Voltage transformer resonance elimination device and method based on current limiting technology

Abstract

The invention relates to the technical field of voltage transformer ferromagnetic resonance elimination, and particularly provides a voltage transformer resonance elimination device and method based on a current limiting technology. The device comprises a resonance eliminator; the limiting assembly comprises a rotating ring and a plurality of threaded fasteners; the rotating ring is rotatably arranged on the grounding platform; the grounding platform is provided with a plurality of internal threaded holes, and the threaded fasteners are connected with the corresponding internal threaded holes in a matched mode through external threads. The threaded fastener is used for clamping the fixing rod during rotation; the adjusting assembly is used for adsorbing the fixing rod when being electrified, so that the resonance eliminator is grounded; the distance measuring assembly is used for detecting the mounting distance between the fixing rod and the grounding platform; the control device is used for judging whether the resonance eliminator is completely grounded or not based on the installation distance and the preset distance and controlling the limiting assembly and the adjusting assembly to act. According to the voltage transformer resonance elimination device and method based on the current limiting technology, the problem that grounding is incomplete due to the fact that fixing bolts of a resonance eliminator are prone to loosening can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ferromagnetic resonance elimination of voltage transformers, and particularly relates to a voltage transformer resonance elimination device and method based on current limiting technology. BACKGROUND

[0002] The power distribution network of 6kV-35kV in the related art has a complex network structure and low insulation strength, and single-phase grounding faults are prone to occur. In order to reduce power loss and improve power supply reliability, a neutral point is not directly grounded in the operation mode of the power distribution network. In this operation mode, the system does not need to be tripped immediately when a single-phase grounding fault occurs, and can be operated with the fault for two hours. During this period, the operating personnel can take measures to isolate the fault point and eliminate the fault to reduce the power outage range. However, during the time when the system is operated with the fault, the voltage of the power grid will appear asymmetric mutation, which is easy to cause ferromagnetic resonance overvoltage phenomenon, and then cause the fuse of the high-voltage side of the voltage transformer to be blown and the voltage transformer to be burned, etc. The single-phase grounding fault is developed into a multi-phase grounding, which expands the accident and causes greater losses.

[0003] For the problem of ferromagnetic resonance overvoltage, the traditional method usually connects a passive resonance eliminator in series at the neutral point of the voltage transformer, and the passive resonance eliminator passively eliminates the ferromagnetic resonance overvoltage after it occurs. This method has the following defects.

[0004] (1) The resonance eliminator needs to be grounded during use, but due to the influence of electromagnetic vibration of the power grid, the fixing bolt for fixing the passive resonance eliminator is prone to looseness, which causes the resonance eliminator to be incompletely grounded and affects normal work.

[0005] (2) The resonance elimination range is limited and cannot adapt to different types of ferromagnetic resonance overvoltage problems. SUMMARY

[0006] The voltage transformer resonance elimination device and method based on current limiting technology provided by the embodiments of the present application at least solve the problem that the fixing bolt of the resonance eliminator is prone to looseness, which causes incomplete grounding.

[0007] To achieve the above object, the present application provides the following technical solutions.

[0008] In a first aspect, the present application provides a voltage transformer anti-cancellation device based on current limiting technology, comprising: an anti-cancellation device, a fixed rod is arranged on the anti-cancellation device, and the anti-cancellation device is used for anti-cancellation of the voltage transformer in the case of grounding; a limiting component, comprising: a swivel and a plurality of threaded fasteners; the swivel is rotatably arranged on a grounding platform, and an inner edge of the swivel is provided with internal teeth; each threaded fastener is provided with a first gear, and each first gear is in meshing connection with the internal teeth; the threaded fastener is provided with a first through hole through which the fixed rod passes; the grounding platform is provided with a plurality of internal threaded holes, and the threaded fastener is connected with the corresponding internal threaded hole through external threads; the threaded fastener is used for clamping the fixed rod when rotating; an adjusting component is arranged at the bottom of the internal threaded hole and is used for adsorbing the fixed rod when power is on, so that the anti-cancellation device is grounded; a distance measuring component is arranged on the fixed rod and is used for detecting the installation distance between the fixed rod and the grounding platform; a control device is connected with the distance measuring component, the limiting component and the adjusting component, and is used for judging whether the anti-cancellation device is completely grounded based on the installation distance and a preset distance, and controlling the limiting component and the adjusting component to act.

[0009] Preferably, the limiting component further comprises: a fixed block; the fixed block is symmetrically arranged on opposite sides of the anti-cancellation device; the fixed rod is arranged on each fixed block, and the center line of the fixed rod and the center line of the anti-cancellation device are parallel to the normal line of the grounding platform; the bottom surface height of the fixed rod is not lower than the bottom surface height of the anti-cancellation device.

[0010] Preferably, the distance measuring component comprises: a laser; the laser is arranged at the bottom of each fixed block and is connected with the control device, and is used for detecting the straight-line distance between the fixed block and the grounding platform.

[0011] Preferably, the limiting component further comprises: a fixed cylinder arranged on the grounding platform; the internal thread hole is arranged in the inside of the fixed cylinder; a fixed clamp is arranged in the inside of the internal thread hole and between the threaded fastener and the grounding platform; the fixed clamp is provided with a movable clamp opening, and the fixed rod passes through the movable clamp opening; the threaded fastener is used for pressing the movable clamp opening when rotating, and limiting the fixed rod.

[0012] Preferably, the fixing clamp comprises: a fixing disc fixedly arranged inside the internally threaded hole; the fixing disc is provided with a second through hole through which the fixing rod passes; at least two clamping pieces are arranged on one side of the fixing disc close to the threaded fastener; the inner surface of each clamping piece is matched in shape with the outer surface of the fixing rod, and the outer surface of the clamping piece is provided with a flange; the flange is matched with the bottom clamping groove of the threaded fastener.

[0013] Preferably, the limiting assembly further comprises: a motor arranged on the grounding platform; and a second gear arranged on the output shaft of the motor and engaged with the outer gear arranged on the outer edge of the rotating ring.

