JPH0143253B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to such a device which is susceptible to internal heating and which therefore has means for monitoring the internal temperature.

BACKGROUND OF THE INVENTION Devices such as transformers, generators, electric motors, etc. commonly use temperature sensors to detect internal heating points. Fiber optic probes are small, flexible, insensitive to high voltage ranges, electrically and thermally nonconductive, and chemically inert, making them ideal as temperature sensors. It has recently been found that they are particularly suitable for use in such applications.

However, optical fibers have the disadvantage that they are relatively fragile and often break during handling, which can be a particular problem when installing fiber optic probes.

DISCLOSURE OF THE INVENTION The present invention is primarily aimed at alleviating these drawbacks by sensing the temperature at a predetermined location within an appliance that is prone to internal heating and providing a signal indicative of this sensed temperature. a fiber optic probe having a sensing end and an opposite end adapted to be connected to an optical signal processing device; the protective tube extends to the predetermined position in the equipment, at least the inner wall of the protective tube is formed of a material with a small coefficient of friction, and the protective tube is such that the optical fiber probe This invention relates to a temperature measuring device constructed and assembled so that it can be freely inserted into and taken out from the temperature measuring device.

The above-described device is designed to first install the protection tube without inserting the fiber optic probe, then complete the assembly of the equipment requiring the fiber optic probe and the installation of the protection tube into this equipment, and then remove the protection tube. The advantage is that the fiber optic probe can be easily inserted into the protection tube when the fiber optic probe no longer needs to be tampered with, allowing the fiber optic probe to be installed virtually without any fear of damage. There is. For further protection, the tube may be provided with a temporary reinforcing wire that is removably inserted into the tube during installation, instead of a fiber optic probe. A further advantage of the arrangement according to the invention is that if the fiber optic probe in the protection tube is defective, it can be removed and a new fiber probe inserted into the protection tube.
This means that a probe can be inserted.

Embodiments of the Invention A preferred embodiment of the invention will be described in detail below with reference to an example illustrated in the accompanying drawings.

Although the temperature probe disclosed herein is suitable for use with various types of equipment in which internal temperatures need to be monitored, it is shown here applied to power transformers, and in particular to their magnetic core-coil assemblies. ing.

In FIG. 1, magnetic core-coil assembly 18 includes a magnetic core 20 and a plurality of coils (only one coil 22 is shown).
This coil 22 is of a so-called pancake shape, and has a plurality of spirally wound conductor windings 26.
Consists of. Coil 22 is representative of all the coils of magnetic core-coil assembly 18 stacked on top of each other. A radially extending spacer 24 is arranged between the conductor windings 26.

As shown in FIG. 1, magnetic core-coil assembly 18 is coupled to temperature monitoring means. This temperature monitoring means includes an optical signal processing device 30 and a temperature probe 10. This temperature probe 10 extends from the inside of the coil 22 to the outside, and further to the transformer tank wall 16.
It extends to the optical signal processing device 30 through a gasket 28 provided in the optical signal processing device 30 . This optical signal processing device 30 is adapted to process an optical signal received from a well-known temperature probe 10.

As can be clearly seen in FIGS. 2 and 3, temperature probe 10 includes a protective tube 12 and a fiber optic probe 14 made of silica glass inserted into and extending therethrough. . This optical fiber probe 14 is shown at 2 in FIG.
As shown in 6a, two adjacent conductor windings 26
It extends into the space created by separating one of the two from the other. In order to protect the temperature probe 10 from compressive forces acting on the temperature probe 10 through adjacent conductor windings, a pair of wires made of a suitable electrically insulating or dielectric material and placed on either side of the temperature probe 10 are provided. A compressive force absorbing member or strip 32 is sandwiched between conductor windings 26 and 26a. Compressive force absorbing member 32 can be utilized to secure the inner tip of protection tube 12 in place.

