CN102539960A - Method for measuring variable ratio nonlinear primary current threshold value of current transformer - Google Patents
Method for measuring variable ratio nonlinear primary current threshold value of current transformer Download PDFInfo
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- CN102539960A CN102539960A CN201110427814XA CN201110427814A CN102539960A CN 102539960 A CN102539960 A CN 102539960A CN 201110427814X A CN201110427814X A CN 201110427814XA CN 201110427814 A CN201110427814 A CN 201110427814A CN 102539960 A CN102539960 A CN 102539960A
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Abstract
The invention relates to a method for measuring a variable ratio nonlinear primary current threshold value of a current transformer, belonging to the field of measurement. A first-channel output of a test power supply is sleeved with a current transformer to be measured and a standard current transformer; a second-channel output of the test power supply is provided with a power switch; after passing through the current transformer to be measured and the standard current transformer, the first-channel output of the test power supply is connected with a rheostat in series, and is correspondingly connected with the other end of the power switch on the second-channel output of the test power supply; signal output ends of the current transformer to be measured and the standard current transformer are respectively and correspondingly connected with a signal input end of an oscillograph; and the variable ratio nonlinear primary current threshold value of the measured current transformer is obtained by observing a difference value of sampling curves in the oscillograph. According to the invention, the measuring problem of the primary current threshold value of the current transformer is solved; and the method provided by the invention has a great significance to enhancement of the management working level of an electric network and the division of management work and can be widely used for the fields of measurement of the electric network, relay protection, check and the like.
Description
Technical field
The invention belongs to field of measurement, relate in particular to a kind of method of testing that is used for the current transformer electromagnetic property.
Background technology
In order to guarantee the power system security economical operation, must carry out monitoring and measuring to the ruuning situation of power equipment.
But based on the reason of aspects such as electric pressure, insulation or safety, general measurement and protective device can not directly insert high-tension apparatus No. one time, and need the big electric current scaling transformation of primary system be become little electric current, supply with measurement instrument and protective device and use.
Current transformer is used to the primary current that numerical value is bigger usually, through certain no-load voltage ratio, converts the less secondary current of numerical value into, is used for protecting, purposes such as measurement.For example: no-load voltage ratio is 400/5 current transformer, can be reality that the current transitions of 400A is the electric current of 5A.
Current transformer has played the effect of unsteady flow and electrical isolation; It is the sensor that secondary device such as measurement instrument, relay protection obtains electric primary circuit current information in the electric system; Current transformer converts high electric current to low current in proportion; The current transformer primary side is connected on primary system, secondary side joint measurement instrument, relay protection etc.
Along with the raising of administration of power networks working level and the refinement of management work; Net to underloading electric line and transformer decreases statistics; Grasp electromagnetic current transducer the nonlinear primary current section of no-load voltage ratio is all arranged; Have very big reference significance, it has very great help to the differentiation tool of technological line loss with the management line loss.
Electromagnetic current transducer all has the nonlinear primary current section of no-load voltage ratio at present, and based on the restriction of method, device in existing measurement, the vertification regulation, traditional current transformer error determination test still can't detect this interval threshold value.
Summary of the invention
Technical matters to be solved by this invention provides the measuring method of the non-linear primary current threshold value of a kind of current transformer ratio; It passes through the difference of sampling curve in the observation oscilloscope, and then can obtain the non-linear primary current threshold value of no-load voltage ratio of tested current transformer easily.
Technical scheme of the present invention is: the measuring method that the non-linear primary current threshold value of a kind of current transformer ratio is provided; Comprise through measurement parameter comparing the measuring error that obtains current transformer to be measured that the described measuring method of its characteristic comprises the following steps: to current transformer to be measured and standard current transformer
1) current transformer to be measured and standard current transformer are sleeved in one tunnel output of experiment power supply;
2) in the second tunnel output of experiment power supply, power switch is set;
3) behind the first via of experiment power supply output process current transformer to be measured and the standard current transformer, be connected in series a rheostat, the other end of going up power switch with experiment power supply the second tunnel output is connected;
4) with the signal output part of said current transformer to be measured and standard current transformer, respectively with the corresponding connection of an oscillographic signal input part;
5) open the experiment power supply power switch, the resistance of standardsizing rheostat makes through CT
SurveyWith CT
xElectric current rise to 1% CT from zero
SurveyRated current;
6) difference of sampling curve among the observation oscilloscope B;
7) when the sample rate current difference of two mutual inductors from the primary current of bigger numerical to the time less than the tested current transformer class of accuracy of twice, be the non-linear primary current threshold value of tested current transformer ratio.
Concrete, the maximum range of said standard current transformer is 10% of a current transformer to be measured.
