JP2947300B2 - Abnormality detection device for rotating electric machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electrical machine abnormality detecting apparatus capable of detecting and constantly monitoring an abnormality caused by insulation deterioration of a stator winding.

[0002]

2. Description of the Related Art In recent years, the scale of plants in general industry has been steadily increasing in size, and as a result, the size of rotating electric machines has increased and the number of installations has also increased.

Therefore, since high reliability is particularly required for such a rotating electric machine, it is necessary to reliably perform maintenance and inspection and to prevent sudden accidents such as insulation breakdown.

Conventionally, as a method of judging insulation deterioration of a rotating electric machine, for example, for a stator, after stopping the operation of the rotating electric machine, a high voltage is applied to a winding to obtain various electrical characteristics (insulation resistance, AC current). , Dielectric loss angle, partial discharge, etc.), and an electrical method is used to estimate the degree of deterioration of the insulator at each location. For the rotor, the rotating electric machine is disassembled and the rotor is taken out In addition, a mechanical method of judging the mechanical damage state of the insulating portion and the deterioration state of the winding fixing force by visual inspection and tapping sound is used.

However, in order to judge deterioration by these methods, it is necessary not only to stop the operation of the rotating electric machine but also to disconnect the line connection and, in some cases, to remove the rotor. For this reason, performing a deterioration judgment by such a series of methods requires a great deal of time, labor and cost, and has a drawback that frequent deterioration judgment tests are difficult to perform. In addition, since the preparation may take time to carry out such a method, there is a disadvantage that when the deterioration progresses rapidly, it is not possible to sufficiently cope with the deterioration.

Therefore, in order to eliminate such inconvenience, there has been proposed a partial discharge detecting device for electric equipment in which a metal conductor is arranged as an antenna for detecting partial discharge in the vicinity of an insulated winding of electric equipment.

FIG. 5 is a perspective explanatory view showing a conventional partial discharge detecting device for electric equipment disclosed in Japanese Utility Model Laid-Open No. 55-51775, and FIG. 6 is a block diagram of the same. In FIG.
1 is a stator, 2 is a stator core, 3 is a stator winding end, 4
Is an antenna wire for detecting partial discharge. This antenna line 4
The electromagnetic wave generated by the partial discharge pulse current is captured, and the output from the antenna wire 4 is led to the detection circuit 6 via the lead wire 5 as shown in FIG. 6, and the detection output extracted here is sent to the high-pass filter 7. In this case, the normal voltage frequency component is removed by passing the partial discharge counter 8 into the partial discharge counter 8 to measure the partial discharge.

However, subsequent research results have revealed that high-frequency currents based on partial discharges propagating in the stator windings are significantly attenuated in the windings. For example, FIG.
Is a magazine: IEEE PROCEEDINGS, VOL. 1
32, Pt. B, No. 5, SEPTEMBER, 19
FIG. 85 is a characteristic diagram of a signal level propagating in a winding for each frequency band shown in 85. Characteristic curve a is 20-100k
Hz, b is 20-300kHz, c is 20-1000k
Hz and D are characteristics of a frequency band of 20-3000 kHz. As is clear from the figure, the signal attenuation in the winding is remarkable, and especially in a high frequency band effective for electromagnetic wave detection, the signal level is reduced to 1/2 to 1 /
It can be seen that the sensitivity is reduced to 10, and the detection sensitivity is lowered.

[0009]

A conventional partial discharge detecting device for detecting a partial discharge of an electric device is constructed as described above, and a high frequency current based on the partial discharge propagating in a stator winding is applied to a stator. There is a problem that the attenuation in the winding is remarkable, and the gain of the antenna arranged in the stator part of the rotating electric machine is small, and the detection sensitivity of the partial discharge signal generated especially at a position far from the antenna is very poor. Yes, and
Conventionally, high-frequency signals are detected in a frequency band of about 1 MHz or less. Therefore, considering the time required for signal processing, a plurality of signals generated within several microseconds cannot be separated and detected, resulting in poor measurement accuracy. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an abnormality detecting device for a rotating electric machine which can constantly monitor an abnormality of a stator winding with high detection sensitivity and measurement accuracy. And

[0011]

SUMMARY OF THE INVENTION The abnormality detecting device of a rotary electric machine of the invention, the based Ku electromagnetic wave abnormally with generated partial discharge of the stator winding is detected by the antenna, the stator winding Surface that is perpendicular to the rotation axis of the rotor.
At several positions above, facing the end face of the stator core,
Directivity to stator winding end protruding from stator core
And a microwave band antenna having the following.

