Mechanism of monitoring unit of electric rotating machinery and monitoring method of electric rotating machinery

A mechanism of a monitoring unit of an electric rotating machinery covered in a housing that intercepts photoelectron transmission, the mechanism has: a monitoring window penetrating a part of the housing and configured to allow passage of photoelectrons and not to allow passage of gas; a camera arranged outside the monitoring window and configured to receive radiated photoelectron generated in the housing and passing through the monitoring window and to generate image data from the radiated photoelectron; and a computing unit configured to process the image data. The computing unit has reference image data storage means for storing image data resulting from blackbody radiation occurring in a reference state in the housing, as reference image data, and temperature calculating means for comparing the image data with the reference image data, thereby to calculate the temperature in the housing.

TECHNICAL FIELD

The present invention relates to mechanism and method of monitoring the temperature in the housing of electric rotating machinery, where the housing to which photoelectron is intercepted.

BACKGROUND TECHNOLOGY

Monitoring method of a temperature of winding of electric rotating machinery is evaluated from the resistance value of the winding of electric rotating machinery have hitherto known. There is a method of using the sensor as other methods, such as a temperature measuring resistor or a thermocouple, is arranged near the winding, thereby to measure the temperature.

The method of the insulation diagnosis of winding of electric rotating machinery measures the size and frequency of the partial discharge pulse generated are hitherto known. There is a method of detecting a partial discharge signal by using the static electric coupling of one specified phase and the other method is to detect a pulsating current signal by a high-frequency current transformer are known.

The method of detecting abnormal state of gas in the housing of electric rotating machinery is known. There is a method of extraction of gas in case, and measurement with macro analysis device.

The following three Patent Documents are known as disclosing spectroscopy analysis methods:

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

The method of evaluating the temperature from the resistance value of the winding can indeed evaluate the average temperature of the entire winding. However, the method cannot detect a local temperature change of the winding.

The method, in which a sensor, such as a temperature measuring resistor or a thermocouple, arranged near the winding, can detect a local temperature rise in the winding. In the method of measuring the temperature of neighborhood, abnormality in the measurement part can be detected. However other abnormalities cannot be detected by the method of measuring a part of temperature. If more temperature-measuring positions are provided, as many sensors as the positions must be provided. This will increase the cost.

The method of detecting a partial discharge signal by using the static electric coupling of one specified phase of the stator and the method of detecting a pulsating current signal by a high-frequency current transformer, it is difficult to detect it for the influence of turbulence.

The abnormal state cannot be in real-time detected by method of extraction of gas in the housing of electric rotating machinery and analysis with macro analyzer.

Furthermore, the conventional techniques need to use a sensor for detecting the temperature of electric rotating machinery, a sensor for detecting the partial discharge and a sensor for analyzing the gas in the housing.

The present invention has been made in consideration of the background technology described above. An object of the invention is to detect easily at least an abnormal temperature of electric rotating machinery.

Another object of the present invention is to detect easily the abnormality of partial discharge caused by deterioration of the insulation in electric rotating machinery, almost in real-time. A further object of the invention is to analyze easily the gas in the housing of electric rotating machinery. Still another object of the invention is to detect the above-mentioned various conditions of electric rotating machinery, by using a single device.

Means for Solving the Problems

This invention is used to solve the problem in the above-mentioned. According to an aspect of the present invention, a mechanism of monitoring in a housing of electric rotating machinery, where the housing to which photoelectron is intercepted, the mechanism comprising: a monitoring window penetrating a part of the housing and configured to allow passage of photoelectron and not to allow passage of gas; a camera arranged outside the monitoring window and configured to receive radiated photoelectron generated in the housing of electric rotating machinery and passing through the monitoring window and to generate image data from the radiated photoelectron; and a computing unit configured to process the image data, wherein the computing unit has reference image data storage means for storing image data resulting from blackbody radiation occurring in a reference state in the housing of electric rotating machinery, as reference image data, and temperature calculating means for comparing the image data with the reference image data, thereby to calculate the temperature in the housing of electric rotating machinery.

