CN104730353A - Turns ratio measuring method for current transformer - Google Patents
Turns ratio measuring method for current transformer Download PDFInfo
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- CN104730353A CN104730353A CN201510188459.3A CN201510188459A CN104730353A CN 104730353 A CN104730353 A CN 104730353A CN 201510188459 A CN201510188459 A CN 201510188459A CN 104730353 A CN104730353 A CN 104730353A
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Abstract
The invention relates to a turns ratio measuring method for a current transformer. The turns ratio measuring method includes the steps of (1), measuring and voltage applying, namely, applying voltage on a secondary side of the current transformer and then measuring induced voltage on a primary side of the current transformer; (2) power frequency component filtering, namely, when measurement voltage higher than power frequency is applied to the secondary side of the current transformer, enabling a measurement signal to be separated from an on-site power frequency voltage signal in a frequency spectrum, and filtering power frequency induction voltage on site via a low-pass filter; (3) turns ratio measuring of the current transformer, namely, measuring turns ratio of the current transformer by the aid of the measurement voltage with the power frequency being 70Hz. The turns ratio measuring method has the advantages that an actual measuring result of on-site turns ratio is extremely high in precision, and typical measuring error is normally lower than 0.02%, so that precision of a ratio difference measuring result is guaranteed effectively.
Description
Technical field
The invention belongs to power measurement, metering field, especially a kind of current transformer turn ratio measuring method.
Background technology
When detecting metering mutual inductor, usually all adopt big current source to inject detected mutual inductor and standard mutual inductor simultaneously, and detected mutual inductor and standard mutual inductor secondary side all connection standard loads, then standard mutual inductor is exported and contrast with the output being detected mutual inductor, thus obtain ratio and the angular difference of detected mutual inductor.This method can obtain the error information of detected mutual inductor accurately, but equipment required during site test is very many, comprise big current source, standard current transformer, load box and mutual-inductor tester etc., and when detected mutual inductor rated primary current is very high, required instrument current source capability will be very high, now used standard device can be very heavy, makes on-the-spot detection very inconvenient.
In order to substitute traditional current transformer error calibration equipment, voltage method can be adopted to carry out error checking to current transformer, when adopting voltage method to carry out error checking to current transformer, first need the mathematical model setting up current transformer then by the turn ratio of measured current mutual inductor, excitation loss and load can calculate ratio and the angular difference data of current transformer.In order to obtain accurate current transformer ratio and angular difference measurement result, excitation loss, turn ratio and Coil resistance three partial parameters all need first to obtain by measuring, especially the measurement result impact of turn ratio contrast differences is very large, turn ratio measures the error of introducing 0.2%, final ratio result will introduce the error of about 0.2%, and therefore its accuracy is most important to measurement result.But the how accurately turn ratio of measurement current transform er, Accurate measurement never simple and easy to implement, the impact of the factors such as test result is as easy as rolling off a log is subject to line-frequency induction voltage, the magnetic saturation of current transformer exciting current summation current transformer.
Through retrieval, find the existing publication of following analogous technical fields.
A kind of Multifunctional three-phase transformer CT loop-around test instrument (CN 103278735A), comprise primary side test terminal and secondary side test terminal, primary side test terminal and secondary side test terminal are connected in primary side and the secondary side of three-phase transformer respectively, Electricity Federation between primary side test terminal and secondary side test terminal, wherein: primary side test terminal is made up of primary side polarity test module, primary side switch and three-phase current inductor; Secondary side test terminal is by test connection terminal, secondary side switch and secondary side polarity test module, and test connection terminal is six and connects with secondary side switch respectively.The front-rear switch cabinet working equipment of polarity test and loop resistance test focuses in one group of device before switch cubicle by this multi-functional loop-around test instrument, after switch cubicle, personnel are only responsible for the wiring work of a three-phase CT, without the need to switch cubicle before personnel carry out compounding practice, the working strength of reduction.
A kind of high precision magnetic modulation type DC current measurement method (CN 104374984A), to the magnetic flux of measuring coil, the cross-sectional area of coil, the magnetic permeability of magnetic induction density or magnetic flux density and ring skeleton magnetic material is measured, setting: the magnetic flux being 1 circle coil, for the total magnetic flux of N circle coil, S is the cross-sectional area of coil, B is magnetic induction density or magnetic flux density, μ is the magnetic permeability of ring skeleton magnetic material, utilize formula and choose configuration parameter and select one section of operation interval in the μ-H curve of core material, make measuring coil inductance value and measured DC linear.Contactless DC current mutual inductor is utilized to measure.The present invention can realize between core inductance value and measured DC linear, thus make the moment of arrival reference voltage and measured DC linear, eliminate nonlinearity erron in existing DC current measurement result, improve measuring accuracy.
