CN1241027C - High precision online monitoring sensor for a.c. current leakage - Google Patents
High precision online monitoring sensor for a.c. current leakage Download PDFInfo
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- CN1241027C CN1241027C CN 200410025979 CN200410025979A CN1241027C CN 1241027 C CN1241027 C CN 1241027C CN 200410025979 CN200410025979 CN 200410025979 CN 200410025979 A CN200410025979 A CN 200410025979A CN 1241027 C CN1241027 C CN 1241027C
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- shielding box
- leakage current
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- line monitoring
- monitoring sensor
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Abstract
The present invention discloses a high-precision on-line monitoring sensor for AC leakage current. The present invention comprises a shielding box with central through hole and a shielding box cover matched with the shielding box, wherein a bayonet nut connector (BNC) used for signal output is arranged on the shielding box, and an insulation film, a sloped alloy film, an insulation film and an iron-sheet film are sequentially stuck from an inner wall to the center in the shielding box. An annular iron core wound with a coil is arranged in the center, and both ends of the coil are connected with an integrator resistor of which both ends are respectively connected with a core wire and an outer casing of the BNC on the shielding box by wires. The sensor can be used for online monitoring of AC leakage current and dielectric loss tangent of electric power equipment of which the AC leakage current is in the order of magnitude of mu A and 50Hz AC power frequency signals of which the measuring range is from 1 muA to 2mA. A grounding wire of the electric power equipment directly penetrates through from the center of the device for monitoring; the present invention realizes electrical isolation without affecting normal operation of equipment.
Description
Technical field
The invention belongs to power equipment on-line monitoring technique field, relate to a kind of device of on-line monitoring power equipment, be specifically related to a kind of high-accuracy ac leakage current on-line monitoring sensor.
Background technology
Power equipment can be because the effect of extraneous factor progressively be worn out long-term in service, and these extraneous factors comprise electricity, heat, mechanical stress, environmental factor etc., often are called as aging factor.Power equipment is in operational process, and insulation system takes place to wear out under the combined action of multiple aging factor, and decreasing insulating will become accident potential when acquiring a certain degree.In a single day dielectric breakdown accident takes place in power equipment, will cause large-area power-cuts, will cause the tremendous economic loss to industrial and agricultural production and life.
Power equipment is carried out on-line monitoring, can obtain the parameter of equipment in the actual motion, improved the authenticity and the sensitivity of test figure greatly, can in time find defective, eliminate potential faults.The ac leakage current of power equipment and dielectric loss angle tangent (abbreviation dielectric loss) are the important parameters of on-line monitoring, ac leakage current can reflect the insulation resistance situation of equipment, and dielectric loss can reflect the integral insulation situations such as making moist, wear out of equipment integral insulation.
The ac leakage current sensor is the requisite device of on-line monitoring that carries out ac leakage current and dielectric loss, the amplitude range of power equipment ac leakage current differs greatly because of equipment is different, from μ A level to the mA level, the ac leakage current value of good cross-inked polyethylene power cable of for example insulating is very faint, usually at the μ A order of magnitude.And the electromagnetic environment at power equipment operation scene is very abominable, and electromagnetic interference (EMI) is serious, the ac leakage current value of accurate measuring equipment very difficult.The sensor measurement scope of monitoring power equipment ac leakage current can only reach a milliampere level both at home and abroad at present.So present monitoring leakage electric current can not be applied to the on-line monitoring of leakage current at μ A order of magnitude power equipment with sensor.
Summary of the invention
Defective and deficiency at above-mentioned prior art exists the objective of the invention is to, and a kind of high-accuracy ac leakage current on-line monitoring sensor is provided, and it can effectively shield the on-the-spot strong electromagnetic of power equipment operation, and its measuring accuracy can reach 1 μ A.
To achieve these goals, the technical solution that the present invention takes is, a kind of high-accuracy ac leakage current on-line monitoring sensor, comprise that one has the shielding box of central through hole and the shielding box cover that matches with shielding box, be characterized in, shielding box is provided with the BNC as signal output, be pasted with the ground floor insulation film successively to the center by inwall in the shielding box, permalloy film, second layer insulation film and iron sheet film, in the middle of an annular core is arranged on, be wound with coil above, between annular core and the coil insulating tape is arranged, the two ends of coil are connected with an integrating resistor, the integrating resistor two ends respectively with shielding box on the heart yearn of BNC be connected with the shell line.
Some other characteristics of the present invention are that the thickness of described iron sheet film and permalloy film is 1mm.
Described first, second layer insulation film selected polytetrafluoroethylene film for use.
Described coil selects for use the copper enameled wire coiling of 0.3mm to form, and coil turn is 700 circles.
The resistance value of described integrating resistor is 50 Ω.
High-accuracy ac leakage current on-line monitoring sensor of the present invention, being used for the on-line monitoring ac leakage current is the ac leakage current and the dielectric loss angle tangent of the power equipment of the μ A order of magnitude, measurement range is the 50Hz AC power frequency signal of 1-～2mA, is applicable to the on-line monitoring of power equipment ac leakage current.The power equipment ground wire directly penetrates from this device center and monitors, and realizes electrical isolation, and the equipment that do not influence normally moves.
Description of drawings
Fig. 1 (a) and (b) are respectively the structure vertical view and the sensor mask lid vertical view of sensor of the present invention, the symbolic representation among Fig. 1: 1. shielding box; The 2-insulation film; The 3-permalloy film; The 4-insulation film; 5-iron sheet film; The 6-iron core; The 7-coil; The 8-integrating resistor; The 9-BNC; The 10-fixed screw; 11-shielding box lid.
