CN103235280B - 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 PDF

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CN103235280B
CN103235280B CN201310113636.2A CN201310113636A CN103235280B CN 103235280 B CN103235280 B CN 103235280B CN 201310113636 A CN201310113636 A CN 201310113636A CN 103235280 B CN103235280 B CN 103235280B
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current
current transformer
transformer
test product
magnetic saturation
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CN103235280A (en
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靳绍平
刘见
张春强
李东江
王浔
李欣
聂方明
唐新宇
刘经昊
胡岸
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KECHENG HIGH-NEW TECHNOLOGY DEVELOPMENT Co JIANGXI
State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Jiangxi Electric Power Co Ltd
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KECHENG HIGH-NEW TECHNOLOGY DEVELOPMENT Co JIANGXI
State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Jiangxi Electric Power Co Ltd
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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

Based on the current transformer magnetic saturation nargin direct measuring method of scaling converter
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: " current transformer iron core magnetic flux density when being equivalent to 1.5 times under rated current and rated load state, error should be not more than 1.5 times of error limit under rated current and rated load." south electric network requires: current transformer iron core magnetic flux density is when being equivalent to 2 times under rated current and rated load state, and error should be not more than 2 times of error limit under rated current and rated load.Current transformer calibrating device primarily of: standard current transformer, mutual-inductor tester and Burden box form, according to JJG313-2010 " Verification of Measuring Current Transformer vertification regulation ", JJG169-2010 " mutual-inductor tester vertification regulation " and JJF1264-2010 " mutual inductor load box calibrating standard " requires that standard current transformer, mutual-inductor tester and Burden box all can not meet the requirement being overload up to rated current 1.5 times, and existing current transformer calibrating device can not the magnetic saturation nargin of direct measurement current transform er.JJG1021-2007 " electric power mutual-inductor vertification regulation " § 6.3.8.2 indirect inspection: " if do not possess the standard set-up in 150% rated current point measuring error; can by increasing the method indirect inspection of secondary load, the electric current selected during measurement be not less than 20% of rated current.If selected electric current percentage point is m%, the rated sencondaryload 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, under electric current percentage point 0.5 m%, the error of measurement current transform er, obtains f 1, δ 1and f 2, δ 2.Then at secondary load (150/m) Z b+ (150/m-1) Z 2, under electric current percentage point m%, the error of measurement current transform er, obtains f 3, δ 3.Error under tested current transformer 150% electric current percentage point is calculated as follows:
…………⑴
…………⑵
The indirect method of measurement needs to measure the impedance of test product Secondary Winding, and calculates Z 2; According to Z 2value configuration secondary load; But Z 2value is random number, and conventional serial mode Burden box cannot meet the demands, necessary development of new impedance network; There is the short slab in principle in this secondary load case, 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, there is realistic meaning.
Summary of the invention
The object of the invention is, in order to the checkout equipment solving estimated current mutual inductor all can not meet the requirement being overload up to rated current 1.5 times, the problem of the magnetic saturation nargin of current transformer cannot be carried out, how on existing equipment detection basis, to carry out technological improvement, the magnetic saturation nargin realizing current transformer is measured, and 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 " detecting current transformer code ", by current ratio transducer and test product current transformer TA xcascade, forms the circuit of new measurement current transform er magnetic saturation nargin with mutual-inductor tester, standard current transformer, Burden box, mutual-inductor tester reads the error of test product current transformer, be i.e. ratio difference f and phase differential δ; The magnetic saturation nargin completing this test product current transformer is measured.F is ratio difference, unit: (%); δ phase differential, unit: (') point.
The present invention, according to the calibrating wiring diagram (see figure 1) of JJG1021-2007 " detecting current transformer code ", uses 1 no-load voltage ratio to be 10A/5A; Class of accuracy is current ratio transducer and the test product current transformer TA of 0.01% grade xcascade, the current transformer magnetic saturation nargin connected into as shown in Figure 2 directly measures detection wiring diagram.
The circuit of measurement current transform er magnetic saturation nargin of the present invention is: by 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 polar terminals K 1with current ratio transducer secondary current polar terminals K 2and be attached to mutual-inductor tester difference current loop-around test terminal K, current ratio transducer secondary current polar terminals K 1meet mutual-inductor tester working current loop calibrating terminal T x; Standard current transformer TA oprimary current polar terminals L 1with test product current transformer TA xprimary current polar terminals L 1series connection, standard current transformer TA oprimary current polar terminals L 2with test product current transformer TA xprimary current polar terminals L 2connect current lifting device output terminal respectively; Current ratio transducer primary current polar terminals L 1by Burden box Z and test product current transformer TA xsecondary current polar terminals K 2be connected, current ratio transducer primary current polar terminals L 2with test product current transformer TA xsecondary current polar terminals K 1be connected; Mutual-inductor tester difference current loop-around test terminal D ground connection.
According to GB1208-2006 " current transformer " § 5.2 rated secondary current standard value: " 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 cascade is K x1:
…………⑷
From formula (4), no-load voltage ratio is the current ratio transducer of 10A/5A and tested current transformer TA xcurrent ratio transducer secondary loop current can be made after cascade to reduce 50%.Namely, when test product current transformer primary current is 150% of rated primary current, the secondary current of current ratio transducer is:
