JP3149646B2 - Conductor temperature monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductor temperature monitoring device used for detecting abnormal overheating due to a poor contact of a contact portion of a current-carrying conductor of, for example, a power device.

[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, when the power equipment is a gas-insulated switchgear, the conductor is surrounded by the tank,
In order to detect abnormal overheating of the conductor, a thermo label is attached to the conductor and the color change of the thermo label is observed from a distance, or a thermo camera is used. In addition, in order to indirectly detect overheating of the conductor, the temperature of the tank wall near the conductor is measured using a thermocouple, a resistance temperature detector, or a thermistor.

[0003]

However, although thermolabels are inexpensive, they cannot be constantly monitored unless a method for detecting a change in color is considered, and also have a problem of poor durability.

[0004] Further, thermo cameras are expensive, and there is a problem in long-term stability of a sensor portion. Furthermore, there is a problem that a thermocouple, a resistance temperature detector, and a thermistor cannot be directly attached to a conductor due to difficulty in electrically insulating the conductor. Each of these temperature sensors measures the temperature transmitted to a gas or an insulator, and thus has a problem of low sensitivity and is greatly affected by other heat sources.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and is durable, can be easily attached to a conductor, and detects overheating of the conductor by detecting the presence or absence of ultrasonic waves generated by vibration. It is an object of the present invention to provide a conductor temperature monitoring device that can be detected by a conductor.

[0006]

According to the present invention, there is provided a bottomed cylinder having a vibrating plate at the other end by providing a cutout hole from one end to the vicinity of the other end of a columnar member. A non-magnetic case is formed in the shape and buried in the conductor to be measured from the opening side, and the temperature-sensitive magnetic material changes from a ferromagnetic state to a paramagnetic state as the temperature rises. And the first and second recesses are formed in the axial direction from both ends in the axial direction of the temperature-sensitive magnetic body, and the first permanent magnet is fitted into the first recess of the temperature-sensitive magnetic body, An end facing the first permanent magnet has a second permanent magnet having the same magnetic pole, and a guide rod made of a non-magnetic material penetrating the second permanent magnet is fixed to the bottom of the second recess. The outer diameter of the guide rod is The second permanent magnet, which forms a tapered portion that decreases as it moves toward An ultrasonic microphone that detects the ultrasonic vibration sound generated by the second permanent magnet repeatedly colliding with the diaphragm part, vibrating in the direction of the external magnetic field due to the electromagnetic force generated between it and the magnetic field created by the permanent magnet Wherein the ultrasonic microphone is connected to the display means via the determination device.

[0007]

When the temperature-sensitive magnetic material is lower than the operating temperature (Curie point), the temperature-sensitive magnetic material itself becomes a ferromagnetic state and acts as a magnetic shield, and the magnetic poles of the same polarity are arranged opposite to each other. , The magnetic fields of the second permanent magnet do not affect each other. For this reason, the second permanent magnet does not move due to the repulsive force. However, when the temperature-sensitive magnetic material exceeds the operating temperature, it becomes paramagnetic and the magnetic fields of the first and second permanent magnets affect each other, and the second permanent magnet is repelled by the temperature-sensitive magnetic material. Vibrates by the action of an alternating magnetic field formed by the current flowing through the conductor, and repeatedly collides with the diaphragm to generate ultrasonic waves. This ultrasonic wave is detected by an ultrasonic microphone and is displayed on a display means via a determination device, whereby overheating of the conductor can be detected.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, reference numeral 1 denotes a hexagonal bolt as a case made of a non-magnetic material, and a shaft portion 2 of the hexagonal bolt has a hollow 3 formed from a lower portion to an upper portion in the drawings. The hollow 3 is formed such that the head 4 is slightly eccentric with respect to the screw 6 of the hexagonal bolt 1, and the hollow 3 reaches the vicinity of the end face of the head 4, and the diaphragm 5 is formed. Form.

Reference numeral 10 denotes a temperature sensor main body, and the temperature sensor main body 10 is configured as follows. Reference numeral 11 denotes first and second concave portions 12 and 1 each having a cylindrical shape extending in the axial direction from both ends.
3 is a substantially columnar temperature-sensitive magnetic body in which
Numeral 1 is made of Mn-Zn or Ni-Zn soft ferrite. A columnar first permanent magnet 14 is fitted into and adhered to the first concave portion 12 of the temperature-sensitive magnetic body 11, for example, in the direction of the illustrated magnetic pole.