The protective tube 12 is made of a material that is heat resistant and has a low coefficient of friction, at least its inner wall, and preferably the entire protective tube, such as a fluorinated ethylene-propylene resin, a tetrafluoroethylene fluorocarbon polymer or a polytetrafluoroethylene. It will be done. The protection tube 12 is an optical fiber.
The probe 14 is assembled and arranged in such a way that it can be freely inserted into and removed from the protective tube 12. In particular, the protection tube 12 is
It has an inner diameter large enough to allow the fiber optic probe 14 to be easily slid into and out of it, and is flexible and free of curvature less than about 1 inch in radius. To limit the inward movement of the fiber optic probe 14 within the protection tube 12 and thereby prevent the sensing end of the fiber optic probe 14 from coming into direct contact with the conductor windings 26, 26a, an optical A stop member 36 (see FIG. 3) having a recess 38 axially aligned with the sensing end of the fiber optic probe 14 is located near the tip of the fiber optic probe 14.

The sensing end of the fiber optic probe 14 is provided with a transparent cement bead 40 coated with a mixture of two fluorophores A and B. Each fluorescent substance is
It absorbs UV rays (ultraviolet rays) induced by the heat generated in the conductor winding 26. As is well known, beads 4
A part of the energy absorbed by the fluorescent substance A
is emitted in the form of red light, and from fluorescent substance B in the form of green light. As the temperature rises from 0°C to 125°C, the amount of red light emitted from fluorescent material A and the green light emitted from fluorescent material B was approximately the same, but the amount of green light gradually decreased and eventually Becomes zero. On the other hand, the amount of red light remains the same, so 125℃
Only red light is emitted. The green and red lights emitted from the mixture of two fluorescent substances are passed through an optical fiber probe 14 to an optical signal processing device 3.
0 to the photocell, where a red filter and a green filter are placed alternately at the end of the receiving fiber (probe), and a solid-state photosensitive electronic device (photocell) is sent to the photocell.
The light intensity is converted into voltage and the ratio of green light to red light is measured. In order to accomplish the above method, the optical signal processing device 30 is first adapted to direct ultraviolet light into the probe.

[Brief explanation of drawings]

FIG. 1 is a partial plan view of a magnetic core-coil assembly of a transformer provided with temperature monitoring means, FIG. 2 is a sectional view taken along the line of FIG. 1, and FIG. 3 is a diagram showing an embodiment of the present invention. FIG. 2 is an exploded perspective view of a portion of a magnetic core-coil assembly with a temperature probe; 10... Temperature probe, 12... Protection tube, 14
...Optical fiber probe, 18...Magnetic core-
Coil assembly, 30... Optical signal processing device, 32...
...Compressive force absorbing member.

Claims (1)

Claims: 1. A device that is prone to internal heating and includes a temperature probe for sensing temperature at a predetermined location within the device and providing a signal indicative of the sensed temperature, the temperature probe comprising: an optical fiber probe having a sensing end and an opposite end adapted to be connected to an optical signal processing device;
A protective tube for the probe is provided, the protective tube extends to the predetermined position in the equipment, at least an inner wall of the protective tube is formed of a material with a low coefficient of friction, and the protective tube is configured to accommodate the optical fiber probe. A temperature measuring device configured and assembled so that it can be freely inserted into and taken out from the protective tube. 2. The temperature measuring device according to claim 1, wherein the protective tube does not have a curve smaller than about 2.5 centimeters (1 inch) in radius. 3. The temperature measuring device according to claim 1 or 2, wherein the material with a low coefficient of friction is one of the group consisting of fluorinated ethylene-propylene resin and tetrafluoroethylene fluorocarbon polymer. 4. Claims 1 to 3 in which the material with a small coefficient of friction is polytetrafluoroethylene.
The temperature measuring device according to any one of paragraphs. 5. The temperature measuring device according to any one of claims 1 to 4, wherein the optical fiber probe is a silica optical fiber having a fluorescent substance at its sensing end. 6. The temperature measuring device according to any one of claims 1 to 5, wherein the temperature probe extends between compressive force absorbing members arranged within the device so as to absorb the compressive force applied thereto. 7 When installing the protection tube, make sure that the optical fiber
7. A temperature measuring device according to any one of claims 1 to 6, comprising a temporary reinforcing wire removably inserted in place of the probe. 8. The device comprises a magnetic core-coil assembly including a coil formed of a plurality of conductor windings, and the predetermined position is between two of the conductor windings. The temperature measuring device according to any one of the above.