Insulator arrangement for an overhead line

Abstract

An insulator arrangement for an overhead line includes a suspension insulator for securing an overhead line to a tower and a line arrester arrangement which is disposed electrically parallel to the suspension insulator. The line arrester arrangement has a surge arrester, which is electrically connected to ground or earth potential, and a spark gap, which is connected to the surge arrester in series and which includes a first spark electrode connected to the overhead line and a second spark electrode connected to the surge arrester. The line arrester arrangement has an assembly or mounting insulator which can be secured to the overhead line. The first spark electrode is secured to a first securing device at a first end of the assembly or mounting insulator, and the second spark electrode is secured to a second securing device at a second end of the assembly or mounting insulator.

Claims

1. An insulator arrangement for an overhead line, the insulator arrangement comprising: a suspension insulator disposed above the overhead line for securing the overhead line to a tower; a line arrester arrangement disposed below the overhead line and connected electrically parallel to said suspension insulator; said line arrester arrangement including a mounting insulator to be secured to the overhead line, said mounting insulator having first and second ends; a first securing device disposed at said first end of said mounting insulator and a second securing device disposed at said second end of said mounting insulator; said line arrester arrangement including a surge arrester being electrically connected to earth potential; said line arrester arrangement including a spark gap connected in series with said surge arrester, said spark gap including first and second spark electrodes; and said first spark electrode being connected to the overhead line and being secured to said first securing device, and said second spark electrode being connected to said surge arrester and being secured to said second securing device.

2. The insulator arrangement according to claim 1, wherein said mounting insulator is a long-rod insulator.

3. An insulator arrangement for an overhead line, the insulator arrangement comprising: a suspension insulator for securing the overhead line to a tower; a line arrester arrangement disposed electrically parallel to said suspension insulator; said line arrester arrangement including a mounting insulator to be secured to the overhead line, said mounting insulator having first and second ends and said mounting insulator having a lower mechanical stability than said suspension insulator; a first securing device disposed at said first end of said mounting insulator and a second securing device disposed at said second end of said mounting insulator; said line arrester arrangement including a surge arrester being electrically connected to earth potential; said line arrester arrangement including a spark gap connected in series with said surge arrester, said spark gap including first and second spark electrodes; and said first spark electrode being connected to the overhead line and being secured to said first securing device, and said second spark electrode being connected to said surge arrester and being secured to said second securing device.

4. The insulator arrangement according to claim 1, wherein at least one of said first or second securing devices connects one of said first or second spark electrodes or said surge arrester to said mounting insulator in an angularly rigid manner.

5. An insulator arrangement for an overhead line, the insulator arrangement comprising: a suspension insulator for securing the overhead line to a tower; a line arrester arrangement disposed electrically parallel to said suspension insulator; said line arrester arrangement including a mounting insulator to be secured to the overhead line, said mounting insulator having first and second ends; a first securing device disposed at said first end of said mounting insulator and a second securing device disposed at said second end of said mounting insulator; said line arrester arrangement including a surge arrester being electrically connected to earth potential; said line arrester arrangement including a spark gap connected in series with said surge arrester, said spark gap including first and second spark electrodes; and said first spark electrode being connected to the overhead line and being secured to said first securing device, and said second spark electrode being connected to said surge arrester and being secured to said second securing device; said surge arrester being one of at least two surge arresters of said line arrester arrangement, said surge arresters each having a first end secured to a respective one of said securing devices in an angularly rigid manner, and said surge arresters each having a second end at which a respective one of said spark electrodes is disposed.

6. The insulator arrangement according to claim 5, wherein said at least two surge arresters are identically constructed.

