JPH0194206A - Abnormal position detector - Google Patents

Abstract

PURPOSE:To enable the locating of a generator of an ultrasonic wave without being affected by reflection or the like from a flange of a container, by detecting and computing two envelope signals and peak values thereof from a vibration waveform of an ultrasonic wave signal. CONSTITUTION:When an ultrasonic wave is generated within a metal container 1, ultrasonic wave sensors 11a and 11b detect signals with a complicated waveform through various paths. After amplified 12, these signals are inputted into envelope detection circuits 21 and 22 to make first and second envelope signals and when an instantaneous value of at least one envelope signal exceeds a specified level, a detection control circuit 23 outputs a peak detection signal with a specified time range and peak value detection circuits 31 and 32 detect first and second peak value signals from an envelope signal existing between the signals. Then, mean circuits 41 and 42 compute an arithmetic average of a specified number of peak value signals and a computation is performed with a computing circuit 43 by a specified formula thereby enabling the locating of the position of the generation thereof however complicate the overlapping of an ultrasonic wave signal may be.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention detects the generation position of ultrasonic waves due to vibrations of a part number 6L or minute foreign matter inside a metal container filled with insulating gas of a gas-insulated electric device, for example. The present invention relates to an abnormal position detection device for locating.

[Conventional technology]

For example, if a partial discharge occurs inside a metal container filled with insulating gas in gas-insulated electrical equipment, vibrations of microscopic foreign objects driven by an electric field, or vibrations of loose fastening bolts driven by electromagnetic force occur, the insulation capacity and current carrying capacity will decrease. To avoid this, an abnormal position detection device is used to detect ultrasonic waves caused by partial discharges, vibrations of minute foreign objects, or vibrations of fastening bolts based on the ultrasonic waves propagating through the metal part of the metal container as a medium. Measures to prevent accidents by locating the location where they occur have been well known for some time.

Figure 2 shows, for example, "Development of a 1160 minute anomalous sound search device" published on page 496 of the 1981 National Conference of the Institute of Electrical Engineers of Japan (IEEJ) collection of lecture papers (authors: Masami Ikeda, Namebe Aoyagi, Yoshihiro Kanno, Takashi Amemiya). ) is a block diagram showing the configuration of the conventional abnormal position detection device shown in FIG.

In the figure, (1) is a metal container filled with insulating gas, (
2) is the flange of this metal container, (lla) (-Llb
) is an ultrasonic sensor that detects an ultrasonic signal corresponding to the intensity of ultrasonic waves propagating through the metal part of the metal container (1) as a medium, and is mounted on the outer surface of the metal container (1) in the axial direction. They are mounted parallel to each other at predetermined intervals.

@ is an amplifier that amplifies the ultrasonic signal detected by the ultrasonic sensor (lla) (1lb), and (to) is a first-come-first-served discrimination circuit, which of the ultrasonic sensors (uni-a) and (uni-b) is faster. It determines whether an ultrasonic signal is detected and outputs two corresponding determination signals. α→ is a display circuit having two light emitting diodes, and lights up and displays the light emitting diode in accordance with the discrimination signal output from the first arrival discrimination circuit (to).

The conventional abnormal position detection device is constructed as described above, and when a high voltage is applied to the conductive part (not shown) in the metal container (1), an electric field is generated between the metal container (1) at ground potential and the metal When conductive minute foreign matter is present as a contaminant in the container (1), this minute foreign matter is charged and driven by the electric field to vibrate. The ultrasonic waves generated by this vibration are transmitted to the metal container (
The ultrasonic wave propagates through the metal part of (1) as a medium and is detected by ultrasonic sensors (lxa) (lxa) mounted at arbitrary positions on the outer surface of the metal container (1) at predetermined intervals parallel to its axis. SoO
It is detected as an ultrasonic signal corresponding to the intensity of the ultrasonic wave.

