CN203117414U - Alternating-current large-current checking system of current transformer - Google Patents
Alternating-current large-current checking system of current transformer Download PDFInfo
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- CN203117414U CN203117414U CN 201320113113 CN201320113113U CN203117414U CN 203117414 U CN203117414 U CN 203117414U CN 201320113113 CN201320113113 CN 201320113113 CN 201320113113 U CN201320113113 U CN 201320113113U CN 203117414 U CN203117414 U CN 203117414U
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- 239000004020 conductor Substances 0.000 claims description 20
- 238000004080 punching Methods 0.000 claims description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 6
- 230000003750 conditioning effect Effects 0.000 abstract description 4
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 abstract 2
- 238000012795 verification Methods 0.000 description 30
- 238000000034 method Methods 0.000 description 8
- 210000005069 ears Anatomy 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000001915 proofreading effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000011900 installation process Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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Abstract
The utility model discloses an alternating-current large-current checking system of a current transformer. The alternating-current large-current checking system of the current transformer comprises a large-current sensing unit, a data collecting unit and a PC, wherein the large-current sensing unit comprises an iron core coil, a hollow coil, a signal conditioning unit and a shielding shade, the hollow coil and the signal conditioning unit are fixedly arranged inside shielding shade, the iron core coil, the hollow coil and the shielding shade are respectively arranged on a current-carrying lead wire, a first bypass lead wire is arranged between the iron core coil and the hollow coil, and the output end of the signal conditioning unit is connected with the PC through the data collecting unit. According to the alternating-current large-current checking system of the current transformer, mutual inductance coefficient of the hollow coil after being mounted is corrected through utilization of the iron core coil, whether the hollow coil meets the checking conditions or not is judged, closed-loop control during checking is achieved through feedback of the mutual inductance coefficient of the hollow coil, high-precision alternating-current large-current checking is achieved, and output precision of the current transformer with the hollow coil is ensured.
Description
Technical field
The utility model is specifically related to a kind of current transformer AC great current check system and method based on air core coil coefficient of mutual inductance self checking principle, belongs to the electrical energy parameter field of measuring technique.
Background technology
Fast development along with electric system, the electric pressure of electrical network improves constantly, electric current also constantly increases, but the performance of metering outfit is subjected to bigger test under high voltage, the big current conditions, as one of important metering outfit of transformer station, performance and the verification thereof of current transformer under big current conditions is subjected to increasing attention.
The general calibration equipment that adopts based on electromagnetic transformer of traditional current transformer calibration equipment, can only be under little current conditions the performance of verification current transformer, electric current for tens of kA, because the saturation characteristic of iron core cause the accuracy of standard current transformer can't reach the verification requirement, even deviation is very big, if the coil of iron core will reach the precision that verification is used, volume can be very big, is unfavorable for processing, more is not suitable for execute-in-place.
At present, based on the current transformer of air core coil, have dynamic range big, measure advantages such as bandwidth, the linearity are good, the first-selection when becoming the AC great current measurement.Yet, because the output signal of air core coil is little, be subjected to the influence of external electromagnetic field and current carrying conductor position bigger, therefore its precision is not high, theoretical precision is up to 0.1%, yet do not reach theoretical precision in the reality far away, in order to improve measuring accuracy, some researchist adopts many forms to the series connection of PCB type air core coil, in order to improve the amplitude of output signal, (Granted publication number: just adopt this form CN 1967267A), the quantity of series coil depends on size and the permissible accuracy of primary current as patent; Also have patent (Granted publication number: CN 2099085Y) also be mentioned to current transformer based on air core coil, but above-mentioned patent has the following disadvantages:
1) air core coil is output as differential signal, need in subsequent conditioning circuit, add the hardware integrating circuit or in software, handle, the hardware integrating circuit can be subjected to the influence of temperature drift and time drift, the software integration can be subjected to the influence of flip-flop in the signal, therefore all can introduce additional error to signal, iron-core coil does not then need corresponding integrating circuit, and its output can directly be gathered through behind the resistance sampling, so ratio of precision air core coil height;
2) although the series connection of a plurality of air core coils can increase output signal, can increase the internal resistance of air core coil simultaneously, make output produce error;
3) measuring accuracy of air core coil is subjected to the influence of installation site very big, so during big electric current verification, under installation process and the uncontrollable prerequisite of result, the measuring accuracy of air core coil also is uncontrollable, be difficult to guarantee the current measurement precision of normalized current passage, to such an extent as to the confidence level of check results is under suspicion.