[0014] Preferably, the adjusting assembly comprises: an electromagnet arranged at the bottom of the internally threaded hole and connected to the control device; and the relative distance between the electromagnet and the fixing rod is equal to the relative distance between the grounding platform and the grounding end on the harmonic eliminator.

[0015] Preferably, the image detection assembly comprises: a camera arranged on the grounding platform and configured to capture image information of a surface within the detection range of the measuring assembly corresponding to the grounding platform; and an image recognizer connected to the camera and the control device and configured to identify whether the surface of the grounding platform has foreign matter based on the image information and send the identification result to the control device.

[0016] Preferably, the harmonic eliminator comprises: a primary harmonic eliminator connected in series with the neutral point of the voltage transformer and configured to passively eliminate the harmonic of the voltage transformer when grounding; and a secondary harmonic eliminator connected to both ends of the open-delta winding of the voltage transformer and configured to connect a parallel impedance to the open-delta winding to actively eliminate the harmonic of the voltage transformer when the detection device detects that the voltage transformer has a ferromagnetic resonance overvoltage phenomenon; wherein the detection device is connected to the control device.

[0017] In another aspect, the present application provides a voltage transformer anti-harmonic method of current limiting technology, comprising the following steps: obtaining the installation distance between the fixed rod and the grounding platform through the distance measuring assembly; wherein the fixed rod is arranged on the anti-harmonic device; the distance measuring assembly is arranged on the fixed rod; judging whether the anti-harmonic device is completely grounded based on the installation distance and the preset distance; when the anti-harmonic device is not completely grounded, controlling the limiting assembly to release the fixed rod, and controlling the adjusting assembly to be electrified to adsorb the fixed rod; wherein the limiting assembly comprises: a swivel and a plurality of threaded fasteners; the swivel is rotatably arranged on the grounding platform, and the inner edge of the swivel is provided with internal teeth; a plurality of threaded fasteners are arranged inside the swivel; each threaded fastener is provided with a first gear, and the first gear is connected with the internal teeth in meshing connection; the threaded fastener is provided with a first through hole for the fixed rod to pass through; the grounding platform is provided with an internal threaded hole, and the outer surface of the threaded fastener is provided with an external thread; the external thread is connected with the internal threaded hole in cooperation; the threaded fastener is used to clamp the fixed rod when rotating; the adjusting assembly is arranged at the bottom of the internal threaded hole, and is used to adsorb the fixed rod when electrified, so that the anti-harmonic device contacts with the grounding platform; when the anti-harmonic device is completely grounded, the adjusting assembly is controlled to stop electrifying, and the limiting assembly is controlled to clamp the fixed rod, so that the anti-harmonic device is used to anti-harmonic the voltage transformer.

[0018] Preferably, before judging whether the anti-harmonic device is completely grounded based on the installation distance and the preset distance, the method further comprises: when the installation distance is not equal to the preset distance, starting the image detection assembly to detect whether there is sundry on the surface of the detection range of the distance measuring assembly corresponding to the grounding platform 400 through the control device; when there is sundry, the sundry is cleaned; when there is no sundry, whether the anti-harmonic device is grounded is judged.

[0019] Preferably, judging whether the anti-harmonic device is completely grounded based on the installation distance and the preset distance comprises the following steps: based on the installation distance and the preset distance, the state characteristic value is calculated according to the following formula:

[0020] wherein, the state characteristic value is represented by, the first distance between the first fixed block and the grounding platform collected for the nth time is represented by, the second distance between the second fixed block and the grounding platform collected for the nth time is represented by; the first fixed block and the second fixed block are symmetrically arranged on both sides of the anti-harmonic device and are fixedly connected with the fixed rod; ​The preset distance represents a distance between the first fixed block and the second fixed block and the grounding platform when the harmonic eliminator contacts the grounding platform; when the state characteristic value is not 0 and is less than a set threshold, it is determined that the harmonic eliminator is not completely grounded, wherein the set threshold is 1 / S-3 / S.

[0021] Compared with the prior art, the above technical scheme of the present application has the following beneficial effects.

[0022] The voltage transformer harmonic elimination device and method based on the current limiting technology provided by the embodiment of the present application can limit the fixed rod on the voltage transformer through the limiting assembly, compared with the bolt connection in the related art, the limiting assembly provided by the present application rotates and presses the fixed rod through the threaded fastener, and the rotation of the threaded fastener is driven through the meshing transmission of the rotating ring and the first gear, so that the fixation of the fixed rod is more reliable and is not prone to loosening, and the installation and disassembly of the harmonic eliminator can be quickly realized. In addition, the embodiment of the present application further detects the installation distance between the fixed rod and the grounding platform through the distance measuring assembly, and controls the limiting assembly and the adjusting assembly to act based on the installation distance and the preset distance through the control device, so that whether the harmonic eliminator is completely grounded can be automatically detected, and when the grounding is not complete, the fixed rod is released through the limiting assembly, and then the fixed rod is adsorbed through the adjusting assembly, so that the harmonic eliminator restores the grounding, thereby avoiding the problem that the harmonic eliminator cannot be normally used due to incomplete grounding, and the detection and grounding adjustment of the harmonic eliminator can be timely and efficiently performed, so that the voltage transformer is provided with more stable and reliable harmonic elimination effect, and the problem that the fixing bolt of the harmonic eliminator is prone to loosening and causes incomplete grounding is solved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical schemes in the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other embodiments can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0024] Figure 1 is a structural block diagram of the voltage transformer harmonic elimination device based on the current limiting technology of the embodiment of the present application.

[0025] Figure 2 is an action principle diagram of the voltage transformer harmonic elimination device based on the current limiting technology of the embodiment of the present application.

[0026] Figure 3 is a structural schematic diagram of the secondary harmonic eliminator of the embodiment of the present application.

[0027] Figure 4The overall structure schematic diagram of the one-time harmonic eliminator, the fixing assembly, the adjusting assembly and the mounting platform of the embodiment of the present application.

