DE29513343U1 - Optical fiber arcing fault detector for switchgear for the distribution of electrical energy - Google Patents

Description

Klöckner-Moeller GmbH -1- 0 515 GM

28.06.95

Fiber optic arc fault detector for switchgear for the distribution of electrical energy.

The invention relates to an optical fiber arc fault detector for switchgear for the distribution of electrical energy according to the preamble of claim 1.

A fiber optic arc fault detector has been made known by DD 271 397 Al. This is arranged near busbars without special mountings. In Fig. 2, the fiber optic arc fault detector is located on both narrow sides of a busbar with a rectangular cross-section. In Fig. 3 of the document mentioned at the beginning, the fiber optic cable is wound around the busbar. With this arrangement, there is a risk that the fiber optic cable can break, especially at the contact points or in the area of the busbar edges. If a fiber breaks, the sensor is inoperable.

DE 43 31 716 also shows and describes various arrangements of an optical waveguide arc fault detector. The optical waveguide used there has a thin fiber core, which improves the optical coupling, but has a relatively small front surface coupled to a photodiode. High amplification factors are required for this sensor, which is more susceptible to interference and requires a relatively high level of circuit complexity.
Furthermore, the thin optical fiber can break more easily than one with a larger diameter.

The object of the invention is therefore to create an optical fiber arc fault detector according to the preamble of claim 1, which has improved optical properties and at the same time is less sensitive to mechanical influences.

Klöckner-Moeller GmbH -2- 0 515 GM

28.06.95

The object of the invention is achieved by the characterizing features of claim 1, while particularly advantageous developments of the invention are characterized in the subclaims.

It is particularly advantageous that if a single fiber breaks, the detector remains essentially functional. The optical properties are significantly improved, which simplifies the detector circuit.

The invention, further refinements and improvements of the invention and further advantages will be described and explained in more detail with reference to the drawing, in which an embodiment is shown.

It shows:

Fig. 1 a representation of the detector center,

Fig. 2 is a representation of an end of the detector to be processed,

Fig. 3 is a view of a machined end of the detector and

Fig. 4 is an enlarged view of the detector end from the front face side.

Fig. 1 shows a fiber optic arc fault detector 1. This consists of a support rod 2, three fiber optic cables or fibers L1, L2, L3 wound spirally around the support rod 2 and a translucent or transparent protective tube as a shrink tube 3.

The support rod 2 is made of soft elastic material, e.g. a thermoplastic, and can be wound on a cable reel

Klöckner-Moeller GmbH -3- 0 515 GM

28.06.95

become.

The fibers Ll, L2, L3 of the fiber bundle are wound at approximately the same distance from each other and are arranged parallel to one another. The light coupling is three times higher than with a simple winding with just one fiber.

The fibers Ll, L2, L3 can be arranged practically endlessly on a support rod, which could previously have been wound on a roll. The roll can be 10 to 100 meters long, for example.

The resulting detector can be produced by the meter.

The cut detector piece is already covered with a shrink tube 3.

The shrink tube 3 can be attached by extruding it.

The detached detector section can be 2 to 4 meters or longer for monitoring busbars or other current-carrying conductors in a low-voltage switchgear.

To make a detector, a piece is cut off from the roll. The cutting point is indicated in Fig. 1 by two (black) filled arrows. To the right of the black arrows is the cut off piece and to the left of it is the cable roll.

Once the piece is separated, a portion of the pre-formed shrink or protective tubing is cut off to expose the fibers Ll, L2 and L3.

An inlet opening 5 leads the fibers Ll, L2, L3 from the outer surface into the outlet opening 6 arranged on the front side into the center or core area of the

Klöckner-Moeller GmbH -4- 0 515 GM

28.06.95

support bar 2, as shown in Fig. 2. This is achieved either by a diagonal hole or by a straight hole, whereby the core area of the support bar is then hollow.

In order to be able to connect a sleeve 4 in the end area, an extension piece 7 with a hollow core in which the fibers L1, L2, L3 are guided, a first piece of shrink tubing 8 is arranged over the sleeve 4 and the extension piece 7 and a second piece of shrink tubing 9 is arranged over the first piece of shrink tubing 8 and the shrink tubing 3, as shown in Fig. 3.

The sleeve 4 can be connected to a commercially available socket for receiver diodes.

Optical fibers or fibers with different colors, diameters, optical, physical and chemical properties, etc. can be wound onto the carrier rod 2.

The mechanical protective covering can either consist of shrink tubing or an extruded protective covering.

Other non-shrinkable protective coverings can also be used as protective tubing.

Klöckner-Moeller GmbH -5- 0 515 GM

28.06.95

List of reference symbols

L1-L3 fibers

1 fiber optic arc fault detector

2 support rod

3 Shrink tubing

4 Sleeve

5 Entrance opening

6 Outlet opening

7 Extension piece

8 piece of shrink tubing (first)

9 Shrink tubing piece (second)

Claims (11)

• ·· Klöckner-Moeller GmbH -6- 0 515 GM 28.06.95 Protection claims 1. Optical fiber arc fault detector for switchgear for the distribution of electrical energy, the detector consisting of optical fibers in which the light generated by an arc fault and coupled radially through its sheaths serves as a triggering or reporting criterion, characterized in that several optical fibers (1) are arranged as fiber bundles and that the end faces and ends of the individual fibers (L1, L2, L3) are brought together and connected to a common photo element. 2. Optical fiber arc fault detector according to claim 1, characterized in that the fibers (L1, L2, L3) of the fiber bundle are twisted against each other. 3. Optical fiber arc fault detector according to claim 1 or 2, characterized in that the fibers (L1, L2, L3) of the fiber bundle are wound around a carrier rod (2). 4. Optical fiber arc fault detector according to one of the preceding claims, characterized in that the fibers (L1, L2, L3) of the fiber bundle are wound offset from one another at approximately the same distance. 5. Optical fiber arc fault detector according to one of the preceding claims, characterized in that the fibers (L1, L2, L3) are protected by a light-permeable protective or shrink-fit tube. 6. Optical fiber arc fault detector according to one of the preceding claims, characterized in that the support rod (2) is elastic in such a way that it can be wound up. •·♦· · Klöckner-Moeller GmbH -7- 0 515 GM 28.06.95 7. Optical fiber arc fault detector according to one of the preceding claims, characterized in that the support rod (2) has an inlet opening (5) at both ends, which guides the fibers (L1, L2, L3) from the outer jacket surface into an outlet opening (6) arranged on the front side in the center or core area of the support rod (2). 8. Optical fiber arc fault detector according to one of the preceding claims, characterized in that in order to be able to connect a sleeve (4) in the end region, an extension piece (7) with a hollow core in which the fibers (L1, L2, L3) are guided, a first shrink tube piece (8) over the sleeve (4) and the extension piece (7) and a second shrink tube piece (9) over the first shrink tube piece (8) and the shrink tube (3) are arranged. 9. Optical fiber arc fault detector according to one of the preceding claims, characterized in that optical fibers or fibers with different colors, diameters, optical, physical or chemical properties or combinations thereof are wound on the carrier rod (2). 10. Optical fiber arc fault detector according to one of the preceding claims, characterized in that the mechanical protective sheath consists of an extruded protective sheath. 11. Optical fiber arc fault detector according to one of the preceding claims, characterized in that the fibers (L1 to L3) are wound helically around the carrier rod (2).