JP2010151552A - System for diagnosing partial discharge of transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a partial discharge generated inside a coil of a transformer with high detection sensitivity by a small sensor. <P>SOLUTION: A partial-discharge diagnostic system for the transformer composed by housing the contents of the transformer wherein coils are wound around the main leg portion of an iron core formed by laminating steel plates in a transformer tank 13 includes: an antenna wherein an electrode 21 having a slit is arranged in a hole 13a provided in the transformer tank 13 so that the slit becomes perpendicular to the axial direction of the coils, and which detects an electromagnetic wave generated by the partial discharge of the coil as a voltage appearing between the electrode portions on both sides of the slit; and a partial-discharge diagnostic processing means which obtains the voltage signal detected by this antenna and performs diagnostic processing of the partial discharge of the coil. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a partial discharge diagnostic apparatus capable of detecting with high sensitivity a partial discharge generated inside a transformer winding.

  In power equipment such as SF6 gas insulated switches, transformers, and lightning arresters installed for power supply in substations, there is insulation diagnosis technology that detects partial discharge in order to quickly identify insulation abnormalities inside the equipment. Has been developed.

  By the way, as a conventional method for detecting partial discharge due to an abnormal insulation of a transformer winding, there is a capacitance C1 between the transformer winding and the magnetic shield attached to the tank, and an electrostatic capacitance between the magnetic shield and the tank. There is a method of measuring an electromagnetic wave with a partial pressure of a capacitance in a series arrangement composed of a capacitor C2 (Patent Document 1). However, in this method, since the area of the magnetic shield is large, the signal of the electromagnetic wave that has reached the magnetic shield portion is synthesized and becomes a small signal, so that partial discharge cannot be detected with high sensitivity.

  As another detection method, a method of detecting a high-frequency current due to partial discharge by attaching a high-frequency CT for measuring a high-frequency current to the current terminal on the ground side of the transformer winding is also employed. In this method, when an external electromagnetic wave enters, if the electromagnetic wave is erroneously detected by high-frequency CT, it may be determined that partial discharge has occurred.

  For this reason, there is a configuration in which a microphone for detecting sound waves is attached to the tank wall, and the high-frequency current detected when sound waves due to the partial discharge are generated is used as the partial discharge.

  However, since the high voltage winding of the power transformer needs to output a high voltage, the number of windings is usually large. If the number of turns of the winding is large, the inductance component of the winding becomes large and high frequency is difficult to transmit. As a result, when a partial discharge occurs at the center of the winding of the transformer, the evaluation amount of the discharge charge is 1/50 to 1/100 compared to the case of measuring near the partial discharge when measured at the end of the winding. Will be reduced.

  For this reason, there is a demand for a method of observing with high sensitivity by capturing electromagnetic waves that propagate directly from the partial discharge, rather than signals that propagate along the winding, with respect to the partial discharge that occurs inside the winding.

  As such a technique, a method of detecting an electromagnetic wave having a frequency of 100 MHz to several GHz in the UHF band, which is being developed with a gas insulated switchgear, using an antenna is considered promising (Patent Document 2).

However, the mainstream of this sensor is that a partial discharge detection electrode is attached to the tank manhole or a partial discharge detection electrode is attached to the base of the bushing, which is a current extraction port. However, the detection sensitivity is not always good because a sensor for detecting partial discharge is attached without changing the tank configuration.
Japanese Examined Patent Publication No. 63-62708 Japanese Patent No. 2881941

  For example, as shown in FIG. 18, in a gas-insulated transformer in which a transformer 13 formed by winding a winding 11 around an iron core 12 in a tank 13 filled with an insulating gas, a circular manhole included in the tank 13. The potential difference generated when the electromagnetic wave 9 reaches the gap between the disc-shaped partial discharge detection electrode (sensor) 25 provided on the opening surface of the electrode and the manhole and the partial discharge detection electrode 25 is detected, and the detection signal Is input to an external partial discharge diagnosis processing section through a coaxial cable 16 provided through a tank flange lid 18 that closes the opening of the manhole.

  With this disk-shaped electrode shape, it is possible to detect the electromagnetic wave of the polarization plane in any direction, but there are the following problems.