[0028] Figure 5 The structure schematic diagram of the one-time harmonic eliminator and the fixing assembly of the embodiment of the present application.

[0029] Figure 6 The overall structure schematic diagram of the adjusting assembly of the embodiment of the present application.

[0030] Figure 7 The exploded view of the adjusting assembly of the embodiment of the present application.

[0031] Figure 8 The structure schematic diagram of the connection between the fixing assembly, the adjusting assembly and the mounting platform of the embodiment of the present application.

[0032] Figure 9 The structure schematic diagram of the connection between the fixing assembly, the adjusting assembly and the mounting platform of the embodiment of the present application. Figure 8 The partial enlarged view of the structure at A of the embodiment of the present application.

[0033] Figure 10 The flowchart of the voltage transformer harmonic elimination method based on the current limiting technology of the embodiment of the present application.

[0034] In the figure, the reference signs are as follows: 100, harmonic eliminator; 200, fixing assembly; 210, fixing block; 220, fixing rod; 221, anti-skid protrusion; 300, limiting assembly; 310, motor; 311, second gear; 320, annular base; 321, rotating ring; 322, external teeth; 323, internal teeth; 330, fixing cylinder; 331, internal thread; 332, first cavity; 333, second cavity; 340, threaded fastener; 341, first gear; 342, external thread; 343, first through hole; 344, clamping groove; 350, fixing disc; 351, clamping piece; 352, flange; 360, electromagnet; 370, camera; 400, grounding platform. DETAILED DESCRIPTION

[0035] The embodiments of the present application will be described in more detail by making reference to the accompanying drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be realized in various forms and should not be interpreted as being limited to the embodiments set forth herein, rather these embodiments are provided for a more thorough and complete understanding of the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes and are not intended to limit the scope of protection of the present application.

[0036] As Figure 1 , Figures 4-7As shown, at least to solve the problem that the fixing bolt of the harmonic eliminator is easy to loosen, resulting in incomplete grounding, the embodiment of the application provides a voltage transformer harmonic elimination device based on current limiting technology, which comprises a harmonic eliminator 100, a limiting assembly 300, an adjusting assembly, a distance measuring assembly and a control device.

[0037] The harmonic eliminator 100 is provided with a fixing rod 220 for eliminating the harmonic of the voltage transformer in the case of grounding.

[0038] The limiting assembly 300 comprises a swivel ring 321 and a plurality of threaded fasteners 340; the swivel ring 321 is rotatably arranged on a grounding platform 400, and the inner edge of the swivel ring 321 is provided with internal teeth 323; the plurality of threaded fasteners 340 are arranged inside the swivel ring 321; each threaded fastener 340 is provided with a first gear 341, and the first gear 341 is in meshing connection with the internal teeth 323; the threaded fastener 340 is provided with a first through hole through which the fixing rod 220 passes; the grounding platform 400 is provided with a plurality of internal threaded holes 331, and the threaded fastener 340 is in matching connection with the corresponding internal threaded hole 331 through an external thread 342; the threaded fastener 340 is used for clamping the fixing rod 220 when rotating.

[0039] The adjusting assembly is arranged at the bottom of the internal threaded hole 331 and is used for adsorbing the fixing rod 220 when power is on, so that the harmonic eliminator 100 is grounded.

[0040] The distance measuring assembly is arranged on the fixing rod 220 and is used for detecting the installation distance between the fixing rod 220 and the grounding platform 400.

[0041] The control device is connected with the distance measuring assembly, the limiting assembly 300 and the adjusting assembly, and is used for controlling the limiting assembly 300 and the adjusting assembly to act based on the installation distance and a preset distance.

[0042] Specifically, the harmonic eliminator 100 is a protection device for suppressing the resonance overvoltage in the power system, which eliminates the resonance condition by consuming resonance energy or changing the loop parameters based on the “damping” or “frequency offset” of the resonance loop, and is mainly applied to the power system with neutral point not grounded or grounded through arc suppression coil, and is especially commonly used in the voltage transformer (PT) loop to avoid the problems of equipment damage, metering abnormality, protection misoperation and the like caused by resonance.

[0043] The distance measuring assembly is part of the detection unit. After the distance measuring assembly detects the installation distance between the fixing rod 220 and the grounding platform 400, the control device judges whether the harmonic eliminator 100 is completely grounded based on the installation distance and the preset distance.

[0044] When the harmonic eliminator 100 is not completely grounded, the control device drives the rotation of the rotating ring 321 in the limiting assembly 300, and after the rotation of the rotating ring 321 in the limiting assembly 300, the rotating ring 321 drives the rotation of the plurality of first gears 341 and the threaded fasteners 340 connected therewith, and each threaded fastener 340 moves away from the threaded hole 331 while rotating in the threaded hole 331, thereby releasing the clamping force on the fixed rod 220 passing through the threaded fastener 340, and thereby releasing the limiting of the fixed rod 220.

[0045] When the fixed rod 220 is released, the control device energizes the adjusting assembly, the adjusting assembly adsorbs the fixed rod 220, and the harmonic eliminator 100 is restored to be grounded.

[0046] When the control device determines that the harmonic eliminator 100 is completely grounded based on the installation distance and the preset distance, the rotating ring 321 in the limiting assembly 300 is driven to rotate again, and the plurality of first gears 341 and the threaded fasteners 340 connected therewith are driven to rotate, and each threaded fastener 340 moves towards the threaded hole 331 while rotating in the threaded hole 331, thereby clamping and limiting the fixed rod 220 passing through the threaded fastener 340, and thereby reliably fixing the fixed rod 220 on the grounding platform 400.

[0047] The voltage transformer harmonic eliminator based on the current limiting technology provided by the embodiment of the application fixes the fixed rod on the voltage transformer through the limiting assembly, compared with the bolt connection in the related art, the limiting assembly provided by the application rotates and compresses the fixed rod through the threaded fastener, and the rotation of the threaded fastener is driven through the meshing transmission of the rotating ring and the first gear, so that the fixing of the fixed rod is more reliable and is not prone to loosening, and the installation and dismounting of the harmonic eliminator can be quickly realized.