Described power switch is a fuse cutout.
Described experiment power supply is an AC power.
Compare with prior art, advantage of the present invention is:
1. the output waveform through observation oscilloscope; Record the non-linear primary current threshold value of no-load voltage ratio of tested current transformer; Solved the problems of measurement of current transformer primary current threshold value, the net damage statistics to underloading electric line and transformer has greatly help;
2. whole testing device need not to develop new testing apparatus based on existing testing apparatus, is easy to realize and promote;
3. popularizing and popularization of current transformer primary current threshold measurement to the raising of administration of power networks working level and the refinement of management work, has the help meaning.
Description of drawings
Fig. 1 is the interval synoptic diagram of the no-load voltage ratio of current transformer;
Fig. 2 is the electric principle schematic of the used measurement mechanism of the inventive method;
Fig. 3 is the block scheme of the present invention's measuring method step.
Embodiment
Below in conjunction with accompanying drawing the present invention is further specified.
Among Fig. 1, provided the interval signal of current transformer ratio, wherein mark has the interval of tee, is between the no-load voltage ratio inelastic region of current transformer.
Because this section interval is between the inelastic region, so in existing mutual inductor measurement, vertification regulation, get rid of.
But; Along with the raising of administration of power networks working level and the refinement of management work; Net to underloading electric line and transformer decreases statistics; Grasping electromagnetic current transducer all has the nonlinear primary current section of no-load voltage ratio, has very big reference significance, and it has very great help to the differentiation tool of technological line loss with the management line loss.
So,, the problems of measurement to the primary current threshold value between above-mentioned inelastic region has been proposed based on the requirement that management becomes more meticulous.
Among Fig. 2, technical scheme of the present invention in fact also provides a kind of current transformer primary current threshold measurement device, and it comprises experiment power supply AC, current transformer CT to be measured
XWith standard current transformer CT
Survey, its suit in the first via output of experiment power supply AC is provided with current transformer CT to be measured
XWith standard current transformer CT
SurveyIn the second tunnel output of experiment power supply, power switch K is set; Behind the first via output process current transformer to be measured and standard current transformer of experiment power supply, be connected in series a rheostat RT, the other end of going up power switch K with experiment power supply the second tunnel output is connected; The signal output part of said current transformer to be measured and standard current transformer is respectively with the corresponding connection of signal input part of an oscillograph B.
Concrete, described standard current transformer is an a small amount of journey high precision current transformer.
Further, the maximum range of above-mentioned standard current transformer is 10% of a current transformer to be measured.
Described power switch is a fuse cutout, perhaps, and for having the power switch of fuse.
Described experiment power supply is conventional ac test power supply.
Among Fig. 3, through adopting said apparatus shown in Figure 2, method of testing of the present invention comprises the following steps: at least
1) current transformer to be measured and standard current transformer are sleeved in one tunnel output of experiment power supply;
2) in the second tunnel output of experiment power supply, power switch is set;
3) behind the first via of experiment power supply output process current transformer to be measured and the standard current transformer, be connected in series a rheostat, the other end of going up power switch with experiment power supply the second tunnel output is connected;
4) with the signal output part of said current transformer to be measured and standard current transformer, respectively with the corresponding connection of an oscillographic signal input part;
5) open the experiment power supply power switch, the resistance of standardsizing rheostat makes through CT
SurveyWith CT
xElectric current rise to 1% CT from zero
SurveyRated current;
6) difference of sampling curve among the observation oscilloscope B;
7) when the sample rate current difference of two mutual inductors from the primary current of bigger numerical to the time less than the tested current transformer class of accuracy of twice, be the non-linear primary current threshold value of tested current transformer ratio.
Because involved parts and the instrument of above-mentioned measurement mechanism is this area usual means; Add that step and concrete operations that this method is involved also are the conventional steps in electric test/verification work; So those skilled in the art need not through performing creative labour, can reproduce the technique effect of present technique scheme according to the thinking of dealing with problems of present technique scheme; Realize its goal of the invention, so the connected mode of concrete operations details in the said process and concrete instrument is not described in detail in this.
Because the enforcement through the present technique scheme can record the non-linear primary current threshold value of tested current transformer ratio easily, has solved the problems of measurement of current transformer primary current threshold value; Net to underloading electric line and transformer decreases statistics, has greatly help, and whole testing device is based on the combination of existing testing apparatus; Need not to develop new testing apparatus, be easy to realize and promote, in addition; The enforcement of present technique scheme; Make that current transformer primary current threshold measurement is able to popularize and promote,, have the help meaning the raising of administration of power networks working level and the refinement of management work.
The present invention can be widely used in fields such as can being widely used in electrical network measurement, relay protection and verification.