  That is, the distance that electromagnetic waves travel in the space is about 30 cm per ns in a gas having a relative dielectric constant of about 1. On the other hand, in oil having a relative dielectric constant of about 2, it is about 21 (= 30 / √2) cm per ns. Here, the propagation speed of the electromagnetic wave differs depending on the magnitude of the relative dielectric constant, but the following explanation will be made on propagation in a gas having a relative dielectric constant of approximately 1.

  A partial discharge is generated in the transformer, and an electromagnetic wave resulting from the partial discharge reaches the sensor portion as shown in FIG. At this time, assuming that the electric field component 9 of the partial discharge is inclined with respect to the electrode surface of the sensor 25, the partial discharge in the space normally rises with a rise time of about 0.5 ns as shown in FIG. The down time also has a bell-shaped waveform 29 generated in about 1 ns in total of 0.5 ns.

  At this time, when the electromagnetic wave reaches the upper end portion of the sensor (disk electrode) 25 and the electromagnetic wave reaching the lower part of the sensor is 30 cm away from the sensor, the electromagnetic wave detected by the sensor is as shown in FIG. The electromagnetic wave 20 shown in the upper part of the figure is detected by synthesizing the electromagnetic wave 19 shown in the lower part.

  This is because, as shown in FIG. 22, a positive voltage is generated in the sensor when the electromagnetic wave passes through the upper part of the sensor, but a negative voltage is generated when the electromagnetic wave passes through the lower part of the sensor. Thus, when the electromagnetic wave reaches the end portion of the upper part of the sensor, the diameter of the sensor needs to be 30 cm or more so that the electromagnetic wave reaching the lower part of the sensor is 30 cm away from the sensor.

  Here, 9A is a detected electromagnetic wave, and 9B is an undetected electromagnetic wave.

  However, a sensor for partial discharge detection attached to a hole provided in a normal transformer tank may have a diameter of 15 cm or less due to a restriction on the size of the flange portion at the opening end of the hole.

  Thus, when the electromagnetic wave reaches the lower end of the sensor when the diameter of the sensor is small and the electromagnetic wave reaching the lower part of the sensor is not 30 cm away from the sensor, the partial discharge electromagnetic wave reaches the upper part of the sensor. Since the electromagnetic wave reaches the lower part of the sensor within 1 ns, only a small partial discharge signal can be detected as shown in FIG. Thus, in the case of a sensor using a disk-shaped partial discharge detection electrode, there is a problem that only a signal output proportional to the diameter of the sensor can be obtained.

  An object of the present invention is to provide a partial discharge diagnostic device for a transformer that can solve the above-described problems and can detect a partial discharge generated inside a winding of a transformer with a small detection sensor with high detection sensitivity. And

  In order to achieve the above object, the present invention constitutes a partial discharge diagnostic device for a transformer by the following means.

(1) The present invention relates to a partial discharge diagnostic device for a transformer, in which a transformer core having a winding wound around a main leg portion of an iron core in which steel plates are stacked in a transformer tank is housed in the transformer tank. In a hole provided, an electrode having a slit is arranged so that the slit is perpendicular to the axial direction of the winding, and an electromagnetic wave generated by partial discharge of the winding appears on the electrode portions on both sides of the slit. And a partial discharge diagnosis processing means for taking in a voltage signal detected by the antenna and diagnosing the partial discharge of the winding.

(2) The present invention relates to a partial discharge diagnostic device for a transformer, in which a transformer core having a winding wound around a main leg portion of an iron core in which steel plates are laminated in a transformer tank, A plurality of magnetic shields respectively disposed on the inner surface at appropriate intervals are formed as electrodes having slits perpendicular to the axial direction of the windings of the transformer contents, and the windings of the transformer contents are formed. An antenna for detecting an electromagnetic wave generated by partial discharge as a voltage appearing at electrode portions on both sides of the slit, and a partial discharge diagnostic processing means for taking in a voltage signal detected by the antenna and diagnosing the partial discharge of the winding With.