On the other hand, a pipe-shaped second permanent magnet 16 is fitted in the second recess 13 of the temperature-sensitive magnetic body 11.
A guide rod 17 made of a non-magnetic material is provided, and the guide rod 17 is inserted into a hollow portion of the second permanent magnet 16 to guide the second permanent magnet 16 movably in the axial direction. ing. The lower end of the guide rod 17 is fitted in a communication hole 18 that connects the first concave portion 12 and the second concave portion 13, and the upper end is incorporated with a slight gap between the hexagon bolt 1 and the vibration plate portion 5. ing. Here, FIG.
As shown in (b), the position of the guide rod 17 is
Of these, the lower part is located at the axial center position, but the upper part is disposed at a position eccentric from the axial center position.
The gap between the guide rod 17 and the second permanent magnet 16 is extremely small in the portion penetrated by the second permanent magnet 16, and the portion of the guide rod 17 protruding from the second permanent magnet 16 has an outer diameter toward the distal end. A tapered portion 17a whose size is gradually reduced is formed. A bottom cover 15 made of a non-magnetic material is attached to an opening at the lower end of the hollow 3.

As shown in FIG. 4, a plurality of contacts 43 are provided between contacts 42a and 42b of conductors 41a and 41b provided in a tank 40 filled with an insulating gas via a pair of ring springs 44. Conductor 41
a, 41b are connected, and the hexagon bolt 1 housing the temperature sensor main body 10 is screwed to the conductor 41a connected in this manner. At this time, the eccentric direction of the guide rod 17 is set so as to match the direction of the magnetic field H. An ultrasonic microphone 45 is hermetically mounted via a gas seal connector 46 at a position facing the bolt 1 in the tank 40, and the ultrasonic microphone 45 is connected to an alarm 49 via an amplifier 47 and a level determiner 48. It is connected to the.

Next, the operation of the conductor temperature monitoring device will be described. The second permanent magnet 16 does not move from the position shown in FIG. 2 because the second permanent magnet 16 shows a ferromagnetic state when the temperature-sensitive magnetic body 11 is lower than the operating temperature. However, when the temperature exceeds the operating temperature,
The temperature-sensitive magnetic body 11 is in a paramagnetic state and the influence on the permanent magnet is reduced, and the magnetic repulsion between the first and second permanent magnets 14 and 16 causes the second permanent magnet 16 to move as shown in FIG. It moves upward and reaches the diaphragm portion 5.

When the temperature becomes higher than the operating temperature, the second permanent magnet 16
FIG. 3 is an enlarged view of the vicinity of the head 4 of the bolt when is moved.
(A). The thickness t of the vibrating plate portion 5 is thin, and the second permanent magnet 16 is a reciprocating swinging motion about an axis perpendicular to the axis of the guide rod 17 and perpendicular to the plane of the drawing above the hollow 3. Since the electromagnetic vibration is performed and the vibration plate portion 5 is repeatedly hit by the electromagnetic vibration, an ultrasonic wave is generated in the insulating gas in the tank 40. As described above, since the position of the guide rod 17 is eccentric in the upper part of the hollow 3, the outer peripheral side of the upper part of the second permanent magnet 16 hits the center of the diaphragm 5 and the superconducting gas generated in the insulating gas. The sound pressure of the sound wave increases.

Then, the guide rod 17 and the second permanent magnet 1
6, the electromagnetic vibration of the second permanent magnet 16 due to an external magnetic field near the operating temperature is small, and the second permanent magnet 16 is hard to move toward the diaphragm 5, so that the operating temperature varies. Is small. On the other hand, after the second permanent magnet 16 moves toward the diaphragm section 5, the gap between the second permanent magnet 16 and the guide rod 17 is large, so that the second permanent magnet 16 is greatly inclined and The impact force on the part 5 increases, and the amount of ultrasonic waves emitted into the insulating gas increases. For this reason, the overheating state of the conductor 41a can be detected more reliably.

The vibration frequency f of the diaphragm 5 is given by the following equation (1) based on the thickness t, the outer diameter D, and the Young's modulus E of the diaphragm 5.

[0016]

(Equation 1)

Here, ρ is the density of the diaphragm, σ is the Poisson's ratio of the diaphragm, and K is a constant.

The second permanent magnet 16 reaching the bolt head 4
Due to the interaction between the magnetic field (H) generated by the current (I) flowing between the conductors 41a and 41b and the magnetic field of the second permanent magnet 16, the second permanent magnet 16 Generates vibration and repeatedly collides with the diaphragm 5 to generate a vibration sound. This vibration sound is detected by an ultrasonic microphone 45 attached to the inner wall of the tank 40 in the form of an ultrasonic wave as shown in FIG. At this time, the output signal of the ultrasonic microphone 45 is detected and amplified by the amplifier 47, and then, when the ultrasonic level is determined to be higher than the reference value by the ultrasonic level determiner 48 set to be linked to the monitored temperature, a signal is sent to the alarm 49. Give an alarm and notify outsiders.