By the requirement of south electric network, when test product current transformer primary current is 200% of rated primary current, the secondary current of current ratio transducer is:
Will the test product current transformer TA of more above-mentioned no-load voltage ratio xmust select the standard current transformer of no-load voltage ratio identical with it, must choice criteria current transformer ratio be namely K x1.Standard current transformer secondary current in like manner can be made to reduce 50%, make standard current transformer be operated in 50% or 100% of rated current.The method solves 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, when rated secondary current is 5A, rated current can be selected to be the Burden box of 10A, solve 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 adopted, the equipment that the embodiment of the present invention adopts has (1): standard current transformer (0.02 grade), mutual-inductor tester (2 grades), rated current are the Burden box (3 grades) of 10A, a no-load voltage ratio is 10A/5A; Class of accuracy is the current ratio transducer of 0.01% grade;
(2) wiring is carried out by the mode of connection shown in Fig. 2;
(3) Burden box is set according to test product current transformer nameplate parameter " rated sencondaryload ";
(4) primary current of test product current transformer is risen to 150% of rated primary current by regulatory requirements, now, standard current transformer and current ratio transducer secondary current are 75% of rated secondary current.Or the primary current of test product current transformer is risen to 200% of rated primary current by Southern Power Grid Company requirement, now, standard current transformer and current ratio transducer secondary current are 100% of rated secondary current.
(5) on mutual-inductor tester, read test product current transformer error f and δ, f are ratio difference, unit: (%); δ phase differential, unit: (') point.
(6) the primary current electric current of test product current transformer is down to 0.
(7) the magnetic saturation nargin completing 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 a standard current transformer (0.02 grade), mutual-inductor tester (2 grades), rated current be the Burden box (3 grades) of 10A, a no-load voltage ratio is 10A/5A; Class of accuracy is the current ratio transducer of 0.01% grade.The detection line that the magnetic saturation nargin forming current transformer is directly measured, utilizes the detecting current transformer equipment such as existing standard current transformer, mutual-inductor tester, can realize directly measuring current transformer magnetic saturation nargin.Make standard current transformer, mutual-inductor tester is operated in rated current 50% or 100%, guarantee the tractability 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.
Accompanying drawing explanation
Fig. 1 is that conventional current mutual inductor detects wiring diagram;
Fig. 2 is that current transformer magnetic saturation nargin directly measures detection wiring diagram;
Symbol in figure: TA 0it is standard current transformer; TA xit is test product current transformer; TA tit is current ratio transducer; Z is current transformer load box; I 0it is 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 is measuring circuit difference current; I 1it is testing circuit primary current; L 1, L 2be respectively standard current transformer, current ratio transducer and test product current transformer primary current polar terminals; K 1, K 2be respectively standard current transformer, current ratio transducer and test product Current Transformer Secondary current polarity terminal; T 0, T xfor mutual-inductor tester working current loop calibrating terminal; K, D are mutual-inductor tester difference current loop-around test terminal.
Embodiment
Below in conjunction with accompanying drawing, the present invention is described in detail.
1, the equipment of this method employing:
Standard current transformer (0.02 grade), mutual-inductor tester (2 grades), rated current are the Burden box (3 grades) of 10A, a no-load voltage ratio is 10A/5A; Class of accuracy is the current ratio transducer of 0.01% grade.
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 2n.Such as: the no-load voltage ratio of test product current transformer is 100A/5A, 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;
By 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 polar terminals K 1with current ratio transducer secondary current polar terminals K 2and be attached to mutual-inductor tester difference current loop-around test terminal K, current ratio transducer secondary current polar terminals K 1meet mutual-inductor tester working current loop calibrating terminal T x; Standard current transformer TA oprimary current polar terminals L 1with test product current transformer TA xprimary current polar terminals L 1series connection, standard current transformer TA oprimary current polar terminals L 2with test product current transformer TA xprimary current polar terminals L 2connect current lifting device output terminal respectively; Current ratio transducer primary current polar terminals L 1by Burden box Z and test product current transformer TA xsecondary current polar terminals K 2be connected, current ratio transducer primary current polar terminals L 2with test product current transformer TA xsecondary current polar terminals K 1be connected; Mutual-inductor tester difference current loop-around test terminal D ground connection.
3, detect by the requirement of relevant code.
(1) Burden box is set according to test product current transformer nameplate parameter " rated sencondaryload ";
First Burden box resistance value is calculated:
According to the principles of electric and electronic engineering:
…………⑸
Such as: test product current transformer rated sencondaryload: S=20VA; Rated secondary current: I=5A, then:
(2) Burden box range is set according to result of calculation;
(3) primary current of test product current transformer is risen to 150% of rated primary current by regulatory requirements, now, standard current transformer and current ratio transducer secondary current are 75% of rated secondary current.Or the primary current of test product current transformer is risen to 200% of rated primary current by Southern Power Grid Company requirement, now, standard current transformer and current ratio transducer secondary current are 100% of rated secondary current.
(4) on mutual-inductor tester, read error f and the δ of test product current transformer.F is ratio difference, unit: (%); δ phase differential, unit: (') point;
(5) the primary current electric current of test product current transformer is down to 0;
(6) the magnetic saturation nargin completing this test product current transformer is measured.

