JP4690428B2 - Device for detecting partial discharge intensity of conductive device - Google Patents

Description

  The present invention relates to a partial discharge generation position detection device for a conductive device such as a gas insulated switchgear or a power cable, and particularly to a partial discharge generation of a conductive device that can accurately know the position in the direction intersecting the length direction of the cylindrical body. The present invention relates to a position detection device.

  As a partial discharge detection device for gas insulation equipment, which is a conventional conductive device, it detects anomalies from the characteristics of the frequency spectrum of partial discharge. For example, it measures or compares the spectral widths of multiple spectral intensity peaks that appear in the frequency spectrum. Some of them attempt to diagnose abnormal causes such as contact failure, electrical float, spacer cracks and voids, and metal wires (see, for example, Patent Document 1).

JP-A-5-12350

  The conventional partial discharge detection apparatus is as described above. However, in this method, it has not been possible to know exactly where the partial discharge is generated in the radial direction. Depending on the position of the abnormal radial direction, there is a thing that requires immediate inspection, and there are some that are not harmful if left unattended for a while, so a device that can accurately determine the abnormal position in the radial direction is desired. Yes.

  That is, for example, when considering the entry of foreign matter into a tank that is a cylindrical body of a gas insulated switchgear (hereinafter referred to as GIS), even if the same shape of foreign matter is on the tank side, the steps of standing up → floating → destruction are taken. On the other hand, if it is on the internal high-voltage conductor side, it may lead to destruction immediately. Therefore, knowing the position of the foreign material in the radial direction is important for insulation diagnosis.

  An object of the present invention is to solve the above-described problems, and a cylindrical body formed of a conductive material and a conductor accommodated in the cylindrical body and extended in the length direction of the cylindrical body The partial discharge generated in the cylindrical body in the conductive device having the above is generated at which position in the direction intersecting the longitudinal direction of the cylindrical body, that is, in the radial direction if the cylindrical body is cylindrical. The object is to obtain a partial discharge occurrence position detection device for a conductive device that can know at which position it has occurred. Furthermore, it aims at obtaining the partial discharge intensity | strength detection apparatus which can know the intensity | strength of partial discharge.

  In the partial discharge strong detection device for a conductive device of the present invention according to the present invention, a cylindrical body made of a conductive material and a conductor accommodated in the cylindrical body and extended in the length direction of the cylindrical body. The TE21 mode intensity of electromagnetic waves generated in the cylindrical body of the conductive device is obtained and used as an index of partial discharge intensity.

  The present invention relates to an electromagnetic wave generated in a cylindrical body in a conductive device having a cylindrical body formed of a conductive material and a conductor accommodated in the cylindrical body and extended in the length direction of the cylindrical body. Since the TE21 mode intensity is obtained and used as an indicator of the partial discharge intensity, the TE21 mode hardly depends on the position in the direction intersecting the longitudinal direction of the cylindrical body, so that the discharge is detected by detecting this mode. Accurate measurement of intensity is possible.

  An internal abnormality of a conductive device such as a gas insulation device can be diagnosed by detecting a frequency spectrum of the partial discharge that occurs. Since the phase separation bus GIS has a cylindrical coaxial structure, it can be regarded as a coaxial waveguide with respect to propagation of electromagnetic waves. There are basically three types of electromagnetic wave modes propagating in the coaxial waveguide: a TEM mode (transverse electro-magnetic mode), a TEmn mode, and a TMmn mode. Here, in the TEmn mode (transverse electric mode), m and n are integers of 1 or more. In the TMmn mode (transverse magnetic mode), m is an integer of 0 or more, and n is an integer of 1 or more. Each electromagnetic wave mode has a unique electromagnetic field distribution.

  1 to 4 are characteristic diagrams showing an example of an electric field distribution in each mode. FIG. 1 shows the characteristics of the TEM mode and the TEm1 mode, and FIG. 2 shows the radial distribution of the radial electric field component of the TMm1 mode. FIG. 3 is a characteristic diagram showing the radial component of the electric field of the TE11 mode and the TM01 mode, and FIG. 4 is a frequency distribution diagram of each mode.

  As is well known, the TEM mode shows an electric field distribution that is inversely proportional to the distance from the coaxial center. Therefore, as shown in FIG. 1, the electric field intensity and the radial position correspond one-to-one. When the discharge generation source is on the tank side, the electromagnetic wave radiated from the discharge generation source is weakly coupled to the internal high-voltage conductor as compared to when the discharge generation source is on the internal high-voltage conductor side. Since two conductors are required to generate the TEM mode electromagnetic wave, the TEM mode electromagnetic wave is less coupled with the internal high voltage conductor when discharged on the tank side than when discharged on the internal high voltage conductor side. Is less likely to occur.

  On the other hand, as shown in FIG. 2, the TMm1 mode has a position where the strength is minimal between the center conductor and the tank bottom surface, and the electric field strength and the radial position do not correspond one-to-one. Although not shown in the figure, among the TEmn and TMmn modes where n is 2 or more, there is a position where the strength is minimal between the central conductor and the tank, and the electric field strength and the radial position are Does not correspond one to one.

  By the way, the partial discharge power supply is accidentally present at a certain position in the tank of the GIS. For example, the central conductor surface, the tank bottom surface, the spacer surface, and the like are possible. When discharge occurs in those discharge sources, electromagnetic waves are excited. As described above, each electromagnetic wave mode is excited by the energy of discharge in the coaxial structure container like GIS. The intensity of each excited electromagnetic wave mode depends on the magnitude of the discharge and the position of the discharge source.

  In general, if the intensity of the excitation source, that is, the intensity of the discharge is the same, the mode is strongly excited when excited in a place where the electric field is high in the electric field intensity distribution specific to the mode. That is, the electric field distribution of each mode shown in FIGS. 1 and 2 shows the dependency of the electromagnetic wave intensity of each mode on the discharge source position. Therefore, for example, in the case of the TE11 mode, it is shown that the presence of the discharge source on the bottom surface of the tank is more strongly excited when it exists on the center conductor side. On the other hand, regarding the TE31 mode, it is shown that the one existing on the bottom side of the tank is strongly excited.

Therefore, the radial position of the discharge source can be known by using the intensity of the TEM mode and the TEm1 mode among the TEM, TEmn, and TMmn modes generated by the partial discharge.
As shown in FIG. 2, in the TM mode, the electric field distribution has a minimum value between the center conductor surface and the tank bottom surface, and the radial position and the mode intensity do not correspond one-to-one. Although not shown, even in the case of the TEmn mode where n is 2 or more, the intensity of the mode and the position in the radial direction may not always correspond to each other as in the TM mode. Therefore, it is not appropriate to use the TM mode as a single indicator. However, as shown in the characteristic diagram of FIG. 3, the value is smaller than that of the TEM mode or the TE11 mode, so even if they are mixed in the TEM mode, the TE11 mode, or the like, the influence is not so much.

  By the way, the magnitude of discharge varies depending on the type of discharge and the electric field around the discharge source determined by the applied voltage. That is, it is impossible to know whether the difference in the magnitude of the discharge is reflected or the difference in the radial position of the partial discharge is reflected only by the difference in the intensity of the specific electromagnetic wave mode. Therefore, it is difficult to identify the radial position of the discharge source with only the intensity of a specific mode.