[0012]

An abnormality detecting device for a rotating electric machine according to the present invention comprises a rotor
End of the stator core at several positions on a plane perpendicular to the axis of rotation
Stator windings that protrude from the stator core above the surface
Since the microwave band antenna having directivity with respect to the end is disposed, a sufficient insulation distance can be provided from the high-voltage stator winding, and the reliability of the rotating electric machine is not reduced. Further, since the large size of the antenna gain has the directivity may be used by detecting the wave collector of the microwave band, less susceptible to noise, the detection sensitivity is improved. In addition, since signals in a wider frequency band are detected than before, errors due to overlapping of a plurality of high-frequency signals can be reduced, and the time resolution of detection is improved.

[0013]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. FIG.
1 is a cross-sectional configuration diagram illustrating an abnormality detection device for a rotating electric machine according to a first embodiment of the present invention. Reference numeral 10 denotes a rotating electric machine, in this case, a generator, and a stator frame 11, a stator core 2, a stator winding 1
2 and a rotor 13. The stator winding 12 is accommodated and wound in a slot groove provided in the stator core 2, and a portion of the stator winding 2 which is outside the stator core 2 for winding is formed by a stator winding end 3. Called.

[0014] opposite to the end portion of the stator core 2, one reflector antenna 14, 15 (the remainder is an antenna in the microwave band to the inner wall surface with three directional stator frame 11 is not shown ) Is on a plane perpendicular to the axis of rotation of the rotor
In addition, they are arranged on the same circumference facing the end face of the stator core . Each of the reflector antennas 14 and 15 is attached via a bushing 19 which penetrates a central portion of a metal cover 18 which closes an opening of a small case 17 attached to the stator frame 11.

FIG. 2 is an explanatory view showing an installation position of the reflector antenna with respect to a longitudinal sectional view of the fixed winding end 3. The stator winding 12 accommodated in the stator core 2 is a conductor 21
And an insulating layer 22 surrounding the stator core, and several tens c from the inside of the slot groove of the stator core 2 and the end of the stator core 2.
For m, the low resistance paint 23 is applied to the outside of the insulating layer 22. A filler 24 for filling a gap is inserted between the two stator windings 12. The reflector antenna 14 is arranged such that the electromagnetic wave radiated from the stator winding end 3 where the stator winding 12 protrudes from the stator core 2 is detected as a direct wave. The three reflector antennas 14 are arranged in a circumferential direction so that electromagnetic waves radiated from all stator winding ends 3 can be detected.
It has a directivity capable of detecting an electromagnetic wave radiated from the stator winding end 3 within a range of 0 degrees. Note that the other two reflector antennas are similarly installed.

The reflector antennas 14 and 15 are connected to an abnormality detector 20 shown in the block diagram of FIG. 3 by a measuring cable 16 for transmitting detection signals S ₁ and S ₂ . Other reflector antennas have the same configuration. Abnormality detector 2
Reference numeral 0 denotes an amplifier circuit 25, a filter circuit 26, a discharge detection operation circuit 27, an abnormality determination circuit 28, and a display circuit 29.

Next, the operation of this embodiment will be described. During operation of the generator 10, the conductor 2 in the stator winding 12
1 generates a high voltage. If an abnormality occurs in the stator winding 12 during operation, a partial discharge occurs in the stator winding 12. Since the stator winding 12 has a form similar to a coaxial line due to the conductor 21, the low-resistance paint 23, and the insulating layer 22 therein, a high-frequency current propagates through the conductor 21 in the stator winding 12 due to the occurrence of partial discharge. At the same time, the transmission electromagnetic wave propagates in the insulating layer 22. An electromagnetic wave of several tens kHz to several tens GHz is radiated into the space at the stator winding end 3 where the low-resistance paint 23 as the outer conductor is interrupted. Dozens of MH of this radiated electromagnetic wave
The components of the microwave band of z to several tens of GHz are
Fixing that is provided facing the end face and protrudes from the stator core
It is detected by the reflector antennas 14 and 15 in the microwave band having directivity with respect to the end of the slave winding .

Since the voltage generated in the stator winding 12 is highest at a portion electrically close to the output terminal, an abnormality of the stator winding 12 due to an electrical factor is more likely to occur near the output terminal. Since the antennas 14 and 15 are provided such that the stator winding end 3 closest to the output terminal is closest, the stator winding 12 having the highest probability of occurrence of partial discharge is provided.
The electromagnetic wave radiated from is detected with the highest sensitivity.

Further, since components in the microwave band of several tens of MHz to several tens of GHz are detected among the radiated electromagnetic waves, signals based on individual discharges are attenuated in a short time, and errors due to overlapping of a plurality of high-frequency signals. Is small. Further, the time resolution of detection can be greatly improved.