The utility model content
In order to overcome problems of the prior art, the utility model proposes current transformer AC great current check system and method based on air core coil coefficient of mutual inductance self checking principle, utilize iron-core coil that the coefficient of mutual inductance that the back air core coil is installed is proofreaied and correct, judge whether the air core coil state satisfies the verification condition, and the feedback by the air core coil coefficient of mutual inductance, closed-loop control when finishing verification, realize high-precision AC great current verification, guaranteed the output accuracy of hollow coil current transformer.
In order to achieve the above object, the technical scheme that adopts of the utility model is:
A kind of AC great current check system of current transformer, it is characterized in that: comprise big current sensing unit, data acquisition unit and PC, it is characterized in that: described big current sensing unit comprises iron-core coil, air core coil, signal condition unit and radome, described air core coil and signal condition unit are fixed on radome inside, described iron-core coil, air core coil and radome are installed on the current carrying conductor respectively, be provided with the first bypass lead between described iron-core coil and the air core coil, the end of the described first bypass lead is provided with the first input end that first splicing ear is big current sensing unit, the end of described current carrying conductor is provided with second input end that second splicing ear is big current sensing unit, and the output terminal of described signal condition unit is connected with PC by data acquisition unit as the signal output part of big current sensing unit.
The AC great current check system of aforesaid current transformer is characterized in that: described iron-core coil is that punching is fixed on the current carrying conductor.
The AC great current check system of aforesaid current transformer is characterized in that: the described first bypass lead is connected with current carrying conductor is vertical.
The AC great current check system of aforesaid current transformer is characterized in that: described data acquisition unit is data collecting card.
The AC great current check system of aforesaid current transformer is characterized in that: described current carrying conductor is the metallic hard lead.
The AC great current check system of aforesaid current transformer is characterized in that: described iron-core coil, air core coil and radome are installed in respectively on the current carrying conductor, and the distance between iron-core coil and the air core coil can be adjusted.
The beneficial effects of the utility model are: current transformer AC great current check system and the method based on the verification of air core coil coefficient of mutual inductance that the utility model proposes, utilize iron-core coil that the coefficient of mutual inductance that the back air core coil is installed is proofreaied and correct, judge whether the air core coil state satisfies the verification condition, pass through the feedback of air core coil coefficient of mutual inductance then, closed-loop control when finishing verification, realize high-precision AC great current verification, guaranteed the output accuracy of hollow coil current transformer.
Description of drawings
Fig. 1 is the system chart of the AC great current check system of current transformer of the present utility model.
Fig. 2 is the connection layout of air core coil coefficient of mutual inductance calibration phase of the present utility model.
Fig. 3 is the connection layout in AC great current verification stage of the present utility model.
The mark implication of accompanying drawing is as follows:
1: big current sensing unit; 2: data acquisition unit; The 3:PC machine; 4: iron-core coil; 5: air core coil; 6: the signal condition unit; 7: radome; 8: current carrying conductor; 9: the first bypass leads; 10: the first splicing ears; 11: the second splicing ears.
Embodiment
Below in conjunction with Figure of description, the utility model is further described.
