Electromagnetic wave detector, partial discharge monitoring system and partial discharge monitoring method

Abstract

The present invention provides an electromagnetic wave detector, a partial discharge monitoring system and a partial discharge monitoring method. The electromagnetic wave detector is suitable for detecting electromagnetic waves radiated by an oil-paper insulated bushing. The oil-paper insulated bushing includes an insulating sleeve arranged at intervals along the axial direction of the oil-paper insulated bushing and a fixed connection sleeve connected to the insulating sleeve. The electromagnetic wave detector includes: a sleeving member, which is suitable for being sleeved on the outer side near the connection between the fixed connection sleeve and the insulating sleeve, and the sleeving member includes a first electrode region; a second electrode spaced apart from and opposite to the first electrode region; and an inductance coil located between the first electrode region and the second electrode, and two ends of the inductance coil are respectively connected to the first electrode region and the second electrode. The electromagnetic wave detector can detect whether partial discharge occurs in the oil-paper insulated bushing, is not only applicable to a variety of oil-paper insulated bushings, but also can improve the detection sensitivity and detection effect, providing guarantee for the safe and reliable operation of the transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of power system monitoring, and particularly to an electromagnetic wave detector, a partial discharge monitoring system and a partial discharge monitoring method. Background Art

[0002] At present, the transmission capacity of the power grid is continuously increasing, the capacity of transformers is also gradually increasing, and the output current of transformers is also increasing simultaneously. The occurrence of a fire or explosion in a transformer not only causes damage to the transformer, but may even cause damage to other adjacent electrical equipment, leading to power outages in local areas or even large areas, bringing huge negative impacts to the national economy and social stability. Among them, bushing insulation failure is one of the direct causes of transformer fires or explosions, with the characteristics of strong occasionality and long fault influence time. And partial discharge is an early sign and an important inducement of bushing insulation failure. Specifically, the partial discharge area includes the lower porcelain bushing of the bushing and the outgoing line device inside the riser. It is of great significance to carry out partial discharge monitoring on operating power transformers.

[0003] However, the sensitivity of existing partial discharge monitoring technologies is not good. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect of poor sensitivity of existing partial discharge monitoring technologies, and thus provide an electromagnetic wave detector, a partial discharge monitoring system and a partial discharge monitoring method.

[0005] The present invention provides an electromagnetic wave detector adapted to detect electromagnetic waves radiated by an oil-paper insulated bushing. The oil-paper insulated bushing includes an insulating sleeve and a fixed connection sleeve connected to the insulating sleeve, which are arranged at intervals along the axial direction of the oil-paper insulated bushing. The electromagnetic wave detector includes: a sleeving member adapted to be sleeved on the outer side near the connection between the fixed connection sleeve and the insulating sleeve. The sleeving member includes a first electrode region; a second electrode spaced apart and opposite to the first electrode region; and an inductor coil located between the first electrode region and the second electrode, with both ends of the inductor coil connected to the first electrode region and the second electrode respectively.

[0006] Optionally, the sleeving member includes a first sleeving ring, a second sleeving ring, and a connecting member connecting the first sleeving ring and the second sleeving ring. The diameter of the first sleeving ring is larger than that of the second sleeving ring. The second sleeving ring is adapted to surround the oil-paper insulated bushing and is fixedly connected to the oil-paper insulated bushing. The first sleeving ring is adapted to surround the oil-paper insulated bushing and is spaced apart from the oil-paper insulated bushing. At least part of the area of the first sleeving ring serves as the first electrode region.

[0007] Optionally, the insulating sleeve includes an upper insulating sleeve and a lower insulating sleeve that are axially spaced along the oil-paper insulating bushing, and the fixed connection sleeve is located between the upper insulating sleeve and the lower insulating sleeve and is connected to the upper insulating sleeve and the lower insulating sleeve.

[0008] Optionally, the second sleeved ring is adapted to be fixedly connected to the fixed connection sleeve, the upper insulating sleeve or the lower insulating sleeve.

[0009] Optionally, the first electrode region includes a spaced first connection region and a second connection region, and the second electrode includes a spaced third connection region and a fourth connection region; the first connection region is connected to one end of the inductor coil, and the third connection region is connected to the other end of the inductor coil; the electromagnetic wave detector further includes: a first conductive member connected to the second connection region; and a second conductive member connected to the fourth connection region.

[0010] Optionally, the second electrode has a first opening therethrough, and the first conductive member passes through the first opening and is spaced from the second electrode; the second conductive member is fixed on one side surface of the second electrode and is electrically connected to the second electrode at the edge of the first opening.

