CN206132915U - High frequency current sensor - Google Patents
High frequency current sensor Download PDFInfo
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- CN206132915U CN206132915U CN201621034112.XU CN201621034112U CN206132915U CN 206132915 U CN206132915 U CN 206132915U CN 201621034112 U CN201621034112 U CN 201621034112U CN 206132915 U CN206132915 U CN 206132915U
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- magnetic core
- high frequency
- current sensor
- frequency current
- groove
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Abstract
The utility model discloses a high frequency current sensor, including two split type metal shielding shell, metal shielding shell's inner wall is seted up flutedly, the embedding has semi -ring type magnetic core in the recess, offer the loop type gap that is used for through magnetic force on the recess, leave the space between semi -ring type magnetic core and the recess, fill in the space has insulating material, when two metal shielding shell's both ends are connected respectively, the loop type magnetic core is constituteed to two semi -ring type magnetic cores in the metal shielding shell. The utility model provides a high frequency current sensor compares with present sensor of the same kind, because the above -mentioned scheme that adopts, and its frequency band width, can the sensitivity high frequency be to 400MHz, sensitivity 10dBm, can the low frequency be to 2MHz, sensitivity 12dBm, optimum frequency 25MHz, sensitivity 40dBm.
Description
Technical field
This utility model is related to Partial Discharge Detecting Technology field, particularly a kind of to be used for cable and partial discharge of transformer
The High Frequency Current Sensor of test.
Background technology
Partial Discharge Detection is that the high voltage electric equipments such as inspection high-voltage switch gear GIS, transformator, electromotor, power cable are exhausted
The important tests of edge state.In prior art, except supercritical ultrasonics technology and hyperfrequency method can be used directly to high voltage electric equipment
Shelf depreciation measure it is outer, it is also possible to detected in it by detecting the high-frequency current signal of high voltage electric equipment earth lead
The shelf depreciation situation in portion.High frequency electric method not only can realize the cable local discharge that the insulation defect small to some causes
Microsignal detection, and the state of insulation of the apparatus insulated medium such as cable, transformator and generating set can be monitored on-line.Make
To detect and judging the effective ways of partial discharges fault, high frequency electric method is put in the office of electromotor, transformator and high tension cable
It is widely used in Site Detection and on-line monitoring.
High Frequency Current Sensor (HFCT) detects the sensor element of shelf depreciation as high frequency electric detection method, typically makes
Rogowski coil mode is used, multiturn conductive coil is surrounded on the core material of ring-type, high frequency electric draws through core center
The high-frequency alternating magnetic field for rising can produce faradic current in coil.The bandwidth of High Frequency Current Sensor and sensitivity are to weigh
Most important two parameters of sensor performance.Additionally, sensor scene capacity of resisting disturbance is also the weight for weighing sensor performance
Want index.However, there is bandwidth in design in existing High Frequency Current Sensor and sensitivity is not enough or sensitivity is high and frequency
The narrower defect of band, or due to there is electromagnetic shielding defect in design, cause to yet suffer from certain problem in actual applications.
Utility model content
In view of this, the purpose of this utility model is to propose a kind of High Frequency Current Sensor, to improve capacity of resisting disturbance,
Have the advantages that to detect that bandwidth, sensitivity are high simultaneously.
Based on above-mentioned purpose, the High Frequency Current Sensor that this utility model is provided is included outside two split type metallic shields
Shell, the inwall of the Metal shielding shell opens up fluted, and the groove has been embedded in half ring type magnetic core, opens up on the groove
Have for by the ring-like gap of magnetic force；Space is left between half ring type magnetic core and groove, the space is filled with insulation
Material, the two and half ring type magnetic core groups when the two ends of two Metal shielding shells connect respectively, in the Metal shielding shell
Into ring type magnetic core.