Current transformer AC great current check system and method based on the verification of air core coil coefficient of mutual inductance of the present utility model, utilize iron-core coil that the coefficient of mutual inductance that the back air core coil is installed is proofreaied and correct, judge whether the air core coil state satisfies the verification condition, pass through the feedback of air core coil coefficient of mutual inductance then, closed-loop control when finishing verification, realized high-precision AC great current verification, guarantee the output accuracy of hollow coil current transformer, as shown in Figure 1, the AC great current check system of current transformer of the present utility model, comprise big current sensing unit 1, data acquisition unit 2 and PC 3, big current sensing unit comprises iron-core coil 4, air core coil 5, signal condition unit 6 and radome 7, air core coil 5 and signal condition unit 6 are fixed on radome 7 inside, air core coil 5 and signal condition unit 6, size (the external diameter of radome 7, internal diameter, thickness) can actual conditions adjust.Iron-core coil 4, air core coil 5 and radome 6 are installed in respectively on the current carrying conductor 8, current carrying conductor 8 is the metallic hard lead, be provided with the first bypass lead 9 between iron-core coil 4 and the air core coil 5, the first bypass lead 9 is drawn from current carrying conductor 8 by bolt, and the distance between iron-core coil 4 and the air core coil 5 can be adjusted, the end of the first bypass lead 9 is provided with first splicing ear 10 and is the first input end of big current sensing unit 1, the end of current carrying conductor 8 is provided with second splicing ear 11 and is second input end of big current sensing unit 1, the output terminal of signal condition unit 6 is connected with PC 3 by data acquisition unit 2 as the signal output part of big current sensing unit 1, data acquisition unit 2 is data collecting card, PC 3 arranges accordingly by the data of gathering, prepare to measure and verification, wherein iron-core coil 4 is fixed on the current carrying conductor 1 for punching, the first bypass lead 9 and 8 vertical connections of current carrying conductor, to reduce the electromagnetic interference (EMI) to big current sensing unit 1, improve the accuracy of proofreading and correct, guarantee the output accuracy of hollow coil current transformer.
AC great current method of calibration based on above-mentioned current transformer is characterized in that: may further comprise the steps:
The first step, the coefficient of mutual inductance self checking stage of air core coil 5
By the first input end input of big current sensing unit 1, iron-core coil 4 and air core coil 5 all insert the verification loop, and iron-core coil 4 and air core coil 5 all insert in the loop, and the method that the coefficient of mutual inductance of air core coil 1 is proofreaied and correct is as follows:
1) output valve of record iron-core coil 4, with the output valve of iron-core coil 1 as the standard value of proofreading and correct;
2) according to the calculated value that calculates of the coefficient of mutual inductance of air core coil 5, calculate both errors;
3) when error met corresponding class of accuracy regulation, the state of air core coil 5 satisfied the conditional request of verification standard channel, and the class of accuracy here is no more than 0.05% for being generally;
4) surpass the upper threshold of regulation when error, then adjust the spacing between iron-core coil 4 and the air core coil 5, repeat 1 again after the adjustment)-2), satisfy the conditional request of verification standard channel until the state of air core coil 5.
Second step, the AC great current verification stage
By second input end input of big current sensing unit 1, iron-core coil 4 is removed the verification loop, have only this moment air core coil 5 to insert the verification loop, calculate and verification carried out error by the big electric current of current transformer output AC of verification.
In sum, AC great current check system level method based on the verification of air core coil coefficient of mutual inductance, according to iron-core coil and air core coil characteristic separately, be the accuracy height of iron-core coil when measuring little electric current, good stability, good these two characteristics of situation lower linear degree that air core coil is fixing in the installation site, in both common current measuring ranges, at first utilize iron-core coil that the coefficient of mutual inductance that the back air core coil is installed is proofreaied and correct, judge whether the air core coil state satisfies the verification condition, thereby realize the whether satisfactory judgement of hollow coil current-sensing device service condition, pass through the feedback of air core coil coefficient of mutual inductance then, closed-loop control when finishing verification has realized high-precision AC great current verification.
