SU1123079A1 - Stator for high-voltage electric machine - Google Patents

Abstract

1. STATOR OF A HIGH-VOLTAGE ELECTRIC MACHINE containing a winding made in the form of flat spiral Katuns, divided into sections, separated from one another by insulating layers n placed between two insulating cylinders, in order to increase the operational reliability of the winding and improving manufacturability, each phase coil is provided with at least one toroidal shield, electrically connected to it and grasping it around the entire perimeter. 2. The stator according to claim 1, which is also distinguished by the fact that at least one section of the phase coil consists of four parts, and the rest of the two. with:

Description

The invention relates to electrical engineering, and more specifically to the design of turbo-generators.

A well-known design of a powerless gas-free turbo-generator, in which the stator is made with flat spiral katutaki, separated by layers of insulation 1.

The disadvantage of this construction is a large voltage gradient along the coils of the coils and the poor shape of the electric field at the edges of the coils, which makes it difficult to perform the stator windings for a voltage of 30-60 kV.

Closest to the invention the technical essence is the stator design of an electric machine, in which each phase consists of several flat spiral coils divided into sections with transposition, separated from each other by insulating layers and ground between two insulating cylinders And .-,

The disadvantages of the known construction are the unfavorable shape of the electric field of the edges of the coils, especially at the edges of the coils of adjacent phases, separated by a very thin insulation layer, which can lead to breakdown, as well as the need to make flat spiral katuvake with a variable cross-section in the tangential direction of copper and isolation, which makes it very difficult to implement such a construction, i.e. reduces its manufacturability.

The purpose of the invention is to improve the reliability of the winding and improve the manufacturability.

This goal is achieved by the fact that in the stator there is a high-voltage electric machine containing a winding made in the form of flat spiral phase coils divided into sections separated from one another by layers of insulation placed between themselves: two insulation cylinders, each Phase coil is provided with at least one screen with a hinged shape, electrically connected to it and encircling it along the entire perimeter, with at least one section of the phase coil being made; from four parts, and the rest - from two. .

Figure 1 shows the cross section of the stator, figure 2 shows the phase winding, general view, figure 3 shows the D-section of figure 2, figure 4 -electric connection. Of the sections and screen parts that are wrapped around them Fig. 5 is an electrical circuit diagram of the kaTyuieK sections, Fig. 6. - an embodiment of the coils without dividing them into sections.

 The stator contains three phase windings 1, interposed between insulating cylinders 2 and 3, respectively cylinder 2 joins the stator active steel ring (not shown, and cylinder 3 separates the stator winding area from the rotor of the generator (p. Not shown). Between Dielectric filler 4 is placed in phase windings 1. At this, the structure is clamped between cylinders 2 and 3, thus ensuring mechanical fastening of the phase windings. All phase windings are made equally. Phase winding 1 consists of flat spiral cat . Nis Each kOe them consists of three series-connected sections 5 - 7 {fig.Z and 4). The central section 5 consists of two parts 8 and 9 connected in series. The nearest to the central section 6 consists of four parts: 10 - 13 (5), forming a closed circuit. The next section 6 is similar. It consists of four parts 14 - 17, connected in a similar way (figure 5). The cross-connection of parts of sections 6 and 7 is made so as to avoid equalizing currents in parallel-connected parts, i.e. is a transg position.

The conductive layers of each section are somewhat curved across the cross section, but in FIG. 3 for simplicity, the copper layers 18 are shown to be flat. Between the layers there are channels for the refrigerant 19. All sections of which the coils are made are identical flat spiral helical coils, made to the subtype shown in Fig. 2, placed one above the wheel (FIG. 3) and separated mi 20 isolation. The beginning and KOHii i parts of section b and 7 are electrically interconnected by means of electrostatic screens 21 24. Thus, the beginning of part 10 of section b is connected to the beginning of part 12 of the same section with the screen 21. Similarly, the end of part 13 of section 6 is connected to a part of 11 of the same section using the screen 23. Similarly, the beginning and the ends of section 7 are connected by screens 23 and 24 (FIGS. 3 and 4).

