CN103235280A - Direct measuring method of magnetic saturation margin of current transformer based on scaling converter - Google Patents
Direct measuring method of magnetic saturation margin of current transformer based on scaling converter Download PDFInfo
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- CN103235280A CN103235280A CN2013101136362A CN201310113636A CN103235280A CN 103235280 A CN103235280 A CN 103235280A CN 2013101136362 A CN2013101136362 A CN 2013101136362A CN 201310113636 A CN201310113636 A CN 201310113636A CN 103235280 A CN103235280 A CN 103235280A
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Abstract
The invention discloses a direct measuring method of magnetic saturation margin of a current transformer based on a scaling converter. The method includes that the current scaling converter is connected with a subjected current transformer TAx in a cascade manner, and forms a new measuring circuit of the magnetic saturation margin of the current transformer with a transformer calibrator, a standard current transformer and a load box; subjected current transformer errors which are ratio difference f and phase difference delta are read on the transformer calibrator; and thus the magnetic saturation margin measurement of the subjected current transformer is completed. By the aid of existing current transformer measuring equipment such as the standard current transformer and the transformer calibrator, direct measurement of the magnetic saturation margin of the current transformer can be realized. The standard current transformer and the transformer calibrator are operated on 50% or 100% of a rated current, so that traceability of measuring device values is guaranteed. The direct measuring method has the advantages of excellent conciseness, high economical efficiency, strong scientificalness, good practicability, strong operability, low cost and the like, and is applicable to the technical field of current transformer measurement.
Description
Technical field
The present invention relates to the current transformer magnetic saturation nargin direct measuring method based on scaling converter, belong to electric-power metering current transformer detection technique field.
Background technology
JJG1021-2007 " electric power mutual-inductor vertification regulation " § 4.5 magnetic saturation nargin: " during current transformer magnetic flux density unshakable in one's determination 1.5 times under being equivalent to rated current and rated load state, error should be not more than 1.5 times of error limit value under rated current and the rated load." south electric network requires: during current transformer magnetic flux density unshakable in one's determination 2 times under being equivalent to rated current and rated load state, error should be not more than 2 times of error limit value under rated current and the rated load.Current transformer calibrating device mainly is made of: standard current transformer, mutual-inductor tester and Burden box, require standard current transformer, mutual-inductor tester and Burden box all can not satisfy the requirement that is overload up to 1.5 times of rated current according to JJG313-2010 " Verification of Measuring Current Transformer vertification regulation ", JJG169-2010 " mutual-inductor tester vertification regulation " and JJF1264-2010 " mutual inductor Burden box calibrating standard ", existing current transformer calibrating device can not directly be measured the magnetic saturation nargin of current transformer.JJG1021-2007 " electric power mutual-inductor vertification regulation " § 6.3.8.2 measures indirectly: " if do not possess standard set-up in 150% rated current point measurement error; can measure indirectly by the method that increases secondary load, electric current selected during measurement is not less than 20% of rated current.If selected electric current percentage point is m%, the specified secondary load of current transformer is Z
B, the leakage reactance of Secondary Winding resistance is Z
2, respectively at secondary load Z
B, electric current percentage point m% and secondary load 2Z
B+ Z
2, the error of measurement current transformer obtains f under electric current percentage point 0.5 m%
1, δ
1And f
2, δ
2Then at secondary load (150/m) Z
B+ (150/m-1) Z
2, the error of measurement current transformer obtains f under the electric current percentage point m%
3, δ
3Error under the tested current transformer 150% electric current percentage point is calculated as follows:
The indirect method of measurement need be measured the impedance of test product Secondary Winding, and calculates Z
2According to Z
2Value configuration secondary load; But Z
2Value is random number, and traditional series system Burden box can't meet the demands, must develop novel impedance network; There is the short slab on the principle in this secondary load case, and the resistance of external wire is difficult to deduction.Study a kind of science, accurate, workable current transformer magnetic saturation nargin direct detecting method for this reason, have realistic meaning.