These ultrasonic signals are each amplified by an amplifier (2), the gain is adjusted, and then input to the first-come-first-served discrimination circuit (2), which of the ultrasonic sensors (11a) and (11b) detects the ultrasonic wave No. 1 sooner. Determine whether Since either the ultrasonic sensor (Unit A) or (Unit B) installed closer to the vibrating part of the minute foreign object, which is the source of ultrasonic waves, detects the ultrasonic signal sooner, the first-come-first-served discrimination circuit ) discriminates the ultrasonic signal and outputs a discrimination number M corresponding to it, and the display circuit α lights and displays the corresponding light emitting diode based on this discrimination signal. The direction of the source of the ultrasonic wave can be determined by the lighting display of the light emitting diode. A metal container to which the ultrasonic sensors (11a) (11b) are attached
1) Repeatedly locate the direction of the ultrasonic source by changing the position on the outer surface of the display circuit.
The source of the ultrasonic wave exists on the cross section that includes the midline of the mounting position of llb).

[Problem that the invention seeks to solve]

In the conventional abnormal position detection device as mentioned above, the first-come-first-served determination time F
I! ! 0 detects an ultrasonic signal earlier than either of the ultrasonic sensors (11et) or (11b), so it is determined whether the ultrasonic signal is detected earlier than the ultrasonic sensor (11et) or (11b). This method requires a complicated configuration to eliminate differences in the propagation time of ultrasonic waves, and there are also problems in that discrimination becomes difficult as the frequency of ultrasonic wave generation increases.

This invention was made to solve the above-mentioned problems, which are affected by the difference in propagation time of ultrasonic waves due to reflection at the flange of a metal container and the difference in propagation paths, and the frequency at which ultrasonic waves are generated. The purpose of the present invention is to obtain an abnormal position detection device that will never cause abnormal position detection.

[Means for solving problems]

The abnormal position 11 detection device according to the present invention uses two ultrasonic sensors mounted at arbitrary positions on the outer surface of a cylindrical metal container filled with an insulating fluid at a predetermined interval in parallel to the central axis of the metal container. In a device that simultaneously detects each ultrasonic signal corresponding to the intensity of the ultrasonic wave generated inside the device and propagates through the metal part as a medium, and locates the generation position of the ultrasonic wave based on each ultrasonic signal, each ultrasonic wave is detected simultaneously. a first envelope detection circuit and a second envelope detection circuit that respectively detect a first envelope signal and a second envelope signal corresponding to the envelope of the vibration waveform based on the signal; a detection control circuit that outputs a peak detection signal of a predetermined time width when at least one instantaneous value exceeds a predetermined level based on the envelope signal of the envelope signal; a first envelope signal within the time width based on the peak detection signal; The first peak value signal and the second peak value signal corresponding to each peak value of the No. 8 and Z-th envelope signals
A first peak value detection circuit and a second peak value detection circuit each detect a peak value signal of A first average value circuit and a second average value circuit that respectively output a first average value signal and a second average value signal corresponding to the arithmetic average value, and a first average value signal and a second average value. The device is equipped with an arithmetic circuit that calculates the distance between the ultrasonic sensor mounting position and the ultrasonic generation position based on the signal and the distance between the ultrasonic sensors.

[Effect]

