CN106569163A - Method for detecting trailing amount of transformer - Google Patents
Method for detecting trailing amount of transformer Download PDFInfo
- Publication number
- CN106569163A CN106569163A CN201510645955.7A CN201510645955A CN106569163A CN 106569163 A CN106569163 A CN 106569163A CN 201510645955 A CN201510645955 A CN 201510645955A CN 106569163 A CN106569163 A CN 106569163A
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- Prior art keywords
- definite value
- value
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- sampled
- current
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Protection Of Transformers (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a method for detecting a trailing amount of a transformer. The method comprises: (1), a monotonic property of a sample value is detected; (2), if the sample value has a monotone increasing characteristic or a monotone decreasing characteristic and a constant time value is exceeded, a sample current is determined to be a trailing amount. In addition, a method for detecting the monotonic property of the sample value includes: differences between a current sample point and previous N sample points are calculated; if the difference values are larger than zero, the current sample point has a monotone increasing characteristic; and otherwise, if the difference values are smaller than zero, the current sample point has a monotone decreasing characteristic. The N is larger than 1 and is smaller than the sampling point number per cycle. If the monotone increasing characteristic of the sampling point is larger than constant time value continuously, the sampling current is the trailing amount; and if the monotone decreasing characteristic of the sampling point is larger than constant time value continuously, the sampling current is the trailing amount. On the basis of the monotonic property of the trailing amount, the trailing amount can be detected rapidly; the return speed of a tripping protection command increases; and reliability of failure protection is improved.
Description
Technical field
The present invention relates to electric power network technique field, more particularly to a kind of detection transformer trailing amount
Method.
Background technology
When power system is broken down, relay protection detects action outlet tripping operation after failure,
Breaker disconnects excision failure electrical primary part.Theoretical and actual field record wave table is bright, disconnected
After road device disconnects, electromagnetic type current transformer there may be current tail phenomenon, i.e. primary equipment
After disconnection, current transformer vice-side winding yet suffers from waiting current component the aperiodic of decay.Electricity
The origin cause of formation of stream conditions of streaking be due to when primary side breaker disconnects, the secondary of current transformer around
Organize electric current now and be not zero, now Exciting Windings for Transverse Differential Protection, vice-side winding and transformer institute is with secondary negative
Lotus formation loop simultaneously discharges the energy being stored in current loop inductance when breaker disconnects.
For the electronic mutual inductor with integrating network, after primary equipment disconnects, product
Electric capacity in parallel circuit has storage energy, and now this energy also can discharge along its integrating network,
Form trailing amount.
The tail currents of this trailing amount, especially current transformer, have important to protection
Affect.For main protection, the tripping operation pulse of general protection is to judge just after switching off
Withdraw, and the appearance of tail currents so that protection may think that switch still has electric current, and prolong
When withdraw tripping operation pulse.For failure protection, the presence of tail currents so that protection can
Can be judged as switching the error starting failure without tripping.
So protection needs quickly to identify this tail currents, the wind of false protection is reduced
Danger.
《Guangdong Electric Power》" current transformer tail currents are to open circuit for the article of 7 phases in 2012
The impact of device failure protection " analyzes tail currents Producing reason, and proposes by software
The method that filtering algorithm filters the DC component in electric current.The deficiency of the method is, software filtering
DC component can only be filtered, and tail currents are the DC components of a decay, it is impossible to disappear completely
Remove, in extreme circumstances, such as tail currents are very big, and failure definite value is than relatively low, now
May still result in failure protection.
《Henan science and technology》" current transformer trails to breaker failure the article of 9 phases in 2014
The simulation study that protection affects " analyzes tail currents Producing reason, and to three kinds of algorithms
Pluses and minuses are analyzed, method 1 be compound voltage lockout criterion, the weak point of the method
It is that the insufficient sensitivity of multiple pressure may cause tripping.Method 2 is the all-round algorithm of difference, this
Method is disadvantageous in that, it is impossible to filter tail currents completely, the risk that can there is malfunction.
Method 3 is zero-crossing examination, and the method is disadvantageous in that, failure is likely to occur in system
Electric current is partial to completely after a failure the situation of reference axis side in 1～2 cycle, is likely to result in
Failure tripping or action are very slow.
