JP2967646B2 - Temperature sensor and conductor abnormal overheat monitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor and an abnormal overheat monitoring device used for detecting abnormal overheating of a current-carrying conductor of a power device or the like.

[0002]

2. Description of the Related Art Since a high voltage is applied to a current-carrying conductor of a power device and a large current flows, the conductor may be abnormally overheated. For this reason, a means is employed to detect abnormal overheating by attaching a thermo label to the conductor and observing a change in color from a distance, or to detect an abnormal overheating state of the conductor using a thermo camera. In addition, there are a thermocouple, a thermometer, and a thermistor for measuring the temperature of the conductor.

[0003]

As described above, in order to detect the abnormal overheating of the conductor of the power equipment as described above, the first is a thermo label and the second is a thermo camera, but the first thermo label is inexpensive. However, unless a method for detecting a color change is considered, there is a problem that monitoring cannot be performed at all times and also a problem that durability is poor.

Although the second thermo camera is expensive, it has a problem in long-term stability of the sensor portion. In addition, thermocouples, thermometers and thermistors have the problem that they cannot be directly attached to conductors due to their electrical insulation.These temperature sensors measure the temperature transmitted to gas and insulators, and therefore have low sensitivity. There is a problem, and the influence of other heat sources is great.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a temperature sensor and a conductor abnormal overheat monitor which are small, lightweight, have excellent durability and earthquake resistance, can always monitor, and can directly monitor an abnormal state of the conductor. It is intended to provide a device.

[0006]

In order to achieve the above object, the present invention is directed to a temperature-sensitive magnetic material which is formed in a cylindrical shape and changes from a ferromagnetic state to a paramagnetic state in response to a temperature change. A temperature sensor comprising: a cylindrical or cylindrical permanent magnet inserted into the hollow portion of the magnetic material and oscillating in the hollow portion by an external magnetic field; and a light transmitting member fixed to both ends of the temperature-sensitive magnetic material. .

The second invention is characterized in that one of the light transmitting members is a light reflecting member. .

According to a third aspect of the present invention, there is provided a temperature sensor provided on a current-carrying conductor, and attached to a light-transmitting member of the temperature sensor. An optical fiber that receives the light beam, a photoelectric conversion unit provided in the optical fiber, and an electrical output signal of the photoelectric conversion unit are supplied,
And a judging unit for judging an abnormality of the conductor from the output signal state.

[0009]

In the first aspect of the invention, when the temperature around the temperature-sensitive magnetic material becomes abnormal at the set temperature, the temperature-sensitive magnetic material enters a paramagnetic state. Then, the external magnetic field acts on the permanent magnet in the temperature-sensitive magnetic material. Then, the permanent magnet is swung by the action of the external magnetic field. This swing changes the amount of light passing through the temperature-sensitive magnetic body.

[0010] In the second invention, the amount of light reflected by the light reflecting member changes when passing through the temperature-sensitive magnetic material.

In the third aspect, the light beam transmitted through the temperature sensor or the reflected light beam changes due to abnormal heating of the current-carrying conductor. The change is converted into an electric signal by the photoelectric conversion unit, and the abnormality of the conductor is determined.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the temperature sensor will be described with reference to an exploded perspective view of FIG. In FIG. 1, reference numeral 1 denotes a cylindrical temperature-sensitive magnetic material made of a temperature-sensitive ferrite.
Shows a ferromagnetic state up to a certain set temperature (Curie temperature), and has a property of changing to a paramagnetic state when the temperature exceeds that temperature. In the through hole 1a of the temperature-sensitive magnetic body 1,
For example, a nonmagnetic thin pipe 2 made of brass is inserted. A cylindrical permanent magnet 3 is accommodated in the non-magnetic thin pipe 2 so as to be swingable. Reference numerals 4 and 5 denote translucent members through which light can pass. These translucent members 4 and 5 are adhered to both end surfaces of the temperature-sensitive magnetic body 1 to constitute a temperature sensor 6. FIG. 2 is a completed view of the temperature sensor 6.

Next, the operation of the first embodiment will be described. In the temperature sensor 6 configured as shown in FIG. 2, when the temperature-sensitive magnetic body 1 is in the ferromagnetic state, the lines of magnetic force emitted from the permanent magnet 3 almost pass through the temperature-sensitive magnetic body 1 as indicated by arrows in FIG. 3. On the other hand, the lines of magnetic force caused by the external magnetic field hardly affect the inside of the temperature-sensitive magnetic body 1 as shown in FIG. In FIG. 4, H _o is the external magnetic field, the H _i is the internal magnetic field.