[0048] In addition, the embodiment of the application further detects the installation distance between the fixed rod and the grounding platform through the distance measuring assembly, and controls the actions of the limiting assembly and the adjusting assembly based on the installation distance and the preset distance through the control device, so that whether the harmonic eliminator is completely grounded can be automatically detected, the fixed rod is released through the limiting assembly when the harmonic eliminator is not completely grounded, and the fixed rod is adsorbed through the adjusting assembly, so that the harmonic eliminator is restored to be grounded, thereby avoiding the problem that the harmonic eliminator cannot be normally used due to incomplete grounding, and the detection and grounding adjustment of the harmonic eliminator can be timely and efficiently performed, so that the harmonic eliminator provides more stable and reliable harmonic elimination effect for the voltage transformer, and solves the problem that the fixing bolt of the harmonic eliminator is prone to loosening and causes incomplete grounding.

[0049] As shown in Figure 4 , Figure 5 , the limiting assembly 300 further preferably comprises a fixed block 210.

[0050] The fixed blocks 210 are symmetrically arranged on opposite sides of the harmonic eliminator 100. The fixed rods 220 pass through each fixed block 210 and are fixedly connected with the corresponding fixed block 210. The center line of the fixed rod 220 and the center line of the harmonic eliminator 100 are parallel to the normal line of the grounding platform 400. The bottom surface height of the fixed rod 220 is not lower than the bottom surface height of the harmonic eliminator 100.

[0051] The embodiment of the present application creates by arranging the fixed blocks 210 on opposite sides of the harmonic eliminator 100, so that the harmonic eliminator 100 is uniformly stressed on both sides, and the fixation is more reliable. By arranging the fixed rod 220 and the harmonic eliminator 100 parallel to the normal line of the grounding platform 100, and the bottom surface height of the fixed rod 220 is not lower than the bottom surface height of the harmonic eliminator 100, so that the fixed rod 220 can contact the grounding end of the bottom of the harmonic eliminator 100 with the grounding platform 400 when moving, and ensure that the harmonic eliminator 100 can be grounded.

[0052] Further, the outer surface of the fixed rod 220 is provided with anti-skid protrusions 221. By arranging the anti-skid protrusions 221 on the surface of the fixed rod 220, the friction of the outer surface of the fixed rod 220 can be increased, so that the limiting between the fixed rod 220 and the threaded fastener 340 is more reliable.

[0053] The distance measuring assembly preferably comprises a laser. The laser is arranged at the bottom of each fixed block 210 and is connected with the control device, for detecting the straight-line distance between the fixed block 210 and the grounding platform 400.

[0054] The two fixed blocks 210 are respectively referred to as a first fixed block and a second fixed block. The laser arranged at the bottom of the first fixed block is a first laser, and the laser arranged at the bottom of the second fixed block is a second laser. The installation distance between the first fixed block and the grounding platform detected by the first laser is denoted as L1. The installation distance between the second fixed block and the grounding platform detected by the second laser is denoted as L2. .

[0055] The embodiment of the present application creates by arranging the laser, which can automatically obtain the distance between the fixed block 210 and the grounding platform 400, and send the distance to the control device, so as to analyze the grounding condition of the harmonic eliminator.

[0056] Further, in combination with the fixed rod 220 shown in Figure 8 , Figure 9 The limiting assembly 300 preferably further comprises a fixed cylinder 330 and a fixed clamp.

[0057] The fixed cylinder 330 is arranged on the grounding platform 400, and the number and position of the fixed cylinder 330 are matched with the fixed rod 220. The inside of the fixed cylinder 330 is provided with an internal threaded hole 331.

[0058] The fixed clamp is arranged inside the internally threaded hole 331 and between the threaded fastener 340 and the grounding platform 400, is provided with a movable clamp opening, and the fixed rod 220 passes through the movable clamp opening; the threaded fastener 340 is used to press the movable clamp opening when being rotated and position the fixed rod 220.

[0059] Further, the fixed cylinder 330 is internally provided with a first cavity 332 and a second cavity 333, wherein the first cavity 332 is between the second cavity 333 and the grounding platform 400; the first cavity 332 and the second cavity 333 are shaped to match the fixed rod 220; and the internally threaded hole 331 is arranged in the second cavity 333.

[0060] The fixed rod 220, the first cavity 332 and the second cavity 333 are preferably cylindrical, the inner diameter of the first cavity 332 is greater than the outer diameter of the fixed rod 220 and smaller than the inner diameter of the second cavity, so that a stepped surface is formed between the first cavity 332 and the second cavity 333, and the fixed clamp is fixed on the stepped surface at the bottom of the second cavity 333.

[0061] Further, the fixed clamp preferably comprises a fixed disc 350 and at least two clamping pieces 351.

[0062] The fixed disc 350 is fixedly arranged inside the internally threaded hole 331, and the bottom of the fixed disc 350 is fixed on the stepped surface; and the fixed disc 350 is provided with a second through hole for the fixed rod 220 to pass through.

[0063] The at least two clamping pieces 351 are arranged on one side of the fixed disc 350 close to the threaded fastener 340; and each clamping piece 351 is provided with a movable clamp opening between an adjacent clamping piece 351. The inner surface of the clamping piece 351 matches the shape of the outer surface of the fixed rod 220, and the outer surface of the clamping piece 351 is provided with a flange 352; and the flange 352 matches the clamping groove arranged at the bottom of the threaded fastener 340.

[0064] The clamping piece 351 is elastic and can be elastically deformed. When the clamping groove of the threaded fastener presses the clamping piece 351, the clamping piece 351 is elastically deformed, so that the movable clamp opening is tightened.