Summary of the invention
The objective of the invention is, for the checkout equipment that solves the estimated current mutual inductor all can not satisfy the requirement that is overload up to 1.5 times of rated current, can't carry out the problem of the magnetic saturation nargin of current transformer, how to detect the basis at existing equipment and carry out technological improvement, realize the magnetic saturation nargin measurement of current transformer, the invention provides a kind of current transformer magnetic saturation nargin direct measuring method.
Technical scheme of the present invention is, on the calibrating line tower foundation of existing " current transformer vertification regulation ", with current ratio transducer and test product current transformer TA
XCascade is formed the circuit of new measurement current transformer magnetic saturation nargin with mutual-inductor tester, standard current transformer, Burden box, reads the error of test product current transformer, i.e. ratio difference f and phase differential δ at mutual-inductor tester; Finishing the magnetic saturation nargin of this test product current transformer measures.F is ratio difference, unit: (%); The δ phase differential, unit: (') divides.
The present invention uses 1 no-load voltage ratio to be 10A/5A according to the calibrating wiring diagram (see figure 1) of JJG1021-2007 " current transformer vertification regulation "; Class of accuracy is 0.01% grade current ratio transducer and test product current transformer TA
XCascade, the current transformer magnetic saturation nargin that connects into is as shown in Figure 2 directly measured the detection wiring diagram.
The circuit that the present invention measures current transformer magnetic saturation nargin is: with standard current transformer TA
OSecondary current terminal K
2Meet mutual-inductor tester working current loop calibrating terminal T
0, standard current transformer TA
OSecondary current polarity terminal K
1With current ratio transducer secondary current polarity terminal K
2And be attached to mutual-inductor tester difference current return calibrating terminal K, current ratio transducer secondary current polarity terminal K
1Meet mutual-inductor tester working current loop calibrating terminal T
XStandard current transformer TA
OPrimary current polarity terminal L
1With test product current transformer TA
XPrimary current polarity terminal L
1Series connection, standard current transformer TA
OPrimary current polarity terminal L
2With test product current transformer TA
XPrimary current polarity terminal L
2Connect the current lifting device output terminal respectively; Current ratio transducer primary current polarity terminal L
1By Burden box Z and test product current transformer TA
XSecondary current polarity terminal K
2Link to each other current ratio transducer primary current polarity terminal L
2With test product current transformer TA
XSecondary current polarity terminal K
1Link to each other; Mutual-inductor tester difference current return calibrating terminal D ground connection.
According to GB1208-2006 " current transformer " § 5.2 rated secondary current standard values: " the rated secondary current standard value is: 1A and 5A." therefore, the inventive method only considers that rated secondary current is the measurement of 1A and 5A current transformer magnetic saturation nargin.
If: test product current transformer TA
XNo-load voltage ratio be K
x, then:
…………⑶
Current ratio transducer and test product current transformer TA
XEquivalent no-load voltage ratio after the cascade is K
X1:
…………⑷
By formula ⑷ as can be known, no-load voltage ratio is current ratio transducer and the tested current transformer TA of 10A/5A
XCan make current ratio transducer secondary loop current reduce 50% after the cascade.Namely when test product current transformer primary current be rated primary current 150% the time, the secondary current of current ratio transducer is:
By the requirement of south electric network, when test product current transformer primary current be rated primary current 200% the time, the secondary current of current ratio transducer is:
The test product current transformer TA of more above-mentioned no-load voltage ratio
XMust select the standard current transformer with its identical no-load voltage ratio, must the choice criteria current transformer ratio be K namely
X1In like manner can make the standard current transformer secondary current reduce 50%, make standard current transformer be operated in 50% or 100% of rated current.This method has solved the overcurrent problem of mutual-inductor tester and standard current transformer simultaneously.The rated current of Burden box can be selected by 2 times of test product current transformer rated secondary current, and when rated secondary current was 5A, can select rated current was the Burden box of 10A, solves the overcurrent problem of Burden box.
