CS229647B2 - High-voltage inlet bushing - Google Patents

Description

(54)

High-voltage grommet for conducting wires

The invention relates ^to hair dryers she ew £ ^p of sleeves for introducing the conductors, which in comparison with the known construction has a much more favorable conditions for production and particularly favorable conditions for assembling and přioom complies fully - the requirements for dielectric strength and safety.

The insulating body surrounds a cavity whose longitudinal axis extends parallel to the longitudinal axis of the conductor (s) and the air space of the cavity is divided into two parts by a plane perpendicular to the longitudinal axis through the partition wall.

The insulating body of the invention has at least two or more walls along two mutually opposed sheath paths of the through space of the cavity, arranged so that the outer wall surrounds the at least one inner wall, further that the insulating body is formed by two adjacent body halves along In contrast to the partial flats formed in the inner wall, the partial surfaces formed in the outer wall are displaced along the circumference of the walls. the outer walls by a plurality of wall pieces arranged between the walls and inside the inner wall, wherein two adjacent parts are each displaced along the longitudinal axis of the cavity.

229 647

228 647

The invention relates to a high-voltage conductor lead-through, the insulating body of which can be made of any material known in the art and using any technology, for example by pressing and firing from a ceramic, porcelain or synthetic resin in a vacuum by so-called die casting.

It is well known that electrical strength and ease of assembly requirements are difficult to reconcile with these products. In assembled conductor systems, an insulating fittings made of insulating material must completely surround the conductor to be fastened, but arise at the same time in split insulators and on site mounting undesirable insulation distances in the separation plane. For this reason, the use of split insulators has so far been abandoned in high voltage technology. Insulators corresponding to the prior art consist essentially of a single piece, in that at least the surfaces extending approximately parallel 8 along the longitudinal axis of the conductor are not divided. In the following, all partial surfaces whose orientation deviates from the direction of the longitudinal axis only to the extent permissible or merely because of the manufacturing technology as practically parallel to the longitudinal axis of the conductor are considered. If the cable entry bushing is installed when laying the conductor system, the cable to be fastened - consisting mostly of the contact bus - must be threaded through

-2.229 647 insulator in the direction of the longitudinal axis. Especially in the case of longer wires, this operation is associated with difficulties and disadvantages, and high assembly effort results in less productive technology. Similar problems may arise if the conductor bushing is additionally to be replaced in the finished switchgear.

It is an object of the present invention to provide a high-voltage insulating body which makes assembly quick, easy and economical, both for mounting and for subsequent replacement of the lead-in grommet.

The invention is based on the discovery that the required electrical strength and operational safety can be ensured by such a high-voltage lead-through bushing consisting of two body halves whose partial surfaces are aligned substantially parallel to the longitudinal axis of the conductor when the insulating body surrounds the conductor the circumferential paths extending over more than one wall, in such a way that each of the adjacent partial surfaces formed relative to one another in the inner wall or outer wall of the wall perimeter are offset so that the breakdown voltage value corresponding to the insulating distances exceeds the value prescribed for the insulator as the test voltage, the partition wall is a bisecting air space of the cavity surrounding the insulator in a plane perpendicular to the longitudinal axis, also consisting of several parts, that the adjacent parts are always displaced along the longitudinal axis.

Accordingly, the split lead-in bushing according to the invention is formed such that it consists of two body halves which can be aligned with each other along a dividing surface practically parallel to the longitudinal axis, said body halves forming comb-overlapping insulating caps; after the installation of the 3 229 647 assembly, the remaining small gaps along the mating sub-surfaces can only be closed over long distances by air or the creeping paths - in terms of electrical breakdowns - are added together in series. When mounting the insulating body halves, it is possible to fasten the inserts which come into contact with the conductors according to their shape, and extensive clarification seems unnecessary, since such fastening is well known to the person skilled in the art. The insulating body surrounds a cavity, the longitudinal axis of which extends parallel to the longitudinal axis of the conductor, along a practically continuous circumference, since the air gap resulting from the division on the partial surface forms only a small part of the circumference.

The conductors are usually in the form of a rectangle, circle, ring or U-profile. Accordingly, it is possible to select the shape of the insulator in accordance with said conductor shapes, although this is not a requirement. In this case, the cross-sectional profile of the roof elements perpendicular to the longitudinal axis of the conductor forms a circular ring, or in another case, an overlapped embedded U-profile or any other profile of similar nature.

With such an arrangement, the conductors can be immediately inserted in the direction perpendicular to the longitudinal axis, the insulating body being mounted directly on the conductors, and the insertion in the longitudinal direction is eliminated.