Claims (4)
1. the measuring method of the non-linear primary current threshold value of current transformer ratio; Comprise through measurement parameter comparing the measuring error that obtains current transformer to be measured that the described measuring method of its characteristic comprises the following steps: to current transformer to be measured and standard current transformer
1) current transformer to be measured and standard current transformer are sleeved in one tunnel output of experiment power supply;
2) in the second tunnel output of experiment power supply, power switch is set;
3) behind the first via of experiment power supply output process current transformer to be measured and the standard current transformer, be connected in series a rheostat, the other end of going up power switch with experiment power supply the second tunnel output is connected;
4) with the signal output part of said current transformer to be measured and standard current transformer, respectively with the corresponding connection of an oscillographic signal input part;
5) open the experiment power supply power switch, the resistance of standardsizing rheostat makes through CT
SurveyWith CT
xElectric current rise to 1% CT from zero
SurveyRated current;
6) difference of sampling curve among the observation oscilloscope B;
7) when the sample rate current difference of two mutual inductors from the primary current of bigger numerical to the time less than the tested current transformer class of accuracy of twice, be the non-linear primary current threshold value of tested current transformer ratio.
2. according to the measuring method of the non-linear primary current threshold value of the described current transformer ratio of claim 1, the maximum range that it is characterized in that said standard current transformer is 10% of a current transformer to be measured.
3. according to the measuring method of the non-linear primary current threshold value of the described current transformer ratio of claim 1, it is characterized in that described power switch is a fuse cutout.
4. according to the measuring method of the non-linear primary current threshold value of the described current transformer ratio of claim 1, it is characterized in that described experiment power supply is an AC power.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110427814.XA CN102539960B (en) | 2011-12-19 | 2011-12-19 | Method for measuring variable ratio nonlinear primary current threshold value of current transformer |
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| CN201110427814.XA CN102539960B (en) | 2011-12-19 | 2011-12-19 | Method for measuring variable ratio nonlinear primary current threshold value of current transformer |
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| CN102539960A true CN102539960A (en) | 2012-07-04 |
| CN102539960B CN102539960B (en) | 2014-04-09 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106093637A (en) * | 2016-06-07 | 2016-11-09 | 国网四川省电力公司电力科学研究院 | The removing method of dead band defect between intelligent substation primary equipment and secondary device |
| CN111722172A (en) * | 2020-06-16 | 2020-09-29 | 浙江工业职业技术学院 | Novel alternating current transformer online detection device and method |
| CN113804989A (en) * | 2021-11-17 | 2021-12-17 | 武汉磐电科技股份有限公司 | Method, device, equipment and storage medium for calibrating variable ratio group tester |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5457620A (en) * | 1993-07-30 | 1995-10-10 | At&T Ipm Corp. | Current estimating circuit for switch mode power supply |
| CN201975755U (en) * | 2011-03-11 | 2011-09-14 | 上海诺雅克电气有限公司 | Current diagnosis device for monitoring state of current transformer |
-
2011
- 2011-12-19 CN CN201110427814.XA patent/CN102539960B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5457620A (en) * | 1993-07-30 | 1995-10-10 | At&T Ipm Corp. | Current estimating circuit for switch mode power supply |
| CN201975755U (en) * | 2011-03-11 | 2011-09-14 | 上海诺雅克电气有限公司 | Current diagnosis device for monitoring state of current transformer |
Non-Patent Citations (1)
| Title |
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| 袁康敏: "电流互感器变比测试仪的研制", 《传感器与仪器仪表》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106093637A (en) * | 2016-06-07 | 2016-11-09 | 国网四川省电力公司电力科学研究院 | The removing method of dead band defect between intelligent substation primary equipment and secondary device |
| CN106093637B (en) * | 2016-06-07 | 2019-04-23 | 国网四川省电力公司电力科学研究院 | The removing method of dead zone defect between intelligent substation primary equipment and secondary device |
| CN111722172A (en) * | 2020-06-16 | 2020-09-29 | 浙江工业职业技术学院 | Novel alternating current transformer online detection device and method |
| CN113804989A (en) * | 2021-11-17 | 2021-12-17 | 武汉磐电科技股份有限公司 | Method, device, equipment and storage medium for calibrating variable ratio group tester |
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| CN102539960B (en) | 2014-04-09 |
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Owner name: STATE ELECTRIC NET CROP. Effective date: 20121012 |
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Effective date of registration: 20121012 Address after: 200122 Shanghai City, Pudong New Area source deep road, No. 1122 Applicant after: Shanghai Electric Power Corporation Applicant after: State Grid Corporation of China Address before: 200122 Shanghai City, Pudong New Area source deep road, No. 1122 Applicant before: Shanghai Electric Power Corporation |
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