The step of current transformer magnetic saturation nargin direct measuring method of the present invention is as follows:
(1) equipment that the equipment of Cai Yonging, the embodiment of the invention adopt has (1): Burden box (3 grades), a no-load voltage ratio that the accurate current transformer of a station symbol (0.02 grade), a mutual-inductor tester (2 grades), rated current are 10A are 10A/5A; Class of accuracy is 0.01% grade current ratio transducer;
(2) carry out wiring by the mode of connection shown in Figure 2;
(3) according to test product current transformer nameplate parameter " specified secondary load " Burden box is set;
(4) by the rules requirement primary current of test product current transformer is risen to 150% of rated primary current, at this moment, standard current transformer and current ratio transducer secondary current are 75% of rated secondary current.Or by the Southern Power Grid Company requirement primary current of test product current transformer is risen to 200% of rated primary current, at this moment, standard current transformer and current ratio transducer secondary current are 100% of rated secondary current.
(5) read error f and the δ of test product current transformer at mutual-inductor tester, f is ratio difference, unit: (%); The δ phase differential, unit: (') divides.
(6) the primary current electric current of test product current transformer is down to 0.
(7) the magnetic saturation nargin of finishing this test product current transformer is measured.
The invention has the beneficial effects as follows, when detecting the magnetic saturation nargin of test product current transformer, use the accurate current transformer of a station symbol (0.02 grade), a mutual-inductor tester (2 grades), a rated current to be 10A/5A as the Burden box (3 grades) of 10A, a no-load voltage ratio; Class of accuracy is 0.01% grade current ratio transducer.The detection line that the magnetic saturation nargin of formation current transformer is directly measured utilizes current transformer calibration equipments such as existing standard current transformer, mutual-inductor tester, can realize current transformer magnetic saturation nargin is directly measured.Make standard current transformer, mutual-inductor tester be operated in 50% or 100% of rated current, but guarantee the traceability of pick-up unit value.Have that method is succinct, economy, science, practicality, workable, low cost and other advantages.
The present invention is applicable to current transformer detection technique field.
Description of drawings
Fig. 1 is that the conventional current mutual inductor detects wiring diagram;
Fig. 2 is that current transformer magnetic saturation nargin is directly measured the detection wiring diagram;
Symbol among the figure: TA
0It is standard current transformer; TA
xIt is the test product current transformer; TA
TIt is the current ratio transducer; Z is the current transformer Burden box; I
0It is the standard current transformer secondary current; I
xIt is test product Current Transformer Secondary electric current; I
TIt is current ratio transducer primary current; Δ I measures loop difference electric current; I
1It is the testing circuit primary current; L
1, L
2Be respectively standard current transformer, current ratio transducer and test product current transformer primary current polarity terminal; K
1, K
2Be respectively standard current transformer, current ratio transducer and test product Current Transformer Secondary current polarity terminal; T
0, T
XBe mutual-inductor tester working current loop calibrating terminal; K, D are mutual-inductor tester difference current return calibrating terminal.
Embodiment
The present invention is described in detail below in conjunction with accompanying drawing.
1, the equipment of this method employing:
Burden box (3 grades), a no-load voltage ratio that the accurate current transformer of one station symbol (0.02 grade), a mutual-inductor tester (2 grades), rated current are 10A are 10A/5A; Class of accuracy is 0.01% grade current ratio transducer.
2, the mode of connection
(1) no-load voltage ratio of choice criteria current transformer:
If: the no-load voltage ratio of test product current transformer is I
1n/ I
2n, then the no-load voltage ratio of choice criteria current transformer is 2I
1n/ I
2nFor example: the no-load voltage ratio of test product current transformer is 100A/5A, and then the no-load voltage ratio of choice criteria current transformer is 200A/5A.