Claims (2)

1., based on a current transformer magnetic saturation nargin direct measuring method for scaling converter, it is characterized in that, described method by current ratio transducer and test product current transformer TAx cascade, with mutual-inductor tester, standard current transformer TA o, Burden box Z forms the circuit of new measurement current transform er magnetic saturation nargin, mutual-inductor tester reads the error of test product current transformer TAx, i.e. ratio difference f and phase differential δ; The magnetic saturation nargin completing this test product current transformer TAx is measured;
The circuit of described measurement current transform er 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 polar terminals K 1with current ratio transducer secondary current polar terminals K 2and be attached to mutual-inductor tester difference current loop-around test terminal K, current ratio transducer secondary current polar terminals K 1meet mutual-inductor tester working current loop calibrating terminal T x; Standard current transformer TA oprimary current polar terminals L 1with test product current transformer TA xprimary current polar terminals L 1series connection, standard current transformer TA oprimary current polar terminals L 2with test product current transformer TA xprimary current polar terminals L 2connect current lifting device output terminal respectively; Current ratio transducer primary current polar terminals L 1by Burden box Z and test product current transformer TA xsecondary current polar terminals K 2be connected, current ratio transducer primary current polar terminals L 2with test product current transformer TA xsecondary current polar terminals K 1be connected; Mutual-inductor tester difference current loop-around test terminal D ground connection.
2. a kind of current transformer magnetic saturation nargin direct measuring method based on scaling converter according to claim 1, it is characterized in that, the step of current transformer magnetic saturation nargin direct measuring method is as follows:
(1) equipment adopted: a standard current transformer TA o0.02 grade; Mutual-inductor tester 2 grades; A rated current is the Burden box Z3 level of 10A; The current ratio transducer that no-load voltage ratio is 10A/5A, class of accuracy is 0.01% grade;
(2) wiring is carried out by the circuit of measurement current transform er magnetic saturation nargin;
(3) Burden box Z is set according to test product current transformer TAx nameplate parameter " rated sencondaryload ";
(4) primary current of test product current transformer TAx is risen to 150% of rated primary current, now, standard current transformer TA obe 75% of rated secondary current with current ratio transducer secondary current; Or the primary current of test product current transformer TAx is risen to 200% of rated primary current, and now, standard current transformer TA obe 100% of rated secondary current with current ratio transducer secondary current;
(5) on mutual-inductor tester, read error f and the δ of test product current transformer TAx; F is ratio difference, unit: %; δ is phase differential, unit: point;
(6) electric current is down to 0;
(7) the magnetic saturation nargin completing this test product current transformer TAx is measured.
CN201310113636.2A 2013-04-03 2013-04-03 Direct measuring method of magnetic saturation margin of current transformer based on scaling converter Active CN103235280B (en)

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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
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CN109655777B (en) * 2019-01-15 2021-10-08 昆明理工大学 Method and device for evaluating PT magnetic saturation margin performance of distribution network
CN111487576B (en) * 2020-04-30 2022-12-30 浙江省计量科学研究院 Miniature current transformer measuring device based on direct measurement method
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