[0065] The embodiment of the application sets the at least two clamping pieces 351 and arranges the movable clamp opening between the adjacent clamping pieces 351, so that the fixed rod 220 can pass through the movable clamp opening. When the threaded fastener 340 moves to the side close to the grounding platform 400 until the flange 352 is inserted into the inside of the clamping groove, the movable clamp opening is tightened inwardly under the extrusion of the clamping groove of the threaded fastener 340, so as to clamp the fixed rod 220 inside the fixed clamp and position the fixed rod 220.

[0066] Further, the outer surface of the flange 352 is provided with a guide inclined surface, and the width of the flange 352 gradually decreases from the side close to the fixed disc 350 to the side away from the fixed disc 350. The plurality of flanges 352 of the plurality of clamping pieces 351 are arranged in a circular truncated cone shape.

[0067] The inner surface of the clamping groove matches the outer surface of the flange 352, and is preferably a tapered expansion hole.

[0068] When the threaded fastener 340 gradually presses the clamping piece 351, the tapered hole gradually extrudes the flange 352, so that the movable clamp is tightened, thereby clamping the fixed rod 220.

[0069] Further, the rotating ring 321 is rotatably installed on the annular base 320, one side of the annular base 320 is fixedly connected with the grounding platform 400, and the other side is provided with a sliding groove, and the rotating ring 321 is rotatably connected with the sliding groove. The fixed cylinder 330 is arranged on the inner side of the annular base 320.

[0070] Further, the limiting assembly 300 preferably further comprises: a motor 310 and a second gear 311.

[0071] The motor 310 is arranged on the grounding platform 400 and is outside the annular base 320. The motor 310 is preferably a reciprocating motor.

[0072] The second gear 311 is arranged on the output shaft of the motor 310 and is in meshing connection with the outer gear 322 arranged on the outer edge of the rotating ring 321.

[0073] The embodiment of the application creates a motor 310 to drive the second gear 311 to rotate, which can drive the rotating ring 321 and the first gear 341 to mesh transmission, and then control the switch of the motor 310 through the control device, so as to automatically start the limiting assembly 300 to work, and realize the quick fixing and dismounting of the fixed rod 220.

[0074] Further, the adjusting assembly comprises: an electromagnet 360. The electromagnet 360 is arranged at the bottom of the inner threaded hole 331 and is connected with the control device; the relative distance between the electromagnet 360 and the fixed rod 220 is equal to the relative distance between the grounding platform 400 and the grounding end of the harmonic eliminator 100.

[0075] The embodiment of the application creates an electromagnet 360, which can attract the fixed rod 220 when powered on. When the fixed rod 220 contacts the electromagnet 360, the grounding end of the harmonic eliminator 100 contacts the grounding platform, so that the harmonic eliminator 100 is in a grounded state. When the control device detects that the harmonic eliminator is in a completely grounded state, the electromagnet 360 is controlled to be in a power-off state, which does not affect the normal work of the harmonic eliminator 100.

[0076] Further preferably, the electromagnet 360 is embedded in the interior of the grounding platform 400, and the surface height of the electromagnet 360 is flush with the surface height of the grounding platform 400. The surface height of the grounding end of the harmonic eliminator 100 is flush with the bottom surface height of the fixing rod 220, so that when the fixing rod 220 is in contact with the electromagnet 360, the grounding end of the harmonic eliminator 100 is in contact with the grounding platform 400 and remains in a grounded state.

[0077] Further, the detection unit of the embodiment of the present application further comprises an image detection assembly. The image detection assembly comprises a camera 370 and an image recognizer.

[0078] The camera 370 is arranged on the grounding platform 400 and fixedly connected with the inner surface of the annular base 320, and is used to capture image information of the surface within the detection range of the distance measuring assembly corresponding to the grounding platform 400.

[0079] The image recognizer is connected with the camera 370 and the control device, and is used to identify whether there is debris on the surface of the grounding platform based on the image information, and send the identification result to the control device.

[0080] When the control device receives the installation distance between the fixing block 210 and the grounding platform 400 and detects that the installation distance is not equal to the preset distance, the image detection assembly is first started to identify whether there is debris on the surface of the grounding platform 400. When there is debris, the debris needs to be cleaned. When the surface of the grounding platform 400 within the detection range of the distance measuring assembly does not have debris, the control device starts the limiting assembly and the adjusting assembly to adjust the position of the harmonic eliminator, so that the harmonic eliminator returns to the grounded state.

[0081] Further, for the cleaning of the debris, a swing rod structure can be installed on the annular base 320 to remove the debris on the surface of the mounting plate 400 in the direction of the laser output end by driving the swing rod, so as to ensure that there is no debris on the surface of the mounting plate 400 in the direction of the laser output end, and avoid affecting the distance measurement of the laser. The swing rod can be realized by the existing swing structure, which is a technology known to those skilled in the art and will not be described here.

[0082] Further, as shown in Figure 2 The harmonic eliminator 100 comprises a primary harmonic eliminator and a secondary harmonic eliminator.

[0083] The primary harmonic eliminator is connected in series with the neutral point of the voltage transformer, and is used to passively eliminate the harmonic of the voltage transformer when grounded.

[0084] The secondary ferroresonance eliminator is connected with two ends of the open-delta winding of the voltage transformer, and is used for connecting a parallel impedance to the open-delta winding to actively eliminate the ferroresonance of the voltage transformer when the detection device detects that the voltage transformer has the ferroresonance overvoltage phenomenon.

[0085] The primary ferroresonance eliminator includes a current-sensitive ferroresonance eliminator, a resistance-type ferroresonance eliminator, an inductance-type ferroresonance eliminator, and the like, and the core feature is to realize the ferroresonance elimination through the “nonlinear” characteristic that the resistance value of the ferroresonance eliminator changes with the current. In normal operation, the current flowing through the ferroresonance eliminator is extremely small (such as the excitation current of the voltage transformer), and the resistance value is high, and the influence on the circuit can be ignored. When the system has the ferroresonance, the resonance current significantly increases, the resistance value of the ferroresonance eliminator rapidly decreases with the increase of the current, a low-impedance path is formed, the resonance energy is consumed, the resonance overvoltage is suppressed, and thus the voltage transformer (PT) and other equipment are protected.

[0086] Further, as Figure 3 The secondary ferroresonance eliminator 100 preferably includes a detection device, a ferroresonance elimination device, and a switch.

[0087] The detection device is connected with the control device, and is used for detecting whether the voltage transformer has the ferroresonance overvoltage phenomenon, and sending the detection result to the control device.

[0088] The ferroresonance elimination device is connected with two ends of the open-delta winding of the voltage transformer, forms a ferroresonance elimination loop, and is used for connecting an impedance load RZ to the open-delta winding to actively eliminate the ferroresonance of the voltage transformer.

[0089] The switch K is connected in series with the ferroresonance elimination loop and is connected with the control device.

[0090] The control device is configured to close the switch and turn on the ferroresonance elimination loop when the detection result that the voltage transformer has the ferroresonance overvoltage is received.

[0091] Specifically, the switch K is preferably a bidirectional solid switch based on an SCR (Silicon Controlled Rectifier), because the on-state resistance of the SCR is very small, and the influence on the connected loop can be ignored. The controller of the SCR is composed of a Siemens PLC (Programmable Logic Controller) and an optical isolation circuit, and has the advantages of simple structure, strong anti-interference ability, and high reliability.

[0092] The embodiment of the present application creates a synergistic protection system of "front-end suppression + rear-end precise intervention" by using a primary harmonic eliminator and a secondary harmonic eliminator in cooperation. The primary current limiting technology based on the flow sensitivity characteristics and the secondary current limiting technology with the saturation current as the action criterion are combined, and the two technologies interact with each other through the neutral point current of the voltage transformer to ensure that the voltage transformer is not saturated and does not resonate.

[0093] The primary harmonic eliminator works before the secondary harmonic eliminator, and the primary harmonic eliminator can quickly respond to current changes by changing the loop parameters to play the role of eliminating the resonance as soon as it occurs. The secondary harmonic eliminator actively releases residual resonance energy to solve the problem of moderate resonance that is not completely suppressed by the primary harmonic eliminator, thereby significantly improving the adaptive ability to different resonance causes.

[0094] Further, the detection device is also used for monitoring the three-phase voltage of the power grid, the open voltage, and the PT neutral point current to realize real-time understanding of the running state of the power grid and the running state of the flow-sensitive harmonic eliminator, quickly identify the fault type (arc grounding, metal grounding, low-resistance grounding, high-resistance grounding, resonance, system over / under voltage, PT disconnection) in the system, alarm for the fault, and record the wave of the fault voltage and current, which is beneficial to analyze the causes of resonance and fault occurrence.

[0095] For example: the open delta voltage is between 89.6-100V, the fault phase voltage is less than or equal to 6V, the normal phase voltage is 94-100V, and the fault type is judged to be metal grounding; when the fault phase voltage is less than or equal to 50V, the fault type is judged to be under-voltage; and when the fault phase voltage is greater than 65V, the fault type is judged to be over-voltage.

[0096] Further, the control device of the embodiment of the present application is provided with an analysis unit, which can judge whether the harmonic eliminator is completely grounded based on the installation distance and the set distance, and the specific method is referred to the following current limiting technology voltage transformer harmonic elimination method.

[0097] As shown in Figure 10 Another embodiment of the present application provides a current limiting technology voltage transformer harmonic elimination method, which includes the following steps.

[0098] Step S501: Obtain the installation distance between the fixed rod 220 and the grounding platform 400 through the distance measuring assembly; wherein the fixed rod 220 is arranged on the harmonic eliminator 100; and the distance measuring assembly is arranged on the fixed rod 220.

[0099] Step S502: Judge whether the harmonic eliminator 100 is completely grounded based on the installation distance and the preset distance.

[0100] Step S503, when the harmonic eliminator 100 is not grounded completely, the control limiting assembly 300 releases the fixed rod 220, and the control adjusting assembly is powered to adsorb the fixed rod 220; wherein the limiting assembly 300 comprises: a swivel 321 and a plurality of threaded fasteners 340; the swivel 321 is rotatably arranged on the grounding platform 400, and the inner edge of the swivel 321 is provided with an inner tooth 323; the plurality of threaded fasteners 340 are arranged in the interior of the swivel 321; each threaded fastener 340 is provided with a first gear 341, and the first gear 341 is in meshing connection with the inner tooth 323; the threaded fastener 340 is provided with a first through hole for the fixed rod 220 to pass through; the grounding platform 400 is provided with an internal threaded hole 331, and the outer surface of the threaded fastener 340 is provided with an external thread 342; the external thread 342 is in matching connection with the internal threaded hole 331; the threaded fastener 340 is used for clamping the fixed rod 220 when rotating; the adjusting assembly is arranged at the bottom of the internal threaded hole 331, and is used for adsorbing the fixed rod 220 when powered, so that the harmonic eliminator 100 is in contact with the grounding platform 400.

[0101] Step S504, when the harmonic eliminator 100 is grounded completely, the control adjusting assembly stops being powered, and the control limiting assembly 300 clamps the fixed rod 220, so that the harmonic eliminator 100 performs harmonic elimination on the voltage transformer.

[0102] The voltage transformer harmonic elimination method based on the current limiting technology provided by the embodiment of the application can timely and quickly find whether the harmonic eliminator is not grounded completely by periodically detecting the installation distance between the fixed rod 220 and the grounding platform 400. The control device is used to control the limiting assembly and the adjusting assembly to work, so that the release and clamping of the fixed rod can be quickly adjusted, and the fixed rod is not prone to loosening. Then the adjusting assembly is used to adsorb the fixed rod, so that the harmonic eliminator is grounded again, thereby avoiding the problem that the harmonic eliminator cannot be normally used due to incomplete grounding, and the harmonic eliminator can be timely and efficiently detected and grounded, so that the voltage transformer can be provided with more stable and reliable harmonic elimination effect.

[0103] Before step S502, the method of the embodiment of the application further comprises:

[0104] Step S0521, when the installation distance is not equal to the preset distance, the control device is used to start the image detection assembly to detect whether there is sundry on the surface of the detection range of the grounding platform 400 corresponding to the distance measuring assembly; wherein the preset distance is the distance between the first fixed block 210 and the second fixed block 210 and the grounding platform 400 when the harmonic eliminator 100 is in contact with the grounding platform 400.

[0105] Step S0522, when there is sundry, the sundry is cleaned; when there is no sundry, step S502 is performed.

[0106] The embodiment of the present application avoids the influence of the sundries on the measurement result of the distance measuring assembly by detecting the sundries on the surface of the grounding platform 400 between steps S502, so as to ensure that step S502 can more accurately determine whether the harmonic eliminator 100 is completely grounded.

[0107] Step S502 preferably comprises the following steps.

[0108] Step S5021, based on the installation distance and the preset distance, calculates the state characteristic value according to the following formula.

[0109] ;

[0110] Wherein, denotes the state characteristic value, denotes the first distance between the first fixed block and the grounding platform 400 collected for the nth time, denotes the second distance between the second fixed block and the grounding platform 400 collected for the nth time; the first fixed block and the second fixed block are symmetrically arranged on both sides of the harmonic eliminator 100 and are fixedly connected with the fixed rod 220; denotes the preset distance, which is the distance between the first fixed block and the second fixed block and the grounding platform 400 when the harmonic eliminator 100 contacts the grounding platform 400.

[0111] Step S5022, when the state characteristic value is not 0 and less than the set threshold value, it is determined that the harmonic eliminator 100 is not completely grounded, wherein the set threshold value is 1 / S-3 / S.

[0112] The present application compares the installation distance with the set distance and calculates the state characteristic value, which can quickly and timely identify the grounding state of the harmonic eliminator, so as to adjust the harmonic eliminator and ensure the normal use of the harmonic eliminator.

[0113] Specifically, the formula is divided into two parts: and Wherein, denotes the movement change amount of the first fixed block, denotes the movement change amount of the first fixed block, in the case that one of the fixed blocks 210 moves down and the other moves up, the two movement change amounts should be positive and negative; in the case that both of the fixed blocks 210 move up, both of the movement change amounts should be positive.

[0114] The method of the embodiment of the present application further comprises the following steps.

[0115] ​Step S505, when the state characteristic value is greater than the set threshold value, it is judged that the harmonic eliminator 100 is completely not grounded, and the alarm device is started to issue an alarm, reminding the staff to adjust the position of the harmonic eliminator 100, so that the harmonic eliminator 100 restores the grounding. Avoid the problem that the installation distance exceeds the adjustment range of the adjustment assembly and is invalid, can intervene in time, and ensure the stable grounding of the harmonic eliminator.

[0116] It should be noted that the term "comprising" and its variants, used in the embodiments of the present application, are open-ended, i.e., "including, but not limited to". The term "based on" is "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The terms "a" and "an" are intended to mean "one or more" unless explicitly indicated to the contrary.

[0117] The steps described in the method embodiments provided by the embodiments of the present application can be executed in different orders and / or in parallel. In addition, the method embodiments can include additional steps and / or omit the execution of the steps shown. The scope of protection of the present application is not limited in this respect.

[0118] The word "embodiment" in the present specification means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The presence of this phrase in various places in the specification does not necessarily mean the same embodiment, nor does it mean independence or choice from other embodiments. Each embodiment in the present specification is described in a relevant manner, and the same or similar parts between each embodiment are referred to each other. In particular, for device, equipment, system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts are referred to the part of the method embodiment.

[0119] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of protection. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A voltage transformer harmonic elimination device based on current limiting technology, characterized in that, include: A harmonic suppressor (100) is provided with a fixing rod (220) for suppressing harmonics in a voltage transformer when it is grounded; The limiting component (300) includes: a swivel ring (321) and a plurality of threaded fasteners (340); the swivel ring (321) is rotatably mounted on the grounding platform (400), and the inner edge of the swivel ring (321) is provided with internal teeth (323); each of the threaded fasteners (340) is provided with a first gear (341), and each of the first gears (341) is meshed with the internal teeth (323); the threaded fastener (340) is provided with a first through hole through which the fixing rod (220) passes; the grounding platform (400) is provided with a plurality of internal threaded holes (331), and the threaded fastener (340) is connected to the corresponding internal threaded hole (331) through an external thread (342); the threaded fastener (340) is used to clamp the fixing rod (220) when rotating. An adjustment component is provided at the bottom of the internal threaded hole (331) for adsorbing the fixing rod (220) when energized, so that the harmonic suppressor (100) is grounded; A ranging component is mounted on the fixed rod (220) and is used to detect the installation distance between the fixed rod (220) and the grounding platform (400); The control device is connected to the ranging component, the limiting component (300) and the adjusting component, and is used to determine whether the harmonic suppressor (100) is fully grounded based on the installation distance and the preset distance, and to control the operation of the limiting component (300) and the adjusting component.

2. The voltage transformer harmonic elimination device based on current limiting technology according to claim 1, characterized in that, The limiting component (300) further includes: a fixing block (210); The fixing blocks (210) are symmetrically arranged on opposite sides of the harmonic suppressor (100); The fixing rod (220) is set on each of the fixing blocks (210). The center line of the fixing rod (220) and the center line of the harmonic suppressor (100) are both parallel to the normal line of the grounding platform (400). The bottom height of the fixing rod (220) is not lower than the bottom height of the harmonic suppressor (100).

3. The voltage transformer harmonic elimination device based on current limiting technology as described in claim 2, characterized in that, The ranging component includes: a laser; The laser is disposed at the bottom of each of the fixed blocks (210) and connected to the control device for detecting the straight-line distance between the fixed block (210) and the grounding platform (400).

4. The voltage transformer harmonic elimination device based on current limiting technology according to claim 1, characterized in that, The limiting component (300) further includes: A fixed cylinder (330) is disposed on the grounding platform (400); the fixed cylinder (330) has an internal threaded hole (331) inside. A fixing clamp is disposed inside the internal threaded hole (331) and located between the threaded fastener (340) and the grounding platform (400); the fixing clamp is provided with a movable clamping opening, through which the fixing rod (220) passes; the threaded fastener (340) is used to press the movable clamping opening when rotating, thereby limiting the fixing rod (220).

5. The voltage transformer harmonic elimination device based on current limiting technology according to claim 4, characterized in that, The fixing clip includes: A fixing plate (350) is fixedly disposed inside the internal threaded hole (331); the fixing plate (350) is provided with a second through hole through which the fixing rod (220) passes; At least two clamping pieces (351) are disposed on the side of the fixed plate (350) near the threaded fastener (340); each clamping piece (351) is provided with a movable clamping jaw between it and the adjacent clamping piece (351); The inner surface of the clamping piece (351) matches the shape of the outer surface of the fixing rod (220), and the outer surface of the clamping piece (351) is provided with a flange (352); the flange (352) matches the bottom groove provided in the threaded fastener (340).

6. The voltage transformer harmonic elimination device based on current limiting technology according to claim 1, characterized in that, The limiting component (300) further includes: The motor (310) is mounted on the grounding platform (400); The second gear (311) is disposed on the output shaft of the motor (310) and meshes with the external gear (322) disposed on the outer edge of the rotating ring (321).

7. The voltage transformer harmonic elimination device based on current limiting technology according to claim 1, characterized in that, The adjustment component includes: an electromagnet (360); The electromagnet (360) is disposed at the bottom of the internal threaded hole (331) and is connected to the control device; The relative distance between the electromagnet (360) and the fixed rod (220) is equal to the relative distance between the grounding platform (400) and the grounding terminal on the harmonic suppressor (100).

8. The voltage transformer harmonic elimination device based on current limiting technology as described in claim 1, characterized in that, Also includes: Image detection component; the image detection component includes: A camera (370) is mounted on the grounding platform (400) and is used to capture image information of the surface of the grounding platform (400) within the detection range of the ranging component; An image recognition device, connected to the camera (370) and the control device, is used to identify whether there are debris on the surface of the grounding platform based on the image information, and to send the recognition result to the control device.

9. The voltage transformer harmonic elimination device based on current limiting technology according to claim 1, characterized in that, The harmonic suppressor (100) includes: A primary harmonic suppressor (100) is connected in series with the neutral point of the voltage transformer and is used to passively suppress harmonics in the voltage transformer when it is grounded. A secondary harmonic suppressor (100) is connected to both ends of the open delta winding of the voltage transformer. When the detection device detects that there is a ferromagnetic demagnetization overvoltage phenomenon in the voltage transformer, it connects an impedance in parallel to the open delta winding to actively suppress the harmonics of the voltage transformer. The detection device is connected to the control device.

10. A voltage transformer harmonic elimination method with current limiting technology, characterized in that, Includes the following steps: The installation distance between the fixed rod (220) and the grounding platform (400) is obtained by a ranging component; wherein the fixed rod (220) is disposed on the harmonic suppressor (100); and the ranging component is disposed on the fixed rod (220); Based on the installation distance and the preset distance, determine whether the harmonic suppressor (100) is fully grounded; When the harmonic suppressor (100) is not fully grounded, the control limiting component (300) releases the fixing rod (220), and controls the adjusting component to be energized to attract the fixing rod (220); wherein, the limiting component (300) includes: a rotating ring (321) and a plurality of threaded fasteners (340); the rotating ring (321) is rotatably disposed on the grounding platform (400), and the inner edge of the rotating ring (321) is provided with internal teeth (323); the plurality of threaded fasteners (340) are all disposed inside the rotating ring (321); each of the threaded fasteners (340) is provided with a first gear (341), the first gear (341) and the The internal teeth (323) engage; the threaded fastener (340) is provided with a first through hole through which the fixing rod (220) passes; the grounding platform (400) is provided with an internal threaded hole (331), and the outer surface of the threaded fastener (340) is provided with an external thread (342); the external thread (342) is engaged with the internal threaded hole (331); the threaded fastener (340) is used to clamp the fixing rod (220) when rotating; the adjusting component is provided at the bottom of the internal threaded hole (331) and is used to attract the fixing rod (220) when energized, so that the harmonic suppressor (100) contacts the grounding platform (400); When the harmonic suppressor (100) is fully grounded, the regulating component is controlled to stop being powered on, and the limiting component (300) is controlled to clamp the fixing rod (220), so that the voltage transformer is harmonic suppressed by the harmonic suppressor (100).

11. The voltage transformer harmonic elimination method according to claim 10, characterized in that, Before determining whether the harmonic suppressor (100) is fully grounded based on the installation distance and the preset distance, the method further includes: When the installation distance is not equal to the preset distance, the image detection component is activated by the control device to detect whether there are foreign objects on the surface of the grounding platform 400 corresponding to the detection range of the ranging component; When debris is present, it is cleaned up; when no debris is present, it is determined whether the harmonic suppressor (100) is grounded.

12. The voltage transformer harmonic elimination method according to claim 10, characterized in that, Based on the installation distance and the preset distance, determining whether the harmonic suppressor (100) is fully grounded includes the following steps: Based on the installation distance and the preset distance, the state characteristic value is calculated according to the following formula; ； in, Represents the state characteristic value. The first distance between the first fixed block (210) and the grounding platform (400) during the nth acquisition is represented by the following. The second distance between the second fixed block (210) and the grounding platform (400) is indicated by the nth acquisition; the first fixed block (210) and the second fixed block (210) are symmetrically arranged on both sides of the harmonic suppressor (100) and are fixedly connected to the fixed rod (220); The preset distance is the distance between the first fixing block (210) and the second fixing block (210) and the grounding platform (400) when the harmonic suppressor (100) contacts the grounding platform (400); When the state characteristic value is not 0 and is less than the set threshold, it is determined that the grounding of the harmonic suppressor (100) is incomplete, wherein the set threshold is 1 / S-3 / S.

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