(3) The present invention relates to a partial discharge diagnostic device for a transformer, in which a transformer core having a winding wound around a main leg portion of an iron core in which steel plates are laminated in a transformer tank is housed in the transformer tank. A metal cylindrical electrode having a slit in the longitudinal direction is arranged on the inner surface so that the slit is perpendicular to the axial direction of the winding, and electromagnetic waves generated by partial discharge of the winding are arranged on the electrode portions on both sides of the slit. And a partial discharge diagnosis processing means for taking in a voltage signal detected by the antenna and diagnosing the partial discharge of the winding.

  According to the present invention, a power transformer having a small antenna capable of highly sensitively detecting internal partial discharge between winding sections, between turns, regardless of whether the insulating medium of the transformer is gas or oil. The partial discharge diagnostic apparatus can be provided.

  First, in describing an embodiment of the present invention, a mode of partial discharge generated in a winding of an inner iron type transformer to be diagnosed will be described.

  As shown in FIG. 6, the winding of the inner iron type transformer is a strand wire in the radial direction via a duct piece 4 disposed in the axial direction with an appropriate space between the inner and outer insulating cylinders 2. The disk windings 1 in which are arranged are sequentially stacked in the axial direction. In addition, 3 is a refrigerant | coolant flow control board inserted between the lamination | stacking of the disk winding 1 suitably.

  The form of partial discharge generated in the winding portion having such a configuration is as follows.

  That is, the first type of partial discharge is one in which a partial discharge 7 is generated between two disk windings 1 in which the outer periphery of the conducting wire 5 is covered with an insulator 6 as shown in FIG. . In this embodiment, as shown in FIG. 6, the main electric field component 9 of the electromagnetic wave due to the partial discharge is generated in the axial direction of the winding, and the magnetic field 10 is generated in the radial direction of the winding.

  The electromagnetic wave generated by partial discharge in this way is prevented from propagating by the inductance component of the winding even if it propagates along the strand of the winding, and at the same time, the skin effect when propagating through the conductor portion of the strand Will be greatly attenuated.

  As shown in FIG. 7, the second type of partial discharge is one in which partial discharge occurs between so-called turns of strands in which one disk winding 1 is arranged. In this embodiment, as shown in FIG. 8 in which the same reference numerals are assigned to the same parts as in FIG. 6, the electric field component 9 of the electromagnetic wave due to the occurrence of partial discharge is such that the radial direction of the winding and the magnetic field 10 circulates in this radial direction. It occurs in the combined direction of the axial direction and the rotational direction of the winding.

  On the other hand, when the frequency of the electromagnetic wave trying to propagate through the space is very high, the electromagnetic wave having an electric field in the creeping direction of the bare metal is reflected on the surface of the metal and cannot be released from the winding. Since the light is attenuated while it is repeatedly reflected, it cannot be transmitted outward from the winding. For this reason, the electromagnetic wave caused by the partial discharge generated between turns can propagate in the radial direction of the winding and the axial direction of the winding from the position where the partial discharge has occurred, but in the direction perpendicular to it. I can't communicate. On the other hand, electromagnetic waves generated between sections can propagate in all directions.

  As a result, the electromagnetic wave generated between the sections propagates in all directions and is reflected by the tank and the iron core, but is not reflected by the winding portion.

  On the other hand, when the partial discharge generated between turns is observed with a sensor installed on the upper part of the winding, it is possible to know in which direction of the winding it is generated by knowing its polarization plane. Also, the electromagnetic wave traveling in the radial direction of the winding reaches the tank and repeats reflection on the tank and the outermost winding surface.

  Thus, in the partial discharge generated inside the winding, the direction of the electric field and the magnetic field is different between the electromagnetic wave generated between the sections of the winding and the electromagnetic wave generated between the turns.

  Therefore, in the present invention, partial discharge can be detected with high sensitivity by paying attention to one of the electromagnetic fields and efficiently detecting electromagnetic waves.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a sectional view showing a partial discharge detector in a first embodiment of a partial discharge diagnostic device for a transformer according to the present invention, and FIG. 2 shows a partial discharge detector of the same embodiment in a hole provided in a tank. It is the figure seen from the outside.

  In FIGS. 1 and 2, reference numeral 13 denotes a transformer tank that contains a transformer core (not shown) composed of an iron core in which silicon steel plates are laminated and a winding formed by winding a conductive wire around the main leg portion of the iron core. The transformer tank 13 is provided with a substantially circular hole 13a in a part of its peripheral wall, and a flange 13c is formed at the protruding end of a cylindrical part 13b in which the peripheral edge of the hole 13a protrudes outward from the tank. A lid 18 is attached to the flange 13c.