The magnitude of the discharge changes each time it occurs, but if the influence of the magnitude of the discharge can be eliminated by some method, it does not depend on the magnitude of the discharge, but only on the radial direction. The difference in the intensity of the electromagnetic wave mode should reflect the difference in the radial position of the partial discharge. Then, the position of the discharge source in the radial direction can be known by detecting the strength of any electromagnetic wave mode of the TEM mode and the TEm1 mode.
The present invention has been made on the basis of the above idea, and several embodiments will be described below.

Embodiment 1 FIG.
Hereinafter, an embodiment of the present invention will be specifically described with reference to FIGS. FIG. 5 is a block diagram showing the configuration of the conductive foreign matter and partial discharge detection device mixed in the GIS tank, which is a cylindrical body, and FIG. 6 is a flowchart showing the operation of the detection device. FIG. 7 is a spectrum diagram showing the frequency spectrum of the electromagnetic wave generated when the partial discharge is generated on the internal high-voltage conductor side, and FIG. 8 is a spectrum diagram showing the frequency spectrum of the electromagnetic wave generated when the partial discharge is generated on the tank side. FIG. 9 is a characteristic diagram showing a detection result of the detection device, and FIG. 10 is a characteristic diagram showing a time change of the detection result.

  By the way, the frequency ranges of the TEM, TE, and TM modes described above have a relationship as shown in the frequency distribution diagram of FIG. For example, the electromagnetic wave in the TE11 mode does not exist in an area below a predetermined frequency fcTE11. That is, each electromagnetic wave mode has a cutoff frequency fc. The cut-off frequency fc is a frequency at which a certain electromagnetic wave mode exists only at or above that frequency.

This cutoff frequency fc can be theoretically calculated in the case of a coaxial cylindrical structure such as GIS. The cutoff frequency fc is determined by the shape of the GIS 10 that functions as a waveguide. When the outer diameter of the internal high-voltage conductor 12 is x and the inner diameter of the tank 11 is y, the cutoff frequency of the TEm1 mode is approximately the following ( 1) Formula fc = 2c · m / π (x + y) where c: speed of light (1)
Given in. For example, if the outer diameter x of the internal high voltage conductor 12 is 130 mm and the inner diameter y of the tank 11 is 550 mm, the cutoff frequency fcTE11 in the TE11 mode is about 281 MHz. However, strictly, it can be obtained by numerical analysis based on the boundary condition of the electromagnetic field.

In some cases, the electromagnetic wave mode can be specified from the cutoff frequency fc. For example, since only the TEM mode can exist at the cutoff frequency fcTE11 or less in the TE11 mode, it can be determined that the spectrum intensity below the fcTE11 is that in the TEM mode.
Therefore, if the strength of a component at a predetermined frequency smaller than the cutoff frequency fcTE11 is obtained, that is the strength of the TEM mode. In order to eliminate the influence of the discharge intensity, normalization is performed by obtaining a ratio between the intensity of the TEM mode and the intensity of TE or TM mode other than the TEM mode. The intensity of the normalized electric field component in the TEM mode and the position d in the radial direction of discharge generation have a one-to-one correspondence. Therefore, from the intensity of the normalized TEM mode, the radial direction of the discharge Can be known.

  In FIG. 5, a GIS 10 as a conductive device is configured as follows, and a detection device 20 of the present invention is provided. An internal high-voltage conductor 12 having a hollow circular cross section is provided at the center of the cylindrical tank 11 so as to be coaxial with the tank 11. The internal high voltage conductor 12 is supported and fixed by a cone-shaped insulating spacer 13 provided at a predetermined interval in the length direction of the tank 11. Further, the inside of the tank 11, that is, the periphery of the internal high-voltage conductor 12, is filled with sulfur hexafluoride gas (hereinafter referred to as SF 6 gas) that is an insulating medium.

  As an abnormal state inside the tank 11, an internal high voltage conductor fixing needle 15 standing and fixed on the surface of the internal high voltage conductor 12, a tank fixing needle 16 standing and fixed on the inner wall surface of the tank 12, and an unfixed free Consider a case in which the foreign matter 17 is a discharge generation source.

  The detection device 20 is configured as follows. An electromagnetic wave detector 21 is installed in the tank 11. When a partial discharge occurs inside the tank 11, an electromagnetic wave is generated. This electromagnetic wave is detected by the electromagnetic wave detector 21, and the detected signal is amplified by the amplifier 22 and taken into the fast Fourier transform device 23. The electromagnetic wave detector 21 is a flat antenna formed flush with the inner surface of the tank 11.

  Then, a fast Fourier transform is performed by the fast Fourier transform device 23 to obtain a frequency spectrum. Further, by the extractor 25, the magnitude A1 (dBV) of the component of the first frequency f1 less than the cutoff frequency fcTE11 in the TE11 mode and the second frequency f2 greater than or equal to the cutoff frequency fcTE11 in the TE11 mode are included in this frequency spectrum. Extract component magnitude A2 (dBV).

The ratio U = A1 / A2 is obtained by the divider 26. The determination device 27 determines whether the foreign object is a fixed foreign object or a free foreign object based on the size of the ratio U and whether there is a change over time. calculate. The display device 28 displays the character information of the determination result of the determination device 27 and the value of the ratio U. Details will be described later.
The fast Fourier transform device 23, the extractor 25, and the divider 26 in FIG. 5 are normalization means in the present invention.

  The first and second frequencies f1 and f2 are selected from a region having a frequency lower than the cut-off frequency fcTE11 in the TE11 mode and a region having fcTE11 or higher. Then, only the TEM mode wave is included in the first frequency f1. As described above, for example, when the outer diameter x of the internal high-voltage conductor 12 is 130 mm and the inner diameter y of the tank 11 is 550 mm, the cutoff frequency fcTE11 in the TE11 mode is about 281 MHz.

  For example, f1 = 80 MHz and f2 = 1 GHz are selected. When selected in this way, the difference in magnitude between the component of the first frequency f1 and the component of the second frequency f2 reflects the difference between the TEM wave and the TE wave contained in the electromagnetic wave. The ratio of the TEM wave contained in the electromagnetic wave differs depending on whether the discharge generation source is on the internal high-voltage conductor 12 side or the tank 11 side.

  Next, the operation will be described with reference to the flowchart of FIG. In the tank 11, one of the above-mentioned various high-voltage conductor fixing needles 15, the tank fixing needle 16, and the free foreign material 17 as a discharge source is attached and a voltage is applied. In step S11, the electromagnetic wave generated by the partial discharge at that time is detected by the electromagnetic wave detector 21, and in step S12, the signal from the electromagnetic wave detector 21 is amplified by the amplifier 22.

  In step S13, the amplified signal is taken into the fast Fourier transform device 23, the waveform is subjected to fast Fourier transform, and a frequency spectrum is obtained. FIG. 7 shows a frequency spectrum when the discharge source is the internal high-voltage conductor fixing needle 15 (see FIG. 5), and FIG. 8 shows a frequency spectrum when the discharge generating source is the tank fixing needle 16 (see FIG. 5). 7 and 8, the horizontal axis represents the frequency (Hz), and the vertical axis represents the amplitude Ampli (dBV).

  Focusing on the component of the TE11 mode below the cut-off frequency fcTE11, FIG. 7 in which the discharge generation source is the internal high-voltage conductor fixed needle 15 is considerably more than FIG. 8 in which the discharge generation source is the tank fixed needle 16. It is getting bigger.