In some embodiments of the present utility model, the Metal shielding shell includes the magnetic core groove and cover plate of arc, institute
State and cover plate is fixedly connected with the side wall of magnetic core groove, the cover plate is constituted for being embedded in half ring type magnetic core with the inwall of magnetic core groove
Groove.
In some embodiments of the present utility model, the cover plate be L fonts, the opposite side wall and cover plate of the magnetic core groove
Between leave ring-like gap.
In some embodiments of the present utility model, one end of the magnetic core groove lateral wall is hinged by hinge, the other end
It is hinged by hasp, one end of described two magnetic core grooves rotates around hinge, the hasp is used for the another of two magnetic core grooves
Open the latter and close in end.
In some embodiments of the present utility model, location hole is provided with an end face of the magnetic core groove, another
Locating piece is provided with end face, when two magnetic core grooves mutually close, the locating piece on one of magnetic core groove inserts another
In the location hole of magnetic core groove.
In some embodiments of the present utility model, coil is wound with the middle part of one and half ring type magnetic cores, the coil
Two ends are connected with signal output plug.
In some embodiments of the present utility model, the winding number of turn of the coil is 1 circle, and the coil is copper sheet, institute
The cross-sectional area for stating coil is 4-10mm2。
In some embodiments of the present utility model, the thickness of the copper sheet is 0.5-1.2mm, and width is 5-15mm.
In some embodiments of the present utility model, the width in the ring-like gap is 2-10mm, the ring type magnetic core
Internal diameter is 50-70mm, and external diameter is 70-100mm, is highly 20-40mm.
In some embodiments of the present utility model, the insulant is polystyrene.
From the above it can be seen that the High Frequency Current Sensor that this utility model is provided is complete by Metal shielding shell
The signal from outside is shielded, background signal is low, so as to more preferably be applied to complicated test environment, effectively improve its detection
Effect and practicality, and the sensor has the characteristics of detecting bandwidth, sensitivity height, live powered simple installation.
Description of the drawings
Fig. 1 is the structural representation of this utility model embodiment High Frequency Current Sensor；
Fig. 2 is the half-sectional left view of this utility model embodiment High Frequency Current Sensor；
Fig. 3 winds schematic diagram for the coil of this utility model embodiment High Frequency Current Sensor；
Fig. 4 is the equivalent circuit of this utility model embodiment High Frequency Current Sensor；
Fig. 5 is the sensitivity response figure of each frequency of this utility model embodiment High Frequency Current Sensor.
Specific embodiment
To make the purpose of this utility model, technical scheme and advantage become more apparent, below in conjunction with specific embodiment, and
Referring to the drawings, this utility model is further described.
It should be noted that the statement of all uses " first " and " second " is for distinguishing in utility model embodiment
The entity of two same names non-equal or the parameter of non-equal, it is seen that " first " " second " only for statement convenience, no
It is interpreted as the restriction to utility model embodiment, subsequent embodiment is no longer illustrated one by one to this.
Referring to Fig. 1 and Fig. 2, the respectively structural representation of this utility model embodiment High Frequency Current Sensor and a half-sectional left side
View.Used as one embodiment of the present utility model, the High Frequency Current Sensor is included outside two split type metallic shields
Shell 1, the inwall of the Metal shielding shell 1 opens up fluted, and the groove has been embedded in half ring type magnetic core 4, on the groove
Offer for by the ring-like gap 9 of magnetic force；Space, the space filling are left between half ring type magnetic core 4 and groove
There is insulant 11, when the two ends of two Metal shielding shells 1 connect respectively, two and half in the Metal shielding shell 1
Ring type magnetic core 4 constitutes a ring type magnetic core.Alternatively, the insulant 11 can be waterproof silicone rubber.It is new as this practicality
One preferred embodiment of type, the width in the ring-like gap 9 is 2-10mm, is passed through for magnetic force, can well shield biography
Various interference signals on the outside of sensor.