  In the first embodiment, in the inner iron type transformer having such a configuration, a semicircular electrode 21 (antenna) obtained by dividing a circular plate electrode into two in the hole portion 13a of the transformer tank 13 is provided. A pair of electrodes arranged so as to be opposed to each other so that a slit-like gap perpendicular to the axial direction of the winding is formed by a straight line of the chord portion of the electrode, and introduced into the cylindrical portion 13b through the lid 18 from the outside of the tank. One end of the coaxial cable 16 is connected to each semicircular electrode, and the other end is connected to a partial discharge diagnosis processing unit (not shown).

  In the first embodiment configured as described above, the electric field component 9 is in the direction of the winding axis and the magnetic field 10 is in the direction perpendicular to the electric field component as shown in FIG. The electromagnetic wave which has is generated. When this electromagnetic wave passes through the winding portion, it travels through the gap portion between the sections.

  Then, the electromagnetic wave comes out of the winding and travels toward the tank side, or directly or reflects by the magnetic shield and the tank and reaches the gap portion between the semicircular electrodes 21. In this case, since the electric field component of the electromagnetic wave is parallel to the winding axis direction, a voltage is generated at both ends of the gap portion existing between the semicircular electrodes.

  Thus, in the first embodiment, since the electric field component is parallel to the winding, a voltage can be generated in proportion to the length of the gap portion existing between the two semicircular electrodes. On the other hand, since the electric field component can detect the electromagnetic wave in the axial direction of the winding, not only partial discharge between sections but also partial electric discharge between turns and having an electric field component perpendicular to the tank can be detected.

  In addition, multiple antennas with gaps between semi-disc-shaped electrodes attached to the flange part are attached to the tank, and the voltage signal detected by each of these antennas is taken into the partial discharge diagnostic processing unit to reach it. The occurrence position of the partial discharge can be estimated from the time difference. Furthermore, when the heights of the plurality of slits are different, the three-dimensional position can be identified, and the position of the partial discharge can be specified.

  In the above embodiment, an antenna having a configuration in which two semi-disc-shaped electrodes 21 are arranged to face each other so that a slit-shaped gap perpendicular to the axial direction of the winding is formed by a straight line of a chord portion of each electrode. As shown in FIGS. 3 and 4, the disk electrode 26 is provided with slits 27 at appropriate positions off the center, and the cable signal wires are electrically connected to both sides of the disk electrode 26 sandwiching the slits 27. Even if they are connected and installed, the same effect as an antenna having a gap between the two semicircular electrodes 21 can be obtained.

  Furthermore, as shown in FIG. 9, when the flange for mounting the antenna is not in the direction perpendicular to the axial direction of the winding (indicated by the one-dot chain line in the drawing) but has an angle of 45 degrees, for example, the winding as shown in FIG. Not only the electric field component in the winding axis direction due to the partial discharge generated between the internal sections, but also the electric field component in the winding axis direction due to the partial discharge generated between the turns inside the winding as shown in FIGS. be able to.

(Second Embodiment)
FIG. 10 is a cross-sectional view showing a state in which a partial discharge detector in a second embodiment of a partial discharge diagnostic device for a transformer according to the present invention is mounted in a tank, and FIG. 11 is a partial discharge detector of the same embodiment. FIG.

  In the second embodiment, as shown in FIG. 6, the strands are arranged radially in the metal tank via duct pieces 4 arranged in the axial direction with an appropriate space between the inner and outer insulating cylinders 2. 11 is a metal cylindrical electrode (antenna cylinder) provided with one slit 24 at the center in the longitudinal direction as shown in FIG. As shown in FIG. 10, the slit 24 of the antenna cylinder 22 is formed on the inner surface of the transformer tank 13 corresponding to the side surfaces of the upper and lower iron yoke portions of the transformer via the electrode support member 23 in the axial direction of the winding (the one-dot chain line in the figure). ) To be arranged and attached so as to be perpendicular to.

  The center electrode and the ground electrode of the coaxial cable 16 are connected to the upper and lower electrodes of one slit 24 as shown in FIGS.