China Patent Publication No. CN201410281034.2, publication date on November 5th, 2014,
Entitled one kind of invention prevents current transformer tail currents from affecting on breaker fail protection
Method, which disclose one kind prevent current transformer tail currents to breaker failure protect
The method that shield affects, the current transformer tail currents wherein in claim 1 judge to include adopting
Sample value zero passage judges and electric current reduces judgement, and weak point is that failure electricity is likely to occur in system
The situation for being partial to reference axis side in 1～2 cycle after a failure completely is flowed, zero crossing judges
It is likely to result in failure tripping or action is very slow.
The content of the invention
In view of the shortcomings of the prior art, it is an object of the invention to provide a kind of high efficient and reliable
The method of detection trailing amount, it is ensured that can accurately identify trailing amount, and then improve protection
Reliability.
To achieve these goals, the present invention is realized by following technical scheme：Detection
The method of transformer trailing amount, it is characterised in that comprise the steps of：
(1) monotonicity of sampled value is detected；
(2) if sampled value is monotone increasing characteristic or monotone decreasing characteristic, and over-time is fixed
Value then judges that sample rate current is trailing amount.
Further, the method for the monotonicity of detection sampled value is：Calculate current sampling point and front
The difference of N sampled points, current sampling point is monotone increasing characteristic if difference is more than zero；Conversely,
If difference be less than zero if current sampling point be monotone decreasing characteristic, 1<N<Per cycle sampling number.
Further, persistently more than time definite value, then sample rate current is to drag to sampled point monotone increasing characteristic
Tail amount, persistently more than time definite value, then sample rate current is trailing amount to sampled point monotone decreasing characteristic.
Further, time definite value is more than 10ms.
Further, fluctuate larger or 60Hz system when being applied to system frequency fs, then when
Between definite value be greater than 1/2*fsmin, the minimum frequency that wherein fsmin is likely to occur for system.
Further, the method for the monotonicity of detection sampled value is：Calculate current sampling point and front
The difference of N sampled points, mathematic interpolation result is more than the first definite value, then detect that electric current is monotone increasing
Characteristic；Mathematic interpolation result is less than the second definite value, then detect that electric current is monotone decreasing characteristic.
Further, the first definite value and the second definite value according to sampling resolution, have matching relationship
Protection definite value determines.
Further, when sampled value is less than the 3rd definite value and be that monotone increasing characteristic or sampled value are more than
4th definite value 4 and for monotone decreasing characteristic, over-time definite value then sentences sample rate current for trailing amount.
Further, the selection of the 3rd definite value and the 4th definite value can be according to the little mutual inductance of detection means
Device characteristic is chosen.
The method of the monotonicity of the detection sampled value of the method for this detection transformer trailing amount is：Meter
The difference of current sampling point and previous sampled point is calculated, is considered currently to adopt if difference is more than zero
Sampling point monotone increasing characteristic., whereas if difference is considered current sampling point monotone decreasing less than zero
Characteristic.
The method for being judged as trailing amount is：Sampled point monotone increasing characteristic is persistently more than time definite value then
Trailing amount is regarded as, sampled point monotone decreasing characteristic persistently then regards as hangover more than time definite value
Amount.
Detecting the method for the monotonicity of sampled value can also be：Mathematic interpolation can adopt current point
With the sampled value of front N points, 1<N<Per cycle sampling number.
Detecting the method for the monotonicity of sampled value can also be：Mathematic interpolation result is certain more than certain
Value 1, then it is assumed that monotone increasing；Mathematic interpolation result is less than certain certain value 2, then it is assumed that monotone decreasing.
Definite value 1 and definite value 2 according to the sampling resolution of device, have protection definite value of matching relationship etc. to join
Number determines.
The selection principle of time definite value：Time definite value is typically chosen and is more than 10ms.If using
Fluctuate larger or 60Hz system in system frequency (fs), then time definite value is greater than 1/
(2*fsmin) minimum frequency that, wherein fsmin is likely to occur for system.