There is also provided, according to another aspect of the present invention, a monitoring method of an electric rotating machinery covered in a housing, where the housing to which photoelectron is intercepted, the method comprising: providing a monitoring window penetrating a part of the housing of electric rotating machinery and configured to allow passage of photoelectron and not to allow passage of gas; arranging a camera outside the monitoring window, the camera configured to receive radiated photoelectron generated in the housing and passing through the monitoring window and to generate image data from the radiated photoelectron; storing image data resulting from blackbody radiation occurring in a reference state in the housing of electric rotating machinery, as reference image data; and comparing the image data with the reference image data, thereby to calculate the temperature in the housing of electric rotating machinery.

EFFECT IN THE INVENTION

The present invention can easily detect at least an abnormal temperature of electric rotating machinery. Further more, if this invention is used, abnormality of partial discharge caused by deterioration of the insulation, if any, in electric rotating machinery can be easily detected almost in real time, the gas in the housing of electric rotating machinery can be easily analyzed, and the various conditions of electric rotating machinery can be detected by using a single device.

EXPLANATION OF REFERENCE SYMBOLS

4Winding end point

6Photoelectron processing unit

20First optical path

21Second optical path

22Third optical path

23First partial mirror

24Second partial mirror

27Heater power supply

30Surface-temperature measuring unit

51,52,53Junction protective covers

70,71: Image data

Best Mode Embodiment For Carrying Out The Invention

An embodiment of mechanism of monitoring unit and monitoring method of electric rotating machinery, both according to the present invention, will be described with reference to the accompanying drawings.

An embodiment of mechanism of monitoring unit and monitoring method of electric rotating machinery, according to this embodiment, will be described with reference toFIG. 1toFIG. 4.FIG. 1is one execution chart of monitoring unit in the housing of electric rotating machinery when this invention is used; longitudinal section model chart.FIG. 2is a block diagram showing the configuration of the photoelectron processing unit of the mechanism shown inFIG. 1and the configuration of the components peripheral to the photoelectron processing unit.FIG. 3is a diagram explaining the photoelectron processing unit and the image data about the components peripheral to the photoelectron processing unit.FIG. 4is a magnified, longitudinal sectional view of the auxiliary-member heater (attached heater) provided in the mechanism of monitoring unit of the electric rotating machinery.

The electric rotating machinery shown inFIG. 1is, for example, an electric motor. The electric rotating machinery comprises a housing (frame)1and a stator2. The stator2is arranged in the housing (frame)1. The housing1is made of, for example, steel, and covers the entire stator2. The housing1is configured to intercept photoelectrons. The housing1has an opening made in a part near the winding end point4of the stator2. In this opening, a monitoring window5is fitted, closing the opening. The monitoring window5is configured to allow the passage of photoelectrons, but not the passage of gas. The monitoring window5can remain intact even if an explosion occurs in the housing1.

A photoelectron processing unit6is provided outside the monitoring window5. The photoelectron processing unit6generates information, which is input to a camera7. The camera7generates image data. The image data is supplied from the camera7, in the form of a signal, through a cable8to a computing unit9. The computing unit9processes the signal.

As shown inFIG. 2andFIG. 3, the photoelectron processing unit6has a photomultiplier10, a first optical path20and a photoelectron distributor11. The photomultiplier10generates more photoelectrons than the photoelectrons it has received. The photoelectron distributor11receives photoelectrons from the photomultiplier10and distributes the electrons to a first optical path20, a second optical path21and a third optical path22. The photoelectron processing unit6further has a first photoelectron condenser12, a second photoelectron condenser13, a first spectrometer14, and a second spectrometer15. The first photoelectron condenser12condenses the photoelectrons coming through the first optical path20. The second photoelectron condenser13condenses the photoelectrons coming through the second optical path21. The first spectrometer14receives photoelectrons from the first photoelectron condenser12and splits the photoelectrons into beams of different wavelengths. The second spectrometer15receives photoelectrons from the second photoelectron condenser13and splits the photoelectrons into beams of different wavelengths.