Screen 25 encloses the phase capacitance ku 1 around its entire perimeter. It is also possible to install screens 26 along the ends of section 5 and auxiliary forming screens 27. Screens 21 25 have a toroidal shape and fit the ends of the corresponding sections (in Fig.2, the screens are not shown, in Fig; 1 only the outline of the external screen 25 of the phase winding is shown) . In the known structures near the sharp edges formed by copper tubes of the ends (edges) of the coils, an extremely unfavorable distribution of the electric field is formed, especially if we take into account that between the edges of the coils of adjacent phases, separated by a very small insulating gap, there is a potential difference is close to phase to phase voltage. This significantly reduces the electrical strength of the insulation and does not significantly increase the stator voltage of the generator. Thus, with specific parameters characteristic of cryoturbine generators (radial distance between insulating cylinders 2 and 3, about 40 cm, it is almost impossible to implement a known construction for a voltage of 220-500 kV. Separating a part of a coil into parallel-connected parts and using electrostatic screens allows not only obladuyudit picture of the electric field in between the coils and around them, but also forcibly set the potential of the floor, dividing the entire field of action of the field into a number of areas of the task floor, limited smooth1 "surfaces with large rounding radii, which ensures that everywhere in these areas there is a refined weakly inhomogeneous electric field, in which the insulation has increased electrical strength. So, at a phase voltage of 300 kV (which corresponds to a linear 500 kV), dividing the phase winding into 3 sections and with the series connection of sections 5-7, each of them has a potential difference of 100 kV and each part of the section 50 kV. Thus, at the beginning of part 8 (to which voltage is applied) tial of 300 kP, at its end (at its last turn) - 250 kV, a portion 9 voltage drops from 250 to 200 HFig.Z), the potentials are indicated in figures at the beginning and end of each part, etc. Thus, on the screen 21, the potential is 200 kV, on the screens 22 and 23 is 100 kV, on the screens 24 and 25 is 0. As a result, between screens 23 and 21 there is a potential difference of 100 kV, between screens 24 and 22 a potential difference of 100 kV, also. as between shields 24 and Z2 and between shields 25 and 23 Since the screens listed above have relatively large rounding radii, a weakly non-uniform electric field is obtained everywhere in the space between them, which guarantees high dielectric strength and reliable insulation of the phase winding up to phase voltage 300-400 kV. Special attention should be paid to the fact that, in general, each phase winding is surrounded by screens 24 and 25 with zero potential, which eliminates the problem of the formation of powerful insulating layers, designed to withstand the voltage across the copper between the coils of adjacent phases. This question is particularly acute in the known designs of generators, since the coils of all phases must be placed in a very compact volume (unlike high-voltage transformers). The problem of interphase insulation is one of the main problems when trying to increase the voltage in the known stator winding structures. In contrast to the known construction, the copper coils and the insulation between them have a shaped cross section, in this case all parts of the section are made with copper and insulation of the same size in the tangential direction, which greatly simplifies the technology of their manufacture. Separating the phase coil into 3 serially connected sections is optional; it can also be divided into another number of sections, which is dictated by the specific machine data. Parts of the sections do not necessarily have to be located on ONE axis one above the other (FIG. 3). They can be slightly shifted relative to each other like a ladder, for example, to improve the winding ratio. Screens do not necessarily have to wrap around all sections. Can only be limited to external screens 24-25. Electrostatic screens can be made in various ways, for example, in the form of sputtering a conductive or semiconducting layer onto a skeleton, a continuous perforated layer or a few layers, foil, in the form of grids of conductive material or in the form of adhered or wound conductive or semi-conductive -, center of tapes. In all cases, the screens must be perforated or their material must be permeable to the coolant, making it possible to cool the turns of the coils. In the face, parts of the screens have electrical breaks to avoid the formation of short-circuited turns. The creation of a favorable weakly non-uniform electric field in the space occupied by the phase coil 1 can be ensured even without dividing each section into two parallel-connected parts (Fig. 6). Here, three sections of the phase coil 28 - 30 are connected in series and surrounded by electrostatic screens 31 - 33 (FIG. 6). The paths of electrical connections between the beginnings and the ends of the sections coincide.

with projections of ebayov (Fig.6). With the proposed scheme for making and joining sections and screens, the same effect is achieved as in the well-known embodiment.

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1

The proposed stator design of a high-voltage electric machine in comparison with the known ones has a higher reliability in operation and is more technological in manufacturing.

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Claims (2)

1. STATOR OF A HIGH-VOLTAGE ELECTRIC MACHINE, containing a winding made in the form of flat spiral coils, divided into sections, separated from one another by layers of insulation and placed between two insulating cylinders, characterized in that, in order to increase the operational reliability of the winding and improve manufacturability of manufacture, each phase coil is equipped with at least one screen of the toroidal Form, electrically connected to it and wrapping it around the entire perimeter. 2. Stator pop. 1, it is distinguished by the fact that at least one section of the phase coil is made of four parts, and the rest of the two. SU, "1123079 1 1123079 2