Surge arrester comprising traction elements maintained by loops

Abstract

A surge arrester has several tensioning elements which brace the discharge column in the axial direction. One or more loop arrangements radially surround the tensioning elements. One loop arrangement has a plurality of loops. Each loop of the plurality of loops surrounds only some, but not all, of the tensioning elements.

Claims

1. A surge arrester, comprising: an arrester column formed of a plurality of varistor elements; a plurality of tensioning elements bracing said arrester column in an axial direction; one or more loop arrangements each looping radially around said tensioning elements, each said loop arrangement having a plurality of loops and each loop of said plurality of loops looping around only some of said tensioning elements.

2. The surge arrester according to claim 1, which comprises a guide element inserted into said arrester column at an axial height of a loop arrangement, said guide element having guide grooves formed therein, and wherein said loops are guided in said guide grooves in direct connection between the respective said tensioning elements around which said loops are looped.

3. The surge arrester according to claim 1, wherein said plurality of tensioning elements are an even number of tensioning elements, and each of said loops loops around exactly two mutually opposite tensioning elements.

4. The surge arrester according to claim 2, wherein said guide element has an upper covering surface and a lower covering surface each formed with said guide grooves, wherein said guide grooves in said upper covering surface extend at right angles to said guide grooves in said lower covering surface.

5. The surge arrester according to claim 1, wherein said loops are formed of a glass-fiber-reinforced plastic.

6. The surge arrester according to claim 1, wherein said guide element is formed of an electrically conductive material.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) The invention will be explained in more detail below with reference to the drawings, in which:

(2) FIG. 1 shows a surge arrester from the prior art in a sectional illustration,

(3) FIG. 2 shows a detail of a surge arrester according to the invention in a perspective illustration,

(4) FIG. 3 shows an exploded illustration of a detail of a surge arrester according to the invention.

DESCRIPTION OF THE INVENTION

(5) Mutually corresponding parts have been provided with the same reference symbols in all of the figures.

(6) A surge arrester 1 in accordance with the prior art is shown in FIG. 1. It consists of a cylindrical arrester column, which is usually formed as a stack from individual, likewise cylindrical varistor elements 2. The longitudinal axis 18 of the arrester column defines an axial direction; directions perpendicular to this longitudinal axis 18 are radial directions. The arrester column is delimited at both of its ends by end fittings 10, which produce the electrical contact to the power supply system and to ground, for example by means of a connection bolt 13.

(7) In order to ensure good electrical contact even under mechanical loading, the varistor elements 2 need to be held together under pressure. This can take place by virtue of tensioning elements 3, for example cables or rods, preferably consisting of glass-fiber-reinforced plastic, being clamped into the end fittings 10 under tension. The tensioning elements 3 in this case surround the arrester column and thus form a cage around said arrester column. In order to protect against environmental effects, such surge arresters are surrounded by a housing 11 consisting of an insulating material such as, for example, silicone. The production of this housing 11 can take place by casting or injection molding. In addition, shields 12 for extending the leakage path can be provided on the housing 11.

(8) FIGS. 2 and 3 show part of a surge arrester according to the invention, which is a development of the known surge arrester 1 shown in FIG. 1 and also has the individual parts thereof. An arrester column, of which only two varistor elements 2 are shown here, extends along the longitudinal axis 18. The arrester column is surrounded by a cage consisting of eight tensioning elements 3a to 3h, which have an identical configuration and only differ in terms of their radial position. Insofar as the different position is inconsequential, the reference sign 3 is used for all tensioning elements. The guide element 6 is inserted into the arrester column between two varistor elements 2. This guide element 6 is in the form of a flat cylinder. The upper covering surface 20 and the lower covering surface 21 each have four parallel guide grooves 7. The guide grooves 7 in the upper covering surface 20 and the guide grooves in the lower covering surface 21 in this case extend perpendicular to one another. The thickness of the guide element 6 and the depth of the guide grooves 7 are matched to one another in this case in such a way that the guide grooves 7 do not cross over one another in one plane.

(9) A loop arrangement 4 holds the cage consisting of tensioning elements 3 together. The loop arrangement 4 consists of four individual loops 5a to 5d, which only differ from one another in terms of their position. Insofar as the position does not play a role, the reference symbol 5 is also used for all loops. Each loop 5 loops around two tensioning elements 3, which are opposite one another based on a plane of symmetry having the longitudinal axis 18, indicated by the line 22 or 23. Thus, the loop 5a loops around the tensioning elements 3a and 3d, which are opposite one another based on the imaginary line 22. A second loop 5b, which extends parallel to this loop 5a, loops around the tensioning elements 3h and 3e. The loops 5a and 5b in this case lie in the same radial plane. Two further loops 5c and 5d, which loop around the tensioning elements 3b and 3g and 3c and 3f, respectively, lie in a plane parallel to this radial plane. The loops 5 extend in direct connection between the tensioning elements 3 around which they loop. The guide grooves 7 in the guide element 6 are thus matched to the loops 5 such that a loop 5 runs in two parallel guide grooves 7. The two loops 5a and 5b in this case extend in four guide grooves 7 in the upper covering surface 20 of the guide element 6, and the two loops 5d and 5c extend in four guide grooves 7 in the lower covering surface 21. The depth of the guide grooves 7 is in this case dimensioned such that the loops 7 can be pushed completely into the guide groove 7 in terms of their width.

(10) However, it is also conceivable for the two parallel sides of the loops 5 to extend, laid against one another, in a guide groove 7. The guide grooves 7 should then be extended in the form of a V at the openings emerging into the lateral surface of the guide element 6 in order to avoid a sharp bend in the loops 5.

(11) It is of course possible for the loop arrangement 4 shown to also be arranged at a plurality of points along the longitudinal axis 18 of the surge arrester 1.