CN102539960B - 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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- CN102539960B CN102539960B CN201110427814.XA CN201110427814A CN102539960B CN 102539960 B CN102539960 B CN 102539960B CN 201110427814 A CN201110427814 A CN 201110427814A CN 102539960 B CN102539960 B CN 102539960B
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- 238000000034 method Methods 0.000 title claims abstract description 20
- 238000005259 measurement Methods 0.000 claims abstract description 21
- 238000002474 experimental method Methods 0.000 claims description 23
- 238000012360 testing method Methods 0.000 abstract description 11
- 238000005070 sampling Methods 0.000 abstract description 4
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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 fields of measurement, relate in particular to a kind of method of testing for current transformer electromagnetic property.
Background technology
In order to guarantee power system security economical operation, must carry out monitoring and measuring to the ruuning situation of power equipment.
But the reason based on aspects such as electric pressure, insulation or safety, general measurement and protective device can not directly access high-tension apparatus No. one time, and the large electric current scaling transformation of primary system need to be become to little electric current, supply with measurement instrument and protective device and use.
Current transformer, is usually used to, by the larger primary current of numerical value, by certain no-load voltage ratio, be converted to the secondary current that numerical value is less, is used for protecting, the purposes such as measurement.For example: the current transformer that no-load voltage ratio is 400/5, the electric current that the current transitions that can be 400A reality is 5A.
Current transformer has played the effect of unsteady flow and electrical isolation; it is the sensor that in electric system, the secondary device such as measurement instrument, relay protection obtains electric primary circuit current information; current transformer converts high electric current to low current in proportion; 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, network loss statistics to underloading electric line and transformer, grasp electromagnetic current transducer and all have the nonlinear primary current section of no-load voltage ratio, have very large reference significance, it has very great help to technical loss and the differentiation tool of management line loss.
Electromagnetic current transducer all has the nonlinear primary current section of no-load voltage ratio at present, the restriction based on method, device in existing measurement, vertification regulation, and traditional current transformer error determination test, the method for there is no detects this interval threshold value.
Summary of the invention
Technical matters to be solved by this invention is to provide 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 observation oscilloscope, and then can obtain easily the non-linear primary current threshold value of no-load voltage ratio of tested current transformer.
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 by the measurement parameter of current transformer to be measured and standard current transformer being compared to the measuring error that obtains current transformer to be measured, the measuring method described in its feature comprises the following steps:
1) current transformer to be measured and standard current transformer are sleeved in the output of experiment power supply Yi road;
2) in the second tunnel output of experiment power supply, power switch is set;
3) output of the first via of experiment power supply is after current transformer to be measured and standard current transformer, and serial connection one rheostat, is connected with the other end of experiment power supply the second tunnel output power source switch;
4) by the signal output part of described current transformer to be measured and standard current transformer, respectively with the corresponding connection of an oscillographic signal input part;
5) open experiment power supply power switch, the resistance of standardsizing rheostat, makes to pass through CT
surveywith CT
xelectric current from zero, rise to 1% CT
surveyrated current;
6) difference of sampling curve in observation oscilloscope B;
7) when the sample rate current difference of two mutual inductors from bigger numerical the primary current when being 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 described standard current transformer is current transformer to be measured 10%.
Described power switch is fuse cutout.
Described experiment power supply is AC power.
Compared with the prior art, the utility model has the advantages that:
1. by the output waveform of observation oscilloscope, record the non-linear primary current threshold value of no-load voltage ratio of tested current transformer, solved the measurement problem of current transformer primary current threshold value, the network loss statistics to underloading electric line and transformer, has greatly help;
2. whole proving installation, based on existing testing apparatus, without the new testing apparatus of development, is easy to realize and promote;
3. the universal and popularization of current transformer primary current threshold measurement, the refinement to the raising of administration of power networks working level and management work, has help meaning.
Accompanying drawing explanation
Fig. 1 is the interval schematic diagram of the no-load voltage ratio of current transformer;
Fig. 2 is the electric principle schematic of the inventive method measurement mechanism used;
Fig. 3 is the block scheme of the present invention's measuring method step.
Embodiment
Below in conjunction with accompanying drawing, the present invention will be further described.
In 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 of interval is between inelastic region, therefore got rid of in existing mutual inductor measurement, vertification regulation.
But, along with the raising of administration of power networks working level and the refinement of management work, network loss statistics to underloading electric line and transformer, grasp electromagnetic current transducer and all have the nonlinear primary current section of no-load voltage ratio, have very large reference significance, it has very great help to technical loss and the differentiation tool of management line loss.