  In the above description, the metal cylindrical electrode (antenna cylinder) 22 provided with one slit 24 is slit on the inner surface of the transformer tank 13 corresponding to the side surfaces of the upper and lower iron yoke portions of the transformer via the electrode support member 23. 24 is arranged and attached so as to be perpendicular to the axial direction of the winding (the one-dot chain line in the figure). However, as shown in FIG. 13, a plurality of slits 24 are arranged at appropriate intervals in the longitudinal direction. As shown in FIG. 14, the slit 24 of the antenna cylinder 22 is formed on the inner surface of the transformer tank 13 corresponding to both side surfaces of the upper and lower iron yoke portions of the transformer via the electrode support member 23 as shown in FIG. It is good also as a structure attached respectively so that it may become perpendicular | vertical with respect to a direction (illustration dashed-dotted line). In this case, the center electrode and the ground electrode of the coaxial cable 16 are respectively connected to the upper and lower electrodes of each slit 24 as shown in FIG.

  On the other hand, in the external partial discharge diagnosis processing unit (not shown) connected via the coaxial cable 16, the electromagnetic waves caused by the partial discharge generated inside the winding during the arrival time of the electromagnetic waves to the plurality of antenna cylinders 22 However, an algorithm for identifying the position of the partial discharge is used by a calculation method based on an arithmetic expression derived so that there is no propagation in the winding axis direction but only propagation in the radial direction.

  In the second embodiment configured as described above, the electric field component 9 is in the direction of the winding axis and the magnetic field 10 is in the direction perpendicular to the electric field component as shown in FIG. The electromagnetic wave which has is generated. When this electromagnetic wave passes through the winding portion, it travels through the gap portion between the sections, and does not travel in the vertical direction of the winding when passing through the winding.

  Then, the electromagnetic wave comes out of the winding, travels to the tank side, is reflected by the magnetic shield and the tank, and reaches the slit 24 portion of the antenna cylinder 22. Since the electric field component of the electromagnetic wave is parallel to the winding axis direction, a voltage is generated at both ends of the slit 24 portion of the antenna cylinder 22.

  Thus, in the second embodiment, since the electric field component is parallel to the winding, a voltage can be generated in proportion to the length of the slit 24 provided in the metal cylindrical electrode (antenna cylinder) 22. On the other hand, since the electric field component can detect the electromagnetic wave in the axial direction of the winding, not only partial discharge between sections but also partial electric discharge between turns and having an electric field component perpendicular to the tank can be detected.

  Further, as shown in FIG. 13, the antenna cylinder 22 having the slits 24 is provided with a plurality of slits 24 at an appropriate interval in the longitudinal direction, so that the occurrence position of the partial discharge can be estimated from the arrival time difference. . Further, when the heights of the slits 24 are different, a three-dimensional position can be identified, and the position of the partial discharge can be specified.

  Furthermore, when the transformer is a gas-insulated transformer, since the tank is cylindrical, there is a distance from the winding to the tank at the most central portion of the winding. If the cylinder 22 with slits is attached to the corresponding inner surface of the tank by the electrode support member 23, the space in the tank can be effectively used.

  In this case, when the slit 24 of the antenna cylinder 22 is directed toward the winding 11, it is necessary to chamfer the edge portion of the slit so as not to discharge due to the voltage generated from the winding. By disposing the antenna cylinder 22 so that it cannot be seen, the entire apparatus can be made inexpensive.

(Third embodiment)
FIG. 16: is sectional drawing which shows the state which attached the partial discharge detection part in 3rd Embodiment of the partial discharge diagnostic apparatus of the transformer by this invention in the tank.

  In the third embodiment, as shown in FIG. 16, an iron core 12 including a core 12 in which silicon steel plates are laminated in a transformer tank 13 and a winding 11 formed by winding a conductive wire around a main leg portion of the iron core 12. In the type transformer, a magnetic shield 14 made of a plurality of magnetic steel plates respectively arranged at equal intervals on the inner surface of the transformer tank 13 is perpendicular to the axial direction of the winding 11 (indicated by the one-dot chain line in the figure). It is configured as an antenna electrode having a slit so that

  In this case, the slits are perpendicular to the axial direction of the winding 11 (in the drawing, in the drawing), but the inner surface of the magnetic shield 14 is arranged at equal intervals with an angle with respect to the axial direction of the winding 11. ing. The center electrode and the ground electrode of the coaxial cable 16 are connected to both poles of the plurality of slits.