The detection signal S _1, S ₂ detected by the reflector antenna 15 is inputted to the amplifier circuit 25, the amplified signal only the frequency band noise less through the filter circuit 26 is taken out, the discharge detection calculation The signal is input to the circuit 27. The discharge detection calculation circuit 27 calculates a discharge charge amount. The output of the discharge detection arithmetic circuit is input to the abnormality determination circuit 28, which compares the output with the pre-registered data to determine the abnormality based on the amount of discharge charge and the frequency of occurrence, and displays the result on the display circuit 29.

In this embodiment, since a plurality of reflector antennas are arranged on the same circumference, the incident blind spot of the electromagnetic wave is eliminated, and the electromagnetic wave radiated from the stator winding end 3 closest to the position where the partial discharge occurs. Can be detected with high sensitivity with little attenuation. In addition, since the reflector antenna is attached to the stator frame 11, a sufficient insulation distance from the high-voltage stator winding 12 can be provided.
It is possible to constantly monitor and detect abnormalities even during operation without reducing the reliability of the rotating electric machine.

Although the abnormality detector 20 is installed outside the stator frame 11 in the embodiment, a part or all of the abnormality detector 20 is installed inside the stator frame 11 by reducing the size. Has the same effect.

In the embodiment, the discharge generated in all the stator windings 12 is detected by installing three reflector antennas. However, the discharge can be detected with higher sensitivity by increasing the number of the reflector antennas. Can be.

Second Embodiment In the first embodiment, the discharges generated in all the stator windings 12 are detected by optimizing the directivity of the reflector antennas 14 and 15. However, even when the movable device 30 is attached to the mounting portions of the reflector antennas 14 and 15 as shown in FIG. 4, a wide range of radiated electromagnetic waves is detected by changing the direction of the reflector antennas 14 and 15 by the movable device 30. be able to. According to this configuration, the directivity of the reflector antenna can be enhanced, and the discharge generated in all the stator windings 12 can be detected with higher sensitivity. There is an effect that the position of the abnormality can be specified.

[0025] In the above embodiments using a reflector antenna as an antenna for the microwave band but other than this aperture antenna, a microstrip array antenna, even with directivity of some other antennas such as Yagi similar It works.

Although the above embodiment has been described with reference to the case of a generator, it goes without saying that the same effect can be obtained with a rotating electric machine such as a water turbine generator or an induction motor.

[0027]

As described above, the abnormality detecting device for a rotating electric machine according to the present invention is radiated from the end of the stator winding near the end of the stator core by the partial discharge generated due to the abnormality of the stator winding. Of electromagnetic waves, which are arranged on the inner wall of the stator frame
With a microwave band antenna that has high sensitivity, detection is performed in a wider frequency band than before, so errors due to signal overlap are small, partial discharges are detected with high time resolution and high sensitivity, and the stator is detected. There is an effect that the abnormality of the winding can be constantly monitored. Further, since a sufficient insulation distance can be provided from the high-voltage stator winding to the antenna, the reliability of the rotating electric machine is not reduced.

[Brief description of the drawings]

FIG. 1 is a sectional configuration diagram showing an abnormality detection device for a rotating electric machine according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a reflector antenna installation position according to the first embodiment of the present invention.

FIG. 3 is a block diagram of an abnormality detector according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional configuration diagram illustrating an abnormality detection device for a rotating electric machine according to a second embodiment of the present invention;

FIG. 5 is a perspective explanatory view showing a conventional partial discharge detection device for electric equipment.

FIG. 6 is a block diagram of a conventional partial discharge detection device for electric equipment.

FIG. 7 is a characteristic diagram of a signal level propagating in a winding for each frequency band.

[Explanation of symbols]

 2 Stator core 10 Generator 11 Stator frame 12 Stator winding 14, 15 Reflector antenna 20 Abnormality detector

Continuation of the front page (56) References JP-A-56-162930 (JP, A) JP-A-62-145176 (JP, A) JP-A-2-27274 (JP, A) Japanese Utility Model Publication No. 55-51775 (JP) , U) Shokai Sho 61-98340 (JP, U) JP-B 5-58512 (JP, B2) JP-B 6-27764 (JP, B2) (58) Fields surveyed (Int. Cl. ⁶ , DB) G01R 31/12-31/20 G01R 31/02-31/07 G01R 31/34

Claims (1)

(57) [Claims] And a rotor disposed around the rotor.
Wound around the stator core and the slot groove of the stator core
And the rotor of the above rotor
At several positions on a plane perpendicular to the axis of rotation, the ends of the stator core
Surface which is disposed opposite to the surface and protrudes from the stator core.
Microwave band with directivity to the end of the stator winding
An antenna; and
Detects electromagnetic waves based on partial discharge generated due to abnormal wire
And detecting an abnormality of the stator winding .