The two photoelectron beams emerging from the first spectrometer14and second spectrometer15, respectively, are applied to a first spectroscopy-image camera7aand a second spectroscopy-image camera7b,respectively. The first spectroscopy-image camera7agenerates image data, and the second spectrometer7bgenerates image data. The photoelectron beam emerging from the photoelectron distributor11to the third optical path22is applied to a 2D-image camera7c,which generates image data. InFIG. 1, the cameras7aand7bare illustrated as one camera7.

The photoelectron distributor11is configured to distribute photoelectrons. The photoelectron distributor11incorporates a first partial mirror (half mirror)23and a second partial mirror24. The first partial mirror23is semitransparent (translucent) in its entirety, allowing passage of a part (not necessarily, exactly a half) of the incident photoelectrons and not allowing the passage of the remaining part of the incident photoelectrons. That part of the photoelectrons, which have passed through the first partial mirror23, enter the third optical path22. The remaining part of the photoelectrons are reflected by the first partial mirror23, are applied to the second partial mirror24. The second partial mirror24has an opening24ain the center part. A part of the photoelectrons applied to the second partial mirror24pass through the opening24aand then enter the second optical path21. The other part of the photoelectrons, which are applied to the peripheral part of the second partial mirror24, are reflected by the second partial mirror24and travel through the first optical path20.

As shown inFIG. 1, the electric rotating machinery further has an attached heater25. The attached heater25penetrates the housing1, secured to that part thereof which is near the monitoring window5.

As shown inFIG. 4, the attached heater25has an electric heater26, a heater power supply27, a heated object28, a surface-temperature sensor29, and a surface-temperature measuring unit30. The heater power supply27supplies electric power to the electric heater26. The electric heater26heats the heated object (auxiliary member)28. The surface-temperature sensor29is designed to detect the surface temperature of the heated object28. The heated object28is made of metal such as copper or aluminum. AsFIG. 1shows, the heated object28is so located that the camera7may photograph it through the monitoring window5.

The mechanism of the monitoring unit of the electric rotating machinery, which is so configured as described above, operates as will be described below.

It will be first explained how the mechanism operates while the attached heater25remains not driven. This is the case where the heater power supply27does not operate at all, or where the attached heater25is not provided at all.

Generally, the radiant light (i.e., electromagnetic wave) radiated from an object has an intensity that is a function of the surface temperature of the object. Hence, the temperature of the object can be estimated if the intensities of light beams emitting from various points in the surface of the object are compared with the intensities of light beams emitting from those points while the object has a reference temperature. The word “light” used here means not only visible light, but also electromagnetic waves such as infrared rays and ultraviolet rays.

Partial discharge may occur due to insufficient insulation of the stator winding of the electric rotating machinery. The partial discharge results in electromagnetic waves. Therefore, abnormality of partial discharge, if any, in electric rotating machinery can be detected from the electromagnetic waves generated in the electric rotating machinery.

Using this principle, in this embodiment, the electromagnetic waves emitting from the electric rotating machinery is detected, and the temperatures of various components are determined from the electromagnetic waves, thereby detecting the abnormality of partial discharge.

Assume that the camera7photographs the blackbody radiation from the winding end point4of the stator2of the electric rotating machinery, through the monitoring window5in the axial direction of the stator2. Then, such image data70as shown inFIG. 5are obtained. The radiation from the high-temperature part of the winding end point4of the stator2is intense. This means that the high-temperature part of the winding end point4is radiating intense light. From the image, which part of the electric rotating machinery emits intense light can therefore be determined. That part of the image, which is specified by an ellipse “A”, emits an electromagnetic wave far stronger than the wave emitting from the other winding end point of the stator. This shows that corona discharge may be taking place at the high-temperature part, due to insufficient insulation at that part. Thus, such abnormality can be easily determined by comparing the image data with the reference image data acquired in normal state and saved in a storage device. The image data is acquired through the third optical path22shown inFIG. 3.