  In step S14, component sizes A1 and A2 at, for example, f1 = 80 MHz and f2 = 1 GHz are extracted from the frequency spectrum obtained by the fast Fourier transform device 23 by the extractor 25.

  In step S15, the divider U calculates the ratio U = A1 / A2. As described above, since the first frequency f1 includes only the TEM mode wave, the ratio U = A1 / A2 reflects the ratio of the TEM wave included in the electromagnetic wave. Note that the ratio U is obtained and the value of the component A1 of the first frequency f1 is normalized by the component A2 of the second frequency f2, even if the discharge source is in the same place, each time A1 or A2 occurs. Although the size changes, the ratio of the TEM wave contained in the discharge electromagnetic wave hardly changes if the discharge source is in the same place. Therefore, the influence of the change in the discharge size can be eliminated by normalization. Because.

  In step S <b> 16, the determination device 27 determines whether the ratio U has changed over time. If there is a time change, it is determined in step S17 that this discharge is caused by free foreign matter, and "partial discharge occurrence, free foreign matter" is displayed on the display device 28 in step S18. In the case of a free foreign object, it goes back and forth between the internal high-voltage conductor 12 and the tank 11, that is, it moves in the radial direction, and the ratio U increases and decreases with time. In this case, it can be said that it is a signal of an electromagnetic wave generated by partial discharge due to free foreign matter.

  If the ratio U does not change with time in step S16 and is constant, it is determined in step S19 that the discharge source has not moved in the radial direction, that is, is a fixed foreign object.

  In the determination of step S16, when the discharge source is a fixed foreign substance and is in the vicinity of the internal high-voltage conductor 12, the predetermined value U1 as in the characteristic E of FIG. A small predetermined value U2 is shown and does not change with time. Further, if it is a free foreign matter, it changes between the predetermined value U1 and the predetermined value U2 in terms of time as in the characteristic G. Therefore, it is possible to determine whether the foreign object is a fixed foreign object or a free foreign object. In FIG. 10, the horizontal axis represents time t (ms), and the vertical axis represents the size of U.

  In step S20, the position of partial discharge is obtained. The ratio U varies in magnitude depending on whether the discharge generation source is on the internal high-voltage conductor 12 side or the tank 11 side. FIG. 9 shows a curve D in which the horizontal axis represents the distance d from the internal high-voltage conductor 12 of the discharge generation source, and the vertical axis represents the value of the ratio U.

  This curve D can be assumed in advance according to the dimensions of the GIS, and the ratio U = U1 when the discharge generation source is in the vicinity of the internal high-voltage conductor 12, and the ratio U = U2 when near the tank 11. It can be seen that the position of the partial discharge is closer to the internal high-voltage conductor 12 as the value of the ratio U is larger. That is, it is possible to know the position in the radial direction of the discharge source, that is, the direction intersecting the length direction of the tank 11.

Therefore, in step S20, the determination device 27 obtains the radial position of the discharge source in the tank 11 based on the data table corresponding to the curve D in FIG.
For example, in the case of U = U1, it can be seen that partial discharge has occurred in the vicinity of the internal high-voltage conductor 12.

  In step S21, “partial discharge occurrence, fixed foreign matter” is displayed on the display device 28, and the radial position in the tank 11 of the discharge generation source obtained by the determination device 27 in step S20 is, for example, “internal high-voltage conductor side”. indicate. In addition, the curve D of FIG. 9 is displayed based on the data table, and the value of the ratio U = U1 is displayed as a point H thereon. Further, the time change of the ratio U is displayed with the time axis as the horizontal axis in the same manner as the characteristics E, F, and G in FIG.

  The display device 28 displays the ratio U = U1 as a point H on a curve D in which U = A1 / A2 is plotted in advance corresponding to the distance from the internal high voltage conductor 12 to the discharge generation position as shown in FIG. Thus, it is possible to visually grasp the position of occurrence of partial discharge due to foreign matter.

Embodiment 2. FIG.
FIGS. 11-14 show other embodiments of the present invention. FIG. 11 shows the frequency spectrum of electromagnetic waves generated when partial discharge occurs on the internal high-voltage conductor side, and FIG. 12 shows partial discharge. It is a spectrum figure which shows the frequency spectrum of the electromagnetic waves which generate | occur | produce when it generate | occur | produces on the tank side. FIG. 13 is a characteristic diagram showing the dependence of the spectral intensity at 650 MHz on the angle between the sensor and the discharge source, and FIG. 14 is a characteristic diagram showing the angular dependence of the sensor on the spectral intensity at 785 MHz and the discharge source.

  As described above, in the embodiment of FIG. 5, the cutoff frequency fcTE11 in the TE11 mode is 281 MHz, the first frequency f1 is selected to be 80 MHz, and the second frequency f2 is selected to be 1 GHz. Therefore, the strength of the component at the first frequency f1 is the strength of the electromagnetic wave in the TEM mode, and the strength of the component at the second frequency f2 is a mixture of electromagnetic waves of the TEM, TE, and TM modes as shown in FIG. It may be the strength of things.

  As shown in FIG. 2 or FIG. 3, the TM mode has a minimum electric field distribution between the center conductor surface and the tank bottom surface (inner surface), and the radial position and mode intensity have a one-to-one correspondence. do not do. For this reason, it is possible to specify the radial position of the occurrence of discharge more sensitively by using a mode that does not include the TM mode, for example, the strength of only the TEm1 mode. This will be specifically described below.

The inspection device 20 is the same as that shown in FIG. However, in this embodiment, the frequency component extracted by the extractor 25 is different from that shown in FIG.
That is, the fast Fourier transform is performed by the fast Fourier transform device 23, and the component size A1 (dBV) of the TE21 mode which is the first mode and the TE31 which is the second mode are extracted from the obtained frequency spectrum by the extractor 25. The mode component magnitude A2 (dBV) is extracted. A method for detecting the frequency in the TE21 and TE31 modes will be described later.

  The ratio U = A1 / A2 is obtained by the divider 26. The determination device 27 determines whether the foreign object is a fixed foreign object or a free foreign object based on the magnitude of the ratio U and whether there is a change in time. In the case of a fixed foreign object, the radial position in the tank 11 is the same as the curve D in FIG. Calculate based on the curve. The display device 28 displays the character information of the determination result of the determination device 27 and the value of the ratio U.

  Here, in order to realize the present embodiment, it is necessary to know in advance at which frequency the electromagnetic waves of the TE21 mode and TE31 mode to be detected can be detected. The frequency indicating the intensity of each mode can be obtained as follows. That is, it is known that an electromagnetic wave in TEmn mode theoretically has a periodicity of sin (mθ) or cos (mθ) in the tank circumferential rotation direction. Here, θ is the rotation angle of the discharge source and the sensor in the tank circumferential direction. That is, when the sensor is moved in the tank circumferential direction, the intensity has a periodicity of sin (mθ) or cos (mθ).

  Therefore, when the circumferential direction dependency of a specific frequency component is measured and the period of the intensity is π / m, the frequency can be determined as the TEmn mode. In this way, it is possible to know which electromagnetic wave mode is a specific frequency peak. Therefore, the frequency of each mode in the GIS can be known by measuring the angle dependency between the sensor and the discharge source at the factory test or at the place of installation of the GIS using a simulated discharge source.

