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.

Method and device for controlling the magnetic flux in a rotating high voltage electric alternating current machine

A power- or regulating transformer (11) with voltage regulating means is disclosed. The transformer comprises regulating windings (15) made of a flexible conductor having electric field containing means forcing the electric field due to the electric current int the winding to be contained within the flexible conductor. Since virtually no electric field is to be found outside the flexible conductor of the regulating winding (15), the regulating winding may be formed without having to consider the electric field distribution, thus providing for a transformer with a favorable regulating winding design.

Transformer with voltage regulating means

The invention relates to a conductor for high-voltage windings, preferably for use in the stator of a high-voltage generator, which is designed to ensure uniform current distribution, to counteract eddy-current losses and to ensure that the inner semiconducting layer of the insulation system has the same potential during operation as the strand layers (K1-K4). This is achieved by the electrical insulation between the strands being such that only certain strands (A) are clad with an electrically insulating layer. The outermost layer of strands (K4) shall have at least one uninsulated strand (B). The invention also relates to a rotating electric machine comprising a conductor in accordance with the above.

Conductor for high-voltage windings and a rotating electric machine comprising a winding including the conductor

The present invention relates to a power transformer/inductor comprising at least one winding. The windings are designed by means of a high voltage cable (10), comprising an electric conductor, and around the conductor there is arranged a first semiconducting layer (14), around the first semiconducting layer (14) there is arranged an insulating layer (16) and around the insulating layer (16) there is arranged a second semiconducting layer (18). The second semiconducting layer (18) is directly earthed at both ends of each winding (221, 222) and furthermore at least at two points per turn of every winding (221, 222), whereby one or several points are indirectly earthed.

Power transformer/inductor

In a plant containing a turbo-generator the magnetic circuit of the turbo-generator is included in an electric generator which directly supplies a high supply voltage of 20-800 kV, preferably higher than 36 kV The insulation of the generator is built up of a cable (6) comprising one or more current-carrying conductors (31) with a number of strands (36) surrounded by outer and inner semiconducting layers (34, 32) and intermediate insulating layers (33) The outer semiconducting layer (34) is at earth potential The phases of the winding are 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

Turbo generator plant with a high voltage electric generator

An inductive device includes a principal magnetic core (11) having a principal winding (10) coupled therewith so that the reluctance of the principal core influences the inductance of the principal winding. A control winding (12) is coupled to a control magnetic core (13) so that the current in the control winding influences the magnetic flux in the control core. The control core intersects the principal core so that magnetic flux produced in the control core interferes with the principal core. Selective control of current in the control winding influences the magnetic flux in the control core, which in turn interferes with the principal core so as to influence the reluctance thereof and thereby vary the inductance of the principal winding. Additional control windings may be coupled to respective additional control cores (13a, 13b, 13c) which intersect the principal core, so that selective control of the currents in the various control windings enables selective control of the degree of interference with the principal core, and hence the reluctance thereof. The dimensions of respective reluctance control regions where the control cores intersect the principal core may be selected such that the degrees of influence of the individual control cores are in a binary sequence.

Ronald Barry Zmood

Papers

Electrically-variable inductor