7. An insulator arrangement for an overhead line, the insulator arrangement comprising: a suspension insulator for securing the overhead line to a tower; a line arrester arrangement disposed electrically parallel to said suspension insulator; said line arrester arrangement including a mounting insulator to be secured to the overhead line, said mounting insulator having first and second ends; a first securing device disposed at said first end of said mounting insulator and a second securing device disposed at said second end of said mounting insulator; said line arrester arrangement including a surge arrester being electrically connected to earth potential; said line arrester arrangement including a spark gap connected in series with said surge arrester, said spark gap including first and second spark electrodes; and said first spark electrode being connected to the overhead line and being secured to said first securing device, and said second spark electrode being connected to said surge arrester and being secured to said second securing device; said surge arrester having a longitudinal axis and an end, and at least one of said spark electrodes being rod-shaped, being situated at said end of said surge arrester and having a longitudinal axis being slanted relative to said longitudinal axis of said surge arrester.

8. The insulator arrangement according to claim 7, wherein said at least one spark electrode is rotatable about said longitudinal axis of said surge arrester.

9. An insulator arrangement for an overhead line, the insulator arrangement comprising: a suspension insulator for securing the overhead line to a tower; a line arrester arrangement disposed electrically parallel to said suspension insulator; said line arrester arrangement including a mounting insulator to be secured to the overhead line, said mounting insulator having first and second ends; a first securing device disposed at said first end of said mounting insulator and a second securing device disposed at said second end of said mounting insulator; said line arrester arrangement including a surge arrester being electrically connected to earth potential; said line arrester arrangement including a spark gap connected in series with said surge arrester, said spark gap including first and second spark electrodes; said first spark electrode being connected to the overhead line and being secured to said first securing device, and said second spark electrode being connected to said surge arrester and being secured to said second securing device; said mounting insulator having installation points each disposed at a respective one of said ends of said mounting insulator; said first and second securing devices each including a respective securing arm extending away from a respective one of said installation points, said securing arms each having two ends; said surge arrester being disposed at one of said ends of one of said securing arms; and an arc electrode being disposed at another of said ends of said one securing arm opposite said surge arrester.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) The invention is shown and described in the following with reference to exemplary embodiments in figures of a drawing, in which:

(2) FIG. 1 shows a side view of a transmission tower including a section of an overhead line and an insulator arrangement according to the invention,

(3) FIG. 2 shows a section of a device similar to that in FIG. 1, wherein the design of the insulator arrangement is different from FIG. 1, and

(4) FIG. 3 shows a more detailed representation of the insulator arrangement of the type that can be used in the designs from FIGS. 1 and 2.

DESCRIPTION OF THE INVENTION

(5) FIG. 1 shows, in detail, an overhead line tower 3 comprising a cross-arm 20 which is a horizontal arm for holding an overhead line 2. Such overhead lines 2 are designed, for example, as stranded, rope-shaped lines for conducting electrical energy.

(6) It is generally common to support such overhead lines 2 on the cross-arms 20 of towers 3 by means of suspension insulators 4. Such suspension insulators 4 are usually made from porcelain or another inorganic material, or from a material such as glass fiber-reinforced plastic, and usually comprise shields for lengthening the creepage distance. When plastics are used, an outer coating is usually provided, which consists of silicone, for example, and forms the shield.

(7) The suspension insulators 4 must support the weight of the overhead line 2, on the one hand and, on the other hand, must absorb the forces that are present due to the slackening of the overhead line. For this reason, such suspension insulators 4 are generally designed to be mechanically stable. According to the present invention, a line arrester arrangement 8 is electrically connected in parallel to the suspension insulator 4. The suspension insulator 4 as well as the line arrester arrangement 8 are electrically connected to the earth between the overhead line 2 and via the tower 3. The line arrester arrangement 8 has the function, in the event that overvoltages occur in the overhead line 2, for example due to lightning strikes, of discharging the overvoltage that occurs toward the earth. The line arrester arrangement 8 consists of a mounting insulator 5, a surge arrester 9, and two spark electrodes 6, 7. The suspension insulator 4 is connected via a first end to the overhead line 2. The second end of the mounting insulator 5, which is positioned opposite said first end, is connected via an earthing cable to the tower 3 or a cross-arm 20 and, thereby, to earth potential. A spark electrode 6 is secured to the first end of the mounting insulator 5. A surge arrester 9 is secured to a second spark electrode 7 at the second end of the mounting insulator 5. The intermediate space between the spark electrodes 6, 7 forms the spark gap 11. Therefore, the mounting insulator 5 is, on the one hand, a securing means for the spark electrode 6 and the surge arrester 9 and, via its length, simultaneously establishes the spacing of the spark electrodes 6 and 7 and, therefore, the length of the spark gap 11.

