CN214473845U - SF6 current transformer for on-line monitoring - Google Patents

SF6 current transformer for on-line monitoring Download PDF

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Publication number
CN214473845U
CN214473845U CN202120028180.XU CN202120028180U CN214473845U CN 214473845 U CN214473845 U CN 214473845U CN 202120028180 U CN202120028180 U CN 202120028180U CN 214473845 U CN214473845 U CN 214473845U
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leakage current
current output
wire
current
current transformer
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蒋汉儒
李朝晖
彭跃辉
曾艳玲
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Hunan Electric Power Porcelain Electric Appliance Co ltd
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Hunan Electric Power Porcelain Electric Appliance Co ltd
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Abstract

The utility model discloses an SF6 current transformer for on-line monitoring, which comprises a current amplification coil, a grounding wire connected with a supporting insulator, a leakage current output line and a leakage current output terminal, wherein the leakage current output terminal is connected with the two ends of the leakage current output line; the primary winding of the current amplification coil is a grounding wire, the secondary winding is a leakage current output wire, and the turn ratio of the primary winding to the secondary winding is more than 102. The current amplifying coil amplifies the leakage current from the μ a level to the mA or a level,the amplified leakage current is positioned in the measurement range of most of the ampere meters, and the measurement of the ampere meters on the leakage current is facilitated. Meanwhile, the equipment can be tested in a normal operation state, and compared with a power failure measuring mode in the prior art, the leakage current real-time monitoring is realized, the insulation fault inside the equipment can be found in time, and the safety risk of a power grid is greatly reduced.