[0011] Optionally, the second conductive member includes a conductive joint flange having a second opening therethrough, and the conductive joint flange is fixed on one side surface of the second electrode at the edge of the first opening; the first conductive member includes a joint core wire passing through the first opening and the second opening.

[0012] Optionally, the second electrode is a complete electrode, the first conductive member is spaced from the second electrode, and the second conductive member is spaced from the sleeved member.

[0013] Optionally, the electromagnetic wave detector further includes: an insulating fixing member, with both ends of the insulating fixing member connected to the second electrode and the first electrode respectively, and the insulating fixing member is spaced from the inductor coil.

[0014] Optionally, the inductor coil includes a spaced first inductor coil and a second inductor coil, and the first inductor coil and the second inductor coil are respectively located at opposite ends of the second electrode.

[0015] Optionally, the sleeved member includes a grading ring.

[0016] Optionally, the second electrode includes a metal strip.

[0017] Optionally, the fixed connection sleeve is a flange and the fixed connection sleeve is grounded.

[0018] Optionally, the inductance value of the inductance coil is less than or equal to 1 μH.

[0019] The present invention further provides a partial discharge monitoring system, including: an oil-paper insulated bushing; the electromagnetic wave detector; the sheathing is sleeved on the outer side near the connection between the fixed connection sleeve and the insulating sleeve.

[0020] Optionally, the first electrode region includes a spaced first connection region and a second connection region, and the second electrode includes a spaced third connection region and a fourth connection region; the first connection region is connected to one end of the inductance coil, and the third connection region is connected to the other end of the inductance coil; the electromagnetic wave detector further includes: a first conductive member connected to the second connection region; a second conductive member connected to the fourth connection region; the partial discharge monitoring system further includes: a filtering module, the first conductive member and the second conductive member are electrically connected to the input end of the filtering module; an amplifying module, the input end of the amplifying module is electrically connected to the output end of the filtering module; a data acquisition module, the input end of the acquisition device is electrically connected to the output end of the amplifying module.

[0021] The present invention further provides a partial discharge monitoring method, using the electromagnetic wave detector, including: providing an oil-paper insulated bushing; sleeving the sheathing of the electromagnetic wave detector on the outer side near the connection between the fixed connection sleeve and the insulating sleeve; determining whether partial discharge occurs in the oil-paper insulated bushing by detecting whether an electrical signal is generated by the electromagnetic wave detector.

[0022] The technical solution of the present invention has the following advantages:

[0023] 1. The electromagnetic wave detector provided by the present invention can be fixed outside the oil-paper insulated bushing and near the connection between the fixed connection sleeve and the insulating sleeve. The electromagnetic waves radiated by the partial discharge of the oil-paper insulated bushing will propagate along the oil gap between the capacitive core in the oil-paper insulated bushing and the fixed connection sleeve, and then radiate outward from the gap at the connection between the fixed connection sleeve and the insulating sleeve. The electric field component of the electromagnetic wave generates induced charges in the first electrode region, the inductor coil, and the second electrode, causing an induced voltage to be generated between the first electrode region and the second electrode. Therefore, it is possible to determine whether partial discharge occurs in the oil-paper insulated bushing by detecting whether an electrical signal is generated by the electromagnetic wave detector. The connection between the fixed connection sleeve and the insulating sleeve is the electromagnetic wave leakage position of the oil-paper insulated bushing. By sleeving the sleeve near the electromagnetic wave leakage position, on the one hand, the anti-interference ability of the electromagnetic wave detector is improved, and on the other hand, the transmission distance of the electromagnetic wave is effectively shortened. The shortening of the electromagnetic wave transmission distance effectively reduces the attenuation degree of the electromagnetic wave, thereby improving the detection sensitivity and detection effect, providing a more reliable basis for partial discharge maintenance, and providing guarantee for the safe and reliable operation of the transformer. At the same time, the setting method of the electromagnetic wave detector makes it applicable to various oil-paper insulated bushings. In addition, the setting area of the electromagnetic wave detector is a low ground potential and low field strength area, with high safety and reliability, and does not affect the safe operation of the electromagnetic wave detector.

[0024] 2. The partial discharge monitoring system provided by the present invention detects whether partial discharge occurs in the oil-paper insulated bushing by sleeving the electromagnetic wave detector outside near the connection between the fixed connection sleeve and the insulating sleeve. The electromagnetic wave detector is not only applicable to various oil-paper insulated bushings, has high anti-interference ability, but also can shorten the transmission distance of the electromagnetic wave, thereby effectively reducing the attenuation degree of the electromagnetic wave, and further improving the detection sensitivity.