  Now, how to obtain the relationship between the electromagnetic wave mode and the frequency will be specifically described. FIG. 11 shows a frequency spectrum measured by installing a simulated discharge source on the central conductor, and FIG. 12 shows a frequency spectrum measured by installing on the bottom side of the tank. In the figure, the cutoff frequencies of the modes TE11, TE21, TE31, TE41, TE12, TE22, TM01, TM11, and TM21 calculated theoretically are also entered.

  FIGS. 13 and 14 show characteristics when the angular positions of the sensor and the discharge source are relatively changed with respect to the intensities at the frequencies f1 and f2 on the frequency spectrum shown in FIG. It can be seen that there are four peaks for the frequency f1, and six peaks for the frequency f2. Therefore, as described above, it can be seen that the frequency f1 is a spectrum peak of the TE21 mode and the frequency f2 is a spectrum peak of the TE31 mode. Thus, the mode of each frequency peak can be known by measuring the circumferential position dependence of the spectrum peak intensity.

  From the above, in the present embodiment, for example, f1 = 650 MHz that is the TE21 mode is selected as the first frequency, and f2 = 785 MHz that is the TE31 mode is selected as the second frequency. When these frequencies are selected, the difference in magnitude between the first frequency f1 component and the second frequency f2 component is the difference between the TE21 mode and the TE31 mode included in the electromagnetic wave.

  Next, the operation will be described with reference to the flowchart of FIG. In the tank 11, one of the above-mentioned various high-voltage conductor fixing needles 15, the tank fixing needle 16, and the free foreign material 17 as a discharge source is attached and a voltage is applied. In step S11, the electromagnetic wave generated by the partial discharge at that time is detected by the electromagnetic wave detector 21, and in step S12, the signal from the electromagnetic wave detector 21 is amplified by the amplifier 22.

  In step S13, the amplified signal is taken into the fast Fourier transform device 23, the waveform is subjected to fast Fourier transform, and a frequency spectrum is obtained. FIG. 11 shows the frequency spectrum when the discharge source is the internal high-voltage conductor fixed needle 15, and FIG. 12 shows the frequency spectrum when the discharge fixed source is the tank fixed needle 16. In FIGS. 11 and 12, the horizontal axis represents the frequency (Hz), and the vertical axis represents the amplitude Ampli (dBV). Focusing on the TE21 mode component, that is, the intensity of the frequency f1, there is little change between the case where the discharge generation source is the internal high-voltage conductor fixed needle and the tank fixed needle 16. Looking at the TE31 mode, that is, the strength at the frequency f2, the installed tank fixing needle has a higher strength.

  In step S 14, component sizes A 1 and A 2 at f 1 = 650 MHz and f 2 = 785 MHz are extracted by the extractor 25 from the frequency spectrum obtained by the fast Fourier transform device 23.

  In step S15, the divider U calculates the ratio U = A1 / A2. As described above, since the first frequency f1 includes only the TE21 mode and the second frequency f2 is selected to include only the TE31 mode, the ratio U = A1 / A2 is TE21 included in the electromagnetic wave. It becomes the ratio of wave and TE31 wave. The ratio U of the value of the component A1 of the first frequency f1 is obtained from the component A2 of the second frequency f2. The magnitude of A1 and A2 changes each time a discharge occurs. This is because the influence can be eliminated.

  In step S19, the determination device 27 determines whether or not the ratio U has changed with time. If there is a time change, it is determined in step S20 that this discharge is caused by free foreign matter, and “partial discharge occurrence, free foreign matter” is displayed on the display device 28 in step S21. In the case of a free foreign object, it goes back and forth between the internal high-voltage conductor 12 and the tank 11, that is, it moves in the radial direction, and the ratio U increases and decreases with time. In this case, it can be said that it is the spectrum of the electromagnetic wave generated by the partial discharge by the free foreign matter.

  When the ratio U does not change with time in step S19 and is constant, it is determined in step S21 that the discharge source has not moved in the radial direction, that is, is a fixed foreign object.

  In the determination of step S19, when the discharge source is a fixed foreign object and is in the vicinity of the internal high-voltage conductor 12, the predetermined value U3 is indicated, and when the discharge source is in the vicinity of the tank 11, the predetermined value U4 that is smaller than U3 is indicated as in the characteristic F Does not change. Moreover, if it is a free foreign material, it will change between predetermined value U3 and predetermined value U4 temporally. Therefore, it is possible to determine whether the foreign object is a fixed foreign object or a free foreign object.

  In step S20, the position of partial discharge is obtained. The ratio U varies in magnitude depending on whether the discharge generation source is on the internal high-voltage conductor 12 side or the tank 11 side. Accordingly, a curve in which the horizontal axis similar to the curve D in FIG. 9 is plotted with the distance d from the internal high-voltage conductor 12 of the discharge source and the value of the ratio U plotted on the vertical axis is obtained in advance.

  This curve is determined in advance by the dimensions of the GIS, and the ratio U = U3 when the discharge generation source is in the vicinity of the internal high-voltage conductor 12, and the ratio U = U4 when near the tank 11. It can be seen that the position of the partial discharge is closer to the internal high-voltage conductor 12 as the value of the ratio U is larger. That is, the radial position of the discharge generation source can be known.

  Accordingly, in step S20, the determination device 27 obtains the radial position of the discharge source in the tank 11 based on the data table indicating the relationship between the ratio U and the distance d. For example, in the case of U = U3, it can be seen that partial discharge is generated in the vicinity of the internal high-voltage conductor 12.

  In the above embodiment, the radial position of the discharge source can be estimated using the intensity ratio U = A1 (TE21) / A2 (TE31) of the TE21 mode as the first mode and the TE31 mode as the second mode. Even if the TEM mode is used as the first mode, the intensity ratio U = A1 (TEM) / A2 (TE21) or U = A1 (TEM) / A2 (TE31) may be used for estimation.

  Using the TEM mode as the first mode has the following effects. The minimum cutoff frequency of the TEM mode is the cutoff frequency of the TE11 mode, and this frequency can be calculated theoretically as described above. Since only the TEM mode exists at a frequency equal to or lower than the cutoff frequency of the TE11 mode, the frequency of the TEM mode can be specified without experimentally measuring the circumferential position dependency. Therefore, by setting the TEM mode to the first detection frequency, the procedure for obtaining the ratio between modes becomes easy.

Embodiment 3 FIG.
FIG. 15 is a block diagram of a detection device showing still another embodiment of the present invention. In this embodiment, the detection device 20a is the same as the detection device 20 of FIG. 5 except for the electromagnetic wave detector 21a. An electromagnetic wave detector 21 a is installed on the outer periphery of the spacer 13 to detect electromagnetic waves leaking from the spacer 13.

  As such an electromagnetic wave detector 21a, a loop type antenna can be used. Since the spacer 13 is a dielectric, electromagnetic waves generated by partial discharge inside the tank 11 leak from the spacer portion to the outside of the tank 11. By rotating the electromagnetic wave detector 21a installed outside the spacer along the outer periphery of the spacer, the relationship between the detected frequency and the mode can be clarified. In this configuration, since the electromagnetic wave detector can be rotated in the circumferential direction, it becomes easy to know the relationship between the frequency and the electromagnetic wave mode by simulated discharge or the like.