(8) FIG. 2 shows an alternative embodiment of the invention, wherein the tower is only partially shown as compared to FIG. 1. In contrast to FIG. 1, surge arresters 9, 10 comprising spark electrodes 6, 7 are secured here to the first and the second ends of the mounting insulator 5.

(9) FIG. 3 shows a more detailed representation of the line arrester arrangement 8 from FIG. 2. The mounting insulator 5 is represented here as a long-rod insulator. Such a long-rod insulator comprises a core made from a glass fiber-reinforced plastic, onto which a protective sleeve, which is usually made from silicone, is applied. The protective sleeve usually comprises shields for lengthening the creepage distance. At a first end, the mounting insulator 5 comprises a securing device 12. The line arrester arrangement 8 is suspended on the overhead line 2 via a holding device 23 situated on the securing device 12. The first securing device 12 as well as the second securing device 13 each comprise a securing arm 25, 26, respectively. A surge arrester 9, 10 is secured to the securing arms 25, 26 at one end in each case.

(10) The securing arms 25, 26 can extend away from their installation point on the mounting insulator 5 on both sides of the mounting insulator 5. The surge arrester 9 or, as shown in this case, two surge arresters 9, 10, are secured on one side of the mounting insulator 5. Further components of the line arrester arrangement 8 can then be secured to the opposite end. For example, arc electrodes 17, 18 can be situated there, as shown in this case, which, in the event that a surge arrester 9, 10 is defective, guide the electric arc occurring in the case of an overvoltage and keep it away from the mounting insulator 5. The spacing of the arc electrodes 17, 18 is smaller in this case than the length of the mounting insulator 5 and is greater than the spark gap 11.

(11) One or both ends of the securing arms 25, 26 can be provided with field-control elements. Plates are situated here, which are rounded at the ends of the fastening arms 25, 26 positioned opposite the surge arresters 9, 10, thereby preventing voltage peaks.

(12) Each surge arrester 9, 10 comprises a spark electrode 6, 7 at its end opposite the securing of the securing arm 25, 26. The spark electrodes 6, 7 are spaced apart from each other. This spacing forms the spark gap 11. The surge arresters 9, 10 comprise an electrically insulating protective housing for protection against weather conditions. Varistors, which are not shown here, are situated in the interior of the protective housing. The two surge arresters 9, 10 are separated from each other via the spark gap 11. The surge arresters 9, 10 are situated on the securing arms 25, 26 in such a way that their longitudinal axis 21 is situated at an angle with respect to the longitudinal axis 30 of the mounting insulator. The angle is approximately 45 in this case and can be between 30 and 60. The spark electrodes 6, 7 are each situated on one end of the surge arrester 9, 10. Their longitudinal axis 22 is slanted with respect to the longitudinal axis 21 of the surge arrester 9, 10. Preferably, the spark electrodes 6, 7 are situated on the surge arresters 9, 10 in such a way that they are rotatable about the longitudinal axis 21 of the particular surge arrester 9, 10. As a result, the spacing of the spark electrodes 6, 7 and, therefore, the length of the spark gap 11 can be finely adjusted. The securing arm 25 is made from an electrically conductive material and establishes an electrical connection of the surge arrester via the securing device 12 and the holding device 23 to the overhead line 2 and, therefore, to the high voltage potential. The surge arrester 9, which is secured to the securing arm 26 at the second end of the mounting insulator 5 via the second securing device 13, is connected by means of an earthing cable 16 to the tower or a tower cross-arm 20 and to the earth.