In this embodiment, a bolt is used as a case. However, the present invention is not limited to this, and a fitting hole may be formed in a conductor and the case may be fitted into the fitting hole. Further, the display means is not limited to the alarm device, and may have a configuration that appeals visually.

[0020]

As described above, according to the first aspect of the present invention, since the first and second permanent magnets are surrounded by the temperature-sensitive magnetic material, the temperature changes from the first permanent magnet to the second permanent magnet. Is converted into a change in the force acting on the permanent magnets, and at or above the operating temperature (Curie point), the repulsive forces of both permanent magnets increase. Therefore, overheating of the conductor can be easily detected and perceived by the ultrasonic microphone and the display means. Further, since the temperature sensor main body is built in the case fixed to the conductor to be measured, the temperature difference from the conductor to be measured is reduced, and the measurement error is small. Further, a portion for embedding the case in the conductor to be measured may be formed, so that the temperature sensor body can be easily attached.

Further, since the tapered portion is formed at the tip of the guide rod, the gap between the guide rod and the second permanent magnet is increased, so that the second permanent magnet hits the vibrating plate portion more strongly. The sound pressure of the generated ultrasonic waves increases. Therefore, overheating of the conductor can be more reliably perceived.

According to the second aspect of the present invention, since the mounting position of the guide rod with respect to the hollow is eccentric,
The vicinity of the center of the vibration plate portion of the bolt head becomes the vibration contact point of the electromagnetic vibration of the second permanent magnet, and the sound pressure of the generated ultrasonic wave increases. Therefore, overheating of the conductor can be more reliably perceived.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part showing one embodiment of a conductor temperature monitoring device according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a conductor temperature monitoring device according to the present invention.

3A is an enlarged view of an upper part of the bolt in a state where the second permanent magnet is moved to an upper part of the bolt by a repulsive force, and FIG. 3B is a cross-sectional view of a head of the hexagonal bolt.

FIG. 4 is a cross-sectional view showing a state where a temperature sensor main body is incorporated in a conductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hex bolt 2 ... Shaft part 3 ... Hollow out hole 4 ... Head 5 ... Diaphragm part 10 ... Temperature sensor main body 11 ... Temperature sensitive magnetic body 12 ... First concave part 13 ... Second concave part 14 ... First permanent Magnet 16 Second permanent magnet 17 Guide rod 17a Tapered part 18 Communication hole 41a, 41b Conductor 45 Ultrasonic microphone 48 Judgment device 49 Alarm

Continuation of front page (56) References JP-A-55-122123 (JP, A) JP-A-5-99975 (JP, A) JP-A-5-223655 (JP, A) JP-A-5-306959 (JP) JP-A-7-43223 (JP, A) JP-A-7-120519 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 31/00 G01K 7/36 G01R 31/08

Claims (2)

(57) [Claims] 1. A cylindrical member having a diaphragm portion at the other end by providing a cutout hole from one end to the vicinity of the other end of the columnar member, and being embedded in the conductor to be measured from the opening side. A case of a magnetic material is provided, and a temperature-sensitive magnetic material that changes from a ferromagnetic state to a paramagnetic state with a rise in temperature is fitted into the hollow and the axial direction from both ends in the axial direction of the temperature-sensitive magnetic body. First and second concave portions are formed, and a first permanent magnet is fitted into the first concave portion of the temperature-sensitive magnetic body, while an end facing the first permanent magnet has a second permanent magnet of the same magnetic pole. A magnet is provided movably in the axial direction by penetrating the second permanent magnet and fixing a guide rod made of a non-magnetic material to the bottom of the second recess, and the guide rod is provided on the opposite fixed end side of the guide rod. Forming a tapered portion where the outer diameter of the The second permanent magnet, which has moved to the diaphragm side of the case due to the repulsive force of the magnet, generates an external magnetic field between the external magnetic field generated by the current flowing through the conductor to be measured and the magnetic field generated by the second permanent magnet. An ultrasonic microphone that detects the ultrasonic vibration sound generated by the second permanent magnet oscillating in the direction of the magnetic field and repeatedly colliding with the diaphragm is provided, and the ultrasonic microphone is connected to the display means via the determiner. A conductor temperature monitoring device, characterized in that: 2. The conductor temperature monitoring device according to claim 1, wherein the mounting position of the guide rod is decentered in the direction of the external magnetic field with respect to the hollow.