Through comparative analysis, the technology contents of above patented claim and the technique effect of generation with present patent application than all there is relatively big difference.
Summary of the invention
The object of the present invention is to provide a kind of simple effectively, current transformer turn ratio measuring method accurately and reliably.
The present invention solves its technical matters and takes following technical scheme to realize:
A kind of current transformer turn ratio measuring method, is characterized in that: measuring process is:
(1) test pressurization, at Current Transformer Secondary side making alive, then measures induced voltage at current transformer primary side;
(2) filtering power frequency component, adds the test voltage higher than power frequency in Current Transformer Secondary side, and test signal and on-the-spot power-frequency voltage signal are made a distinction, by low-pass filter by the filtering of on-the-spot line-frequency induction voltage on frequency spectrum;
(3) current transformer turn ratio is measured, and uses the 70Hz test voltage of power frequency to measure.
And, before carrying out secondary side pressurization, first excitation property test is carried out with the knee voltage obtaining current transformer to current transformer, the test voltage amplitude controlling turn ratio measuring process is got, to ensure that in current transformer turn ratio measuring process, current transformer is in unsaturated state with the knee voltage of actual measurement.
And step (1) secondary side institute making alive uses analog amplifier to produce the higher sinusoidal voltage of frequency.
Advantage of the present invention and good effect are:
1, in test process, use 70Hz as test voltage, and use low-pass filter by the filtering of power frequency 50Hz induced voltage, therefore test result effectively can avoid the interference of power frequency.
2, before measuring turn ratio, first the knee voltage that excitation property test obtains current transformer is carried out to current transformer, control test voltage amplitude to be no more than this knee voltage in measurement turn ratio, therefore in turn ratio measuring process, current transformer can not enter state of saturation, thus test result can effectively be ensured.
3, in test process, use 70Hz test voltage, exciting current decreases about 40% compared with 50Hz power frequency test voltage, and therefore the impact of exciting current on turn ratio measurement result reduces greatly.
4, adopt the actual measured results of the on-the-spot turn ratio of measuring method of the present invention can accomplish very high, typical measuring error is usually less than 0.02%, and this makes to be effectively guaranteed than the precision of level difference measurements.
Embodiment
Below in conjunction with by specific embodiment, the invention will be further described, following examples are descriptive, are not determinate, can not limit protection scope of the present invention with this.
A kind of current transformer turn ratio measuring method, concrete measuring process is:
(1) test pressurization, at Current Transformer Secondary side making alive, institute's making alive uses analog amplifier to produce the higher sinusoidal voltage of frequency as test signal, then measures induced voltage at current transformer primary side;
Before carrying out secondary pressurized, first excitation property test is carried out with the knee voltage obtaining current transformer to current transformer, the test voltage amplitude controlling turn ratio measuring process is got, to ensure that in current transformer turn ratio measuring process, current transformer is in unsaturated state with the knee voltage of actual measurement;
(2) filtering power frequency component, the test voltage higher than power frequency is added in Current Transformer Secondary side, test signal and on-the-spot power-frequency voltage signal are made a distinction on frequency spectrum, by low-pass filter by the filtering of on-the-spot line-frequency induction voltage, thus improves measuring accuracy;
(3) current transformer turn ratio is measured, and uses the 70Hz test voltage of power frequency to measure;
Due in current transformer turn ratio measuring process, the exciting current of secondary coil also can impact turn ratio measuring accuracy, therefore exciting current can form dividing potential drop in the internal resistance of Current Transformer Secondary coil, thus cause the distortion of turn ratio measuring process, the numerical value of exciting current corresponding under using the 70Hz test voltage higher than 50Hz power frequency then can make same test voltage reduces by 40%, thus effectively reduce exciting current to the impact of turn ratio measurement result, improve measuring accuracy.
Technical matters to be solved by this invention be to provide a kind of effectively and the turn ratio of the method for simple possible to current transformer accurately measure, analog amplifier is used to produce the higher sinusoidal voltage of frequency as test signal specifically, and by the power frequency component filtering in sampled data, on-the-spot line-frequency induction voltage can be avoided like this on the impact of measurement result.
Because the voltage frequency ratio power frequency used wants high a lot, excitation loss corresponding under therefore same test voltage also reduces greatly, and excitation loss also reduces greatly on the impact that turn ratio is measured.