More than show and described ultimate principle of the present utility model, principal character and advantage.The technician of the industry should understand; the utility model is not restricted to the described embodiments; that describes in above-described embodiment and the instructions just illustrates principle of the present utility model; under the prerequisite that does not break away from the utility model spirit and scope; the utility model also has various changes and modifications, and these changes and improvements all fall in claimed the utility model scope.The claimed scope of the utility model is defined by appending claims and equivalent thereof.
Claims (6)
1. the AC great current check system of current transformer, it is characterized in that: comprise big current sensing unit, data acquisition unit and PC, it is characterized in that: described big current sensing unit comprises iron-core coil, air core coil, signal condition unit and radome, described air core coil and signal condition unit are fixed on radome inside, described iron-core coil, air core coil and radome are installed on the current carrying conductor respectively, be provided with the first bypass lead between described iron-core coil and the air core coil, the end of the described first bypass lead is provided with the first input end that first splicing ear is big current sensing unit, the end of described current carrying conductor is provided with second input end that second splicing ear is big current sensing unit, and the output terminal of described signal condition unit is connected with PC by data acquisition unit as the signal output part of big current sensing unit.
2. the AC great current check system of current transformer according to claim 1, it is characterized in that: described iron-core coil is that punching is fixed on the current carrying conductor.
3. the AC great current check system of current transformer according to claim 1, it is characterized in that: the described first bypass lead is connected with current carrying conductor is vertical.
4. the AC great current check system of current transformer according to claim 1, it is characterized in that: described data acquisition unit is data collecting card.
5. the AC great current check system of current transformer according to claim 1 and 2, it is characterized in that: described current carrying conductor is the metallic hard lead.
6. the AC great current check system of current transformer according to claim 1, it is characterized in that: described iron-core coil, air core coil and radome are installed in respectively on the current carrying conductor, and the distance between iron-core coil and the air core coil can be adjusted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320113113 CN203117414U (en) | 2013-03-13 | 2013-03-13 | Alternating-current large-current checking system of current transformer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320113113 CN203117414U (en) | 2013-03-13 | 2013-03-13 | Alternating-current large-current checking system of current transformer |
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| CN203117414U true CN203117414U (en) | 2013-08-07 |
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| CN 201320113113 Expired - Lifetime CN203117414U (en) | 2013-03-13 | 2013-03-13 | Alternating-current large-current checking system of current transformer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103197274A (en) * | 2013-03-13 | 2013-07-10 | 江苏省电力公司电力科学研究院 | Calibration system and calibration method of alternating large current of current transformer |
| WO2014194514A1 (en) * | 2013-06-07 | 2014-12-11 | 国家电网公司 | Heavy ac current calibration system based on self-calibration principle of coefficient of mutual induction of hollow coil |
| CN111880138A (en) * | 2020-08-19 | 2020-11-03 | 国网福建省电力有限公司 | Zero-sequence current transformer measurement accuracy optimization method based on ferromagnetic characteristics |
-
2013
- 2013-03-13 CN CN 201320113113 patent/CN203117414U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103197274A (en) * | 2013-03-13 | 2013-07-10 | 江苏省电力公司电力科学研究院 | Calibration system and calibration method of alternating large current of current transformer |
| CN103197274B (en) * | 2013-03-13 | 2014-07-16 | 江苏省电力公司电力科学研究院 | Calibration system and calibration method of alternating large current of current transformer |
| WO2014194514A1 (en) * | 2013-06-07 | 2014-12-11 | 国家电网公司 | Heavy ac current calibration system based on self-calibration principle of coefficient of mutual induction of hollow coil |
| CN111880138A (en) * | 2020-08-19 | 2020-11-03 | 国网福建省电力有限公司 | Zero-sequence current transformer measurement accuracy optimization method based on ferromagnetic characteristics |
| CN111880138B (en) * | 2020-08-19 | 2022-11-08 | 国网福建省电力有限公司 | Zero-sequence current transformer measurement accuracy optimization method based on ferromagnetic characteristics |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20130807 Effective date of abandoning: 20140716 |
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| RGAV | Abandon patent right to avoid regrant |