CN203672953U - Lightning arrester leakage current sensor - Google Patents
Lightning arrester leakage current sensor Download PDFInfo
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- CN203672953U CN203672953U CN201420053629.8U CN201420053629U CN203672953U CN 203672953 U CN203672953 U CN 203672953U CN 201420053629 U CN201420053629 U CN 201420053629U CN 203672953 U CN203672953 U CN 203672953U
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Abstract
The utility model relates to the field of power equipment on-line monitoring, in particular to a lightning arrester leakage current sensor. The lightning arrester leakage current sensor comprises a metal shielding shell and a current mutual inductor sealed in the metal shielding shell, a weak signal amplification circuit, a low-pass filter circuit and a voltage follower circuit. The current mutual inductor is sleeved on a grounding wire, an output end of the mutual inductor is connected with an input end of the weak signal amplification circuit, the output end of the weak signal amplification circuit is connected with the input end of the low-pass filter circuit, the output end of the low-pass filter circuit is connected with the input end of the voltage follower circuit, the output end of the voltage follower circuit, by a shielding wire extending out the metal shielding shell, is connected with a signal collection device, and two ends of the weak signal amplification circuit are connected with a feedback circuit in parallel. The lightning arrester leakage current sensor has a strong anti-electromagnetic interference capability and can exactly measure the leakage current of the lightning arrester.
Description
(1) technical field
The utility model relates to electrical equipment online supervision field, particularly a kind of lightning arrester leakage current sensor.
(2) background technology
Lightning arrester is for protecting various electrical equipments in electric system to avoid a kind of electrical equipment that lightning surge attacks.In the time importing the lightning surge of electric system along circuit into and exceed the level of protection of lightning arrester; first lightning arrester discharges; and by the introducing the earth of lightning current process ground wire safety; utilize earthing device to make lightning voltage amplitude limitation below horizontal at the lightning impulse of protected electrical equipment, electrical equipment is protected.In China, lightning arrester development experience common valve formula SiC lightning arrester, magnetic blow-out SiC lightning arrester and metal zinc oxide lightning arrester (MOA) three generations.Metal zinc oxide lightning arrester is the Novel lightning arrester occurring the beginning of the seventies in last century, its key element is zinc oxide valve plate, with Sic disc comparison before, zinc oxide valve plate has more excellent nonlinear characteristic, can make gapless lightning arrester, replace at present traditional silicon-carbide arrester, be widely used in electric system, become the visual plant that determines power system insulation cooperation level.
Metal zinc oxide lightning arrester (MOA) is under long-term working voltage effect, zinc oxide valve plate can be aging gradually, or because dysplasia makes moist, this will cause MOA leakage current to increase, once there be superpotential to produce in system, will make MOA produce thermal runaway, even make MOA blast, not only can involve nearby device, and because the sudden meeting of fault causes casualties because of blast.Leakage current can react the character that MOA zinc oxide valve plate is aging and make moist, and therefore, can detect the real ruuning situation of MOA by the variation of periodic measurement MOA leakage current, and existing measurement mechanism is common current sensor.
At present, in the time detecting the operation conditions of MOA, because the leakage current of measuring is small electric flow valuve, and the various power equipments that move in electric system can cause interference to the common current sensor of operation with electromagnetism conduction, electromagnetic induction and three kinds of modes of electromagnetic radiation, cause the measurement result of MOA leakage current to be greatly affected, reduced degree of accuracy and the validity of testing result.
(3) summary of the invention
The utility model, in order to make up the deficiencies in the prior art, provides a kind of anti-electromagnetic interference capability strong, and can carry out the sensor of accurately measuring to leakage current of an arrester, has solved problems of the prior art.
The utility model is achieved by the following technical solution:
A kind of lightning arrester leakage current sensor, comprise a metallic shield shell and seal the Current Mutual Inductance coil of being located in metallic shield shell, feeble signal amplifying circuit, low-pass filter circuit and voltage follower circuit, Current Mutual Inductance coil is sheathed on ground wire, its output terminal is connected with the input end of feeble signal amplifying circuit, the output terminal of feeble signal amplifying circuit is connected with the input end of low-pass filter circuit, the output terminal of low-pass filter circuit is connected with the input end of voltage follower circuit, the output terminal of voltage follower circuit is connected with signal pickup assembly by the shielded cable that passes metallic shield shell, at the two ends of a feeble signal amplifying circuit feedback circuit in parallel, the input end of feedback circuit is connected with the output terminal of feeble signal amplifying circuit, the output terminal of feedback circuit is connected with the input end of feeble signal amplifying circuit.