Of the image data70shown inFIG. 5, the part specified by an ellipse “B”, for example, are supposed to radiate an intense electromagnetic wave and therefore to have high temperature. The temperature of this part is determined from the intensity of the electromagnetic wave. In this case, the light traveling through the first optical path20is condensed by the first photoelectron condenser12, and the first spectrometer14splits the light into electromagnetic wave components of different wavelengths. One or some of these wave components are selected. Preferably, the selected wave or each selected wave component is compared with the reference wave component of the same wavelength, which has been generated at a reference temperature.

FIG. 6shows a wavelength distribution curve33for the number of photoelectrons generated through radiation at the reference temperature of, for example, 20 degrees centigrade, and a wavelength distribution34for the number of photoelectrons generated through radiation at the temperature N degrees centigrade measured. If N>20, more photoelectrons are generated through the radiation at the temperature N degrees centigrade than through the radiation at the reference temperature (20 degrees centigrade), as seen fromFIG. 6. Let F1denote a difference in terms of the number of photoelectrons, for a wavelength L1, and F2denote a difference in terms of the number of photoelectrons, for another wavelength L2. F1and F2have positive values if the temperature N degrees centigrade is higher than the reference temperature.

The relation between the difference F1for wavelength L1and the difference between the measured temperature and the reference temperature can be illustrated as, for example, the solid line35shown inFIG. 7. Similarly, the relation between the difference F2for wavelength L2and the difference between the measured temperature and the reference temperature can be illustrated as, for example, the broken line36shown inFIG. 7. As seen from the solid line35and the broken line36, the difference of both the number of photoelectrons at the reference temperature (20 degrees centigrade) are, of course, zero.

At the reference temperature and various temperatures measured, respectively, the numbers of photoelectrons resulting from the radiation can be measured, preparing bothFIG. 6andFIG. 7, and the data representingFIGS. 6 and 7may be stored in the storage device. When the temperature of the electric rotating machinery is measured actually, the number of photoelectrons may be first determined and the temperature may then be estimated from the number of photoelectrons, based on the relations shown inFIG. 7. In this case, the temperature can indeed be estimated from the number of photoelectrons for one wavelength. Instead, the temperatures may first be estimated from the data items about various wavelengths and the temperatures thus estimated may then be compared, thereby making the data more reliable. Alternatively, the temperatures estimated from the data items may be averaged, thereby rendering the data more reliable.

How the attached heater (auxiliary-member heating unit)25operates in the mechanism of monitoring the electric rotating machinery will be explained. The attached heater25cooperates with some other components of the mechanism, such as the photoelectron processing unit6and the camera7, to detect the abnormal gas generation in the housing1of the electric rotating machinery and to determine the concentration of the gas generated in the housing1.

The heated object (auxiliary member)28is attached to the electric heater26inserted in the housing1. The heater power supply27supplies power to the electric heater26on and off, whereby the heated object28is alternately heated and cooled, repeatedly. While the heated object28is being cooled, the gas in the housing1is applied to the surface of the heated object28, forming a layer of gas material. When the heated object28is then heated, the gas-material layer is gasified. At this point, an electromagnetic wave emits from the heated object28. This electromagnetic wave is analyzed, detecting the composition and concentration of the gas in the housing1.

FIG. 8is a timing chart explaining how the attached heater25is intermittently driven in an example of the measuring step. As shown inFIG. 8, the heated object28is repeatedly heated on and off, each time for 10 minutes, heated for five minutes and then cooled for five minutes. While the heated object28is being heated, data about photoelectrons is acquired.