Embodiment 4 FIG.
By the way, in the electromagnetic wave generated by the partial discharge, the TE wave and the TM wave do not exist and only the TEM wave exists in the area below the cutoff frequency fcTE11 of the TE11 mode. However, as shown in FIG. 4 and FIG. 11, the TEM wave exists also in the area of the cutoff frequency fcTE11 or higher in the TE11 mode, and the TE wave, the TM wave, and the TEM wave are mixed.

  As described above, in order to determine which mode a specific frequency peak is in a frequency spectrum, a simulated partial discharge must be generated and the dependence of the spectral intensity on the tank circumference position must be measured. . In a GIS during actual operation, it may be difficult to generate such a simulated partial discharge. In this case, it becomes difficult to select the frequency f2, which is a specific mode. In such a case, instead of selecting the spectrum intensity at a specific frequency, an integral value of the spectrum intensity at a certain frequency band may be selected. As specific areas, an integral value S1 in an area of a predetermined range less than the cutoff frequency fcTE11 of the TE11 mode and an integral value S2 in an area of the predetermined range higher than the cutoff frequency fcTE11 of the TE11 mode are obtained, and the ratio V of both is V = S1 / S2 may be obtained.

  16 to 18 show another embodiment of the present invention that is determined based on the ratio V, and FIG. 16 is a configuration diagram of the detection device. FIG. 17 is a flowchart showing the operation of the detection device, and FIG. 18 is a characteristic diagram showing the detection result of the detection device of FIG. In FIG. 16, the detection device 30 is configured as follows. The amplifier 22 amplifies the signal from the electromagnetic wave detector 21 and supplies the amplified signal to the fast Fourier transform device 23 as in the detection device 20 of FIG.

  The integrating device 31 is based on the frequency spectrum obtained by performing the fast Fourier transform by the fast Fourier transform device 23, and the integral value S1 of the spectrum intensity in a predetermined range in the area below the TE11 mode cutoff frequency fcTE11, and the TE11 mode cutoff frequency fcTE11. An integral value S2 of spectrum intensities in a predetermined range in the above area is obtained. The divider 26 calculates a ratio V = S1 / S2 between the integrated values S1 and S2.

The determination device 27 determines whether the foreign object is a fixed foreign object or a free foreign object based on the magnitude of the ratio V and whether there is a change over time, and in the case of a fixed foreign object, calculates a radial position in the tank 11.
FIG. 18 shows a plot of the ratio V = S1 / S2. The horizontal axis is the distance from the internal high-voltage conductor 12 of the discharge generation source, as in FIG. 9, and a predetermined value V1 when the discharge foreign matter is near the internal high-voltage conductor 12, It becomes another predetermined value V2 smaller than the value V1. As described above, the radial position of the discharge source can also be known by plotting the value of the ratio V on the curve J in FIG.

The display device 28 displays the character information of the determination result of the determination device 27 and the value of the ratio V.
Note that the fast Fourier transform device 23, the integrator 31, and the divider 26 in FIG. 16 are normalization means in the present invention.

Next, the operation will be described with reference to the flowchart of FIG.
In step S34, from the frequency spectrum obtained by the fast Fourier transform device 23, the cutoff frequency fcTE11 of the TE11 mode is set to, for example, the above-described fcTE11 = 281 MHz, and the integral value S1 of the spectrum intensity in the range from f = 0 to 280 MHz, and f = An integral value S2 of the spectrum intensity in the range from 281 to 1200 MHz is obtained by the integrator 31.

  In step S35, the divider 26 calculates the ratio V = S1 / S2. As described above, the obtained frequency spectrum includes only the TEM mode in the area below fcTE11, and the ratio V = S1 / S2 reflects the ratio of the TEM wave included in the electromagnetic wave. The reason why the ratio V is obtained and the integral value S1 is normalized by the integral value S2 is to eliminate this effect by normalizing the influence of S1 and S2 each time a discharge occurs.

  In step S <b> 16, the determination device 27 determines whether or not the ratio V has changed with time. If there is a time change, in step S17, the discharge is caused by free foreign matter, and in step S18, "partial discharge occurrence, free foreign matter" is displayed on the display device 28.

  If the ratio V does not change with time in step S16 and is constant, it is assumed in step S19 that the discharge source does not move in the radial direction, that is, is a fixed foreign object. When the discharge source is a fixed foreign substance and is in the vicinity of the internal high-voltage conductor 12, a predetermined value V1 in the curve J of FIG. 18 is shown, and when it is in the vicinity of the tank 11, a predetermined value V2 that is smaller than V1 is shown and does not change with time. .

  In step S36, the position of partial discharge is obtained. The ratio V varies depending on whether the discharge source is on the internal high-voltage conductor 12 side or the tank 11 side. FIG. 18 shows a curve J in which the horizontal axis represents the distance d from the internal high-voltage conductor 12 of the discharge generation source, and the vertical axis represents the value of the ratio V. This curve J can be assumed in advance by the dimensions of the GIS as in the case of the curve D in FIG. 9 described above. When the discharge generation source is in the vicinity of the internal high-voltage conductor 12, the ratio V = V 1 and in the vicinity of the tank 11. Is the ratio V = V2.

Accordingly, in step S36, the determination device 27 obtains the radial position of the discharge source in the tank 11 based on the data table corresponding to the curve J in FIG.
For example, when V = V2, it is point K on the curve J in FIG. 18, and it can be seen that partial discharge has occurred on the tank 11 side.

  In step S21, "partial discharge occurrence, fixed foreign matter" is displayed on the display device 28, and the radial position in the tank 11 of the discharge generation source obtained by the determination device 27 in step S21 is displayed as, for example, "tank side". . In addition, the curve J in FIG. 18 is displayed based on the data table, and the value of the ratio V = V2 is displayed as a point K thereon. Further, the time change of the ratio V is displayed in the same manner as the characteristics E, F, and G in FIG.

  In the above embodiment, the difference between the two integral values, that is, the integral value S1 of the spectrum intensity in the area below the cutoff frequency fcTE11 in the TE11 mode and the integral value S2 of the spectrum intensity in the area above the cutoff frequency fcTE11 in the TE11 mode is used. It was. However, an integral value ST of spectral intensity over the entire frequency range may be used in addition to these two.

  That is, any two of the three integrated values S1, S2, ST are selected, that is, W = S1 / ST or X = S2 / ST is obtained instead of V = S1 / S2, and is obtained in advance. Based on the data table similar to curve J in FIG. 18, the radial position of the discharge source can be identified. Further, by following the time change of the ratio W and the ratio X, it can be known whether the discharge generation source is a fixed foreign object or a free foreign object.

Embodiment 5 FIG.
Further, in the place where the GIS is actually operating, the sensor position is often fixed. It is also difficult to measure the angle dependency between the sensor and the discharge source as shown in FIGS. 13 and 14 by installing a partial discharge source inside the GIS as a test. Therefore, it may be difficult to know experimentally which mode a particular frequency peak is in.

  In such a case, instead of selecting the spectrum intensity of the frequency corresponding to the specific mode, the integrated value of the frequency spectrum intensity above and below the TE31 mode cutoff frequency calculated from the GIS structure is used as a boundary. You may choose. As specific areas, an integral value S1 in an area of a predetermined range less than the cut-off frequency fcTE31 in the TE31 mode and an integral value S2 in an area of a predetermined range larger than the fcTE31 in the TE31 mode are obtained, and the ratio V = S1 / S2 between the two. You can ask for.