Described Current Mutual Inductance coil is connected and composed by amplitude transformation coil and phase compensation coils from parallel connection of coils, and amplitude transformation coil is connected with the input end of feeble signal amplifying circuit with the output terminal after phase compensation coils from parallel connection of coils.
The beneficial effects of the utility model are: Current Mutual Inductance coil, feeble signal amplifying circuit, low-pass filter circuit and the voltage follower circuit of this lightning arrester leakage current sensor are all sealed in metallic shield shell, electromagnetic interference (EMI) cannot be entered, thereby guaranteed degree of accuracy and validity that leakage current detects; Shielded cable can play shielding action to electromagnetic interference (EMI), reduces and disturbs, and has guaranteed precision and the reliability of signal transmission; Current Mutual Inductance coil is connected and composed by amplitude transformation coil and phase compensation coils from parallel connection of coils, output terminal after its parallel connection is connected with the input end of feeble signal amplifying circuit, amplitude transformation coil can dwindle current signal amplitude 1000 times, phase compensation Coil Compensation phase place make error 1 ' in, Current Mutual Inductance coil can carry out correction-compensation to current signal; Feeble signal amplifying circuit can and be converted to measurable voltage signal by small current amplify; Feedback circuit can eliminate the direct current offset negative feedback in voltage signal; Filtering circuit is by the high fdrequency component filtering in voltage signal; Follow circuit is for improving the load capacity of output voltage signal; By cooperatively interacting of above each circuit, can make the leakage current of an arrester signal of output more accurate.
(4) accompanying drawing explanation
Below in conjunction with accompanying drawing, the utility model is further described.
Fig. 1 is structural representation of the present utility model;
Fig. 2 is module diagram of the present utility model.
In figure, 1 metallic shield shell, 2 shielded cable.
(5) embodiment
For clearly demonstrating the technical characterstic of this programme, below by embodiment, and in conjunction with its accompanying drawing, the utility model is elaborated.
As shown in Fig. 1-Fig. 2, this embodiment comprises a metallic shield shell 1 and seals the Current Mutual Inductance coil of being located in metallic shield shell 1, feeble signal amplifying circuit, low-pass filter circuit and voltage follower circuit, Current Mutual Inductance coil is sheathed on ground wire, its output terminal is connected with the input end of feeble signal amplifying circuit, the output terminal of feeble signal amplifying circuit is connected with the input end of low-pass filter circuit, the output terminal of low-pass filter circuit is connected with the input end of voltage follower circuit, the output terminal of voltage follower circuit is connected with signal pickup assembly by the shielded cable 2 that passes metallic shield shell 1, at the two ends of a feeble signal amplifying circuit feedback circuit in parallel, the input end of feedback circuit is connected with the output terminal of feeble signal amplifying circuit, the output terminal of feedback circuit is connected with the input end of feeble signal amplifying circuit, described Current Mutual Inductance coil is connected and composed by amplitude transformation coil and phase compensation coils from parallel connection of coils, and amplitude transformation coil is connected with the input end of feeble signal amplifying circuit with the output terminal after phase compensation coils from parallel connection of coils.
This leakage current sensor is sheathed on ground wire, because Current Mutual Inductance coil, feeble signal amplifying circuit, low-pass filter circuit and voltage follower circuit are all sealed in metallic shield shell 1, electromagnetic interference (EMI) cannot be entered, thereby degree of accuracy and validity that leakage current detects are guaranteed, shielded cable 2 can play shielding action to electromagnetic interference (EMI), reduce and disturb, guaranteed precision and the reliability of signal transmission, in the time having leakage current on ground wire, Current Mutual Inductance coil just can sense current signal, Current Mutual Inductance coil is sent into the current signal sensing in feeble signal amplifying circuit, current signal is exaggerated and is converted to measurable voltage signal in feeble signal amplifying circuit, at the two ends of a feeble signal amplifying circuit feedback circuit in parallel, feedback circuit eliminates the direct current offset negative feedback in voltage signal, then, feeble signal amplifying circuit will be sent in low-pass filter circuit through feedback circuit voltage signal after treatment, low-pass filter circuit is by the high fdrequency component filtering in voltage signal, then voltage signal is sent to voltage follower circuit by low-pass filter circuit, voltage follower circuit improves after the load capacity of output voltage signal, this signal is delivered to follow-up signal harvester by shielded cable 2 to be processed again.By cooperatively interacting of each circuit, can make the leakage current of an arrester signal of output more accurate.