FIG. 9is a diagram showing image data71of photoelectrons input to the photoelectron processing unit6every time the heated object28is heated on as shown inFIG. 8. InFIG. 9, ellipse B specifies a part that emits an electromagnetic wave corresponding to the heat emitting from the winding end point4of the stator2of the electric rotating machinery, and ellipse A specifies a part that emits an electromagnetic wave due to abnormal discharge, as in the case ofFIG. 5. InFIG. 9, ellipse “C” specifies a part that emits an electromagnetic wave, too. This part radiates an electromagnetic wave that corresponds to the heat radiating from the heated object28.

FIG. 10is a graph representing the relation between the number of photoelectrons and the wavelength, both pertaining to the electromagnetic wave emitting from part C inFIG. 9, i.e., heated object28. This distribution curve consists of a distribution curve40that is as gentle as the distribution curve shown inFIG. 6, and a peaks14at some wavelengths. The gentle distribution curve40is a distribution curve for a specific temperature, or similar to the curves shown inFIG. 6.

On the other hand, the peaks41result from the radiations that correspond to the materials attached to, heated on and emitted from the surface of the heated object28. The wavelengths at which the peaks41are observed (i.e., specific leak wavelengths) pertain to the kinds of gases. Hence, the gases can be identified with the wavelengths at which the peaks41are observed.

The heights of the peaks41may be measured. From the heights of peaks41, the concentrations of gas components in the housing1can be determined.

FIG. 11is a graph showing the difference between the data shown inFIG. 10with the data inherent to the reference temperature, in terms of the number of photoelectrons and wavelength. In the case shown inFIG. 11, the number of photoelectrons sharply increases at three wavelengths Q1, Q2and Q3. This graph may be compared with the data specific to the reference temperature, thereby to determine the numbers D1, D2and D3of photoelectrons which are specific to wavelengths Q1, Q2and Q3, respectively. Increases in the photoelectrons which are specific to various known gas concentrations corresponding to wavelengths Q1, Q2and Q3are then measured, and such relations between the gas concentrations and the photoelectron numbers as shown inFIG. 12(i.e., calibration curves) are obtained to store the data. Then, the number of photoelectrons actually resulting from the electromagnetic wave generated in the electric rotating machinery is measured and compared with each of the calibration curves. Thus, the number of photoelectrons can be converted to the gas concentration that corresponds to a specific wavelength.

In the configuration described above, the electric heater26and the heated object28are two different members. Nonetheless, the heated object28may be an electrical resistor. If this is the case, the electric heater26and the heated object28can be integrated into one member.

If an abnormal temperature of the electric rotating machinery, abnormal discharge, or abnormal as generation in the housing is detected as described above, an alarm may be generated.

FIG. 13illustrates a modification of the configuration for securing the photoelectron processing unit6to the monitoring window5in the mechanism of the monitoring unit of the electric rotating machinery, which is shown inFIG. 1. As shown inFIG. 13, the photoelectron processing unit6is obliquely secured to the monitoring window5. In this case, a holder50is attached to the housing1or the monitoring window5, preventing photoelectrons from leaking at the junction between the unit6and the window5. In the case ofFIG. 14, not only the photoelectron processing unit6is obliquely secured to the monitoring window5, but also a junction protective cover51surrounds the junction between the window5and the unit6and the junction between the unit6and the camera7.FIG. 15shows a modification of the configuration ofFIG. 14. AsFIG. 15shows, two junction protective covers52and53are used. The cover52covers the junction between the monitoring window5and the photoelectron processing unit6, while the cover53covers the junction between the photoelectron processing unit6and the camera7. Still another modification is to fill the gap with putty or to solder the junction, instead of using a junction protective cover or covers.

FIG. 16shows a signal path extending between the camera7and the computing unit9, which differs from those shown inFIG. 1andFIG. 13. In this instance, a transmitter60and a receiver61are arranged at the camera7and the computing unit9, respectively, and a transmission path62connects the transmitter60and the receiver61. The transmission path62may be replaced by radio transmission.