Before describing in detail the structural characteristics of the insulator according to the invention and its embodiment by means of the figures, it is desirable to derive, also from the figure, the considerations which form the basis of the idea of the invention.

FIG. 1 shows, as an example, a monolithic insulator which corresponds to the state of the art in the assembled state, and FIG. 1a is a view perpendicular to the longitudinal axis.

Fig. 1b shows a longitudinal cross-section. Figure 2 shows a simplified plenary section extending parallel to the partition wall of the lead-in bushing. Fig. 3 shows an embodiment of a lead-through bushing according to the invention, in which both the outer wall and the inner wall have the shape of a rotating body. Fig. 4 shows an embodiment of an insulator according to the invention with a parallelogram cross-section. Giant. 5 is a split insulator according to the invention, derived from the shape of the insulator of FIG.

The idea behind the present invention is based on the following considerations: the conductor insertion insulators have the task of passing one or more conductors that are live or can be live through a grounded partition wall, in most cases made of conductive materials such as sheet metal. Due to the high electrical strength requirements, the lead-in bushing must withstand significant mechanical loads. In an insulator according to the prior art, the insulating body 16 surrounds at least one conductor 11 in the vicinity of the partition wall 13 as a tubular, plate or edge whip body. A support wall 1g formed in the insulating body or an insert adjacent to the insulating body 12 or between two conductors 11 can serve as support. Furthermore, possible variations of the support designs will be uniformly referred to as partition walls 18, since in the assembled state the supports eventually fulfill the role of such wall. The spatial separation also applies to the air space outside the insulating body surrounding the cavity. As can be clearly seen from FIG. 1, the outer fitting of the partition wall adjoins the partition wall 13.

In Fig. 1b the shortest distance between the conductor 11 and the partition wall 13 is indicated, the distance L i which expresses the wall thickness of the insulating body 12 in this plane; the shorter distance in the air dielectric between the conductor 11 and the partition wall 11 is also indicated. The wall of the insulating body 16 exemplified is in the form of a rotating body, the axis of rotation being the longitudinal axis of the cavity surrounding the insulating body.

The insulating body 12 can only perform its function if the electrical strength of the distance between the conductor 11 and the partition 13 given by the measurement of the electrical strength along the distance compared to air and dielectric of higher value on the line - L _d is greater than the nominal breakdown strength. The standard and distance as the shortest airway, which is determined essentially by the length of the wall H of the insulating body 12, guarantees an electrical strength which reaches or exceeds the nominal value of the electrical strength according to Погщу. Generally, these requirements are fulfilled under bilateral relationships, and when the conditions are met, the electrical strength of the distance is lower than along the path characterized by the distance L 1, so that any jump does not occur in the insulating material but in the air surrounding the insulating body.

The equally important characteristic of the insulating body can be considered the creeping path: it is the smallest distance that can be measured between the grounded partition wall 13 and the conductor 11, the minimum length being given by the distance Lg. In general, the length of the creep current path for conventional lead-in feedthroughs is as specified in the standard for the insulator.

It will be appreciated by those skilled in the art that when the insulating body 12 is made of two halves and after the two halves have been assembled, the air gap formed will co-operate to produce a breakdown strength value. Such electric fields create a multivariant field; therefore, there is a desire for maximum symmetry in the division. At the same time, however, in any

- 6,229,947 to the dividing plane of a uniquely symmetrical separation due to opposing air gaps will shorten the insulation distance to such an extent that, after considering this clear disadvantage, the use of split bodies has been abandoned.

However, this starting point was found to be incorrect as a premature conclusion. The two body halves may form a mirror image of each other and, in terms of multivariant fields at a given location, may form a balanced mirror mechanism even if the body half is not fully flat-symmetrical. If the insulating body 22 is now formed by at least two parallel walls along at least two mutually opposed paths and the partial surfaces are displaced relative to one another on the two inner and outer walls respectively, the insulation distance can be extended accordingly. This arrangement is evident from Figure 3 »Distance * results from the sum of the following paths:

= the smallest distance between the conductor 31 and the air gap formed on the partial surfaces 37a, 37b arranged on the inner wall = the length of the air gap, = the smallest distance between the air gaps formed in the inner wall 35 and outer wall 11,

L _p '= length of the air gap in the outer wall

Liy = the shortest path between the outer wall 34 of the insulating body 32 and the partition wall 33, then:

4c ^'= 4> ^{+ L} r ^{+ L L} t ⁺ R' ⁺ · 4г líčelným said sub-areas 36a, 36b, 37a, 37b in the outer wall 34 and inner wall 35 can be achieved that l1.