(2) carry out wiring by current transformer magnetic saturation nargin direct measuring method wiring diagram, see Fig. 2;
With standard current transformer TA
OSecondary current terminal K
2Meet mutual-inductor tester working current loop calibrating terminal T
0, standard current transformer TA
OSecondary current polarity terminal K
1With current ratio transducer secondary current polarity terminal K
2And be attached to mutual-inductor tester difference current return calibrating terminal K, current ratio transducer secondary current polarity terminal K
1Meet mutual-inductor tester working current loop calibrating terminal T
XStandard current transformer TA
OPrimary current polarity terminal L
1With test product current transformer TA
XPrimary current polarity terminal L
1Series connection, standard current transformer TA
OPrimary current polarity terminal L
2With test product current transformer TA
XPrimary current polarity terminal L
2Connect the current lifting device output terminal respectively; Current ratio transducer primary current polarity terminal L
1By Burden box Z and test product current transformer TA
XSecondary current polarity terminal K
2Link to each other current ratio transducer primary current polarity terminal L
2With test product current transformer TA
XSecondary current polarity terminal K
1Link to each other; Mutual-inductor tester difference current return calibrating terminal D ground connection.
3, the requirement by relevant rules detects.
(1) according to test product current transformer nameplate parameter " specified secondary load " Burden box is set;
Earlier the Burden box resistance value is calculated:
According to the principles of electric and electronic engineering:
For example: the specified secondary load of test product current transformer: S=20VA; Rated secondary current: I=5A, then:
(2) according to result of calculation the Burden box range is set;
(3) by the rules requirement primary current of test product current transformer is risen to 150% of rated primary current, at this moment, standard current transformer and current ratio transducer secondary current are 75% of rated secondary current.Or by the Southern Power Grid Company requirement primary current of test product current transformer is risen to 200% of rated primary current, at this moment, standard current transformer and current ratio transducer secondary current are 100% of rated secondary current.
(4) read error f and the δ of test product current transformer at mutual-inductor tester.F is ratio difference, unit: (%); The δ phase differential, unit: (') divides;
(5) the primary current electric current of test product current transformer is down to 0;
(6) the magnetic saturation nargin of finishing this test product current transformer is measured.
Claims (3)
1. current transformer magnetic saturation nargin direct measuring method based on scaling converter, it is characterized in that, described method is with current ratio transducer and test product current transformer TAx cascade, form the circuit of new measurement current transformer magnetic saturation nargin with mutual-inductor tester, standard current transformer, Burden box, read the error of test product current transformer, i.e. ratio difference f and phase differential δ at mutual-inductor tester; Finishing the magnetic saturation nargin of this test product current transformer measures.
2. a kind of current transformer magnetic saturation nargin direct measuring method based on scaling converter according to claim 1 is characterized in that the circuit of described measurement current transformer magnetic saturation nargin is standard current transformer TA
OSecondary current terminal K
2Meet mutual-inductor tester working current loop calibrating terminal T
0, standard current transformer TA
OSecondary current polarity terminal K
1With current ratio transducer secondary current polarity terminal K
2And be attached to mutual-inductor tester difference current return calibrating terminal K, current ratio transducer secondary current polarity terminal K
1Meet mutual-inductor tester working current loop calibrating terminal T
XStandard current transformer TA
OPrimary current polarity terminal L
1With test product current transformer TA
XPrimary current polarity terminal L
1Series connection, standard current transformer TA
OPrimary current polarity terminal L
2With test product current transformer TA
XPrimary current polarity terminal L
2Connect the current lifting device output terminal respectively; Current ratio transducer primary current polarity terminal L
1By Burden box Z and test product current transformer TA
XSecondary current polarity terminal K
2Link to each other current ratio transducer primary current polarity terminal L
2With test product current transformer TA
XSecondary current polarity terminal K
1Link to each other; Mutual-inductor tester difference current return calibrating terminal D ground connection.