[0014] Figure 5 is a schematic diagram where the external magnetic field H _o is applied from the radial direction of the temperature-sensitive magnetic substance 1 constituting the temperature sensor 6, the temperature-sensitive magnetic substance 1 is made of a ferromagnetic state to a paramagnetic state,
A suction force F _f of the temperature-sensitive magnetic substance 1 of the permanent magnet 3, the vibration force F _Hi by the external magnetic field H _o of the permanent magnet 3 is the condition of F _f <F _Hi, permanent magnet 3 vibrates. FIGS. 6A, 6B, and 6C show how the permanent magnet 3 vibrates in the direction of the external magnetic field. When a light beam is irradiated from the axial direction of the temperature sensor 6, the light beam is shown by oblique lines. That is,
The permanent magnet 3 vibrates depending on the direction of the magnetic field, and the amount of light changes.

[0015] Figure 7 is a schematic diagram where the external magnetic field H _o is applied to the temperature sensor 6 in the axial direction, in FIG. 7, when the temperature-sensitive magnetic substance 1 is the ferromagnetic state, the interior of the permanent magnet 3 Temperature Depending on the tilt direction of the sensor 6, its north pole or south pole is attracted upward in the drawing. FIG. 8 shows a case where the N pole of the permanent magnet 3 is attracted upward. Thereafter, when the temperature-sensitive magnetic substance 1 is changed from a ferromagnetic state to a paramagnetic state, the vibration permanent magnet 3 is subjected to the action of an external magnetic field H _o, as from the state of FIG. 9A of either FIG. 9B or FIG. 9C I do.

FIG. 10 is an exploded perspective view showing a second embodiment of the temperature sensor. The only difference from the first embodiment is that the permanent magnet is changed from a cylindrical shape to a cylindrical shape. In FIG. 10, 3a is the permanent magnet. The same manner as in the first embodiment the permanent magnet 3a in the case of this second embodiment is vibrated by an external magnetic field H _o. Figure 11A, B, C is obtained when the external magnetic field H _o is applied from the radial direction of the temperature sensor 6, the operation of FIG. 6A, B, the detailed description because it is same as C is omitted. However, since the permanent magnet 3a has a cylindrical shape, the amount of transmitted light is larger than that of the first embodiment,
There is an advantage that detection of vibration, that is, detection of abnormal overheating of the conductor, becomes more reliable.

FIGS. 12A, 12B and 12C are explanatory views showing the operating state of the permanent magnet 3a when an external magnetic field H acts on the temperature sensor 6 from the axial direction. FIGS. 9A, 9B and 9C of the first embodiment.
Since the operation is the same as that described above, a detailed description thereof will be omitted.

FIG. 13A shows the first and second embodiments,
Attraction force F _{f applied} to the temperature-sensitive magnetic body 1 by the permanent magnets 3 and 3a
And an explanatory view for explaining the relationship between the external magnetic field H _o, in this FIG. 13A, the relationship between the inclination angle theta _o and the suction force F _f of the permanent magnet 3,3a, as the curve B ₁ shown in FIG. 13B When the temperature around the temperature-sensitive magnetic body 1 rises, the temperature-sensitive magnetic body 1 changes to a paramagnetic state. Therefore, the suction force F _f is as the curve B ₂ of Fig. 13B decreases.

FIG. 14A, B is the case temperature-sensitive magnetic substance 1 is less than or equal to the Curie temperature, or more suction force F _f and the external magnetic field H _o when
A characteristic diagram showing the relationship between the force F _Hi acting on the permanent magnet 3,3a by, Figure 14A is a time lower than the Curie temperature, the permanent magnet 3,3a Since this time is F _f> F _Hi Figure 1
It looks like 3A. Further, FIG. 14B when the Curie temperature or more, because this time is F _f <F _Hi, permanent magnets 3,3a permanent magnets 3,3a vibrates under the action of external magnetic field H _o.

FIG. 15 shows that the temperature sensor 6 of the first and second embodiments is disposed in a through hole 11 provided in a cylindrical conductor 10, and an abnormal overheating state of the conductor 11 is monitored from a distance. In the third embodiment, an optical fiber 12 (light emitting side) and 13 (light receiving side) are connected to a temperature sensor 6 by a light transmitting member 4.
5, the optical fibers 12 and 13 are provided with an amplifier 14 of a photoelectric switch. In the case of the first embodiment, the output signal of the amplifier 14 of the photoelectric switch sends out an output signal having a relatively short pulse width as shown in FIG. 15B.
In the case of the second embodiment, an output signal having a relatively wide pulse width as shown in FIG. 15C is transmitted. Based on the state of this output signal, the conductor abnormal overheating is performed by the determination unit 17. The dotted arrows in the figure show the arrangement of the optical fibers when the light reflection type temperature sensor is used.