In this invention, based on each ultrasonic signal detected simultaneously by two ultrasonic sensors, a first envelope signal and a second envelope signal corresponding to the envelope of the vibration waveform are detected, and the first envelope signal and the second envelope signal are detected. When at least one instantaneous value exceeds a predetermined level based on the second envelope signal, a peak detection signal of a predetermined time width is output, and based on this peak detection signal, the first envelope signal within the time width is output. A first peak value signal and a second peak value signal corresponding to each peak value of the envelope signal and the second envelope signal are detected, and arithmetic operations are performed on a predetermined number of first peak value signals and second peak value signals, respectively. After calculating the average value and detecting the 10th average value information and the second average value signal corresponding to each arithmetic average value, a signal is detected between the first average value signal, the second average value signal, and the ultrasonic sensor. The distance between the ultrasonic sensor mounting position and the ultrasonic generation position is calculated based on the distance.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of the present invention, and in the figure, (1) (2) (lla) (llb)C
12 is exactly the same as the conventional device described above. Q comic (
2) is a first envelope detection circuit and a second envelope detection circuit that respectively detect a first envelope signal and a second envelope signal corresponding to the envelope of the vibration waveform of each ultrasonic signal amplified by the amplifier (2). circuit,(
E) The instantaneous value of at least one of the first envelope signal detected by the first envelope detection circuit Qυ and the second envelope signal detected by the second envelope detection circuit glr@ exceeds a predetermined level. a detection control circuit c3 that sometimes outputs a peak detection signal with a predetermined time width;
D(2) is a first envelope signal corresponding to each peak value of the first envelope signal and second envelope signal within the time width based on the peak detection signal output from this detection control circuit.
a first peak value detection circuit and a second peak value detection circuit that respectively detect the peak value signal and the second peak value signal;
(6) is the first peak value signal detected by the first peak value detection circuit 01) and the second peak value detection port I.
i1! (2) A first circuit that calculates a predetermined number of respective arithmetic average values of the detected second peak value signals and outputs corresponding first average value signals and second average value signals, respectively.
an average value circuit and a second average value circuit, the first average value signal output from the first average value circuit and the second average value circuit;
The installation position of the ultrasonic sensor (11a) (llb) and the ultrasonic generation position are determined based on the second average value signal outputted from the average value time i (b) and the distance between the ultrasonic sensors (llaXllb). An arithmetic circuit that calculates the distance between the two, and a display circuit that displays a corresponding numerical value based on the output signal of this arithmetic circuit.

Next, the operation will be explained. The ultrasonic waves generated in the metal container (1) propagate through the metal part of the metal container (1) as a medium, and pass through a straight path or a spiral path to the metal container (
In addition to reaching the attachment position of the ultrasonic sensors (11a) (11b) on the outer surface of the ultrasonic sensor (1), reflected waves from the ultrasonic waves propagated through the metal container (1) and reflected by the flange (2), etc.
lla) (llb) is reached. Therefore, the ultrasonic sensors (1la) (llb) detect ultrasonic signals corresponding to the intensities of these superimposed complex waveforms. After amplifying each of these ultrasonic signals with an amplifier @, the first envelope detection circuit Qη and the second envelope detection circuit
A first envelope signal and a second envelope signal corresponding to the envelope of the vibration waveform of each ultrasonic signal are detected. The detection control circuit outputs a peak detection signal of a predetermined time width based on the first envelope signal and the second envelope signal when the instantaneous value of at least one of them exceeds a predetermined level. The first peak value detection circuit 0) and the second peak value detection circuit (A) correspond to the peak values of the first envelope signal and the second envelope signal that exist while receiving this peak detection signal. The first peak value signal and the second peak value signal are detected and outputted to the first average value circuit (b) and second average value circuit (b), respectively, and then reset. fil's average value circuit■ and the second average value circuit)
calculates each arithmetic mean value of a predetermined number, for example 64, of the first peak value signal and the second peak value signal, and outputs the corresponding first mean value signal and second mean value signal.

By the way, no matter how complicated the ultrasonic signal is in the superimposed waveform as described above, the average value of each peak value of the envelope signal corresponding to the envelope of the vibration waveform and the ultrasonic wave from the ultrasonic generation position. V = K-exp(-αt) between the shortest distance t to the Senna mounting position
It has been confirmed that there is a relationship and that it is effective in practice. Here, K is a constant and α is the absorption coefficient per unit length of the medium. Therefore, the ultrasonic sensor (
lla) and ultrasonic sensor C11b), respectively.

n1 Assuming that the first average value signal and second average value signal corresponding to each arithmetic average value of a predetermined number of second peak value signals are ■l and ■2, respectively, ■1≦V2, S=m+n Since 5s and α are known, n can be calculated.