[0025] 3. The partial discharge monitoring method provided by the present invention determines whether partial discharge occurs in the oil-paper insulated bushing by sleeving the electromagnetic wave detector outside near the connection between the fixed connection sleeve and the insulating sleeve and detecting whether an electrical signal is generated by the electromagnetic wave detector. The connection between the fixed connection sleeve and the insulating sleeve is the electromagnetic wave leakage position of the oil-paper insulated bushing. By sleeving the sleeve near the electromagnetic wave leakage position, on the one hand, the anti-interference ability of the electromagnetic wave detector is improved, and on the other hand, the transmission distance of the electromagnetic wave is effectively shortened. The shortening of the electromagnetic wave transmission distance effectively reduces the attenuation degree of the electromagnetic wave, thereby improving the detection sensitivity and detection effect, providing a more reliable basis for partial discharge maintenance. At the same time, the setting area of the electromagnetic wave detector is a low ground potential and low field strength area, with high safety and reliability, and does not affect the safe operation of the electromagnetic wave detector, providing guarantee for the safe and reliable operation of the transformer. Description of the Drawings

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 The front view of the first electromagnetic wave detector provided in Embodiment 1 of the present invention;

[0028] Figure 2 The front view of the second electromagnetic wave detector provided in Embodiment 1 of the present invention;

[0029] Figure 3 The front view of the third electromagnetic wave detector provided in Embodiment 1 of the present invention;

[0030] Figure 4 The front view of the fourth electromagnetic wave detector provided in Embodiment 1 of the present invention;

[0031] Figure 5 The front view of the electromagnetic wave detector in Embodiment 1 of the present invention sleeved on the oil-paper insulated bushing;

[0032] Figure 6 The top view of the sleeving member provided in Embodiment 1 of the present invention;

[0033] Figure 7 The front view of the sleeving member provided in Embodiment 1 of the present invention;

[0034] Figure 8 The front view of the partial discharge monitoring system provided in Embodiment 2 of the present invention;

[0035] Explanation of reference numerals:

[0036] 1 - Electromagnetic wave detector; 11 - Sleeving member; 111 - First sleeving ring; 112 - Second sleeving ring; 113 - Connecting member; 12 - Second electrode; 13 - Inductive coil; 131 - First inductive coil; 132 - Second inductive coil; 133 - Insulating fixing member; 14 - First conductive member; 15 - Second conductive member; 2 - Oil-paper insulated bushing; 21 - Capacitor core; 22 - Upper insulating sleeve; 23 - Fixed connection sleeve; 24 - Lower insulating sleeve; 3 - Bushing riser; 4 - Transformer tank; 5 - Cable. Detailed embodiments

[0037] As described in the background art, the sensitivity of the existing partial discharge monitoring technology is not good.

[0038] The existing partial discharge monitoring technologies mainly include the ultrasonic method, the pulse current method, the UHF method, etc. Among them, the ultrasonic method has low sensitivity and the detection range does not exceed 1 meter. This is because the internal structure and materials of the transformer are relatively complex, resulting in severe attenuation of ultrasonic waves during propagation. The ultrasonic method is powerless for partial discharges inside windings and bushings. The pulse current method has poor anti-interference ability, so it is only applicable to laboratory detection and cannot be used for on-site detection. The UHF method determines whether there is a partial discharge phenomenon and the type of partial discharge inside the equipment by detecting the electromagnetic wave signals radiated by partial discharges. Its detection frequency band is generally in the frequency range of 0.3 GHz to 3 GHz. UHF sensors can be divided into oil drain valve type sensors, manhole type sensors, and tank joint type sensors. Among them, the oil drain valve type sensors and manhole type sensors need to solve the oil seal problem during installation, so it is difficult to promote and apply; the sensitivity of the tank joint type sensors is low.

[0039] The installation methods of UHF sensors include built-in type and external type. Among them, the built-in installation method requires installing the UHF sensor inside the transformer before the transformer is put into operation. Therefore, there are many restrictions on the size of the UHF sensor, which limits the use environment of the UHF sensor. In addition, it is necessary to transform the structure of the transformer, resulting in difficult installation. In the external installation method, the required UHF sensor is arranged outside the transformer and there is a certain distance from the transformer. The electromagnetic waves radiated by partial discharges will attenuate during the transmission from the transformer to the UHF sensor, which directly affects the detection effect of the UHF sensor. Specifically, when the intensity of the electromagnetic waves radiated by a partial discharge in a local area inside the transformer is small, the electromagnetic waves may not be detected by the UHF sensor after attenuation, thus affecting the detection sensitivity and detection effect.