  The detection device is the same as the detection device 30 of FIG. 16, but the operation is slightly different. The integrating device 31 is based on the frequency spectrum obtained by performing the fast Fourier transform by the fast Fourier transform device 23, and the predetermined value in the region larger than the integral values S1 and fcTE31 of the spectrum intensity in a predetermined range in the region below the cutoff frequency fcTE31 in the TE31 mode. An integral value S2 of the spectrum intensity in the range is obtained. The divider 26 calculates a ratio V = S1 / S2 between the integrated values S1 and S2.

  The determination device 27 determines whether the foreign object is a fixed foreign object or a free foreign object based on the magnitude of the ratio V and whether there is a change over time, and in the case of a fixed foreign object, calculates a radial position in the tank 11. Similarly to FIG. 7, by plotting the value of the ratio V on the curve J, the radial position of the discharge source can be known. The display device 28 displays the character information of the determination result of the determination device 27 and the value of the ratio V.

The operation is the same as that of the flowchart of FIG.
In step S35, the integral value S1 of the spectrum intensity in the range from f = 0 to 730 MHz and the integral value S2 of the spectrum intensity in the range from f = 730 to 1200 MHz are integrated from the frequency spectrum obtained by the fast Fourier transform device 23. It is determined by the device 31. 730 MHz is a cutoff frequency of the TE31 mode.

  In step S35, the divider 26 calculates the ratio V = S1 / S2. As described above, the obtained frequency spectrum includes only the TEM mode, TE11, and TE21 in the region of 730 MHz or less. All of these modes are modes in which the strength increases as the discharge source is closer to the central conductor. On the other hand, the frequency component of 730 MHz or more becomes weaker as it is closer to the central conductor. Therefore, the ratio V = S1 / S2 has a one-to-one correspondence with the radial position of the discharge source. The reason why the ratio V of the integral value S1 and the integral value S2 is obtained and used as a criterion for determining the radial position is that the magnitude of S1 and S2 changes while maintaining a proportional relationship each time a discharge occurs, so that this influence is eliminated. is there.

  In step S <b> 16, the determination device 27 determines whether or not the ratio V has changed with time. If there is a time change, in step S17, the discharge is caused by free foreign matter, and in step S18, "partial discharge occurrence, free foreign matter" is displayed on the display device 28.

  If the ratio V does not change with time in step S16 and is constant, it is assumed in step S19 that the discharge source does not move in the radial direction, that is, is a fixed foreign object. When the discharge generation source is a fixed foreign substance and is in the vicinity of the internal high-voltage conductor 12, the predetermined value V3 is displayed. When the discharge source is in the vicinity of the tank 11, the predetermined value V4 is smaller than V3 and does not change with time.

In step S36, the position of partial discharge is obtained. The ratio V varies depending on whether the discharge source is on the internal high-voltage conductor 12 side or the tank 11 side. A curve obtained by plotting the distance d from the internal high-voltage conductor 12 of the discharge generation source on the horizontal axis and the value of the ratio V on the vertical axis is determined in advance according to the dimensions of the GIS, like the curve J in FIG. The ratio V = V3 when the source is in the vicinity of the internal high voltage conductor 12, and the ratio V = V4 when near the tank 11.
Accordingly, in step S36, the determination device 27 obtains the radial position of the discharge source in the tank 11 based on the data table of the ratio U and the distance d.

  In step S21, “partial discharge occurrence, fixed foreign matter” is displayed on the display device 28, and the radial position in the tank 11 of the discharge generation source obtained by the determination device 27 in step S36 is displayed as, for example, “on tank surface”. To do. In addition, a curve similar to the curve J in FIG. 17 is displayed based on the data table, and the value of the ratio V is displayed thereon as a point. Further, the time change of the ratio V is displayed in the same manner as the characteristics E, F, and G in FIG.

Embodiment 6 FIG.
19 to 24 show still another embodiment of the present invention. FIG. 19 is a configuration diagram of the detection device, and FIG. 20 is a flowchart showing the operation of the detection device. 21 and 22 are waveforms of electromagnetic waves generated when a partial discharge is generated on the internal high-voltage conductor side, respectively, passing through a lower band filter and a higher band filter. 23 and 24 show waveforms of electromagnetic waves generated when a partial discharge is generated on the tank side, respectively, passing through a lower band filter and a higher band filter.

  In this embodiment, it is possible to determine the radial position of the discharge source and whether the discharge source is a fixed foreign object or a free foreign object without obtaining a frequency spectrum as in the embodiments shown in FIGS. Is something that can be done.

  In FIG. 19, the detection device 40 is configured as follows. The lower band filter 41 has a predetermined frequency band, for example, 150 to 250 MHz, in the region below the TE11 mode cutoff frequency fcTE11, for example, fcTE11 = 281 MHz, of the signal of the electromagnetic wave detector 21 amplified by the amplifier 22. Let the signal pass. The signal that has passed through the lower band filter 41 is rectified by the rectifier 42, and the maximum value B 1 is stored in the peak hold circuit 43.

  The higher band filter 44 passes a signal in a predetermined frequency band, for example, 900 to 1000 MHz, in the area of the TE11 mode cutoff frequency fcTE11 or higher among the signals of the electromagnetic wave detector 21 amplified by the amplifier 22. The signal that has passed through the higher band filter 44 is rectified by the rectifier 45, and the maximum value B2 is stored in the peak hold circuit 46.

The divider 26 obtains the ratio Y = B1 / B2 of each maximum value B1, B2. The determination device 27 determines whether the foreign object is a fixed foreign object or a free foreign object based on the magnitude of the ratio Y and whether there is a change over time, and in the case of a fixed foreign object, calculates the radial position in the tank 11.
The display device 28 displays the character information of the determination result of the determination device 27 and the value of the ratio Y.
Note that the band-pass filters 41 and 44, the rectifier circuits 42 and 45, the peak hold circuits 43 and 46, and the divider 26 in FIG. 19 are normalization means in the present invention.

Next, the operation will be described with reference to the flowchart of FIG. In step S11, detection is performed by the electromagnetic wave detector 21, and amplification is performed in step S12. In step S53, signals in the respective frequency bands are passed through the lower band filter 41 and the higher band filter 44 and rectified.
In step S54, the signals that have passed through the lower band and the higher band filters 41 and 44 are input to the peak hold circuits 43 and 46, and the maximum values B1 and B2 are stored.

In step S55, the divider 26 obtains Y = B1 / B2. In step S16, the determination device 27 determines whether or not the ratio Y has changed with time. If there is a time change, it is determined in step S17 that this discharge is caused by free foreign matter, and "partial discharge occurrence, free foreign matter" is displayed on the display device 28 in step S18.
If the ratio Y does not change with time in step S16 and is constant, it is determined in step S19 that the discharge source has not moved in the radial direction, that is, is a fixed foreign object.

  In step S56, the position of partial discharge is obtained. The ratio Y varies depending on whether the discharge source is on the internal high-voltage conductor 12 side or the tank 11 side. Similar to steps S20 and S36 of FIGS. 6 and 17, the radial position of the discharge source in the tank 11 is obtained based on the data table regarding the value of the ratio Y and the distance from the internal high-voltage conductor. Similarly, this data table can be preliminarily assumed based on the dimensions of the GIS. When the discharge source is near the internal high-voltage conductor 12, the value of Y is large, and when near the tank 11, the value of Y is small.