As another embodiment of the present utility model, as shown in Fig. 2 the Metal shielding shell 1 includes the magnetic of arc
Core groove 2 and cover plate 3, are fixedly connected with the inwall group of cover plate 3, the cover plate 3 and magnetic core groove 2 on the side wall of the magnetic core groove 2
Into for being embedded in the groove of half ring type magnetic core 4.Preferably, the cover plate 3 is L fonts, the opposite side wall of the magnetic core groove 2 and lid
Ring-like gap 9 is left between plate 3, for by magnetic force.Preferably, the groove be it is half ring-like, with half ring type magnetic core 4
It coincide.Alternatively, the cross section of the groove can be square or rectangle.It should be noted that in this embodiment,
The inner side of the magnetic core groove 2 is semicircle, so that the groove for being formed is half ring-like, the outside of the magnetic core groove 2 can be other
Shape.Alternatively, several installation screw holes 10 are offered on the magnetic core groove 2 and cover plate 3, can be by installing screw by magnetic core
The side wall of groove 2 is fixedly connected with cover plate 3.
Used as a preferred embodiment of the present utility model, the two ends of described two Metal shielding shells 1 are respectively by hinge
Relay part is mutually hinged, to facilitate two Metal shielding shells 1 is taken apart or is closed.Preferably, as shown in figure 1, the magnetic
One end of the lateral wall of core groove 2 is hinged by hinge 6, and the other end is hinged by hasp 7, therefore, one end of described two magnetic core grooves 2
Can rotate around hinge 6, the hasp 7 closes for the other end of two magnetic core grooves 2 to be opened into the latter.
Location hole 12 is provided with one end face of the magnetic core groove 2, locating piece 13 is provided with another end face, it is described
Location hole 13 is inserted in location hole, when two magnetic core grooves 2 mutually close, the locating piece 13 on one of magnetic core groove 2
Insert in the location hole 12 of another magnetic core groove 2, in order to the installation positioning of two magnetic core grooves 2.
Used as further embodiment of the present utility model, the middle part of one and half ring type magnetic cores 4 is wound with coil 14, such as Fig. 3
Shown, the two ends of the coil are connected with signal output plug 5.Alternatively, the signal output plug 5 is N connector, and admittedly
On the lateral wall of magnetic core groove 2.The lateral wall of magnetic core groove 2 is additionally provided with ground hole 8, and the ground hole 8 connects by one
Ground post is connected to ground, and not only can play a part of ground connection, and can play the fixed sensor of support, so as to ensure that wire hangs down
Direct puncture crosses center sensor.
Interference source shields embodiment
The external interference source of partial discharge current sensor mostlys come from the various electromagnetic signals at scene.Good shielding
For sensor signal sensitivity has important function.At present existing high frequency sensors have various shielding modes, including engineering
Plastic shielded, metallic shield adds flanking plastic cover plate and the exterior shield in this utility model, inside to stay the shield side in gap
Formula.
This utility model is using magnetic core, the same number of turns of same specification to these three shielding modes in optimum frequency
Research that sensitivity average and sensitivity peaks in scope (10-50MHz) is carried out, it was demonstrated that the high frequency that this utility model is provided
Current sensor has the sensitivity average and sensitivity peaks of relatively low noise and Geng Gao, referring to table 1.