[0040] On this basis, the present application provides an electromagnetic wave detector suitable for detecting the electromagnetic waves radiated by an oil-paper insulated bushing. The oil-paper insulated bushing includes an insulating sleeve and a fixed connection sleeve connected to the insulating sleeve, which are arranged at intervals along the axial direction of the oil-paper insulated bushing; the electromagnetic wave detector includes: a sleeve member, the sleeve member is suitable for being sleeved outside the connection between the fixed connection sleeve and the insulating sleeve, and the sleeve member includes a first electrode region; a second electrode spaced and opposite to the first electrode region; an inductance coil located between the first electrode region and the second electrode, and both ends of the inductance coil are respectively connected to the first electrode region and the second electrode. The electromagnetic wave detector can detect whether the oil-paper insulated bushing has a partial discharge, is applicable to a variety of oil-paper insulated bushings, and can improve the detection sensitivity and detection effect.

[0041] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In addition, the terms "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0043] Embodiment 1

[0044] See Figures 1 - 4 , this embodiment provides an electromagnetic wave detector 1 suitable for detecting electromagnetic waves radiated by an oil-paper insulated bushing 2. The oil-paper insulated bushing 2 includes an insulating sleeve arranged at intervals along the axial direction of the oil-paper insulated bushing 2 and a fixed connection sleeve 23 connected to the insulating sleeve; the electromagnetic wave detector 1 includes: a sleeving member 11, the sleeving member 11 is suitable for sleeving on the outer side near the connection of the fixed connection sleeve 23 and the insulating sleeve, and the sleeving member 11 includes a first electrode region; a second electrode 12 spaced and opposite to the first electrode region; an inductance coil 13 located between the first electrode region and the second electrode 12, and two ends of the inductance coil 13 are respectively connected to the first electrode region and the second electrode 12. For the structure in which the electromagnetic wave detector 1 is fixed on the outer side of the oil-paper insulated bushing 2, see Figure 5 . Specifically, the oil-paper insulated bushing 2 further includes a capacitor core 21, both the insulating sleeve and the fixed connection sleeve 23 are sleeved on the outer side of the capacitor core 21, and transformer oil is filled between the capacitor core 21 and the insulating sleeve and the fixed connection sleeve 23 to form an oil gap.

[0045] The above-mentioned electromagnetic wave detector 1 can be fixed outside the oil-paper insulating bushing 2 and near the connection between the fixed connection sleeve 23 and the insulating sleeve. The electromagnetic waves radiated by the partial discharge of the oil-paper insulating bushing 2 will propagate along the oil gap between the capacitive core 21 and the fixed connection sleeve 23, and then radiate outward from the gap at the connection between the fixed connection sleeve 23 and the insulating sleeve. The electric field component of the electromagnetic wave generates induced charges in the first electrode region, the inductive coil 13, and the second electrode 12, resulting in an induced voltage between the first electrode region and the second electrode 12. Therefore, it is possible to determine whether the oil-paper insulating bushing 2 has a partial discharge by detecting whether the electromagnetic wave detector 1 generates an electrical signal. The connection between the fixed connection sleeve 23 and the insulating sleeve is the electromagnetic wave leakage position of the oil-paper insulating bushing 2. By sleeving the sleeve member 11 near the electromagnetic wave leakage position, on the one hand, the anti-interference ability of the electromagnetic wave detector 1 is improved, and on the other hand, the transmission distance of the electromagnetic wave is effectively shortened. The shortening of the electromagnetic wave transmission distance effectively reduces the attenuation degree of the electromagnetic wave, thereby improving the detection sensitivity and detection effect, providing a more reliable basis for partial discharge maintenance, and ensuring the safe and reliable operation of the transformer. Specifically, when the intensity of the electromagnetic wave radiated by the partial discharge is small, due to the small attenuation degree, the attenuated electromagnetic wave can also be detected by the electromagnetic wave detector 1, thereby improving the accuracy of the detection result. At the same time, the setting method of the electromagnetic wave detector 1 makes it applicable to various oil-paper insulating bushings 2. In addition, the setting area of the electromagnetic wave detector 1 is a low electric potential and low electric field intensity area, with high safety and reliability, and does not affect the safe operation of the electromagnetic wave detector 1.

[0046] The electromagnetic wave detector 1 provided in this embodiment is a non-contact electromagnetic wave detector and can be applied to power transformer equipment with voltages ranging from 110 kV to 1000 kV to determine the insulation state of the transformer.

