular for surge arrester, comprises an outer, cylindrical envelope and an inner wall both made of electrically non conducting materials. One of the ends of the envelope is closed while the other is open. An electrode with a principal portion inside the enclosure extends through the envelope and projects outside the latter. Bolt anchors are used for fixing the enclosure on a mechanical support and for mounting a closure device on the open end of the envelope. The material constituting the inner wall is impervious to humidity and protects the envelope against breaking thereof by thermal shock caused for example by the production of an electric arc within the enclosure, while the material constituting the cylindrical envelope is a synthetic insulating material capable of withstanding a high mechanical tension.

Abstract: A puffer type liquefied-gas self-injection circuit breaker, used for the interruption at low temperature of a high current carried by a high-voltage power line. The circuit breaker comprises a first fixed contact and a compression chamber. The compression chamber has a bottom part which is fixed and an upper part of which is movable in the axial direction with respect to the bottom part. The upper part of the compression chamber comprises a second contact and an envelope concentrically disposed thereabout. An insulating nozzle is formed in a top portion of the envelope. The internal wall of the envelope is so shaped as to exactly match the external profile of the bottom part of the compression chamber. The breaker is also equipped with a liquefied-gas self-injection system which injects the liquefied-gas from their storage tank via a feed line and valve directly onto the electric arc formed at the moment of current interruption.

Abstract: A gas-cooled magnetic blast circuit breaker made up of a plurality of identical modules. Each module is a flat body made of electrically non-conductive air-permeable material and is formed with an upper and a lower arc breaking chamber, the chambers being separated from one another by a central wall of the body. An electrically conductive stationary contact member is provided in each chamber, each member extending through the body for connection to the power line on opposite faces of the body. There is also provided an electrically conductive dual contact member which is pivotally mounted across the central wall of the body, this dual member having a contact gate at each end, each gate being located in one of the chambers to cooperate with the stationary contact member in that chamber.

Abstract: Process and test generator for simulating the operation requirements of a protection device for an AC low, high or very high voltage power network. The generator comprises a voltage branch connected to the protection device for producing a sparkover voltage and an injection branch in parallel with this voltage branch for producing across the device under test a follow current of a value corresponding to the value of the current injected by the power network through this protection device when the latter is in operation. A resonant branch is connected to the injection branch for producing across the terminals of the protection device an alternating voltage corresponding to the voltage of the power network. The generator can also stimulate a long power transmission line and repetitive sparkovers of the device under test. Furthermore, a sparkover of the device can be performed at any phase angle of the power network voltage. The process and the generator are particularly useful for the testing surge arresters.