Abstract: An isolating switch of a metalclad installation having an earthed metal enclosure is filled with a high dielectric strength gas. The isolation gap "d" separating the stationary contact from the movable sliding pin is surrounded by an annular electrode fitted between this isolation gap "d" and the enclosure. The annular electrode extends over the whole length of the isolation gap "d" and is electrically connected to the stationary contact to prevent any migration of the arc drawn between the contacts towards the earthed enclosure. The metal enclosure is advantageously spherical in shape, the contacts being disposed appreciably in the center of the sphere.

Abstract: The low voltage capacitor of a capacitive divider of a metalclad substation is located in a sealed compartment separated from the substation enclosure. In normal operation, the compartment is in direct communication with the enclosure via a communication orifice. The compartment can be isolated from the enclosure by closing the communication orifice valve to drain this compartment and thus have access to the low voltage capacitor or to other components of the capacitive divider housed in this compartment. Any pressure or temperature difference between the compartment and the enclosure, liable to affect the measurement, is thus avoided, while authorizing access to the low voltage capacitor without having to drain the installation.

Abstract: The present invention relates to an insulated high voltage transmission line and method for pre-assembling in the factory the sections of this line. The busbar is inserted into the cylindrical outer metal casing and held inside the casing by a removable support. On the job site, the removable support is withdrawn from the casing and the sections are connected in the usual manner. Support tools are used to avoid the bar overhanging during pre-assembling in the factory or assembling of the sections on the job site. During shipping the bar is inserted into the metal casing.

Abstract: A metal-clad electric installation for high tension use includes a metallic housing containing a conductor supported by an insulator and surrounded by an insulating gas. The metallic housing has adjacent sections which are joined by pairs of connected flanges. The insulator has an external border which is interposed between the flanges of two successive sections of the housing and is secured thereto by bolts passing through aligned openings in the flanges and external border, thereby partitioning the housing into tight compartments. In order to dismantle a section without affecting the sealed condition of the adjacent section, the bolts are replaced by screws which are screwed into small nut plates inserted into slots provided in the interface of the external border and the flanges.