[0047] See Figures 6 - 7 , in this embodiment, the sleeve member 11 includes a first sleeve ring 111, a second sleeve ring 112, and a connecting member 113 connecting the first sleeve ring 111 and the second sleeve ring 112. The diameter of the first sleeve ring 111 is larger than the diameter of the second sleeve ring 112. The second sleeve ring 112 is adapted to surround the oil-paper insulating bushing 2 and is fixedly connected to the oil-paper insulating bushing 2. The first sleeve ring 111 is adapted to surround the oil-paper insulating bushing 2 and is spaced from the oil-paper insulating bushing 2. At least a part of the first sleeve ring 111 serves as the first electrode region. Further, the connecting member 113 can be a metal rod, and both the first sleeve ring 111 and the second sleeve ring 112 are metal rings. Specifically, the sleeve member 11 includes a grading ring, and the grading ring includes, but is not limited to, the structure as Figures 6 - 7 shown.

[0048] In this embodiment, the second electrode 12 includes a metal strip. Further, the second electrode 12 is arc-shaped and the radius of the second electrode 12 is the same as the radius of the first sleeved ring 111, so that the first electrode region is disposed opposite to the second electrode 12. The material of the second electrode 12 includes, but is not limited to, aluminum.

[0049] It should be understood that the direction from the first electrode region to the second electrode 12 is the same as the axial direction of the oil-paper insulating bushing 2, and the second electrode 12 is located below or above the first electrode region. As Figures 1 - 4 shown, the second electrode 12 is located below the first electrode region.

[0050] See Figure 5 , in this embodiment, the insulating sleeve includes an upper insulating sleeve 22 and a lower insulating sleeve 24 that are spaced apart along the axial direction of the oil-paper insulating bushing 2, and the fixed connection sleeve 23 is located between the upper insulating sleeve 22 and the lower insulating sleeve 24 and is connected to the upper insulating sleeve 22 and the lower insulating sleeve 24. Specifically, the upper insulating sleeve 22 is sleeved on the upper section of the capacitor core 21, the lower insulating sleeve 24 is sleeved on the lower section of the capacitor core 21, the fixed connection sleeve 23 is sleeved on the middle section of the capacitor core 21 and is respectively connected to the upper insulating sleeve 22 and the lower insulating sleeve 24. The upper insulating sleeve 22 is an upper porcelain sleeve, the lower insulating sleeve 24 is a lower porcelain sleeve, the fixed connection sleeve 23 is a flange, and the fixed connection sleeve 23 is grounded.

[0051] Further, the second sleeved ring 112 is adapted to be fixedly connected to the fixed connection sleeve 23, the upper insulating sleeve 22 or the lower insulating sleeve 24, so as to fix the first sleeved ring 111 and even the entire electromagnetic wave detector 1 near the connection between the fixed connection sleeve 23 and the insulating sleeve. Specifically, the second sleeved ring 112 is adapted to be fixedly connected to the fixed connection sleeve 23 near the connection between the fixed connection sleeve 23 and the upper insulating sleeve 22; or, the sleeved part 11 is adapted to be fixedly connected to the upper insulating sleeve 22 near the connection between the fixed connection sleeve 23 and the upper insulating sleeve 22; or, the second sleeved ring 112 is adapted to be fixedly connected to the fixed connection sleeve 23 near the connection between the fixed connection sleeve 23 and the lower insulating sleeve 24; or, the sleeved part 11 is adapted to be fixedly connected to the lower insulating sleeve 24 near the connection between the fixed connection sleeve 23 and the lower insulating sleeve 24.

[0052] It should be understood that, see Figure 8 , the transformer includes, in addition to the oil-paper insulating bushing 2, a transformer tank 4 and a riser 3. A partial region of the fixed connection sleeve 23 and the lower insulating sleeve 24 in the oil-paper insulating bushing 2 are both located inside the riser 3, and the oil-paper insulating bushing 2 is disposed on the transformer tank 4 through the riser 3. As a preferred embodiment, see Figure 5 andFigure 8 The second sleeve ring 112 is adapted to be fixed to the fixed connection sleeve 23 near the connection between the fixed connection sleeve 23 and the upper insulating sleeve 22. On the one hand, it makes the electromagnetic wave detector 1 closer to the electromagnetic wave leakage position, with higher detection sensitivity. On the other hand, when partial discharge detection is required, only the second sleeve ring 112 needs to be sleeved and fixed on the fixed connection sleeve 23, without the need to modify the structure of the transformer, and the installation is convenient.