  When the discharge generation source is in the vicinity of the internal high-voltage conductor 12, the waveform passing through the lower band filter 41 of 150 to 250 MHz is as shown in FIG. 21, and the waveform passing through the higher band filter 44 of 900 to 1000 MHz is As shown in FIG. At this time, the maximum value B1 detected by the peak hold circuit 43 is about 6/1000 V from FIG. 21, and the maximum value B2 detected by the peak hold circuit 46 is 7/1000 V from FIG. 7 = 0.86. 21 and 22, the horizontal axis represents time t (s) and the vertical axis represents amplitude Ampli (V).

When the discharge source is in the vicinity of the tank 11, the waveform passing through the lower band filter 41 is as shown in FIG. 23, and the waveform passing through the higher band filter 44 is as shown in FIG. At this time, the maximum value B1 detected by the peak hold circuit 43 is about 0.62 / 1000 V from FIG. 23, and the maximum value B2 detected by the peak hold circuit 46 is 4/1000 V from FIG. 0.62 / 4 = 0.16. 23 and 24, the horizontal axis represents time t (s), and the vertical axis represents amplitude Ampli (V).
As described above, since the value of the ratio Y greatly varies depending on the position of the discharge generation source, the generation position can be easily obtained.

  In step S21, “partial discharge occurrence, fixed foreign matter” is displayed on the display device 28, and the radial position in the tank 11 of the discharge generation source obtained by the determination device 27 in step S56 is, for example, “tank side”. indicate. In addition, a curve similar to the curve D in FIG. 9 is displayed based on the data table, and the value of the ratio Y is displayed as a point thereon. Further, the time change of the ratio Y is displayed in the same manner as the characteristics E, F, and G in FIG.

  Moreover, even if the pass frequencies of the band-pass filters 41 and 42 in FIG. 19 are selected to other frequency bands, for example, as follows, the same result can be obtained, and the position of discharge generation, due to free foreign matter or fixed foreign matter. You can know what it is. The pass band of the lower band filter 41 is selected so as to pass a signal of a predetermined frequency band, for example, 200 to 300 MHz, in the area below the cutoff frequency fcTE31 of the TE31 mode, for example, fcTE31 = 730 MHz. The higher band filter 44 is selected so as to pass a signal in a predetermined frequency band, for example, 900 to 1000 MHz, in an area having a cutoff frequency fcTE31 (730 MHz) or higher in the TE31 mode.

Embodiment 7 FIG.
FIGS. 25 and 26 show still another embodiment of the present invention. FIG. 25 is a configuration diagram of the detection device, and FIG. 26 is a relationship between the distance from the internal high-voltage conductor and the ratio of two detector outputs. FIG. This embodiment can also determine the radial position of the discharge source and whether the discharge source is a fixed foreign object or a free foreign object without obtaining a frequency spectrum.

  The detection device 50 is configured as follows. In FIG. 25, two electromagnetic wave detectors 51 and 55 are prepared, one electromagnetic wave detector 51 detects a TEM wave, and the other electromagnetic wave detector 55 detects a TE wave. At this time, adjustment is made so that signals can be taken out from the two electromagnetic wave detectors 51 and 55 at the same timing. Then, the signals detected by the electromagnetic wave detectors 51 and 55 are amplified by the amplifiers 52 and 56. The peak hold circuits 54 and 58 store the maximum values C1 and C2 of the electromagnetic waves in the TEM and TE modes.

The divider 26 obtains the ratio Z = C1 / C2 between the maximum values C1 and C2.
Note that the rectifier circuits 53 and 57, the peak hold circuits 54 and 58, and the divider 26 in FIG. 25 are normalization means in the present invention.

From the ratio Z = C1 / C2 of the maximum values of the two electromagnetic wave detectors 51 and 55, the ratio of the TEM mode electromagnetic wave contained in the electromagnetic wave can be found. FIG. 26 shows a curve M in which the ratio Z of the outputs from the two electromagnetic wave detectors 51 and 55 is plotted. It has the same tendency as curve D in FIG. The horizontal axis d at this time is the distance from the high-voltage conductor 12 of the discharge source as in FIG.
The radial position of the discharge generation source can be known from FIG. Further, by following this time change, it is possible to know whether the discharge source is a fixed foreign object or a free foreign object.

Embodiment 8 FIG.
In the embodiment of FIG. 5, as an abnormal state inside the tank 11, an internal high voltage conductor fixing needle 15 that is erected and fixed on the surface of the internal high voltage conductor 12, and a tank that is erected and fixed on the inner wall surface of the tank 12. Although the case where the needle 16 and the unfixed free foreign matter 17 are the respective discharge generation sources has been described, the abnormal state is not limited to this, and the present invention can be applied to other cases.

  27 to 29 show still another embodiment of the present invention. FIG. 27 shows a conductive foreign matter adhering to the surface of an insulating spacer and a partial discharge detecting device mixed in the GIS tank. FIG. 28 is a spectrum diagram showing the frequency spectrum of electromagnetic waves generated when a partial discharge is generated on the insulating spacer and on the internal high-voltage conductor side, and FIG. 29 is a spectrum diagram showing a partial discharge on the insulating spacer and the tank. It is a spectrum figure which shows the frequency spectrum of the electromagnetic waves which generate | occur | produce when it generate | occur | produces in the side.

In FIG. 27, as an abnormal state inside the tank 11, the spacer creeping needle 18, which is a conductive foreign matter fixed near the inner high-voltage conductor 12 on the surface of the insulating spacer 13, is fixed near the tank 11 on the surface of the insulating spacer 13. Consider two cases of a spacer creeping needle 19 that is a conductive foreign matter.
Other configurations are the same as those shown in FIG.

  An electromagnetic wave generated by the internal partial discharge is detected and amplified, and fast Fourier transform is performed by the fast Fourier transform device 23 to obtain a frequency spectrum. This frequency spectrum is shown in FIG. 28 in the case of the partial discharge by the spacer creeping needle 18 fixed in the vicinity of the internal high-voltage conductor 12 of the insulating spacer 13, and in the partial discharge by the spacer creeping needle 19 fixed in the vicinity of the tank 11 of the insulating spacer 13. In this case, it becomes as shown in FIG. In FIGS. 28 and 29, the horizontal axis represents the frequency (Hz), and the vertical axis represents the amplitude Ampli (dBV).

  Therefore, in FIG. 28, the magnitude of the component at f1 = 80 MHz, which is a frequency lower than the cutoff frequency fcTE11 in the TE11 mode (281 MHz in this embodiment), and at f2 = 1 GHz, which is a frequency equal to or higher than the cutoff frequency fcTE11 in the TE11 mode. A1 and A2 are obtained, and U = A1 / A2 is calculated.

  Similarly, in FIG. 29, component sizes A1 and A2 at f1 = 80 MHz and f2 = 1 GHz are obtained, and U = A1 / A2 is calculated. Also in the case of partial discharge due to conductive foreign matter adhering to the surface of the insulating spacer 13, the value of A1 normalized by the component A2 shows the same tendency as the abnormality shown in FIG. It is possible to know at which position in the radial direction of the spacer 13 the partial discharge has occurred.