Impact of the different shielding modes of table 1 to High Frequency Current Sensor sensitivity
Signal detection frequency band and sensitivity test embodiment
Typical current sensor equivalent circuit is as shown in figure 4, it is similar to high frequency small-signal shunt-resonant circuit.Wherein
I1(t) be primary current, U1(t) for coil induced voltage, M is the mutual inductance on former limit and time side, LsFor self-induction of loop, RsFor line
Circle self-resistance, CsFor stray capacitance, R is load resistance.Using high frequency small-signal shunt-resonant circuit theory analysis, can obtain electric
The frequency band of flow sensor is
Lower frequency limit：
Upper limiting frequency：
Working band width：
Sensitivity：
The bandwidth B and sensitivity K of High Frequency Current Sensor by coil self-induction Ls, self-resistance Rs, stray capacitance Cs, mutually
Sense M and load resistance R is together decided on.From 1-4 formulas, sensor bandwidth is improved it is necessary to make f2It is as big as possible, f1As far as possible
It is little.If improving self-induction of loop Ls, lower-cut-off frequency f will be reduced1；Equally, if reducing stray capacitance C of coilsWith oneself
Body resistance Rs, upper cut-off frequency f will be increased2, two ways can all expand bandwidth, but transducer sensitivity is declined；
When load resistance R reduces, lower-cut-off frequency f1Reduce, upper cut-off frequency f2Increase, i.e., working band broadens, but with R
Reduction, the sensitivity of sensor also declines therewith.It can be seen that, should ensure that sensor has sufficiently high sensitivity, ensure again
It is difficult to realize that it has wider frequency band.
The L of coils、CsAnd RsThese parameters are decided by the internal-and external diameter of magnetic core, height, coil turn, the length of coil itself
With sectional area (5-7 formulas).Wherein N is coil turn, and A is the sectional area of magnetic core, and l is the average length of magnetic circuit, and μ is initial magnetic conductance
Rate, ε for coil insulation dielectric constant, r2And r1The respectively external diameter and internal diameter of magnetic core；ρ, L and S are respectively wire used by coil
Resistivity, total length and sectional area.
Self-induction of loop：
Coil stray capacitance：
Coil resistance：
By 5-7 formulas and with reference to analysis above, with regard to bandwidth, in order that the bandwidth of sensor, needs to select magnetic
The big magnetic core of conductance, increases the coil winding number of turn and core cross section product, reduces the length of magnetic path so that self-induction of loop increases；By increasing
Plus loop length and sectional area are reducing coil resistance Rs；It is spuious to reduce coil by increasing core diameter and internal-and external diameter difference
Electric capacity Cs.With regard to sensitivity, understand that level of sensitivity is directly proportional to load resistance R according to analysis, be inversely proportional to turn number N.
Contradiction is so there is, that is, has reduced load resistance, with broadband, but can reduce sensitivity, increased number of turns
Sensitivity equally can be reduced with broadband.And it is current, generally use the coaxial cable that impedance is 50 Ω and believe as sensor
Number output, to make system stability, load resistance R also to select 50 Ω.Therefore magnetic core and line can only be considered in sensor design
Two factors of circle.And be particularly in on-line checking in cable partial discharge on-the-spot test, first have to consideration is sensitivity.Because live
Medium-high frequency interference is extremely complex, causes background signal high, if transducer sensitivity is low, some less high-frequency discharge letters
Number will be submerged in background signal.This utility model design principle be exactly, ensure sensitivity on the premise of, as far as possible
The detection frequency band of broadening sensor.
Known by formula 4, transducer sensitivity is improved as far as possible it is necessary to less coil and winds the number of turn.For this purpose, this utility model
Using the minimum winding circle of the number of turn 1, the coil is copper sheet.Alternatively, the sectional area of the coil can be 4-10mm2, can be with
Improve the upper cut-off frequency of sensor sensing frequency band and the sensitivity of high band.In the case of coil turn is certain, other are adjustable
Parameter for coil be exactly its diameter of wire and isolation material, select the wire that diameter is big, insulant dielectric constant is little can
To reduce coil resistance to increase the bandwidth of sensor detection；Another adjustable parameter is exactly magnetic core.The copper sheet can be with
Selected from copper sheet, latten(-tin), bronze flake and copper-nickel alloy piece.Preferably, the copper sheet is selected from copper sheet, to improve the detection of sensor
Sensitivity.