So the requirement becoming more meticulous based on management, has proposed the measurement problem to the primary current threshold value between above-mentioned inelastic region.
In 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 Transmit to be measured
xwith standard current transformer CT
survey, in its output of first via at experiment power supply AC, suit arranges Current Transmit to be measured
xwith standard current transformer CT
survey; In the second tunnel output of experiment power supply, power switch K is set; The first via output of experiment power supply is after current transformer to be measured and standard current transformer, and serial connection one rheostat RT, is connected with the other end of experiment power supply the second tunnel output power source K switch; The signal output part of described current transformer to be measured and standard current transformer, respectively with the corresponding connection of signal input part of an oscillograph B.
Concrete, described standard current transformer is small-range high precision current transformer.
Further, the maximum range of above-mentioned standard current transformer is current transformer to be measured 10%.
Described power switch is fuse cutout, or, be the power switch with fuse.
Described experiment power supply is conventional AC-testing supply.
In Fig. 3, by adopting the said apparatus shown in Fig. 2, method of testing of the present invention at least comprises the following steps:
1) current transformer to be measured and standard current transformer are sleeved in the output of experiment power supply Yi road;
2) in the second tunnel output of experiment power supply, power switch is set;
3) output of the first via of experiment power supply is after current transformer to be measured and standard current transformer, and serial connection one rheostat, is connected with the other end of experiment power supply the second tunnel output power source switch;
4) by the signal output part of described current transformer to be measured and standard current transformer, respectively with the corresponding connection of an oscillographic signal input part;
5) open experiment power supply power switch, the resistance of standardsizing rheostat, makes to pass through CT
surveywith CT
xelectric current from zero, rise to 1% CT
surveyrated current;
6) difference of sampling curve in observation oscilloscope B;
7) when the sample rate current difference of two mutual inductors from bigger numerical the primary current when being 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 the involved parts of above-mentioned measurement mechanism and instrument are this area usual means, add that step and concrete operations that this method is involved are also the conventional steps in electric test/verifying work, therefore those skilled in the art is without process performing creative labour, can be according to the thinking of dealing with problems of the technical program, reproduce the technique effect of the technical program, realize its goal of the invention, therefore the connected mode of the concrete operations details in said process and concrete instrument is not described in detail in this.
Due to by the enforcement of the technical program, can record easily the non-linear primary current threshold value of tested current transformer ratio, solved the measurement problem of current transformer primary current threshold value, network loss statistics to underloading electric line and transformer, there is greatly help, and the combination of whole proving installation based on existing testing apparatus, without the new testing apparatus of development, be easy to realize and promote, in addition, the enforcement of the technical program, make current transformer primary current threshold measurement be popularized and promote, refinement to the raising of administration of power networks working level and management work, has help meaning.
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 by the measurement parameter of current transformer to be measured and standard current transformer being compared to the measuring error that obtains current transformer to be measured, it is characterized in that described measuring method comprises the following steps:
1) current transformer to be measured and standard current transformer are sleeved in the first via output of experiment power supply;
2) in the second tunnel output of experiment power supply, power switch is set;
3) output of the first via of experiment power supply is after current transformer to be measured and standard current transformer, and serial connection one rheostat, is connected with the other end of experiment power supply the second tunnel output power source switch;
4) by the signal output part of described current transformer to be measured and standard current transformer, respectively with the corresponding connection of an oscillographic signal input part;
5) open the power switch of experiment power supply, the resistance of standardsizing rheostat, makes by standard current transformer CT
surveywith Current Transmit to be measured
xelectric current from zero, rise to 1% CT
surveyrated current;
6) curve of sample rate current difference in observation oscilloscope;
7) as the sample rate current difference of the two mutual inductors standard current transformer CT from 1%
surveyprimary current when rated current is reduced to less than twice current transformer class of accuracy to be measured, is the non-linear primary current threshold value of current transformer ratio to be measured.
2. according to the measuring method of the non-linear primary current threshold value of current transformer ratio claimed in claim 1, the maximum range that it is characterized in that described standard current transformer is current transformer to be measured 10%.
3. according to the measuring method of the non-linear primary current threshold value of current transformer ratio claimed in claim 1, it is characterized in that described power switch is fuse cutout.
4. according to the measuring method of the non-linear primary current threshold value of current transformer ratio claimed in claim 1, it is characterized in that described experiment power supply is AC power.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| 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 CN102539960A (en) | 2012-07-04 |
| CN102539960B true CN102539960B (en) | 2014-04-09 |
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| 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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| 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 |
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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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