  Further, in the partial discharge diagnosis processing unit (not shown) connected via the coaxial cable 16, the electromagnetic waves caused by the partial discharge generated inside the winding during the arrival time of the electromagnetic waves to the plurality of antennas The algorithm for identifying the position of the partial discharge is used by a method that is calculated from an arithmetic expression that is considered to advance only in the radial direction.

  In the third embodiment configured as described above, due to the partial discharge generated between the sections in the winding, as shown in FIG. 5, the electric field component is in the direction of the winding axis and the magnetic field is in the direction perpendicular to the electric field component. Is occurring.

  On the other hand, due to the partial discharge generated between the turns in the winding, as shown in FIG. 7, an electromagnetic wave having an electric field component perpendicular to the winding axis and a magnetic field perpendicular to the electric field component is generated. This electromagnetic wave comes out of the winding and travels to the tank side and reaches the magnetic shield 14 portion. Then, a voltage is generated in the direction perpendicular to the electric field component of the electromagnetic wave in the slit of the antenna electrode.

  As described above, in the third embodiment, the detection waveform 19 by the electromagnetic wave having a time delay is synthesized with the slits of the plurality of magnetic shields 14 as shown in FIG. 17, and the voltage is proportional to the electric field component and the length of the slit. Therefore, partial discharge can be detected efficiently.

Sectional drawing which shows the partial discharge detection part in 1st Embodiment of the partial discharge diagnostic apparatus of the transformer by this invention. The figure which looked at the partial discharge detector of the embodiment from the outside of the hole provided in the tank. Sectional drawing which shows the other example of the partial discharge detector of the embodiment. The figure which looked at the partial discharge detector of the embodiment from the outside of the hole provided in the tank. The schematic diagram of the electromagnetic waves produced by the partial discharge which generate | occur | produces between the sections in a transformer winding. The schematic diagram by which the electromagnetic waves produced by the partial discharge which generate | occur | produces between the sections in a transformer winding propagate to the exterior of a winding. The schematic diagram of the electromagnetic waves produced by the partial discharge generated between the turns in a transformer winding. The schematic diagram by which the electromagnetic waves produced by the partial discharge generated between the turns in the transformer winding propagate to the outside of the winding. Sectional drawing which shows the state with which the partial discharge detector of the embodiment was attached to the hole with an angle of 45 degree | times with respect to the axis | shaft of a transformer winding. Sectional drawing which shows the state which attached the cylindrical partial discharge detector which put the slit perpendicularly to the axial direction of the coil | winding as 2nd Embodiment of the partial discharge diagnostic apparatus of the transformer by this invention. The perspective view which shows the cylindrical partial discharge detector of the embodiment. Sectional drawing which shows the cylindrical partial discharge detector of the embodiment. The perspective view which shows the cylindrical partial discharge detector which put the some slit as another example of the embodiment. Sectional drawing which shows the state which attached the some partial discharge detector in the tank as another example of the embodiment. Sectional drawing which shows the other example of the state which attached the cylindrical partial discharge detector which put the slit perpendicularly | vertically to the axial direction of the coil | winding as the embodiment. Sectional drawing which shows the state which attached in the tank the partial discharge detector using the magnetic shield which made the slit perpendicularly to the axial direction of a coil | winding as 3rd Embodiment of the partial discharge diagnosis apparatus of the transformer by this invention. The partial discharge detection waveform figure detected by the partial discharge detector by this invention. Sectional drawing which shows the state which attached the partial discharge detector using the conventional disk-shaped electrode in the transformer tank perpendicularly to the axis | shaft of a coil | winding. Sectional drawing for demonstrating the arrival delay of the electromagnetic wave to the disk shaped electrode in a partial discharge detector similarly. The figure which shows a standard partial discharge waveform. The figure which shows the detection waveform of the partial discharge in case the diameter of a disk-shaped electrode is large. The figure which shows the detection voltage of electromagnetic waves in a disk-shaped electrode, and the time gap. The figure which shows the detection waveform of the partial discharge in case the diameter of a disk-shaped electrode is small.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Disc winding, 2 ... Insulation cylinder, 3 ... Refrigerant flow control board, 4 ... Duct piece, 5 ... Conductor, 6 ... Insulator, 7 ... Partial discharge current between sections, 8 ... Partial discharge current between turns, 9 Radiated electric field (electric field component), 10 ... radiated magnetic field (magnetic field), 11 ... winding, 12 ... iron core, 13 ... transformer tank, 13a ... hole, 13b ... cylinder, 13c ... flange, 14 ... magnetic shield, DESCRIPTION OF SYMBOLS 15 ... Insulating support body, 16 ... Coaxial cable, 17 ... Disc electrode (antenna) 18 ... Lid body, 21 ... Half-moon-shaped electrode (antenna), 22 ... Cylindrical electrode with a slit (antenna cylinder), 23 ... Electrode support member 24 ... Slit