FIG. 16 shows a fourth embodiment in which the temperature sensor 6 is housed in the case 16 and attached to the flat band conductor 15. The operation and the like are the same as in the third embodiment.

[0022]

As described above, according to the present invention,
Since the temperature sensor is small and lightweight, it has an advantage that it can be directly attached to a conductor of a power device to detect the temperature of the conductor, for example, and is also excellent in earthquake resistance. Also, by using a temperature sensor and an optical fiber, it is possible to detect overheating of the conductor in the high-voltage portion, and it is excellent in durability. It also has a self-checking function for malfunctions of amplifiers and amplifiers.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of the present invention.

FIG. 2 is a completed view when the embodiment of FIG. 1 is assembled.

FIG. 3 is a diagram showing a distribution state of magnetic force lines when the temperature-sensitive magnetic material is in a ferromagnetic state.

FIG. 4 is a diagram illustrating a distribution state of magnetic lines of force due to an external magnetic field when the temperature-sensitive magnetic body is in a ferromagnetic state.

FIG. 5 is an explanatory diagram when an external magnetic field acts on a temperature-sensitive magnetic body from a radial direction.

FIGS. 6A, 6B, and 6C are explanatory diagrams illustrating a state in which a permanent magnet vibrates depending on the direction of an external magnetic field.

FIG. 7 is an explanatory diagram when an external magnetic field acts from the axial direction of the temperature sensor.

FIG. 8 is an explanatory diagram when the temperature-sensitive magnetic material is in a ferromagnetic state.

FIGS. 9A, 9B, and 9C are explanatory diagrams showing elements in which a permanent magnet vibrates depending on the direction of an external magnetic field.

FIG. 10 is an exploded perspective view showing a second embodiment of the present invention.

11A, 11B, and 11C are explanatory diagrams when an external magnetic field acts from the radial direction of the temperature sensor.

12A, 12B and 12C are explanatory diagrams when an external magnetic field acts from the axial direction of the temperature sensor.

13A is an explanatory diagram showing a relationship between an attractive force acting on a temperature-sensitive magnetic body by a permanent magnet and an external magnetic field, and FIG. 13B is an explanatory diagram showing a relationship between a tilt angle of the permanent magnet and an attractive force.

FIGS. 14A and 14B are characteristic diagrams showing the relationship between the inclination angle of the permanent magnet and the Curie temperature.

FIG. 15 is a configuration explanatory view showing a third embodiment of the present invention.

FIG. 16 is a configuration explanatory view showing a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Temperature-sensitive magnetic body 2 ... Non-magnetic thin pipe 3, 3a ... Permanent magnet 4, 5 ... Translucent member 6 ... Temperature sensor 10 ... Cylindrical conductor 12, 13 ... Optical fiber 14 ... Photoelectric switch amplifier 15 ... Flat belt Conductor 17 ... Judgment unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-49-105580 (JP, A) JP-A-56-86322 (JP, A) JP-A-63-300926 (JP, A) JP-A-62 179623 (JP, A) Japanese Utility Model Showa 56-48032 (JP, U) Japanese Utility Model Showa 56-66835 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01K 7/36

Claims (3)

(57) [Claims] 1. A temperature-sensitive magnetic body which is formed in a cylindrical shape and changes from a ferromagnetic state to a paramagnetic state in response to a temperature change, and is inserted into a hollow portion of the magnetic body and shakes inside the hollow portion by an external magnetic field. A temperature sensor comprising: a moving cylindrical or cylindrical permanent magnet; and a light-transmitting member fixed to both ends of the temperature-sensitive magnetic body. 2. The temperature sensor according to claim 1, wherein one of said light transmitting members is a light reflecting member. 3. A temperature sensor provided on a current-carrying conductor, and a light beam attached to a light-transmitting member of the temperature sensor for irradiating an emitted light beam to the temperature sensor and transmitting light through the temperature sensor or light reflected from the inside of the temperature sensor. An optical fiber that receives light, a photoelectric conversion unit provided in the optical fiber,
A conductor abnormality monitoring device, comprising: an electrical output signal of the photoelectric conversion unit; and a determination unit configured to determine an abnormality of the conductor based on the output signal state.