Being judged as the method for trailing amount can also be：When sampled value is less than certain certain value 3 and dullness
Increase characteristic, or sampled value more than certain certain value 4 and for monotone decreasing characteristic, over-time definite value is then
It is judged as trailing amount.The selection of definite value 3 and definite value 4 can be selected according to the little transformer characteristic of device
Take.
The present invention for electromagnetic type transformer or the electronic mutual inductor with integrating network,
After once switching off, due to having energy or integrating network in secondary circuit in have energy, this
Energy can discharge along secondary circuit, form trailing amount.This trailing amount, especially trail electricity
Stream has serious impact to protection, may result in the tripping operation pulse extension of main protection, may
Cause the malfunction of failure protection.The monotonicity feature that the present invention passes through trailing amount, can examine rapidly
Trailing amount is measured, the return speed of trip protection order can be improved, failure protection can be improved
Reliability.
In a word the present invention be directed to the monotonic nature of trailing amount is identified, not by the shadow of failure amount
Ring, can fast and accurately identify trailing amount.After identifying current tail amount, can be quick
Trip signal is withdrawn, the electric current criterion of failure protection can be quickly returned, improve protection can
By property.
Description of the drawings
Fig. 1 is tail currents decision logic figure；
Specific embodiment
In order that the objects, technical solutions and advantages of the present invention become more apparent, below according to
Drawings and Examples, the present invention will be described in further detail.It should be appreciated that this place is retouched
That what is stated is embodied as only to explain the present invention, does not limit the present invention.
Embodiment 1
The method of this detection transformer trailing amount, comprises the following steps：
(1) monotonicity of sampled value is detected.
(2) if sampled value is monotone increasing or monotone decreasing characteristic, and over-time definite value is then
It is judged as trailing amount.
The method of monotonicity of detection sampled value is：Calculate current sampling point and previous sampled point
Difference, if difference is more than zero current sampling point monotone increasing characteristic is considered., whereas if
Difference is considered current sampling point monotone decreasing characteristic less than zero.
The method for being judged as trailing amount is：Sampled point monotone increasing characteristic is persistently more than time definite value then
Trailing amount is regarded as, sampled point monotone decreasing characteristic persistently then regards as hangover more than time definite value
Amount.
Detecting the method for the monotonicity of sampled value can also be：Mathematic interpolation can adopt current point
With the sampled value (1 of front N points<N<Per cycle sampling number).
Detecting the method for the monotonicity of sampled value can also be：Mathematic interpolation result is certain more than certain
Value 1, then it is assumed that monotone increasing；Mathematic interpolation result is less than certain certain value 2, then it is assumed that monotone decreasing.
Definite value 1 and definite value 2 according to the sampling resolution of device, have protection definite value of matching relationship etc. to join
Number determines.
The selection principle of time definite value：Time definite value is typically chosen and is more than 10ms.If using
Fluctuate larger or 60Hz system in system frequency (fs), then time definite value is greater than 1/
(2*fsmin) minimum frequency that, wherein fsmin is likely to occur for system.
Being judged as the method for trailing amount can also be：When sampled value is less than certain certain value 3 and dullness
Increase characteristic, or sampled value more than certain certain value 4 and for monotone decreasing characteristic, over-time definite value is then
It is judged as trailing amount.The selection of definite value 3 and definite value 4 can be selected according to the little transformer characteristic of device
Take.
Embodiment described above only expresses the several embodiments of the present invention, and its description more has
Body and in detail, but therefore can not be interpreted as the restriction to the scope of the claims of the present invention.Should refer to
Go out, for the person of ordinary skill of the art, before without departing from present inventive concept
Put, some deformations and improvement can also be made, these belong to protection scope of the present invention.
Therefore, the protection domain of patent of the present invention should be defined by claims.
Claims (9)
1. it is a kind of detection transformer trailing amount method, it is characterised in that comprise the steps of：
(1) monotonicity of sampled value is detected；
(2) if sampled value is monotone increasing characteristic or monotone decreasing characteristic, and over-time definite value then judges that sample rate current is trailing amount.
2. the method for detection transformer trailing amount according to claim 1, it is characterised in that the method for monotonicity of detection sampled value is：The difference of current sampling point and front N sampled points is calculated, current sampling point is monotone increasing characteristic if difference is more than zero；, whereas if difference is less than zero current sampling point for monotone decreasing characteristic, 1<N<Per cycle sampling number.
