SU509902A1 - Transformer - Google Patents

Description

(54) TRANSFORMER

The invention relates to current limited transformers for protecting the on-board superconducting elements of an installation from a short-circuit pattern.

It is known to connect high-current cryotrons from a superconducting toroidal and controller to the device elements. conductors and connecting coils screened with superconducting material, or making transformers with a high short-circuit voltage, which leads to large scattering fields, resulting in large losses in superconductors in an alternating field. Therefore, transformers with superconducting windings are designed so that they contain a small short circuit voltage, leading to a high short circuit current.

To limit without additional devices, excess currents or short-circuit currents with superconducting elements without loss of superconductivity in the main scattering channels formed by the transformer windings, superconducting screens are placed, resulting in a free iOT of electromagnetic fields during normal operation of the transformer. To screen the stray fields in the winding zone, superconducting screens are made across the stray fields.

FIG. Figure 1 shows schematically the described device in a longitudinal section (in diagrams a and b is the idealized dependence of the scattering fields B (f); Fig. 2 shows the described device with an electromagnetic conductor (in diagrams a and (5 is the idealized dependence of the scattering fields B ( D); in Fig. 3, the device being written off with a screen placed inside the winding (in diagrams a and 5 5 deals the dependence of the scattering fields C (D) along the intersection lines A-A and B-B,

Claims (4)

A screening grid 3 is placed between windings 1 and 2 in the main channel. The shell of the cryostat 4, indicated by dotted lines, indicates that winding 1 is located in the zone of normal temperatures. Both windings can also be located in an ambient or low temperature zone. When the critical electromagnetic intensity of the pop-up grid 3 is exceeded, the dependence of the sex B (f) of FIG. 1a Converts accordingly depending on the field of Fig. 16 in terms of equal magnetising force of windings and 2. The increase in short circuit voltage is shown in diagram 16. Screen 5 (Fig. 2) is shown open on one side. Inside the screen: 5 or 3 {Fig. 1 and 3), an electromagnetic conductor may be provided, amplifying the described effect, which is: 1: Pokaean; - in the diagrams of the dependence of the fields of scattering B () in Figs. 2 and 26. Electromagnetic conductor 6 may have gaps or gaps 7 that affect induction in the electromagnetic conductor. Inside the winding 2 (Fig. 3), screens 8 are placed, which contribute to weakening the dissipation field in winding zone 2, as shown on characteristic B (), along the intersection lines A-A and B-B. The period of termination of superconductivity of screen 3, and 8 corresponds to characteristic B (/ (Fig. 16). Screening elements 3, 5, 8 should not form a closed coil, i.e., they must be provided with a slot, and slots must be installed with offset relative to each other The superconducting screens in the main channel of the scattering are made in the form of a grid which iT can have an opening on the front side, It is preferable to make a conductive connection at the slits between the inner and outer cylinders. internally closed; the grids are made of ferromagnetic material, which is predominantly in the normal temperature zone. For induction in ferromagnetic material, it can be completed with gaps or cracks. Superconducting screens are made, for example, of fabric, braided foil, or otherwise separated material, and the joints of individual elements must be made with a sufficient transmission. The described device works in the following way. Superconducting screens at higher than the critical electromagnetic. field strengths dissipate in the normal conduction mode. In this mode, they are permeated by electromagnetic fields. By the magnitude of the volume of a winding penetrated by electromagnetic fields in the normal conduction mode of shielding, the short circuit current increases, resulting in a current limiting effect. Due to the appropriate installation and selection of the superconducting material, an overcurrent force is limited. The ratio of the values of the short circuit current voltage after (J, and before current limitation is expressed by the formula and (Y + and - - v 1 "and p S., A.c.a, where O), (2, Ctj and a are dimensions in Fig. 1; fU is equivalent magnetic permeability of the shielded space between the windings, and yU 1; Cli C2, Cz are coefficients that take into account the weakening of the floor by installing a superconduct of our screens inside the coil, with C and C2 1, O, and Cz 1, O. Form 1. The transformer containing windings, at least one of which is superconducting, forming the main channels, dissipates, at least one of the current is in the zone of low temperatures, and the superconducting screens and in order to limit the short-circuit currents without disturbing the superconductivity of the windings, the superconducting shields are located in the main scattering channels and in the winding zone across the scattering field. 2. The transformer according to claim 1, which is based on the fact that the superconducting screens in the main channel are dissipated in the form of a grid having a cut on one end side. 3. A transformer according to claim 1, characterized in that the superconducting screens are made in the form of layers of a superconducting braid, for example, of foil, the joints of the layers being made with overlapping. 4. Transformer on PP. 2, 3, which is based on the fact that a magnetic conductor with air gaps is placed in the superconducting screen.