In the embodiment of FIG. 3, both walls 35, 35 have the shape of a rotating body, wherein the axis of rotation of the rotating bodies simultaneously forms the longitudinal axis ^{ш of the} cavity, and the outer partial surfaces 36a, 36b therein.

7 229 647 th wall 34 are formed along two mutually opposed lines passing through the axis of rotation of the separating plane of the rotary body, while the inner partial surfaces 37a, 37b in the inner wall 35 concentric to the outer wall 34 are formed along two opposite lines passing through the axis of rotation of the dividing plane. forming an angle with the dividing plane. Under the assumed geometrical conditions, the rotation is in the range of 165 ° Z cL. If the now-formed body halves 32a, 34b are fixed to one another along the partial surfaces 36a, 36b, 37a, 37b, this split arrangement does not result in any reduction in electrical strength below the standard value; Simultaneously, simplified manufacturing and assembly technology is achieved.

In the embodiment shown in FIG. 4, a cross section in a plane perpendicular to the longitudinal axis of the cavity, both the outer and inner walls 44 and 45, forms a rectangular rectangle, preferably with rounded corners. In the opposing sides 44a and 44b of the outer wall 44, outer partial surfaces 36a and 36b are formed; inner partial surfaces 37a and 37b are formed in the parallel running inner walls 45a and 45b, so that each of the adjacent outer and inner partial surfaces, for example, 36a, falls into one half of the space λ g cut by the dividing plane < f perpendicularly running on pages 44 and 44b and 45a. 45b. while the outer partial surface β78 falls into the second half of the space λ The partial surfaces 36a are not for better illustration. 36b, 37a. 37b are shown consistently in all sub-figures. The positions not shown in Fig. A are similar to Fig. B, where they are shown, with the meanings of the sub-faces J6b and 37b not shown in Fig. 4 being shown in Fig. 3 »

4b and 4c show examples of embodiments in which: FIG

8 229 647 in the insulating body 42 forms a perimeter perpendicular to the cavity in the longitudinal axis ω a parallelogram, suitably a rectangle with rounded corners, along whose opposite sides an outer wall 11 is formed and inside and with which one or more inner In each case, the outer and inner partial surfaces J6a, j6b and J7a, Jjb are formed in the outer wall and the adjacent inner wall, respectively, so that the outer partial surface 36a is perpendicular to one half of the space λ cut out by the dividing plane cT extending to the walls 46, 45, 46, while the inner partial surface 37a falls into the second half of the space λ

As can be seen from the figure, the conductor feedthroughs can be considered transversely insulated. In transverse layered insulating materials, the voltage across the insulators is divided in inverse to the dielectric constant. When operating voltage is applied to the electrodes limited by the layered insulation, the air gap in series with the fixed dielectric may get to a small extent exceeding the breakdown voltage so that partial discharges can occur. For a laminated insulation, if a narrow air gap with a larger air gap 1 is added in series, at a certain value, the resulting breakdown voltage of the air spaces will be greater than the fraction that is attributable to the operating voltage.

The split high voltage insulator according to the invention allows the nominal value of the initial partial discharge voltage to be maintained according to the PON, since said small air gap is connected in series with a large air gap.

This advantageous property exists regardless of the insulating body having the cross-sectional geometry according to the geometry of the conductor to be insulated.

Fig. 5 shows a case in which a child is realized

229647 Lenii invention on the traditional body shown in Figure 1 · ₀

Fig. 5a shows a front view, Fig. 5b shows a sectional view of the assembled system in plan view.

the four conductors 51 are maintained at a suitable standard distance by means of spacers 52 and the conductor cavity is surrounded by a bushing composed of both halves of the body 52a and 52b. The insulating body is fixed to the partition wall 53 by means of a screw 54 »a nut 55 and a washer 53«. Conductors of different dimensions can be inserted into dimensionally uniform insulating bodies 52. only the dimensions of the spacer 57 must be chosen according to the conductor used.