The design of magnetic core includes the internal-and external diameter of magnetic core and height and core material.This utility model with optimal conditions,
Through Theoretical Calculation and actual tests, this utility model preferably uses that 0.5-1.2mm is thick, and the copper sheet of width 5-15mm is used as twining
Coiling, using polystyrene as insulant.Used as another embodiment of the present utility model, this utility model is selected
0.8mm is thick, and width is the copper sheet of 10mm as wound around coil, the winding circle of the number of turn 1, to improve detection sensitivity.As this reality
With another new embodiment, this utility model can be thick from 1mm, width be the copper sheet of 8.8mm as wound around coil,
The winding circle of the number of turn 1, to improve detection sensitivity.Used as further embodiment of the present utility model, this utility model can be selected
0.9mm is thick, and width is the copper sheet of 10mm as wound around coil, the winding circle of the number of turn 1, to improve detection sensitivity.As this reality
With another new embodiment, this utility model can be thick from 1.2mm, width be the copper sheet of 6mm as wound around coil, twine
Around the circle of the number of turn 1, to improve detection sensitivity.The copper sheet
Magnetic core is selected in the good ferrite core of nickel-zinc of high frequency region performance, the size of magnetic core, is to be the bigger the better from principle,
In view of the size of cable itself, its optimal internal diameter just compares fixation, and the internal diameter of this utility model design magnetic core is 50-70mm,
External diameter is 70-100mm, is highly 20-40mm.Used as one embodiment of the present utility model, the internal diameter of the magnetic core is 66mm,
External diameter is 74mm, is highly 30mm, and used as another embodiment of the present utility model, the internal diameter of the magnetic core is 58mm, external diameter
It is highly 35mm for 70mm, used as another embodiment of the present utility model, the internal diameter of the magnetic core is 62mm, and external diameter is
85mm, is highly 28mm, can improve the upper cut-off frequency of sensor sensing frequency band and the sensitivity of high band.Need explanation
, the magnetic core refers to the ring type magnetic core being made up of two and half ring type magnetic cores 4.
Using decision design of the present utility model, actual survey is carried out to the upper lower limiting frequency and sensitivity of sensor
Examination.Signal generator analog high frequency is used during test, sensor output is connected with amplifier, to the signal of amplification with showing
Ripple device is detected.In 2-400MHz frequency ranges, 20 frequency values are selected to be tested.It is every using signal generator simulation
The high-frequency signal of one frequency, and adjusting signal intensity, show the high-frequency signal of sensor sensing on oscillograph, test signal to noise ratio
For 2:Sensitivity when 1.Sensitivity response of the sensor in the frequency range, as shown in Figure 5.High frequency can be to 400MHz, spirit
Sensitivity -10dBm, low frequency can be to 2MHz, sensitivity -12dBm, optimum frequency 10-50MHz, sensitivity -40dBm.
Operationally, two Split type metals shield shell around hinge to the High Frequency Current Sensor that this utility model is provided
Open, shielding box is placed on earth cable, close hinge, buckle hasp to close Metal shielding shell.It is faint in cable
High-frequency current signal senses the magnetic field for generating respective change in magnetic core, and the magnetic field of the change senses generation in coil and mutually strains
The electromotive force of change, the output of induction electromotive force Jing signal outputs plug.
As can be seen here, this utility model provides High Frequency Current Sensor compared with existing same type of sensor, due to adopting
Such scheme, its bandwidth, sensitivity is high, and high frequency can be to 400MHz, sensitivity -10dBm, low frequency can to 2MHz, sensitivity -
12dBm, optimum frequency 25MHz, sensitivity -40dBm.In addition signal output connector is solid and reliable；Earthing rod not only ensure that and connect
The stability on ground, also ensure that stablizing for sensor；Metal shielding shell shields completely the signal from outside, background signal
It is low；These all enable the High Frequency Current Sensor that this utility model is provided more preferably be applied to complicated test environment, effectively improve
Its Detection results and practicality.