The utility model does not describe part in detail, is those skilled in the art of the present technique's known technology.Finally explanation is, above embodiment is only unrestricted in order to the technical solution of the utility model to be described, although the utility model is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can modify or be equal to replacement the technical solution of the utility model, and not departing from aim and the scope of technical solutions of the utility model, it all should be encompassed in the middle of claim scope of the present utility model.
Claims (2)
1. a lightning arrester leakage current sensor, it is characterized in that: comprise a metallic shield shell and seal the Current Mutual Inductance coil of being located in metallic shield shell, feeble signal amplifying circuit, low-pass filter circuit and voltage follower circuit, Current Mutual Inductance coil is sheathed on ground wire, its output terminal is connected with the input end of feeble signal amplifying circuit, the output terminal of feeble signal amplifying circuit is connected with the input end of low-pass filter circuit, the output terminal of low-pass filter circuit is connected with the input end of voltage follower circuit, the output terminal of voltage follower circuit is connected with signal pickup assembly by the shielded cable that passes metallic shield shell, at the two ends of a feeble signal amplifying circuit feedback circuit in parallel, the input end of feedback circuit is connected with the output terminal of feeble signal amplifying circuit, the output terminal of feedback circuit is connected with the input end of feeble signal amplifying circuit.
2. a kind of lightning arrester leakage current sensor according to claim 1, it is characterized in that: described Current Mutual Inductance coil is connected and composed by amplitude transformation coil and phase compensation coils from parallel connection of coils, amplitude transformation coil is connected with the input end of feeble signal amplifying circuit with the output terminal after phase compensation coils from parallel connection of coils.
Priority Applications (1)
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CN201420053629.8U CN203672953U (en) | 2014-01-27 | 2014-01-27 | Lightning arrester leakage current sensor |
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CN201420053629.8U CN203672953U (en) | 2014-01-27 | 2014-01-27 | Lightning arrester leakage current sensor |
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CN201420053629.8U Expired - Fee Related CN203672953U (en) | 2014-01-27 | 2014-01-27 | Lightning arrester leakage current sensor |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104345196A (en) * | 2014-10-30 | 2015-02-11 | 南京信息工程大学 | Active weak power frequency current induction coil |
CN105116221A (en) * | 2015-06-28 | 2015-12-02 | 许继集团有限公司 | Lightning arrester voltage following discrimination method and device |
CN107144719A (en) * | 2017-05-04 | 2017-09-08 | 北京理工大学 | A kind of high-precision testing weak signals instrument and method of testing |
CN108710023A (en) * | 2018-07-26 | 2018-10-26 | 云南电网有限责任公司曲靖供电局 | Current sensor and lightning arrester monitoring device |
CN109620155A (en) * | 2018-09-18 | 2019-04-16 | 北京理工大学 | A kind of high-accuracy self-adaptation physiology signal tester and test method |
CN110460313A (en) * | 2019-08-22 | 2019-11-15 | 湘潭大学 | A kind of small-signal reading circuit for radiation detector |
-
2014
- 2014-01-27 CN CN201420053629.8U patent/CN203672953U/en not_active Expired - Fee Related
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104345196A (en) * | 2014-10-30 | 2015-02-11 | 南京信息工程大学 | Active weak power frequency current induction coil |
CN105116221A (en) * | 2015-06-28 | 2015-12-02 | 许继集团有限公司 | Lightning arrester voltage following discrimination method and device |
CN105116221B (en) * | 2015-06-28 | 2018-01-12 | 许继集团有限公司 | A kind of arrester voltage follow method of discrimination and device |
CN107144719A (en) * | 2017-05-04 | 2017-09-08 | 北京理工大学 | A kind of high-precision testing weak signals instrument and method of testing |
CN108710023A (en) * | 2018-07-26 | 2018-10-26 | 云南电网有限责任公司曲靖供电局 | Current sensor and lightning arrester monitoring device |
CN109620155A (en) * | 2018-09-18 | 2019-04-16 | 北京理工大学 | A kind of high-accuracy self-adaptation physiology signal tester and test method |
CN110460313A (en) * | 2019-08-22 | 2019-11-15 | 湘潭大学 | A kind of small-signal reading circuit for radiation detector |
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C14 | Grant of patent or utility model | ||
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CF01 | Termination of patent right due to non-payment of annual fee | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140625 Termination date: 20200127 |