Fig. 5 shows another feature of the system according to the invention. While the outer and inner partial surfaces 36a. 36b and 37a, respectively. j2b of the two body halves (these position numbers are not repeatedly shown in Fig. 5) - as shown in Fig. 5 - are offset from one another along the perimeter of the walls, the partition wall 18 (Fig. 1) divides the air space the cavities along a plane perpendicular to the longitudinal axis ω into two parts, according to the invention divided into multiple parts (as shown in Fig. 5b), so that adjacent parts are offset from each other along the longitudinal axis of the cavity. The outer wall of the insulating body 52 adjoins the space enclosing the outer wall 58a externally (protruding from the outer wall in our example), from the inside adjoins the inner space closing the wall 58b, while the inner wall of the insulating body 52 adjoins the inner wall space 58c. Both sides adjoining the walls 58a and 58b on one side and 58b and 58c on the other side are offset from each other along the longitudinal axis and

Figure 5 shows an enlarged insulation path obtained by displacement of partial surfaces and shielding. By concentric shift1

229 647, by means of the partition walls 58a, 58b, 58c, a suitable length of the creep discharge path as well as a series connection of a larger air gap with a nice air gap have also been achieved.

An important advantage of the high-voltage conductor lead-through is that, in contrast to traditional insulating bodies, on-site grinding can be easily and simply carried out without reducing the electrical or mechanical or operational reliability. The later replacement of the insulating body is also easy.

A particular advantage is that the body halves themselves can be geomeerically very favorable, the manufacture is easy, the insulating body can be used as a bilaterally replaceable element to conductors of different sizes. Only spacers must always be chosen according to the dimensions of the conductor used. The bushing does not require any / special maintenance.

Claims (2)

11 P J E D T I N T E R E N T E T E R E 229 947 CLAIMS 1. A high voltage conduit for the introduction of conductors for electrical conduits, in particular for electric buses, the insulating body of which encloses a cavity, the longitudinal axis of which extends substantially parallel to the longitudinal axis of the conductor, practically along a perimeter, while the air space of the conduit is divided by two parts by a support, arranged along a plane perpendicular to the longitudinal axis, for example a dividing wall, a spacer, characterized in that the insulating body (32) consists of two at least along two opposite paths of the pass through cavity or a plurality of walls, such that the outer wall (34) surrounds at least one inner wall (35) and the insulating body (32) is formed by two body halves (32a, 32b) adjoining longitudinally adjacent partial surfaces (36a, 36b) 37a, 37b) in such a way that the outer partial surfaces (36a, 36b) formed in the the thicker wall (34) being displaced opposite the inner partial surfaces (37a, 37b) formed in the adjacent inner wall (35) along the periphery of the walls (34, 35), further the lateral and inner partition walls (58a, 58b) formed in the outer wall of the insulating body (52) or adjacent to the outer wall are offset relative to each other, further that the inner partition (58b) adjacent the outer wall (34) is also displaced along the longitudinal axis of the cavity with respect to the inner partition wall (58c) adjacent to the inner wall ( 35) An insulating body (52) 20 A high-voltage conduit for introducing conductors according to claim 1, characterized in that both the outer wall (34) and the inner wall (35) have the shape of a rotating body, the axis of rotation of the rotating bodies simultaneously forming a longitudinal axis (u; ) the cavities and outer sub-surfaces (35a, 35b) are formed in the outer wall (34) along the 12 229 647 of two mutually opposing lines cut from one working plane (ja) passing through the axis of rotation, while the inner sub-surfaces (37a, 37b) are they are formed along two mutually adjacent lines cut from the second dividing plane (Zi) forming. with first division plane () angle (oo) in the range of 165 ° 2 - 15 ° and passing through the axis of rotation. 3. A high-voltage conductor feedthrough according to claim 1, wherein the cross section perpendicular to the longitudinal axis of the cavity forms a parallelogram on the outer wall (44) and on the inner wall (45). with rounded corners, wherein the outer partial surfaces (36a, 36b) are formed in the adjacent sides (44a, 44b) of the outer wall (44), further that the inner partial surfaces (37a, 37b) in the inner wall (45) are they are formed in such a way that the outer partial surface (36a) extends from adjacent outer or inner partial surfaces (36a, 37a) into one half of the space (λ1) cut by the dividing plane (oT) extending perpendicular to said sides, the inner partial surface (37a) extends into the second half of the space (λρ. 4. A high-voltage conductor feedthrough according to claim 1, characterized in that in the insulating body (42), the circumference of the cross-section in the plane perpendicular to the longitudinal axis (ω) of the cavity is limited by a parallelogram, suitably a rectangle with rounded corners. on (44) is formed along its opposing sides and inside, one or more inner walls (45, 46) extending parallel thereto, further in that outer or inner walls are formed in each of the outer and inner walls thereof, respectively. sub-areas such that the outer sub-surface (36a) falls into 13,229,647 half of the space (Ag) cut by the dividing plane () extending perpendicular to the wall (44, 45, 46), while the inner sub-surface (37b) falls into the other half of the space ( 4 * ýkre «y