  Thus, even in the case of discharge on the surface of the insulating spacer 13, the normalized ratio U shows the same tendency as in the case of partial discharge in the internal high-voltage conductor 12 and the tank 11 in FIG. That is, if the discharge generating source is on the internal high-voltage conductor 12 side, the value of U is large, and conversely if it is on the tank 11 side, the value of U is small. From this, the radial position of the occurrence of discharge can be determined from the value of U.

In the above-described embodiment, the case where the partial discharge occurs on the surface of the insulating spacer 13 has been described. However, for example, the position can be detected in the same manner when a partial discharge occurs due to a void inside the insulating spacer 13.
In addition, discharge on the surface of the insulating spacer 13, internal discharge, and the like can also be detected by the detection devices 20a, 30, 40, and 50 shown in FIGS.

Embodiment 9 FIG.
FIG. 30 shows the configuration of a partial discharge intensity detecting apparatus according to another embodiment of the present invention. In this embodiment, the frequency corresponding to the TE21 mode is determined in advance by a method similar to that described in the second embodiment of FIGS. 11 to 14, and the spectrum intensity at the frequency of the TE21 mode is determined as the partial discharge. Used as an indicator of strength.

  As shown in FIG. 1, the strength of the TE21 mode hardly depends on the radial position. Therefore, by using the TE21 mode as an indicator of the magnitude of discharge, the influence of the radial position is eliminated, and an accurate determination can be made as an indicator of the magnitude of discharge.

  Next, operation | movement of the detection apparatus 60 which is an intensity | strength detection apparatus is demonstrated. The electromagnetic wave generated by the partial discharge is detected by the electromagnetic wave detector 21, and the signal from the electromagnetic wave detector 21 is amplified by the amplifier 22. The amplified signal is taken into the fast Fourier transform device 23, and the waveform is subjected to fast Fourier transform. As described in the second embodiment, since 650 MHz is selected as the frequency corresponding to the TE21 mode, the extractor 25 obtains the spectrum intensity at this frequency.

Finally, a change with time in intensity at 650 MHz is displayed on the display device 28. In the present embodiment, TE21 mode electromagnetic waves having no radial direction dependency can be used as an indicator of discharge intensity, and the magnitude of discharge can be determined regardless of the radial position of the discharge source.
The TE mode frequency is not limited to 650 MHz, and another TE21 mode frequency may be selected.

  In order to realize the principle shown in FIG. 5, FIG. 15, FIG. 16, FIG. 19, FIG. 25, FIG. 27, FIG. 30, etc., a discrete circuit using an analog or digital arithmetic amplifier may be used. It can also be realized by software processing with digital control by a microprocessor or a digital signal processor.

In each of the above embodiments, the phase separation type in which one internal high voltage conductor 12 is arranged coaxially with the tank 11 is shown, but the same effect can be obtained even with a three-phase collective bus. . In addition, the conductive device may be another conductive device having a conductive cylindrical body other than GIS and a conductive body accommodated in the cylindrical body, such as a gas insulated bus or a power cable.
As described above, when the partial discharge occurs, the position of the conductive device in the radial direction can be detected, so that an internal breakdown can be prevented and an appropriate response can be made.

It is a characteristic view which shows radial direction electric field distribution of TEM and TEm1 mode. It is a characteristic view which shows radial direction electric field distribution of TMm1 mode. It is a characteristic view which shows the radial direction component of the electric field of TE11 mode and TM01 mode. It is a frequency distribution map of each mode. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention, and is a configuration diagram illustrating a configuration of a conductive foreign matter and partial discharge detection device mixed in a GIS tank. It is a flowchart which shows operation | movement of the detection apparatus of FIG. FIG. 6 is a spectrum diagram showing a frequency spectrum of electromagnetic waves generated when a partial discharge is generated on the internal high-voltage conductor side in FIG. 5. FIG. 6 is a spectrum diagram showing a frequency spectrum of electromagnetic waves generated when partial discharge is generated on the tank side in FIG. 5. It is a characteristic view which shows the detection result of the detection apparatus of FIG. It is a characteristic view which shows the time change of the detection result of the detection apparatus of FIG. FIG. 6 shows Embodiment 2 of the present invention, and is a spectrum diagram showing a frequency spectrum of electromagnetic waves generated when a partial discharge is generated on the internal high-voltage conductor side in FIG. 5. FIG. 6 shows Embodiment 2 of the present invention, and is a spectrum diagram showing a frequency spectrum of electromagnetic waves generated when a partial discharge is generated on the tank side in FIG. 5. It is a characteristic view which shows the angle dependence of the spectrum intensity | strength in 650 MHz of the frequency spectrum shown in FIG. 12, and a discharge source. It is a characteristic view which shows the angle dependence of the spectrum intensity | strength in 785 MHz of the frequency spectrum shown in FIG. 12, and a discharge source. Furthermore, it shows another embodiment of the present invention, and is a configuration diagram of a partial discharge detection device when an external antenna is used. Furthermore, it is a block diagram of the detection apparatus which shows other embodiment of this invention. It is a flowchart which shows operation | movement of the detection apparatus of FIG. It is a characteristic view which shows the detection result of the detection apparatus of FIG. Furthermore, it is a block diagram of the detection apparatus which shows other embodiment of this invention. It is a flowchart which shows operation | movement of the detection apparatus of FIG. In the detection apparatus of FIG. 19, it is the waveform which passed the low band filter of the electromagnetic wave generated when partial discharge generate | occur | produces in the internal high voltage | pressure conductor side. In the detection apparatus of FIG. 19, it is the waveform which passed the band filter with the higher electromagnetic wave generated when partial discharge occurred on the internal high-voltage conductor side. In the detection apparatus of FIG. 19, it is the waveform which passed the band filter with the lower electromagnetic wave generated when the partial discharge occurs on the tank side. In the detection apparatus of FIG. 19, it is the waveform which passed the band filter with the higher electromagnetic wave generated when partial discharge occurred on the tank side. Furthermore, it is a block diagram of the detection apparatus which shows other embodiment of this invention. FIG. 26 is a characteristic diagram illustrating a relationship between a distance from an internal high-voltage conductor and a ratio between two detector outputs in the detection device in FIG. 25. Furthermore, it shows another embodiment of the present invention, and is a configuration diagram showing a configuration of a conductive foreign substance mixed in the tank of the GIS and attached to the surface of the insulating spacer and a partial discharge detector. In the detection apparatus of FIG. 27, it is a spectrum figure which shows the frequency spectrum of the electromagnetic waves which generate | occur | produce when a partial discharge generate | occur | produces on an insulation spacer and the internal high voltage | pressure conductor side. In the detection apparatus of FIG. 27, it is a spectrum figure which shows the frequency spectrum of the electromagnetic waves which generate | occur | produce when a partial discharge generate | occur | produces on the insulating spacer and the tank side. Furthermore, it shows another embodiment of the present invention, and is a configuration diagram of a partial discharge intensity detection apparatus using a TE21 mode as an indicator of discharge intensity.

Explanation of symbols

11 tank, 12 internal high voltage conductor, 60 detector, 21 electromagnetic wave detector,
23 Fast Fourier transform device, 25 extractor.

Claims (1)

TE21 mode of electromagnetic waves generated in the cylindrical body in a conductive device having a cylindrical body formed of a conductive material and a conductor housed in the cylindrical body and extended in the length direction of the cylindrical body A partial discharge intensity detecting device for a conductive device using the obtained intensity as an index of partial discharge intensity.

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