Abstract: The magnetic circuit of a generator in a hydro-generator plant is arranged to directly supply a high supply voltage of 20-800 kV, preferably higher than 36 kV. The generator is provided with solid insulation and its winding includes a cable (6) comprising one or more current-carrying conductors (31) with a number of strands (36) surrounded by at least one outer and one inner semiconducting layer (34, 32) and intermediate insulating layers (33). The outer semiconducting layer (34) is at earth potential. The stator winding may be produced with full or fractional slot winding, the phases of the winding being Y-connected. The Y-point may be insulated and protected from over-voltage by means of surge arresters, or else the Y-point may be earthed via a suppression filter. The invention also relates to a hydro-generator plant, a generator included in the plant and a procedure for building such a plant.

Abstract: An electric high voltage AC machine intended to be directly connected to a distribution or transmission network (16) comprises at least one winding. This winding comprises at least one current-carrying conductor, a first layer having semiconducting properties provided around said conductor, a solid insulating layer provided around said first layer, and a second layer having semiconducting properties provided around said insulating layer. In addition grounding means (18, 24, 26, 28) are provided to connect at least one point of said winding to ground.

Abstract: A synchronous machine for power and/or voltage control comprises a stator with a stator winding and a rotor with a field winding. The stator winding comprises a high-voltage cable with solid insulation. A rotor has a thermally based rotor current limit intersecting with a thermally based stator current limit in a capability graph at a power factor considerably below the rated power factor or has the thermally based rotor current limit above the thermally based stator current limit. In the capability graph. Means are provided for limiting the currents in order to avoid thermal damage. In a method for power and/or voltage control of such a synchronous machine, the machine operates with the stator current exceeding the thermally based stator current limit for a certain time period less than the maxim an permissible time limit, whereafter the overload is reduced by reduction of either the active power or the field current or a combination of both.

Abstract: A high power static electromagnetic device with variable inductance has a magnetic circuit with a flux bearing region. A main winding and at least one control winding surrounds the portions of the flux bearing region. A control device is coupled to the control winding for varying the distribution of flux. The winding is formed of a magnetically permeable, field-confining insulating cable.

Abstract: A rotating electric machine for direct connection to high-voltage networks, in which the magnetic circuit adapted for high voltage comprises a rotor, stator and main and auxiliary windings in operative relation. At least one of the windings is a conductor surrounded by a magnetically permeable, field confining insulation system.

Abstract: An electric switching device for fast closing of a high current in a power network comprising a first electrode (1), a second electrode (2), a movable contact element (3) closing said first and second electrodes, and an operating device. The operating device comprises a helically wound first coil (6) secured to the first electrode. The movable contact element comprises a flange (4) making contact with the coil. A current pulse flowing through the coil forms a repulsive force between the coil and the flange, said repulsive force throwing the movable contact element to the second electrode and completing the closing operation.

Abstract: A device for mechanically securing and controlling the potential of winding cables (10) outer semiconducting layers (14) in the end windings region of the stator (2) of a rotating high-voltage electric machine comprises spacers (12) of resilient, electrically conducting material arranged between the semi-conducting outer layers (14) of adjacent winding cables (10, 10′, 10″) Positioning devices (16, 18) are arranged to secure the cables in relation to each other with the outer layers in contact with the spacers.

Abstract: A method and device for providing series compensation for rotating electric alternating current machines connected either directly, or via a static current converter, to a three-phase distribution or transmission network. The stator of the electric machine is Y-connected. A capacitive circuit for the fundamental frequency of the voltage is connected to each phase between the low voltage side of the winding and a ground of the transmission network.

Abstract: An electric high voltage AC machine intended to be directly connected to a distribution or transmission network (16) comprises at least one winding. This winding comprises at least one current-carrying conductor, a first layer having semiconducting properties provided around said conductor, a solid insulating layer provided around said first layer, and a second layer having semiconducting properties provided around said insulating layer. In addition grounding means (18, 24, 26, 28) are provided to connect at least one point of said winding to ground.