Fig. 2 is the sensor performance Test Drawing, wherein (a) former limit input current 1～15 μ A; (b) former limit input current 15～100 μ A; (c) former limit input current 100 μ A～2mA, 10 times of voltage attenuators of termination behind the sensor;
Embodiment
The present invention is described in further detail for the embodiment that provides below in conjunction with accompanying drawing and inventor and the principle of work of device.
Referring to Fig. 1, Fig. 1 is the structure vertical view of sensor of the present invention, also be a specific embodiment, this high-accuracy ac leakage current on-line monitoring sensor comprises: shielding box 1, insulation film 2, permalloy film 3, insulation film 4, iron sheet film 5, iron core 6, coil 7, integrating resistor 8, BNC 9 and fixed screw 10 constitute.
Shielding box 1 and shielding box cover 11 are all selected the copper product of electric shield function admirable for use, and antirust processing is carried out on the surface, have pasted insulation film 2, permalloy film 3, insulation film 4 and iron sheet film 5 successively in their inboard.The effect of iron sheet film 5 and permalloy film 3 is respectively magnetic shielding and electric shield, and to shield on-the-spot strong electromagnetic interference signal, their thickness is 1mm.The effect of insulation film 2 and insulation film 4 is isolating between copper, iron sheet and the permalloy, avoids their contacts, prevents galvanic corrosion, and they all select the polytetrafluoroethylene film of decay resistance and excellent electrical properties for use.
The effect of three fixed screws 10 is that shielding box 1 and lid 11 are fixed together.
This sensor can sensing range at the 50Hz AC power frequency signal of 1 μ A～2mA, be applicable to the leakage current of the power equipment that the on-line monitoring, particularly ac leakage current of power equipment ac leakage current is very faint and the on-line monitoring of dielectric loss.The present invention has finished a cover sample in the laboratory.
Adopt signal source to produce the sinusoidal current of a 50Hz power frequency in the laboratory,, the current sensor of design is tested, analyze its output-input voltage linear relationship as the former limit of sensor input signal.When experiment, after the primary current input was greater than 100 μ A, the output voltage of sensor was bigger, connected a voltage attenuator during measurement behind sensor, and its attenuation multiple is 10 times.Fig. 2 (a) and (b), (c) represent the former limit of sensor input current respectively at 1～15 μ A, the sensor input and output linear relationship in 15～100 μ A and the 100 μ A～2mA scope.
The present invention installs and uses in the following manner:
Before installation, need to disconnect the ground wire of the power equipment of desiring sensor installation, ground wire is penetrated from the center sensor hole, recover the normal ground connection of ground wire then, utilize the signal output of coax signal cable transmission sensor, carry out signal Processing, analysis for the rear end.
Claims (6)
1. high-accuracy ac leakage current on-line monitoring sensor, comprise that one has the shielding box (1) of central through hole and the shielding box cover (11) that matches with shielding box (1), it is characterized in that, shielding box (1) is provided with the BNC (9) as signal output, be pasted with ground floor insulation film (2) successively to the center by inwall in the shielding box (1), permalloy film (3), second layer insulation film (4) and iron sheet film (5), in the middle of an annular core (6) is arranged on, be wound with coil (7) above, the two ends of coil (7) are connected with an integrating resistor (8), integrating resistor (8) two ends respectively with shielding box (1) on the heart yearn of BNC (9) be connected with the shell line.
2. high-accuracy ac leakage current on-line monitoring sensor as claimed in claim 1 is characterized in that the thickness of described iron sheet film (5) and permalloy film (3) is 1mm.
3. high-accuracy ac leakage current on-line monitoring sensor as claimed in claim 1 is characterized in that described ground floor insulation film (2) and second layer insulation film (4) are all selected polytetrafluoroethylene film for use.
4. high-accuracy ac leakage current on-line monitoring sensor as claimed in claim 1 is characterized in that described annular core (6) is selected the permalloy material for use.
5. high-accuracy ac leakage current on-line monitoring sensor as claimed in claim 1 is characterized in that, described coil (7) selects for use the copper enameled wire coiling of 0.3mm to form, and coil turn is 700 circles.
6. high-accuracy ac leakage current on-line monitoring sensor as claimed in claim 1 is characterized in that the resistance value of described integrating resistor (8) is 50 Ω.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410025979 CN1241027C (en) | 2004-03-22 | 2004-03-22 | High precision online monitoring sensor for a.c. current leakage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410025979 CN1241027C (en) | 2004-03-22 | 2004-03-22 | High precision online monitoring sensor for a.c. current leakage |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1564008A CN1564008A (en) | 2005-01-12 |
| CN1241027C true CN1241027C (en) | 2006-02-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200410025979 Expired - Fee Related CN1241027C (en) | 2004-03-22 | 2004-03-22 | High precision online monitoring sensor for a.c. current leakage |
Country Status (1)
| Country | Link |
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| CN (1) | CN1241027C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100442065C (en) * | 2005-10-10 | 2008-12-10 | 西安交通大学 | Synthetic insulator on-line detector based on pulse current method |
| CN104459437A (en) * | 2014-11-25 | 2015-03-25 | 上海汇鸿智能控制系统有限公司 | Residual current transformer |
| CN111239566A (en) * | 2020-03-02 | 2020-06-05 | 西南交通大学 | High-sensitivity high-frequency pulse current sensor |
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2004
- 2004-03-22 CN CN 200410025979 patent/CN1241027C/en not_active Expired - Fee Related
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| Publication number | Publication date |
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| CN1564008A (en) | 2005-01-12 |
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Granted publication date: 20060208 Termination date: 20140322 |