3. it is according to claim 2 detection transformer trailing amount method, it is characterised in that：Persistently more than time definite value, then sample rate current is trailing amount to sampled point monotone increasing characteristic, and persistently more than time definite value, then sample rate current is trailing amount to sampled point monotone decreasing characteristic.
4. time definite value according to claim 3, it is characterised in that：Time definite value is more than 10ms.
5. time definite value according to claim 3, it is characterised in that：When larger or 60Hz the system of system frequency fs fluctuation is applied to, then time definite value is greater than 1/2*fsmin, the minimum frequency that wherein fsmin is likely to occur for system.
6. the monotonicity for judging sampled value according to claim 1, the method for monotonicity for being further characterized in that detection sampled value is：The difference of current sampling point and front N sampled points is calculated, mathematic interpolation result is more than the first definite value, then detect that electric current is monotone increasing characteristic；Mathematic interpolation result is less than the second definite value, then detect that electric current is monotone decreasing characteristic.
7. the monotonicity for judging sampled value according to claim 6, is further characterized in that：First definite value and the second definite value determine according to sampling resolution, the protection definite value for having matching relationship.
8. the monotonicity for judging sampled value according to claim 1, is further characterized in that：When sampled value is less than the 3rd definite value and be monotone increasing characteristic or sampled value more than the 4th definite value 4 and for monotone decreasing characteristic, over-time definite value then sentences sample rate current for trailing amount.
9. the monotonicity for judging sampled value according to claim 8, is further characterized in that：The selection of the 3rd definite value and the 4th definite value can be chosen according to the little transformer characteristic of device.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510645955.7A CN106569163A (en) | 2015-10-08 | 2015-10-08 | Method for detecting trailing amount of transformer |
| PCT/CN2016/075774 WO2017059655A1 (en) | 2015-10-08 | 2016-03-07 | Method for detecting transformer tail current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510645955.7A CN106569163A (en) | 2015-10-08 | 2015-10-08 | Method for detecting trailing amount of transformer |
Publications (1)
| Publication Number | Publication Date |
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| CN106569163A true CN106569163A (en) | 2017-04-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510645955.7A Pending CN106569163A (en) | 2015-10-08 | 2015-10-08 | Method for detecting trailing amount of transformer |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN106569163A (en) |
| WO (1) | WO2017059655A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108695823A (en) * | 2018-06-26 | 2018-10-23 | 南京南瑞继保电气有限公司 | A kind of differential protection blocking method of series transformer tail currents |
| CN110119696A (en) * | 2019-04-26 | 2019-08-13 | 三峡大学 | Current transformer tail currents recognizer based on wave character difference |
| CN111614061A (en) * | 2020-05-27 | 2020-09-01 | 国网江苏省电力有限公司 | Locking method for differential protection of series transformer |
| CN111797699A (en) * | 2020-06-10 | 2020-10-20 | 积成软件有限公司 | Method for identifying fault-removal CT trailing waveform |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114400622B (en) * | 2021-12-28 | 2024-05-10 | 北京四方继保工程技术有限公司 | Circuit breaker failure protection optimization method and system based on current waveform identification |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108695823A (en) * | 2018-06-26 | 2018-10-23 | 南京南瑞继保电气有限公司 | A kind of differential protection blocking method of series transformer tail currents |
| CN110119696A (en) * | 2019-04-26 | 2019-08-13 | 三峡大学 | Current transformer tail currents recognizer based on wave character difference |
| CN110119696B (en) * | 2019-04-26 | 2023-07-14 | 三峡大学 | Current transformer tailing current identification method based on waveform characteristic difference |
| CN111614061A (en) * | 2020-05-27 | 2020-09-01 | 国网江苏省电力有限公司 | Locking method for differential protection of series transformer |
| CN111614061B (en) * | 2020-05-27 | 2022-06-28 | 国网江苏省电力有限公司 | Locking method for differential protection of series transformer |
| CN111797699A (en) * | 2020-06-10 | 2020-10-20 | 积成软件有限公司 | Method for identifying fault-removal CT trailing waveform |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2017059655A1 (en) | 2017-04-13 |
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