Moreover test signal derives from the sinusoidal voltage of analog amplifier generation, therefore the irregularity of wave form of test voltage is very low.
These factors comprehensive, the actual measured results of on-the-spot turn ratio can be accomplished very high, and typical measuring error is usually less than 0.02%, and this makes to be effectively guaranteed than the precision of level difference measurements.
Although disclose embodiments of the invention for the purpose of illustration, but it will be appreciated by those skilled in the art that: in the spirit and scope not departing from the present invention and claims, various replacement, change and amendment are all possible, therefore, scope of the present invention is not limited to the content disclosed in embodiment.
Claims (3)
1. a current transformer turn ratio measuring method, is characterized in that: measuring process is:
(1) test pressurization, at Current Transformer Secondary side making alive, then measures induced voltage at current transformer primary side;
(2) filtering power frequency component, adds the test voltage higher than power frequency in Current Transformer Secondary side, and test signal and on-the-spot power-frequency voltage signal are made a distinction, by low-pass filter by the filtering of on-the-spot line-frequency induction voltage on frequency spectrum;
(3) current transformer turn ratio is measured, and uses the 70Hz test voltage of power frequency to measure.
2. current transformer turn ratio measuring method according to claim 1, it is characterized in that: before carrying out secondary side pressurization, first excitation property test is carried out with the knee voltage obtaining current transformer to current transformer, the test voltage amplitude controlling turn ratio measuring process is got, to ensure that in current transformer turn ratio measuring process, current transformer is in unsaturated state with the knee voltage of actual measurement.
3. current transformer turn ratio measuring method according to claim 1, is characterized in that: step (1) secondary side institute making alive uses analog amplifier to produce the higher sinusoidal voltage of frequency.
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| CN201510188459.3A CN104730353A (en) | 2015-04-20 | 2015-04-20 | Turns ratio measuring method for current transformer |
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| CN201510188459.3A CN104730353A (en) | 2015-04-20 | 2015-04-20 | Turns ratio measuring method for current transformer |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11142455A (en) * | 1997-11-07 | 1999-05-28 | Toshiba Corp | Transformation ratio testing device for transformer, and carriage |
| CN201600416U (en) * | 2009-12-24 | 2010-10-06 | 宁波电业局 | Transformation ratio tester for mutual inductor |
| CN102087347A (en) * | 2009-12-08 | 2011-06-08 | 张建 | Charged test method for current transformer and application thereof |
| CN103063924A (en) * | 2012-12-27 | 2013-04-24 | 江苏省电力公司电力科学研究院 | Vehicle-mounted integral three-phase direct-current resistance and transformation ratio and load comprehensive testing device and method |
| CN203069683U (en) * | 2012-12-18 | 2013-07-17 | 登封市电业(集团)有限公司 | Online transformer transformation ratio testing device |
| CN103675485A (en) * | 2013-12-11 | 2014-03-26 | 国家电网公司 | Method for measuring transformation ratio of Z-type transformers |
| CN104122483A (en) * | 2014-08-05 | 2014-10-29 | 国家电网公司 | Special current transformer transformation ratio detector for busbar |
-
2015
- 2015-04-20 CN CN201510188459.3A patent/CN104730353A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11142455A (en) * | 1997-11-07 | 1999-05-28 | Toshiba Corp | Transformation ratio testing device for transformer, and carriage |
| CN102087347A (en) * | 2009-12-08 | 2011-06-08 | 张建 | Charged test method for current transformer and application thereof |
| CN201600416U (en) * | 2009-12-24 | 2010-10-06 | 宁波电业局 | Transformation ratio tester for mutual inductor |
| CN203069683U (en) * | 2012-12-18 | 2013-07-17 | 登封市电业(集团)有限公司 | Online transformer transformation ratio testing device |
| CN103063924A (en) * | 2012-12-27 | 2013-04-24 | 江苏省电力公司电力科学研究院 | Vehicle-mounted integral three-phase direct-current resistance and transformation ratio and load comprehensive testing device and method |
| CN103675485A (en) * | 2013-12-11 | 2014-03-26 | 国家电网公司 | Method for measuring transformation ratio of Z-type transformers |
| CN104122483A (en) * | 2014-08-05 | 2014-10-29 | 国家电网公司 | Special current transformer transformation ratio detector for busbar |
Non-Patent Citations (1)
| Title |
|---|
| 陈彬 等: "计量用电流互感器测试与评价", 《电子技术与软件工程》 * |
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Application publication date: 20150624 |