3. a kind of current transformer magnetic saturation nargin direct measuring method based on scaling converter according to claim 1 is characterized in that the step of current transformer magnetic saturation nargin direct measuring method is as follows:
(1) equipment of Cai Yonging: Burden box (3 grades), a no-load voltage ratio that the accurate current transformer of a station symbol (0.02 grade), a mutual-inductor tester (2 grades), rated current are 10A are 10A/5A; Class of accuracy is 0.01% grade current ratio transducer;
(2) carry out wiring by the circuit of measuring current transformer magnetic saturation nargin:
(3) according to test product current transformer nameplate parameter " specified secondary load " Burden box is set;
(4) by the rules requirement primary current of test product current transformer is risen to 150% of rated primary current, at this moment, standard current transformer and current ratio transducer secondary current are 75% of rated secondary current; Or by the Southern Power Grid Company requirement primary current of test product current transformer is risen to 200% of rated primary current, at this moment, standard current transformer and current ratio transducer secondary current are 100% of rated secondary current;
(5) read error f and the δ of test product current transformer at mutual-inductor tester; F is ratio difference, unit: (%); δ is phase differential, unit: (') divides;
(6) electric current is down to 0;
(7) the magnetic saturation nargin of finishing this test product current transformer is measured.
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104251948A (en) * | 2014-10-22 | 2014-12-31 | 华自科技股份有限公司 | Test device and test method suitable for differential protection detection of CT (current transformer) saturation |
| CN105974352A (en) * | 2016-06-20 | 2016-09-28 | 国网天津市电力公司 | Ultra-high voltage current transformer error field test monitoring method |
| CN106205988A (en) * | 2016-08-12 | 2016-12-07 | 山东亿玛信诺电气有限公司 | Wide cut metering combination transformer |
| CN109655777A (en) * | 2019-01-15 | 2019-04-19 | 昆明理工大学 | A kind of method and device for distribution PT magnetic saturation nargin performance of testing and assessing |
| CN111487576A (en) * | 2020-04-30 | 2020-08-04 | 浙江省方正校准有限公司 | Miniature current transformer measuring device based on direct measurement method |
| CN112068062A (en) * | 2020-09-10 | 2020-12-11 | 内蒙古电力(集团)有限责任公司内蒙古电力科学研究院分公司 | Mutual inductor calibration system and calibration method |
| CN112858989A (en) * | 2021-03-30 | 2021-05-28 | 云南电网有限责任公司电力科学研究院 | Current transformer calibration system |
| CN113447878A (en) * | 2021-06-18 | 2021-09-28 | 中国电力科学研究院有限公司 | Error measuring equipment and method for current transformer |
| CN115561695A (en) * | 2022-11-18 | 2023-01-03 | 山西互感器电测设备有限公司 | On-site calibration device and method for three-phase current transformer |
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104251948A (en) * | 2014-10-22 | 2014-12-31 | 华自科技股份有限公司 | Test device and test method suitable for differential protection detection of CT (current transformer) saturation |
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| CN105974352A (en) * | 2016-06-20 | 2016-09-28 | 国网天津市电力公司 | Ultra-high voltage current transformer error field test monitoring method |
| CN106205988A (en) * | 2016-08-12 | 2016-12-07 | 山东亿玛信诺电气有限公司 | Wide cut metering combination transformer |
| CN109655777A (en) * | 2019-01-15 | 2019-04-19 | 昆明理工大学 | A kind of method and device for distribution PT magnetic saturation nargin performance of testing and assessing |
| CN111487576A (en) * | 2020-04-30 | 2020-08-04 | 浙江省方正校准有限公司 | Miniature current transformer measuring device based on direct measurement method |
| CN112068062A (en) * | 2020-09-10 | 2020-12-11 | 内蒙古电力(集团)有限责任公司内蒙古电力科学研究院分公司 | Mutual inductor calibration system and calibration method |
| CN112858989A (en) * | 2021-03-30 | 2021-05-28 | 云南电网有限责任公司电力科学研究院 | Current transformer calibration system |
| CN113447878A (en) * | 2021-06-18 | 2021-09-28 | 中国电力科学研究院有限公司 | Error measuring equipment and method for current transformer |
| CN113447878B (en) * | 2021-06-18 | 2023-12-01 | 中国电力科学研究院有限公司 | Error measurement equipment and method for current transformer |
| CN115561695A (en) * | 2022-11-18 | 2023-01-03 | 山西互感器电测设备有限公司 | On-site calibration device and method for three-phase current transformer |
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