[0053] See Figures 1 - 4 In this embodiment, the first electrode region includes a spaced first connection region and a second connection region, and the second electrode 12 includes a spaced third connection region and a fourth connection region; the first connection region is connected to one end of the inductor coil 13, and the third connection region is connected to the other end of the inductor coil 13; the electromagnetic wave detector 1 further includes: a first conductive member 14, the first conductive member 14 is connected to the second connection region; a second conductive member 15, the second conductive member 15 is connected to the fourth connection region. The first conductive member 14 and the second conductive member 15 are adapted to lead out electrical signals.

[0054] See Figure 3 and Figure 4 In the first implementation manner, the second electrode 12 is a complete electrode, the first conductive member 14 is spaced from the second electrode 12, and the second conductive member 15 is spaced from the sleeved member 11, and the second conductive member 15 is spaced from the sleeved member 11. Specifically, the first conductive member 14 and the second conductive member 15 can be wires.

[0055] See Figure 1 and Figure 2 In the second implementation manner, the second electrode 12 has a first opening penetrating through the second electrode 12, and the first conductive member 14 passes through the first opening and is spaced from the second electrode 12; the second conductive member 15 is fixed on one side surface of the second electrode 12 and is electrically connected to the second electrode 12 at the edge of the first opening. The first opening is located at the middle position or other positions of the second electrode 12.

[0056] Specifically, in the second implementation manner, the second conductive member 15 includes a conductive joint flange, and the conductive joint flange has a second opening penetrating through the conductive joint flange. The conductive joint flange is fixed on one side surface of the second electrode 12 at the edge of the first opening; the first conductive member 14 includes a joint core wire, and the joint core wire passes through the first opening and the second opening. Among them, the joint core wire is welded to the first electrode region, the second opening of the conductive joint flange is disposed opposite to the first opening of the second electrode 12, and a fixing member is used to connect the conductive joint flange and the second electrode 12. The fixing member can be a screw.

[0057] Further, in the second embodiment, at least a part of the region of the conductive joint flange may be located between the first electrode region and the second electrode 12, or may be located on the surface of the second electrode 12 facing away from the first electrode region.

[0058] Further, in the second embodiment, the structure formed by the conductive joint flange and the joint core wire may be a cable joint, such as Figure 8 shown, the cable joint connects the cable 5 to transmit electrical signals. Specifically, the cable joint is a radio frequency cable joint, and the cable 5 is a radio frequency cable. It should be understood that the radio frequency cable has a joint resistance of 50Ω, and using a radio frequency cable joint facilitates impedance matching.

[0059] Further, in the first embodiment and the second embodiment, the number of the inductance coils 13 may be one or two. Such as Figure 2 and Figure 4 shown, when the number of the inductance coils 13 is one, the electromagnetic wave detector further includes an insulating fixing member 133, the insulating fixing member 133 is spaced from the inductance coil 13, and both ends of the insulating fixing member 133 are respectively connected to the second electrode 12 and the first electrode to stabilize the structure of the electromagnetic wave detector 1. Such as Figure 1 and Figure 3 shown, when the number of the inductance coils 13 is two, the inductance coils 13 include a spaced first inductance coil 131 and a second inductance coil 132, the first inductance coil 131 and the second inductance coil 132 are respectively located at opposite ends of the second electrode 12, and the two inductance coils 13 can stabilize the structure of the electromagnetic wave detector 1.

[0060] In this embodiment, the total inductance of the inductance coils 13 is less than or equal to 1 μH. The inductive reactance of the inductance coils 13 is proportional to the frequency of the electromagnetic wave and the inductance of the inductance coils 13. Under power frequency or DC voltage, the inductive reactance of the inductance coils 13 is less than 0.3 mΩ, ensuring good connection between the first electrode region and the second electrode 12 and the inductance coils 13.

[0061] In this embodiment, the electromagnetic wave detector 1 is adapted to detect radio frequency electromagnetic waves radiated by the oil-paper insulated bushing 2, and the detection frequency range is 200 MHz to 1700 MHz. In the above detection frequency range, the inductive reactance of the inductance coils 13 is 1.3 kΩ to 10.7 kΩ, which is convenient for collecting electrical signals.

[0062] This embodiment also provides a partial discharge monitoring method. Using the electromagnetic wave detector 1 provided in this embodiment, the method includes the following steps: providing an oil-paper insulated bushing 2; sleeving the sleeve member 11 of the electromagnetic wave detector 1 on the outer side near the connection between the fixed connection sleeve 23 and the insulating sleeve; and determining whether partial discharge occurs in the oil-paper insulated bushing 2 by detecting whether an electrical signal is generated by the electromagnetic wave detector 1.