Description

SF6 current transformer for on-line monitoring
Technical Field
The utility model relates to a current transformer technical field, more specifically say, relate to an on-line monitoring's SF6 current transformer.
Background
SF6 gas has good insulation properties, especially physical properties without insulation aging, so that the current 35kV-500kV high-voltage SF6 current transformer is basically maintenance-free.
However, in the long-term operation process of the equipment, the surface flashover voltage on the surface of the supporting insulator is reduced due to internal partial discharge, the insulating property of the supporting insulator is greatly reduced, even a major fault of main insulation breakdown of the equipment is caused, and great potential safety hazards exist.
In the prior art, an electric power operation and maintenance company only detects the pressure of SF6 gas of equipment, but detects internal faults thereof, and needs to sample and analyze components of SF6 gas in a power failure state, so that the normal work of an SF6 current transformer is influenced; on the other hand, the detection period is long, the insulation state of SF6 gas is not detected timely, and the operation and maintenance of equipment are not facilitated.
In summary, how to implement real-time monitoring of leakage current on a supporting insulator is a problem to be solved urgently by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
In view of this, the present invention provides an on-line monitoring SF6 current transformer, which can obtain the amplified leakage current signal through the current amplifying coil, thereby realizing the real-time monitoring of the leakage current.
In order to achieve the above object, the present invention provides the following technical solutions:
an SF6 current transformer for on-line monitoring comprises a current amplification coil, a grounding wire connected with a supporting insulator, a leakage current output wire and a leakage current output terminal, wherein the leakage current output terminal is connected to two ends of the leakage current output wire;
the primary winding of the current amplifying coil isThe grounding wire and the secondary winding are the leakage current output wire, and the turn ratio of the primary winding to the secondary winding is more than 102
Preferably, the support insulator is connected with the body through a transition flange, and one end of the grounding wire is connected with the transition flange.
Preferably, the current amplifying coil comprises an annular iron core, the primary winding and the secondary winding, the annular iron core is mounted on an end face, close to the secondary lead pipe, of an inlet flange of the base, and the annular iron core is sleeved outside the secondary lead pipe.
Preferably, the annular core is an ultracrystalline alloy annular core.
Preferably, the ground wire penetrates through the secondary lead tube, and penetrates out of a side hole in the secondary lead tube to be connected with the base.
Preferably, the leakage current output terminal is located on the secondary board.
The utility model provides an on-line monitoring SF6 current transformer, which comprises a current amplification coil, a grounding wire connected with a supporting insulator, a leakage current output line and a leakage current output terminal, wherein the leakage current output terminal is connected with the two ends of the leakage current output line; the primary winding of the current amplification coil is a grounding wire, the secondary winding is a leakage current output wire, and the turn ratio of the primary winding to the secondary winding is more than 102
When leakage current is generated on the supporting insulator, on one hand, the leakage current is led into the ground through the grounding wire, so that the phenomenon that the leakage current discharges to the supporting insulator to cause SF6 gas decomposition is avoided; on the other hand, the ground wire is a primary winding of a current amplifying coil, when leakage current passes through the ground wire, the leakage current is subjected to electromagnetic induction, amplified induced electromotive force is generated between two leakage current output terminals, and after the leakage current output terminals are connected with a measuring instrument, the output of the leakage current output line is at least amplified by 102Thereby realizing the extraction and amplification of the leakage current.
Therefore, the current amplification coil amplifies the leakage current from the mu A level to the mA or A level, so that the amplified leakage current is positioned in the measurement range of most of the ammeters, and the measurement of the ammeters on the leakage current is facilitated.
Meanwhile, the equipment can be tested in a normal operation state, and compared with a power failure measuring mode in the prior art, the leakage current real-time monitoring is realized, the insulation fault inside the equipment can be found in time, and the safety risk of a power grid is greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a specific embodiment of an online monitoring SF6 current transformer provided by the present invention.
In fig. 1:
the transformer comprises a shell 1, a transformer body 2, a transition flange 3, a first screw 4, a grounding wire 5, a supporting insulator 6, a sleeve 7, a secondary lead tube 8, a current amplification coil 9, a second screw 10, a base 11, a leakage current output wire 12, a secondary plate 13 and a leakage current output terminal 14.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The core of the utility model is to provide an on-line monitoring's SF6 current transformer, can acquire the leakage current signal after amplifying through the current amplification coil, realized the real-time supervision to leakage current.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of an SF6 current transformer for online monitoring provided by the present invention.
The utility model provides an online monitoring SF6 current transformer, including current amplification coil 9, earth connection 5, leakage current output line 12 and leakage current output terminal 14 connected with supporting insulator 6, leakage current output terminal 14 is connected to leakage current output line 12 both ends; the primary winding of the current amplification coil 9 is a grounding wire 5, the secondary winding is a leakage current output wire 12, and the turn ratio of the primary winding to the secondary winding is more than 102
The grounding wire 5 is connected with the supporting insulator 6, leakage current on the supporting insulator 6 flows through the grounding wire 5, and the grounding wire 5 is wound on the current amplification coil 9 to form a primary winding of the current amplification coil 9; both ends of the leakage current output line 12 are connected to a leakage current output terminal 14, and the leakage current output line 12 is wound around the current amplifying coil 9 to form a secondary winding of the current amplifying coil 9.
Referring to fig. 1, a grounding line 5 and a leakage current output line 12 are wound around the core of the current amplifying coil 9.
Referring to fig. 1, the SF6 current transformer mainly includes a housing 1, a body 2, a supporting insulator 6, a bushing 7, a base 11, a secondary lead 8, and the like. Wherein, the shell 1 is connected with a high-voltage wire and used for accommodating the body 2 and the supporting insulator 6; the supporting insulator 6 is the only insulating part inside the device; the sleeve 7 is used for isolating the shell 1 at the high-voltage end from the grounded base 11; the base 11 and the secondary lead tube 8 are used for accommodating and protecting a secondary winding lead of the SF6 current transformer and are used as output ends of a secondary winding of the SF6 current transformer.
Preferably, the support insulator 6 and the body 2 may be connected by a transition flange 3, and one end of the ground wire 5 is connected to the transition flange 3. Therefore, when a leakage current occurs on the surface of the supporting insulator 6, the leakage current can be introduced into the ground wire 5 through the transition flange 3, and the supporting insulator 6 is grounded.
Referring to fig. 1, preferably, the ground wire 5 may be connected to the transition flange 3 by first screws 4. It should be noted that the connection position between the two is required to avoid interfering with the function of the transition flange 3.
In order to avoid the exposure of the grounding wire 5, it is preferable that the grounding wire 5 is inserted into the secondary lead tube 8 and is connected to the base 11 through a side hole on the secondary lead tube 8, so as to realize the grounding of the grounding wire 5.
Referring to fig. 1, preferably, the ground wire 5 may be connected to the base 11 by a second screw 10.
The current amplifying coil 9 is used for amplifying the leakage current so as to facilitate measurement of a measuring instrument such as an ammeter.
Preferably, the current amplifying coil 9 may include a toroidal core, a primary winding and a secondary winding, the toroidal core is mounted on an end surface of the inlet flange of the base 11 close to the secondary lead tube 8, and the toroidal core is sleeved outside the secondary lead tube 8.
Because the annular iron core is sleeved outside the secondary lead pipe 8, the secondary lead pipe 8 realizes axial positioning and circumferential positioning of the annular iron core on the end face of the inlet flange, and simultaneously limits the inner diameter of the annular iron core, namely the inner diameter of the annular iron core is equal to the outer diameter of the secondary lead pipe 8 or slightly larger than the outer diameter of the secondary lead pipe 8.
The outer diameter of the annular iron core needs to be specifically set according to the magnitude of leakage current generated by equipment in actual production.
The higher the permeability of the toroidal core, the higher the measurement accuracy of the current amplification coil 9 and the smaller the measurement error. In view of the fact that the leakage current itself is very small, it is preferable that the toroidal core be an ultracrystalline alloy toroidal core. The ultracrystalline alloy material has high magnetic conductivity, high saturation magnetic flux density and high measurement precision.
Because leakage currents generated by different devices in actual production are different, the turn ratio of the primary winding to the secondary winding needs to be determined according to factors such as the magnitude of the leakage current and the size of the annular iron core in actual production.
Considering that the turns ratio of the primary winding and the secondary winding of the current amplifying coil 9 is more than 102Excellence inOptionally, the number of turns of the leakage current output line 12 may be set to one turn to reduce the number of turns of the primary winding.
When leakage current is generated on the supporting insulator 6, on one hand, the leakage current is led into the ground through the grounding wire 5, so that the phenomenon that the leakage current discharges to the supporting insulator 6 to cause SF6 gas decomposition is avoided; on the other hand, the ground line 5 is a primary winding of a current amplifying coil 9, and when a leakage current passes through the ground line 5, an electromagnetic induction effect is exerted, an amplified induced electromotive force is generated between two leakage current output terminals 14, and after a measuring instrument is connected, an output of at least an amplifier 10 is outputted in a leakage current output line 122Thereby realizing the extraction and amplification of the leakage current.
In the present embodiment, the current amplification coil 9 amplifies the leakage current from μ a level to mA or a level, so that the amplified leakage current is within the measurement range of most ammeters, which facilitates the measurement of the ammeters on the leakage current.
Meanwhile, the equipment can be tested in a normal operation state, and compared with a power failure measuring mode in the prior art, the leakage current real-time monitoring is realized, the insulation fault inside the equipment can be found in time, and the safety risk of a power grid is greatly reduced.
It should be noted that, considering that the leakage current on the leakage current output line 12 is amplified, the specification of the leakage current output line 12 should be reasonably selected according to the range of the leakage current on the leakage current output line 12 in actual production, so as to prevent the leakage current output line 12 from being damaged or even burning due to excessive current.
Preferably, the leakage current output terminal 14 may be disposed on the secondary plate 13, so that an original structure in the vertical oil-immersed current transformer may be directly utilized, and no additional new component is required.
Preferably, for the convenience of distinguishing the leakage current output terminal 14 from the secondary output terminal on the secondary plate 13, the two leakage current output terminals 14 may be labeled as Sa and Sb, respectively.
It should be noted that the first and second screws 4 and 10 mentioned in the present document are only used to distinguish the difference of the positions, and do not contain any limitation on the sequence.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The above details the SF6 current transformer for online monitoring provided by the present invention. The principles and embodiments of the present invention have been explained herein using specific examples, and the above descriptions of the embodiments are only used to help understand the method and its core ideas of the present invention. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, the present invention can be further modified and modified, and such modifications and modifications also fall within the protection scope of the appended claims.