Claims (9)

In the partial discharge diagnostic device for a transformer, which houses the transformer contents in which the winding is wound around the main leg portion of the iron core laminated with steel plates in the transformer tank,
An electrode having a slit is disposed in a hole provided in the transformer tank so that the slit is perpendicular to the axial direction of the winding of the transformer, and electromagnetic waves generated by partial discharge of the winding are generated. An antenna that detects the voltage appearing at the electrode portions on both sides of the slit;
A partial discharge diagnosis device for a transformer, comprising: a partial discharge diagnosis processing means for taking in a voltage signal detected by the antenna and diagnosing the partial discharge of the winding.   2. The partial discharge diagnosis device for a transformer according to claim 1, wherein the antenna has a pair of semicircular electrodes and a slit formed by arranging a straight portion of a string portion of each electrode with an appropriate gap. .   The partial discharge diagnostic device for a transformer according to claim 1, wherein the antenna has a disk-like electrode provided with a slit. In the partial discharge diagnostic device for a transformer, which houses the transformer contents in which the winding is wound around the main leg portion of the iron core laminated with steel plates in the transformer tank,
A plurality of magnetic shields respectively disposed on the inner surface of the transformer tank with appropriate intervals are formed as electrodes having slits perpendicular to the axial direction of the windings of the transformer contents, and the transformer An antenna for detecting electromagnetic waves generated by partial discharge of the winding of the contents as a voltage appearing at electrode portions on both sides of the slit;
A partial discharge diagnosis device for a transformer, comprising: a partial discharge diagnosis processing means for taking in a voltage signal detected by the antenna and diagnosing the partial discharge of the winding. In the partial discharge diagnostic device for a transformer, which houses the transformer contents in which the winding is wound around the main leg portion of the iron core laminated with steel plates in the transformer tank,
A metal cylindrical electrode having a slit in the longitudinal direction is disposed on the inner surface of the transformer tank so that the slit is perpendicular to the axial direction of the winding, and electromagnetic waves generated by partial discharge of the winding are An antenna that detects the voltage appearing at the electrode parts on both sides of the slit;
A partial discharge diagnosis device for a transformer, comprising: a partial discharge diagnosis processing means for taking in a voltage signal detected by the antenna and diagnosing the partial discharge of the winding.   6. The transformer partial discharge diagnostic apparatus according to claim 3, wherein the antenna is provided with a plurality of slits.   The partial discharge of a transformer according to any one of claims 1 to 6, wherein the antenna is attached to an inner surface of a transformer tank corresponding to side surfaces of upper and lower iron core yoke portions of the transformer. Diagnostic device.   6. The partial discharge diagnostic device for a transformer according to claim 5, wherein the antenna has a slit portion of the metal cylindrical electrode arranged in a direction not facing the winding side.   9. The partial discharge diagnosis device for a transformer according to claim 1, wherein the partial discharge diagnosis processing means has at least three antennas, and the partial discharge diagnosis processing means generates an electromagnetic wave caused by the partial discharge generated inside the winding. It is characterized in that the position of the partial discharge is identified by an arithmetic expression derived based on the arrival time of electromagnetic waves to a plurality of antennas, assuming that there is no propagation in the winding axis direction in the part and only propagation in the radial direction proceeds Transformer partial discharge diagnostic device.

Images