[0063] In the above partial discharge monitoring method, by sleeving the electromagnetic wave detector 1 on the outer side near the connection between the fixed connection sleeve 23 and the insulating sleeve, and detecting whether an electrical signal is generated by the electromagnetic wave detector 1 to determine whether partial discharge occurs in the oil-paper insulated bushing 2. The connection between the fixed connection sleeve 23 and the insulating sleeve is the electromagnetic wave leakage position of the oil-paper insulated bushing 2. Sleeving the sleeve member 11 near the electromagnetic wave leakage position improves the anti-interference ability of the electromagnetic wave detector 1 on the one hand, and effectively shortens the transmission distance of the electromagnetic wave on the other hand. The shortening of the electromagnetic wave transmission distance effectively reduces the attenuation degree of the electromagnetic wave, thereby improving the detection sensitivity and detection effect, and providing a more reliable basis for partial discharge maintenance. At the same time, the setting area of the electromagnetic wave detector 1 is a low ground potential and low field strength area, with high safety and reliability, which does not affect the safe operation of the electromagnetic wave detector 1, and provides a guarantee for the safe and reliable operation of the transformer.

[0064] Embodiment 2

[0065] See Figure 8 , this embodiment provides a partial discharge monitoring system, including: an oil-paper insulated bushing 2; the electromagnetic wave detector 1 provided in Embodiment 1, and the sleeve member 11 is sleeved on the outer side near the connection between the fixed connection sleeve 23 and the insulating sleeve.

[0066] In the above partial discharge monitoring system, by sleeving the electromagnetic wave detector 1 on the outer side near the connection between the fixed connection sleeve 23 and the insulating sleeve to detect whether partial discharge occurs in the oil-paper insulated bushing 2. The electromagnetic wave detector 1 is not only applicable to a variety of oil-paper insulated bushings 2, has high anti-interference ability, but also can shorten the transmission distance of the electromagnetic wave, thereby effectively reducing the attenuation degree of the electromagnetic wave, and further improving the detection sensitivity.

[0067] It should be understood that the partial discharge monitoring system includes not only the oil-paper insulated bushing 2 in the transformer, but also the transformer tank 4 and the riser 3 in the transformer.

[0068] In this embodiment, the partial discharge monitoring system further includes: a filtering module (not shown in the figure), the first conductive member 14 and the second conductive member 15 are electrically connected to the input end of the filtering module; an amplifying module (not shown in the figure), the input end of the amplifying module is electrically connected to the output end of the filtering module; a data acquisition module (not shown in the figure), the input end of the acquisition device is electrically connected to the output end of the amplifying module. The filtering module is used to filter out interference signals, the amplifying module is used to amplify signals, and the filtering module and the amplifying module can improve the signal-to-noise ratio of the electrical signal. Specifically, the filtering module, the amplifying module, and the acquisition module are all arranged outside the transformer tank 4. The filtering module is a filter, the amplifying module is an amplifier, and the acquisition device is an acquirer.

[0069] In this embodiment, the partial discharge monitoring system further includes a data analysis module (not shown in the figure), the output end of the data acquisition module is electrically connected to the data analysis module, and the data acquisition module is adapted to analyze the filtered and amplified electrical signal to determine the discharge type and locate the discharge position.

[0070] In this embodiment, the partial discharge monitoring system further includes: a third conductive member connecting the filtering module and the first conductive member 14 and a fourth conductive member connecting the filtering module and the second conductive member 15. Specifically, the third conductive member and the fourth conductive member are located in the cable 5, and the cable 5 is laid outside the transformer tank 4, outside the riser 3, and outside the connecting member 113 of the sleeve member 11. Further, for the convenience of installation and measurement and to ensure the safe operation of the partial discharge monitoring system and the transformer equipment, the height of the end of the cable 5 away from the electromagnetic wave detector 1 from the ground is less than or equal to 1.5 meters.