Claims (6)

1. An SF6 current transformer for on-line monitoring, which is characterized by comprising a current amplifying coil (9), a grounding wire (5) connected with a supporting insulator (6), a leakage current output wire (12) and a leakage current output terminal (14), wherein the leakage current output terminal (14) is connected to two ends of the leakage current output wire (12);
the primary winding of the current amplification coil (9) is the grounding wire (5), the secondary winding is the leakage current output wire (12), and the turn ratio of the primary winding to the secondary winding is more than 102
2. An on-line SF6 current transformer according to claim 1, wherein said supporting insulator (6) is connected to the body (2) by a transition flange (3) and one end of said earth wire (5) is connected to said transition flange (3).
3. The SF6 current transformer for on-line monitoring as claimed in claim 1, wherein the current amplifying coil (9) includes a toroidal core, the primary winding and the secondary winding, the toroidal core is installed on the end face of the inlet flange of the base (11) close to the secondary lead tube (8), and the toroidal core is sleeved outside the secondary lead tube (8).
4. The on-line SF6 current transformer of claim 3, wherein said toroidal core is an ultra-crystalline alloy toroidal core.
5. The SF6 current transformer for on-line monitoring of claim 3, wherein the ground wire (5) is inserted into the secondary lead tube (8) and is connected to the base (11) through a side hole on the secondary lead tube (8).
6. An on-line monitored SF6 current transformer according to any of claims 1-5, wherein said leakage current output terminal (14) is located on secondary board (13).
CN202120028180.XU 2021-01-06 2021-01-06 SF6 current transformer for on-line monitoring Active CN214473845U (en)

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Application Number Priority Date Filing Date Title
CN202120028180.XU CN214473845U (en) 2021-01-06 2021-01-06 SF6 current transformer for on-line monitoring

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Application Number Priority Date Filing Date Title
CN202120028180.XU CN214473845U (en) 2021-01-06 2021-01-06 SF6 current transformer for on-line monitoring

Publications (1)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115497405A (en) * 2022-06-29 2022-12-20 京东方科技集团股份有限公司 Detection assembly, display panel and display device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115497405A (en) * 2022-06-29 2022-12-20 京东方科技集团股份有限公司 Detection assembly, display panel and display device
CN115497405B (en) * 2022-06-29 2025-05-23 京东方科技集团股份有限公司 Detection assembly, display panel and display device

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