Those of ordinary skill in the art should be understood：The discussion of any of the above embodiment is exemplary only, not
It is intended to imply that the scope of the present disclosure (including claim) is limited to these examples；Under thinking of the present utility model, above reality
Applying can also be combined between example or the technical characteristic in different embodiments, and exist as above of the present utility model
Many other changes of different aspect, for simple and clear their no offers in details.Therefore, it is all in spirit of the present utility model
Within principle, any omission, modification, equivalent, improvement for being made etc. should be included in protection domain of the present utility model
Within.
Claims (10)
1. a kind of High Frequency Current Sensor, it is characterised in that including two split type Metal shielding shells, the metallic shield
The inwall of shell opens up fluted, and the groove has been embedded in half ring type magnetic core, offers on the groove for by magnetic force
Ring-like gap；Space is left between half ring type magnetic core and groove, the space is filled with insulant, when two metals
Two and half ring type magnetic cores composition ring type magnetic core when the two ends of shielding shell connect respectively, in the Metal shielding shell.
2. High Frequency Current Sensor according to claim 1, it is characterised in that the Metal shielding shell includes arc
Magnetic core groove and cover plate, are fixedly connected with cover plate on the side wall of the magnetic core groove, the cover plate is used with the inwall composition of magnetic core groove
In the groove of embedded half ring type magnetic core.
3. High Frequency Current Sensor according to claim 2, it is characterised in that the cover plate is L fonts, the magnetic core groove
Opposite side wall and cover plate between leave ring-like gap.
4. High Frequency Current Sensor according to claim 2, it is characterised in that one end of the magnetic core groove lateral wall passes through
Hinge is hinged, and the other end is hinged by hasp, and one end of described two magnetic core grooves rotates around hinge, and the hasp is used for two
The other end of individual magnetic core groove is opened the latter and is closed.
5. High Frequency Current Sensor according to claim 2, it is characterised in that arrange on an end face of the magnetic core groove
There is location hole, on another end face locating piece is provided with, when two magnetic core grooves mutually close, determining on one of magnetic core groove
Position block is inserted in the location hole of another magnetic core groove.
6. High Frequency Current Sensor according to claim 2, it is characterised in that be wound with the middle part of one and half ring type magnetic cores
Coil, the two ends of the coil are connected with signal output plug.
7. High Frequency Current Sensor according to claim 6, it is characterised in that the winding number of turn of the coil is 1 circle, institute
It is copper sheet to state coil, and the cross-sectional area of the coil is 4-10mm2。
8. High Frequency Current Sensor according to claim 7, it is characterised in that the thickness of the copper sheet is 0.5-1.2mm,
Width is 5-15mm.
9. High Frequency Current Sensor according to claim 1, it is characterised in that the width in the ring-like gap is 2-
10mm, the internal diameter of the ring type magnetic core is 50-70mm, and external diameter is 70-100mm, is highly 20-40mm.
10. High Frequency Current Sensor according to claim 1, it is characterised in that the insulant is polystyrene.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621034112.XU CN206132915U (en) | 2016-08-31 | 2016-08-31 | High frequency current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621034112.XU CN206132915U (en) | 2016-08-31 | 2016-08-31 | High frequency current sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206132915U true CN206132915U (en) | 2017-04-26 |
Family
ID=58567796
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621034112.XU Expired - Fee Related CN206132915U (en) | 2016-08-31 | 2016-08-31 | High frequency current sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206132915U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106291063A (en) * | 2016-08-31 | 2017-01-04 | 北京兴泰学成仪器有限公司 | High frequency current sensor |
| CN112816763A (en) * | 2021-01-19 | 2021-05-18 | 西南交通大学 | Tooth-shaped opening-closing type small current sensor |
-
2016
- 2016-08-31 CN CN201621034112.XU patent/CN206132915U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106291063A (en) * | 2016-08-31 | 2017-01-04 | 北京兴泰学成仪器有限公司 | High frequency current sensor |
| CN112816763A (en) * | 2021-01-19 | 2021-05-18 | 西南交通大学 | Tooth-shaped opening-closing type small current sensor |
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Granted publication date: 20170426 Termination date: 20210831 |