[0071] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An electromagnetic wave detector adapted to detect electromagnetic waves radiated by an oil-paper insulated bushing, wherein the oil-paper insulated bushing includes an insulating sleeve and a fixed connection sleeve connected to the insulating sleeve, the insulating sleeve and the fixed connection sleeve being arranged at intervals along the axial direction of the oil-paper insulated bushing; It is characterized in that Comprising: A sleeving member adapted to be sleeved outside the vicinity of the connection between the fixed connection sleeve and the insulating sleeve. The sleeving member includes a first electrode region. The sleeving member includes a first sleeving ring, a second sleeving ring, and a connecting member connecting the first sleeving ring and the second sleeving ring. The diameter of the first sleeving ring is larger than that of the second sleeving ring. The second sleeving ring is adapted to surround the oil-paper insulated bushing and be fixedly connected to the oil-paper insulated bushing. The first sleeving ring is adapted to surround the oil-paper insulated bushing and be spaced from the oil-paper insulated bushing. At least a part of the first sleeving ring serves as the first electrode region; A second electrode spaced and oppositely arranged with respect to the first electrode region; An inductance coil located between the first electrode region and the second electrode, with both ends of the inductance coil being respectively connected to the first electrode region and the second electrode. The first electrode region includes a spaced first connection region and a second connection region. The second electrode includes a spaced third connection region and a fourth connection region. The first connection region is connected to one end of the inductance coil, and the third connection region is connected to the other end of the inductance coil. The electromagnetic wave detector further includes: a first conductive member connected to the second connection region; a second conductive member connected to the fourth connection region. The first conductive member and the second conductive member are adapted to lead out electrical signals.

2. The electromagnetic wave detector according to claim 1, characterized in that, The insulating sleeve includes an upper insulating sleeve and a lower insulating sleeve arranged at intervals along the axial direction of the oil-paper insulated bushing. The fixed connection sleeve is located between the upper insulating sleeve and the lower insulating sleeve and is connected to the upper insulating sleeve and the lower insulating sleeve.

3. The electromagnetic wave detector according to claim 2, characterized in that, The second sleeving ring is adapted to be fixedly connected to the fixed connection sleeve, the upper insulating sleeve, or the lower insulating sleeve.

4. The electromagnetic wave detector according to claim 1, wherein The second electrode has a first opening penetrating through the second electrode. The first conductive member passes through the first opening and is spaced from the second electrode. The second conductive member is fixed on one side surface of the second electrode and is electrically connected to the second electrode at the edge of the first opening.

5. The electromagnetic wave detector according to claim 4, wherein The second conductive member includes a conductive joint flange having a second opening penetrating through the conductive joint flange. The conductive joint flange is fixed on one side surface of the second electrode at the edge of the first opening; The first conductive member includes a joint core wire passing through the first opening and the second opening.

6. The electromagnetic wave detector according to claim 1, characterized in that, The second electrode is a complete electrode. The first conductive member is spaced from the second electrode, and the second conductive member is spaced from the sleeving member.

7. The electromagnetic wave detector according to claim 1, characterized in that, Further comprising: An insulating fixing member, with both ends of the insulating fixing member being respectively connected to the second electrode and the first electrode, and the insulating fixing member being spaced from the inductance coil.

8. The electromagnetic wave detector according to claim 1, characterized in that, The inductance coil includes a spaced first inductance coil and a second inductance coil, and the first inductance coil and the second inductance coil are respectively located at opposite ends of the second electrode.

9. The electromagnetic wave detector according to claim 1, wherein The sleeving member includes a grading ring.

10. The electromagnetic wave detector according to claim 1, wherein The second electrode includes a metal strip.

11. The electromagnetic wave detector according to claim 1, wherein, The fixed connection sleeve is a flange and the fixed connection sleeve is grounded.

12. The electromagnetic wave detector according to claim 1, wherein, The inductance value of the inductance coil is less than or equal to 1 μH.

13. A partial discharge monitoring system, characterized in that, Comprising: Oil-paper insulating bushing; The electromagnetic wave detector according to any one of claims 1 to 12; The sleeving member is sleeved on the outer side near the connection between the fixed connection sleeve and the insulating sleeve.

14. The partial discharge monitoring system according to claim 13, wherein The first electrode region includes a spaced first connection region and a second connection region, and the second electrode includes a spaced third connection region and a fourth connection region; the first connection region is connected to one end of the inductance coil, and the third connection region is connected to the other end of the inductance coil; The electromagnetic wave detector further includes: a first conductive member connected to the second connection region; a second conductive member connected to the fourth connection region; The partial discharge monitoring system further includes: A filtering module, and the first conductive member and the second conductive member are electrically connected to the input end of the filtering module; An amplifying module, and the input end of the amplifying module is electrically connected to the output end of the filtering module; A data acquisition module, and the input end of the data acquisition module is electrically connected to the output end of the amplifying module.

15. A method for partial discharge monitoring, characterized in that Using the electromagnetic wave detector according to any one of claims 1 to 12, comprising: Providing an oil-paper insulating bushing; Sleeving the sleeving member of the electromagnetic wave detector on the outer side near the connection between the fixed connection sleeve and the insulating sleeve; Judging whether partial discharge occurs in the oil-paper insulating bushing by detecting whether an electrical signal is generated by the electromagnetic wave detector.

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