A circuit (goods) that calculates the first average value signal and the second average value signal
After performing this calculation, an output signal corresponding to the result of this calculation is input to a display circuit to display the numerical value. The ultrasonic generation source exists on the cross section of the ultrasonic generation position thus located.

In the above embodiment, the display time Fjlr- is the arithmetic circuit (goods).
In addition to this, the first average value signal output from the first average value circuit (6) and the second average value signal output from the second average value circuit (6) are input. (shown by broken lines in FIG. 1) may also be displayed numerically, which is convenient for locating the position where the ultrasonic waves are generated.

〔Effect of the invention〕

As explained above, this invention uses two ultrasonic sensors mounted at arbitrary positions on the outer surface of a cylindrical metal container filled with an insulating fluid at a predetermined interval in parallel to the central axis of the container. Each ultrasonic signal corresponding to the intensity of the ultrasonic wave generated and propagated through the metal part as a medium is simultaneously detected, and based on each ultrasonic signal, a first envelope signal and a second envelope signal corresponding to the envelope of the vibration waveform are detected. a first envelope detection circuit and a second envelope detection circuit, each detecting an envelope signal of the first envelope signal and the second envelope signal; a detection control circuit that outputs a peak detection signal with a predetermined time width, a first peak value signal corresponding to each peak value of the first envelope signal and the second envelope signal within the time width based on the peak detection signal; A first peak value detection circuit and a second peak value detection circuit each detect a second peak value signal, and each calculates an arithmetic mean value for a predetermined number of first peak value signals and a predetermined number of second peak value signals. A first average value circuit and a second average value circuit that respectively output a first average value signal and a second average value signal corresponding to each arithmetic average value; Equipped with an arithmetic circuit that calculates the distance between the ultrasonic sensor mounting position and the ultrasonic generation position based on the average value signal and the distance between the ultrasonic sensors, it is possible to avoid reflections at the flange of the metal container and the propagation path. This has the effect of being able to locate the position where the ultrasonic wave is generated without being affected by the difference in the propagation time of the ultrasonic wave or the frequency at which the ultrasonic wave is generated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
The figure is a block diagram showing the configuration of a conventional abnormal position detection device. In the figure, (1) is a metal container, DlaXlb) is an ultrasonic sensor, 0υ(a) is a first envelope detection circuit and a second envelope detection circuit, respectively, ni) is a detection control circuit, and G1) is a detection control circuit. (b) (6) is a first average value circuit and a second average value circuit, respectively; - is an arithmetic circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] Two ultrasonic sensors installed parallel to the central axis of a cylindrical metal container filled with an insulating fluid at a predetermined interval on the outer surface of the container generate ultrasonic waves inside the metal container. In a device that simultaneously detects each ultrasonic signal corresponding to the intensity of the ultrasonic wave propagating through a metal part as a medium and locates the generation position of the ultrasonic wave based on each of the ultrasonic signals, based on each of the above ultrasonic signals. A first envelope signal and a second envelope signal corresponding to the envelope of the vibration waveform.
a first envelope detection circuit and a second envelope detection circuit, each of which detects an envelope signal, and an instantaneous value of at least one of them exceeds a predetermined level based on the first envelope signal and the second envelope signal. a detection control circuit that sometimes outputs a peak detection signal with a predetermined time width, a first envelope signal corresponding to each peak value of the first envelope signal and the second envelope signal within the time width based on the peak detection signal; A first peak value detection circuit and a second peak value detection circuit that respectively detect a peak value signal and a second peak value signal, and a predetermined number of the first peak value signals and the second peak value signals. a first average value circuit and a second average value circuit that respectively calculate an arithmetic average value and output a first average value signal and a second average value signal corresponding to each arithmetic average value;
an arithmetic circuit that calculates a distance between a mounting position of the ultrasonic sensor and a position where the ultrasonic wave is generated based on the average value signal, the second average value signal, and the distance between the ultrasonic sensors. An abnormal position detection device characterized by: