JP3198856B2 - Abnormality monitoring method and device for stationary induction 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 method and an apparatus for monitoring an internal abnormality of a transformer or a current transformer in which an induction coil is housed together with insulating oil in a tank without malfunction even if it receives noise. About.

[0002]

2. Description of the Related Art In a transformer, a reactor, a current transformer, and the like, an induction electric machine body having a core wound around a core is housed in a tank together with a cooling medium for insulating oil. These devices are
They are collectively called stationary induction appliances. As a method for predicting the abnormality of the stationary induction device in advance, there is a method of externally monitoring an abnormal sound in the tank.

[0005] FIG. 5 is a block diagram showing the configuration of a conventional abnormality monitoring device for a stationary induction device. The high-voltage side of the stationary induction device 1 (in this case, a transformer in each case) is connected to the common power line 2 via the bushing 30 and is operated in parallel. The low-voltage side of the stationary induction device 1 has a bushing 3
1 and connected to the power line 3 to supply power to each load. The stationary induction device 1 incorporates a winding tap changer 4, and the tap changer 4 is operated by an operation device 5 attached outside the tank.

In FIG. 5, as an abnormality monitoring device, there are a microphone 6 attached to the outer wall of the tank of the stationary induction device 1 and a device for processing an output signal 6S thereof. That is, the output side of the microphone 6 is connected to the waveform shaper 8 via the amplifier 7. This wave shaper 8
Is connected to a comparator 9 having a level setter 10, and an output side of the comparator 9 is connected to an alarm 15 for notifying that an abnormal sound has occurred. The microphone 6 includes a sensor for converting a sound pressure into an electric signal. The sensor is arranged so as to contact an outer wall of the tank of the stationary induction device 1 and is fixed to the tank wall by a magnet attached around the sensor. In addition, upon receiving the signal, the annunciator 15 displays, for example, by a buzzer or a panel display, that an abnormal sound has occurred in the stationary induction device 1.

FIG. 6 is a time chart showing a waveform of a signal output when the device of FIG. 5 operates. The horizontal axis indicates time, and the vertical axis indicates signal level.
The upper row shows the output signal 6S of the microphone 6, the second row shows the output signal 8S of the waveform shaper 8, and the third row shows the output signal 9 of the comparator 9.
S. In FIG. 6, when any of the stationary induction devices 1 generates an abnormal sound, a damped vibration wave such as a waveform 19 is generated. This vibration waveform is determined by the ultrasonic component sensed by the microphone 6, and its detection frequency is expressed by the following equation (1).
It ranges from 0 kHz to several 100 kHz. The waveform shaper 8 receives the waveform 19 amplified by the amplifier 7, and performs envelope detection along the peak value like a dotted waveform 19A. Further, the waveform shaper 8 is configured to perform
The waveform is formed into a square wave holding the peak of 9A, and the waveform 20 is output. The comparator 9 takes in only the waveforms of the level Vo or higher from the waveforms 20 by the setting device 10 and outputs the waveforms 21. This is to exclude an iron core sound (for example, a magnetostrictive vibration or a contact sound between iron core steel plates) which is always generated even when the stationary induction device 1 is normal. The annunciator 15 in FIG. 5 receives the output waveform 21 of the comparator 9 and indicates that an abnormal sound has occurred in the stationary induction device ₁ from time t1.

Returning to FIG. 5, the two stationary induction devices 1 are operated in parallel, but it is almost impossible for them to generate abnormal sounds at the same time. As the type of abnormal sound,
There is a sound generated by partial discharge and a mechanical vibration sound of an internal structure due to a high frequency component of a power line. The former sound due to partial discharge is generated when the insulation is partially broken by a high voltage, and it is possible to predict beforehand the breakdown of the entire insulation. On the other hand, in the case of mechanical vibration sound, an internal conductor receives an electromagnetic force due to a high frequency component. The internal structure is pressed against vibration by a predetermined tightening force at the factory. However, if, for example, a fastening bolt such as a lead wire is loosened after the operation, a vibration sound is generated at the fastening position due to a high frequency component. The mechanical vibration due to the loosening of the structure does not occur much at a normal commercial frequency, but the sound becomes louder as the frequency becomes higher.

As described above, since the partial discharge noise and the internal mechanical vibration noise are generated due to defects inherent in the stationary induction device 1, it is not possible for the static induction device 1 to simultaneously generate a plurality of static induction sounds. You can think that it is unlikely. Therefore, as shown in FIG. 5, the abnormal sound is detected by the microphone 6 from each of the stationary induction devices 1, and
By monitoring whether or not such a waveform 19 can be obtained, it is possible to know which stationary induction device 1 has an abnormal sound.

In FIG. 5, when three or more stationary induction devices 1 operating in parallel are installed in the same premises, the microphone 6 is mounted on the tank wall of each stationary induction device 1.
And an abnormality monitoring device for processing the output signal 6S of the microphone 6 is provided in the same manner as in FIG. However, the abnormality monitoring device of FIG. 5 has a drawback that the tap changer 4 of the stationary device 1 operates and the microphone 6 senses a mechanical vibration sound at the time of tap change. The following device shown in FIG. 7 takes measures to avoid this malfunction.

FIG. 7 is a block diagram showing the configuration of a conventional abnormality monitoring device for a stationary induction device. Waveform shaper 8
A gate circuit 17 is interposed between the controller 9 and the comparator 9, and a signal 5 S output from the operating device 5 every time the tap is switched is input to the gate circuit 17. The comparator 9 receives the output signal 17S of the gate circuit 17.
Other configurations are the same as those of the apparatus of FIG. Here, the gate circuit 17 has a function of interrupting the input signal 8S and not outputting the signal 17S while the signal 5S is being input. On the other hand, when there is no input of the signal 5S, the gate circuit 17 outputs the input signal 8S as it is as the signal 17S.

FIGS. 8 and 9 are time charts showing waveforms of signals output when the apparatus of FIG. 7 operates. In each figure, the horizontal axis indicates time, and the vertical axis indicates signal level. FIG. 8 shows a case where the tap is switched, and FIG. 9 shows a case where an abnormal sound is generated. In both figures, the top row shows the output signal 6S of the microphone 6, the second row shows the output signal 8S of the waveform shaper 8, the third row shows the output signal 5S from the controller 5, and the fourth row shows the output signal of the gate circuit 17. 17
S, the bottom row is the output signal 9S of the comparator 9.

In FIG. 8, when the tap of the stationary induction device 1 is switched, an oscillating wave such as a waveform 18 is generated. The waveform 18 causes the waveform shaper 8 to set the time width t ₂ −
and outputs the waveform 24 is t _1. On the other hand, the waveform 25 from the operating device 5 is a square wave rising simultaneously with the waveform 24,
And the time width t ₃ −t ₁ is longer than the time width t ₂ −t ₁ of the waveform 24. While the waveform 24 of the signal 8S is input to the gate circuit 17, the waveform 25 exists as the signal 5S.
The output of the output signal 17S is cut off. Therefore, even if the tap of the stationary induction device 1 is switched, there is no output of the output signal 9S of the comparator 9, and the device does not malfunction.

On the other hand, in FIG. 9, when an abnormal sound is generated in the stationary induction device 1, a waveform 19 similar to that in FIG. This waveform 19, the waveform shaper 8 to output the waveform 20 is a time width t ₂ -t _1. on the other hand,
Since the tap changer 4 is stopped, there is no signal 5S from the operation device 5. Therefore, the waveform 20 passes through the gate circuit 17 as it is and becomes a waveform 34. As a result, the output signal 9S of the comparator 9 becomes the time
rises at t _1, the abnormal noise stationary induction apparatus 1 has occurred is notified.

FIG. 10 is a block diagram showing a configuration of another conventional abnormality monitoring device for a stationary induction device. A gate circuit 36 is interposed between the waveform shaper 8 and the comparator 9, and a high-frequency current sensor 16 is interposed on the ground line 1A of the stationary induction device 1. This current sensor 16
Is input to another waveform shaper 40 via the amplifier 13, and the output signal 40 S of the waveform shaper 40 is input to the gate circuit 36. Other configurations are the same as those of the apparatus shown in FIG.

In FIG. 10, a current sensor 16 can detect a high-frequency current flowing through the ground line 1A. When a partial discharge occurs in the stationary induction device 1 or a high frequency enters from the power line 2, a current having a high frequency component flows through the ground line 2A while being superimposed on the commercial frequency component. Therefore,
The current sensor 16 can detect the occurrence of partial discharge in the stationary induction device 1 and the occurrence of high-frequency components in the power line. The waveform shaper 40 has exactly the same function as the waveform shaper 8 described above, and the signal 16S amplified by the amplifier 13
And outputs a square wave signal 40S holding the peak value. Further, the gate circuit 36 allows the input signal 8S to pass as it is while the signal 40S is being inputted, and blocks the passage of the input signal 8S while the signal 40S is not being inputted. That is, it has a function completely opposite to that of the gate circuit 17 of FIG.

FIGS. 11 and 12 are time charts showing waveforms of signals output when the apparatus of FIG. 10 operates. In each figure, the horizontal axis indicates time, and the vertical axis indicates signal level. FIG. 11 shows a case where the tap is switched, and FIG. 12 shows a case where an abnormal sound that causes partial discharge is generated. In both figures, the top row shows the output signal 6S of the microphone 6 and the second row shows the output signal 16 of the current sensor 16.
S, the third stage shows the output signal 8S of the waveform shaper 8, the fourth stage shows the output signal 40S from another waveform shaper 40, the fifth stage shows the output signal 36S of the gate circuit 36, and the lowermost stage shows the comparator 9
Is the output signal 9S.

In FIG. 11, when the tap of the stationary induction device 1 is switched, an oscillating wave like a waveform 18 is generated. The waveform 18 causes the waveform shaper 8 to set the time width t ₂ −
and outputs the waveform 39 is t _1. On the other hand, since no signal 16S is output from the current sensor 16, no signal 40S is output. Since the signal 40S does not exist while the waveform 39 of the signal 8S is being input to the gate circuit 36,
The output of the output signal 36S is cut off. Therefore, even if the tap of the stationary induction device 1 is switched, there is no output of the output signal 9S of the comparator 9, and the device does not malfunction.

On the other hand, in FIG. 12, when an abnormal sound is generated in the stationary induction device 1, a waveform 19 similar to that in FIG. This waveform 19, the waveform shaper 8 to output the waveform 20 is a time width t ₂ -t _1. On the other hand, the current sensor 16 outputs a signal 16S as a waveform 22 due to partial discharge. This waveform 22 rises in the early time t ₀ from the waveform 19. When a partial discharge occurs, the current pulse rises immediately, but the sound is transmitted as a sound wave from the place of occurrence to the tank wall, so that the propagation distance (t 1500 m / s in oil) is divided by the propagation distance (t). _The rise is delayed by ₁ −t ₀ ). Therefore,
The rise of the waveform 23 of the signal 40S is also earlier than that of the waveform 20. At time t ₁ after the gate circuit 36, since both waveforms 20 and 23 are input, the signal 3 as waveform 39
6S is output. Comparator 9 by the waveform 39 outputs a signal 9S like waveform 21 from time t _1, the partial discharge sound generated in the stationary induction apparatus 1 Cal determine.

In FIG. 12, the notification of the abnormality is delayed from the phenomenon by a time t ₁ -t ₀ . For oil-filled transformers,
Since the width of the tank does not increase beyond 5 m, t ₁
−t ₀ does not become longer than 5 (m) ÷ 1500 (m / s) = 3.3 ms, and there is almost no problem as prediction of abnormality. FIG. 12 shows an example in which the abnormal sound is a partial discharge, but the same applies to a case where the internal structure is mechanically loosened due to a high frequency. That is, since high-frequency components flowing to the ground line, the current sensor 16 detects this high frequency components as a current, and outputs a signal 16S at time t _0, the signal due to mechanical vibration sound microphone 6 at time t ₁ Output 6S. Subsequent signal output states are the same as in FIG.

The difference between the apparatus shown in FIGS. 7 and 10 is that the apparatus shown in FIG. 7 receives the signal 5S from the operation unit 5 of the tap changer 4, whereas the apparatus shown in FIG. Signal 1
6S. In either device,
An abnormal sound in the tank can be detected without malfunctioning with respect to the mechanical vibration sound at the time of tap switching. 7 and 10, even if three or more stationary induction devices 1 are operated in parallel, if the microphones 6 are attached to the respective tank walls and the output signals 6S thereof are processed, abnormalities may occur. The stationary induction device 1 can be specified.

[0020]

However, the conventional device as described above can avoid the mechanical vibration noise caused by the tap changer, but has a drawback that the device malfunctions when rain or hail falls. Was. Further, the method of detecting the current from the ground line also has a disadvantage that the device makes an erroneous determination due to the influence of electric noise.

That is, it is possible that a sound such as rain (which does not feel much like normal rainfall, but a large amount of rain) and a hail hitting the outer wall of the tank enters the microphone and is detected as an abnormal sound as shown in FIGS. Was in the device. FIG.
The device described above only detects sound, so even if a malfunction occurs with respect to the sound of striking the tank, it is natural. Further, in the apparatus shown in FIG. 7, it is impossible to take a signal from the tap changer 4 due to rain or hail.

In the apparatus shown in FIG. 10, no high-frequency current flows through the ground line 1A even when rain or hail falls, so that no malfunction occurs. However, in general, a lot of local electric noise enters the ground line 1A. That is, there are many kinds and large noises at the site, such as switching noise when the power lines 2 and 3 are opened or closed by other departments, high-frequency radio noise entered through aerial radio waves, and communication wave noise. To this end, the current sensor 16 outputs a noisy signal 16S.
Easy to output. Therefore, the detection sensitivity of the current sensor 16 must be reduced, and therefore, there is a possibility that an erroneous determination that the current sensor 16 does not feel even if the microphone 6 captures the internal abnormal sound.

An object of the present invention is to prevent a malfunction even when rain or hail falls, and to prevent the influence of electric noise.

[0024]

In order to achieve the above object, according to the method of the present invention, an abnormal internal sound of a stationary induction electric appliance in which an induction electric appliance main body is housed together with an insulating cooling medium in a tank is monitored. In a method, a microphone is attached to each tank wall of a plurality of stationary induction devices that are operated in parallel, and the presence or absence of an output signal from the microphone is monitored in parallel for each stationary induction device. If a signal is output from any of the microphones, the static induction device to which the signal was output when there was no signal output from any of the remaining microphones from the time when the output signal was generated to a predetermined time. May be determined to be abnormal.

According to the present invention, the microphones attached to the tank walls of the plurality of stationary induction devices that are operated in parallel, and when a signal is output from any of the microphones, the output signal of the microphone is output. When there is no microphone output from any of the remaining microphones from the time of occurrence to a predetermined time, a notification signal is output to notify that there is an abnormality in the stationary induction device to which the signal has been output. It may be configured by an arithmetic unit.

[0026]

According to the structure of the present invention, microphones are mounted on the tank walls of a plurality of stationary induction devices operated in parallel. When a signal is output from any of the microphones, if there is no signal output from any of the remaining microphones from the time when the output signal is generated to a predetermined time, the other microphone outputs the signal which is still. It is determined that there is an abnormality in the induction device. A time range T from the generation time of the output signal to a predetermined time is set to about 0.5 second to 1 second. Vibration noise at the time of tap change is generated almost simultaneously from all stationary induction devices operated in parallel. Also, within the above-mentioned set time range T, sounds due to rain, hail, hail, etc. are generated from all stationary induction devices in parallel operation, and all microphones output signals. It is unlikely that abnormal noise such as partial discharge noise or mechanical vibration noise due to loosening of a structure is generated from two or more stationary induction appliances at the same time. Since the abnormal sound is always generated from only one specific stationary induction device, no signal is output from the remaining microphones. Therefore, even if it rains or hail, it does not malfunction and an abnormal stationary induction device can be specified. In addition, since the current sensor is not used even if electric noise is input, the device does not make an erroneous determination.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 is a block diagram showing a configuration of an abnormality monitoring device for a stationary induction device according to an embodiment of the present invention. The high voltage side of the stationary induction devices 1A and 1B (in this case, both transformers) are connected to the common power line 2 via the bushing 30,
Operated in parallel. The low-voltage sides of the stationary induction devices 1A and 1B are connected to the power line 3 via bushings 31, respectively, to supply power to the loads. Stationary induction device 1A,
1B incorporates a winding tap changer 4, and the tap changer 4 is operated by an operation device 5 attached to the outside of the tank.

In FIG. 1, as an abnormality monitoring device, microphones 6A and 6B attached to the outer walls of the tanks of the stationary induction devices 1A and 1B, respectively, and an output signal 6A
This is an apparatus for processing S, 6BS. That is, the output sides of the microphones 6A and 6B are connected to the waveform shapers 8A and 8B via the amplifier 7, respectively. The output sides of the waveform shapers 8A and 8B are connected to comparators 9A and 9B provided with a level setting unit 10, and the output sides of the comparators 9A and 9B check for the presence or absence of signals of both as described later. Connected to a NAND circuit 27 that outputs a signal. The output side of the NAND circuit 27 is connected to one input terminal of the AND circuits 28A and 28B. The outputs of the comparators 9A and 9B are connected to the other input terminals of the AND circuits 28A and 28B, respectively. NAND circuit 27 and AND circuit 28
A and 28B constitute an operation unit 26, and an AND circuit 28
The output side of each of A and 28B is connected to an alarm 15 for notifying that an abnormal sound has occurred.

In FIG. 1, the stationary induction devices 1A, 1B,
The power lines 2 and 3, the bushings 30 and 31, the tap changer 4, the operating device 5, the microphones 6A and 6B, the amplifier 7, the waveform shapers 8A and 8B, and the alarms 15A and 15B are exactly the same as those described in FIG. It is. The functions of the comparators 9A and 9B, the NAND circuit 27, and the AND circuits 28A and 28B will be described in the description of the operation of the device shown in FIGS.

FIGS. 2 and 3 are time charts showing waveforms of signals output when the apparatus of FIG. 1 operates.
In each figure, the horizontal axis indicates time, and the vertical axis indicates signal level. FIG. 2 shows a case where noise such as rain has occurred, and FIG. 3 shows a case where an abnormal sound has occurred. In both figures, the signals 6AS and 6BS at the first and second stages from the top are the outputs of the microphones 6A and 6B, respectively. The third and fourth stage signals 8AS and 8BS are the outputs of the waveform shapers 8A and 8B. The fifth and sixth stage signals 9AS and 9BS are the outputs of the comparators 9A and 9B, respectively, and the seventh stage signal 27S is the output of the NAND circuit 27. Eighth and ninth signal 28
AS and 28BS are outputs of the AND circuits 28A and 28B, respectively.

In FIG. 2, if noise is generated in the stationary induction devices 1A and 1B due to rain or hail, the signal 6
Vibration waves such as waveforms 50 and 37 are generated as AS and 6BS, respectively. When the time width T from the time t ₁ to t ₄ is set to a width of, for example, 0.5 seconds to 1 second, always sound both within this time width T is generated. In the example of FIG.
There rises to time t _1, the waveform 37 is up to time t ₁ 1. In response to this waveform 50,37, a waveform shaper 8A, 8B is a square waveform 3 of T ₁ of the longer width than T
2 and 38 are output respectively. If the output signals 8AS and 8BS of the waveform shapers 8A and 8B are equal to or higher than the level V _O , the comparators 9A and 9B output the waveforms 44 and 45 as they are.

Further, in FIG.
Receives the waveform 44 to the one input terminal time t _1, then,
When receiving the waveform 45 to another input before a predetermined time t _4, so as not to output anything signal on the output side. Therefore, no waveform appears in the signal 27S in FIG. AND circuits 28A and 28B output signals 27S
And the signals 9AS and 27S and 9BS, respectively, and output the signal only when the signal exists at both of the input terminals. Waveform 4 for signals 9AS and 9BS
4, 45 exist, but there is no signal 27S, so neither signal 28AS, 28BS is output. Therefore, no malfunction occurs even when noise enters the device. As noise, rain, hail, hail, etc., in each stationary induction device 1A, 1B, within the predetermined time width T of about 0.5 second to 1 second, which stationary induction device 1A, 1
B always produces a sound. On the other hand, the vibration noise from the tap changer 4 as other noise is almost simultaneous for each of the stationary induction devices 1A and 1B. However, as can be seen in FIG. 2, it is assumed by the waveform 50,37 vibration sound of the tap changer 4 together, even a time t ₁ and time t ₁ 1 is approximately the same time, the signal 27S nothing occurs do not do. For this reason, there is no problem even if the noise is caused by the tap changer 4.

In FIG. 3, when an abnormal sound is generated only in the stationary induction device 1A, the output signal 6 of the microphone 6A is output.
AS becomes like a waveform 19. On the other hand, there is no output signal 6BS of the microphone 6B. Therefore, the output signal 8
AS, 9AS is as waveforms 33, 41 of the time width T _1, respectively. There is nothing in the output signals 8BS and 9BS. NAND circuit 27 receives the waveform 41 to one input terminal at time t _1, then nothing signal was not (as signal 9bS) to another input terminal until the predetermined time t ₄ times, time as it passes the input waveform 41 from t ₄ to output as the waveform 42. Next, AND circuits 28A and 28B
Notification signal 2 when signals are simultaneously input to two input terminals
8AS and 28BS are output. Signal 28A in FIG.
In S, a waveform 43 is formed because the waveform 42 of the signal 27S and the waveform 41 of the signal 9AS are input. On the other hand, since only the waveform 42 of the signal 27S is input to the signal 28BS, there is no waveform. Therefore, the stationary induction device 1
It is specified that the abnormal sound has occurred in A.

FIG. 4 is a block diagram showing a configuration of an abnormality monitoring apparatus for a stationary induction device according to another embodiment of the present invention. FIG. 4 shows a case where three static induction devices 1A, 1B, and 1C are operated in parallel to the configuration of FIG. Explaining only parts different from FIG. 1, a microphone 6C is attached to another stationary induction device 1C,
The output signal 6CS of the microphone 6C is input to the NAND circuit 51 via the amplifier 7, the waveform shaper 8C, and the comparator 9C. The NAND circuit 51 receives the signals 9AS and 9BS at the remaining two input terminals, and the output signal 51S is
The three AND circuits 28A, 28B, 28C are respectively connected to one input terminals. AND circuits 28A, 28
B, 28C, the output signals 9AS, 9BS, 9CS of the comparators 9A, 9B, 9C are provided in the same manner as in FIG.
Is entered. NAND circuit 51 and AND circuit 28
A, 28B, and 28C constitute an arithmetic unit 29.

In FIG. 4, after receiving a signal at one of the input terminals, all of the remaining input terminals receive signals within a predetermined time width T (for example, 0.5 seconds or 1 second). Upon receiving the signal, no signal 51S is output. When the NAND circuit 51 receives a signal at one of the input terminals and finds that there is no signal remaining at the input terminal within the time width T, the signal 2 in FIG.
A signal 51S similar to the 7S waveform 42 is output. The AND circuits 28A, 28B, and 28C output the signal 28A only when the signal exists at both of the input terminals.
S, 28BS, and 28CS are output.
If the abnormality monitoring device for the three stationary induction devices operated in parallel is configured in this way, even if it receives rain, hail, or the vibration sound of the tap changer, the stationary induction device operates in the same manner as in FIG. Signals are output from the microphones 6A, 6B, 6C for all the electric appliances 1A, 1B, 1C within a predetermined time width T. Therefore, the calculation unit 29 does not output a notification signal. On the other hand, if an abnormal sound is generated from any of the stationary induction devices, the arithmetic unit 29 outputs a specific notification signal, and the stationary induction device that has generated the abnormal sound is specified.

In the case where there are four or more stationary induction devices, generally a plurality of stationary induction devices, a signal processing device below the microphone may be added in the same manner as in FIG. When there are three or more stationary induction devices that are operated in parallel, a notification signal that abnormal noise is occurring from two or more devices is generated.
That is impossible in theory. That is, as described above, it can be said that it is unlikely that any of the two units will cause an internal abnormality within the time width T (0.5 seconds or 1 second).
In the event that an abnormal sound generation signal is output from two stationary induction devices, it is advisable to reconfigure the monitoring devices in units of two as shown in FIG.

[0037]

As described above, the microphones are mounted on the tank walls of a plurality of stationary induction devices operated in parallel as described above. If there is an output signal from any of the microphones, the signal is output when there is no output signal among the remaining microphones from the time when the output signal was generated to a predetermined time. It is determined that the stationary induction device has an abnormality. by this,
This device does not malfunction even if rain or hail falls or the tap changer operates, and the abnormal stationary induction device can be identified. In addition, since the current sensor is not used even if electric noise is input, the device does not make an erroneous determination. By the way, the signal processing is much slower than the ms order so that the time width T is 0.5 seconds to 1 second. For this reason, there is also an effect that the production cost of the monitoring device is very low.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a monitoring device for a stationary induction device according to an embodiment of the present invention.

FIG. 2 is a time chart showing a signal waveform when the apparatus of FIG. 1 processes noise.

FIG. 3 is a time chart showing a signal waveform when the device of FIG. 1 processes an abnormal sound;

FIG. 4 is a block diagram showing a configuration of a monitoring device for a stationary induction device according to another embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional monitoring device for stationary induction equipment.

FIG. 6 is a time chart showing a signal waveform when the device of FIG. 5 processes an abnormal sound;

FIG. 7 is a block diagram showing a configuration of a conventional monitoring device for a different stationary induction device.

8 is a time chart showing a signal waveform when the device of FIG. 7 processes noise.

FIG. 9 is a time chart showing a signal waveform when the device of FIG. 7 processes an abnormal sound;

FIG. 10 is a block diagram showing a configuration of another conventional static induction device monitoring apparatus.

11 is a time chart showing a signal waveform when the apparatus of FIG. 10 processes noise.

FIG. 12 is a time chart showing a signal waveform when the device of FIG. 10 processes an abnormal sound;

[Explanation of symbols]

1A, 1B, 1C: stationary induction device, 6A, 6B, 6C:
Microphones 26 and 29: arithmetic unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31/00 G01M 19/00 G01R 31/12

Claims (2)

(57) [Claims] 1. A method for monitoring an abnormal internal noise of a stationary induction device in which a main body of an induction device is housed together with an insulating cooling medium in a tank, the method comprising the steps of: In a method in which a microphone is attached to a wall and the presence or absence of an output signal from the microphone is monitored in parallel with respect to each stationary induction device, when a signal is output from any of the microphones, a predetermined time from the generation time of the output signal An abnormality monitoring method for a stationary induction device to which a signal is output when there is no signal output from any of the remaining microphones up to this point. . 2. An apparatus for implementing the method according to claim 1, wherein a microphone is mounted on a tank wall of each of a plurality of stationary induction devices operated in parallel, and a signal is output from one of the microphones. If any of the remaining microphones does not output a signal between the time when the output signal was generated and the predetermined time, the static induction device to which the signal was output is abnormal. An abnormality monitoring device for a stationary induction device, comprising: a calculation unit that outputs a notification signal to be reported.