Abstract: The invention concerns a method for manufacturing an electrical insulator that includes a body (1) and a coating (5, 5a) of insulating material arranged on the body (1) where the coating is applied onto the body in a screw-like form or a helical-like form, whereby the coating is applied by extrusion directly on the body (1). In this way, the build-up trapped pockets of air between the applied coating and the body (1) is prevented, and good adhesion is achieved. The invention also concerns an apparatus for manufacturing an insulator as well as the use of the said method or apparatus for the manufacturing of a high voltage insulator.

Abstract: An electrode for control of an electric field strength in a gaseous electrically insulating medium at the surface of the electrode and in the vicinity of the electrode, comprising an electrically conducting inner electrode (1′) and an electrically non-conducting layer (8) on at least parts of the surface of the inner electrode, wherein the thickness of the non-conducting layer is at least 5% of the mean diameter of the inner electrode and that the relative dielectric constant of the non-conducting layer is smaller than 3.

Abstract: This invention is related to a device and a method in an electric power plant for protection of an object (1) against over-currents from a network (3) or another equipment included in the high voltage plant, the device comprising a switching device (4) in a line (2) between the object and the network/equipment. The line (2) between the object and the network/equipment is connected to an arrangement (5) reducing over-currents towards the object (1), said arrangement (5) being actuatable for over-current reduction with the assistance of an over-current condition detecting arrangement (11-13) within a time period substantially less than the break-time of the switching device (4).

Abstract: An arrangement with a conductor (15) intended to be on a high potential and a part (12) connected to ground and separated therefrom by at least a voltage receiving air gap (16, 17), comprising an insulating envelope (18) surrounding said conductor and at least a first member (9) of electrical insulating material arranged to screen off said ground part from said conductor. Said air gap is dimensioned to get such a high electrical field strength by possible sudden, strong voltage raises of said conductor, that air molecules in said air gap will be ionized. Said insulating envelope (18) and the insulating member (9) have surfaces arranged to receive electrical charges generated through said ionizing for creating a voltage over their thicknesses and decreasing the voltage drop in the air gap between the conductor (15) and the ground part (12).

Abstract: The line section of a gas-insulated line contains a high-voltage electric conductor and a pressure pipe which is made from a thermoplastic material and filled with insulating gas. The pressure pipe holds the electric conductor on insulated supports. The pressure pipe has two pipes which are welded to one another on the end faces thereof, the end section being respectively widened to flare outwardly in the radial direction with the welding of the two pipes.