CN104362590B - Main transformer divides the recognition methods of side differential protection public winding CT progress of disease exceptions - Google Patents
Main transformer divides the recognition methods of side differential protection public winding CT progress of disease exceptions Download PDFInfo
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- CN104362590B CN104362590B CN201410523955.5A CN201410523955A CN104362590B CN 104362590 B CN104362590 B CN 104362590B CN 201410523955 A CN201410523955 A CN 201410523955A CN 104362590 B CN104362590 B CN 104362590B
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- 238000004804 winding Methods 0.000 title claims abstract description 67
- 201000010099 disease Diseases 0.000 title claims abstract description 29
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000005070 sampling Methods 0.000 claims description 7
- 230000002159 abnormal effect Effects 0.000 abstract description 6
- 230000007257 malfunction Effects 0.000 abstract description 6
- 238000005516 engineering process Methods 0.000 abstract description 3
- 230000004907 flux Effects 0.000 description 5
- 230000001681 protective effect Effects 0.000 description 4
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000002547 anomalous effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Abstract
The present invention relates to the recognition methods that main transformer divides side differential protection public winding CT progress of disease exceptions, belong to Relay Protection Technology in Power System field.The recognition methods of the public winding CT progress of disease exceptions of the present invention is tested using the sampled data of auto-transformer public winding CT, public winding current waveform is subjected to differential process first, the preceding half cycle of current waveform after differential and second half are then subjected to symmetry comparison.Public winding current waveform symmetry meets all the time during due to power transformer interior fault; and there is point-symmetry property more than more than 1/4 cycle to be unsatisfactory for during transformer air-drop public winding CT progress of disease exceptions; therefore; whether can symmetrically identify that failure and the CT progress of disease are abnormal by comparing public winding current waveform; make point side differential protection not malfunction when main transformer normally drops; quick acting when dropping failure transformer, improves the reliability of main transformer protection device.
Description
Technical field
The invention belongs to Relay Protection Technology in Power System field, and it is differential to be related to a kind of main transformer point side for intelligent grid
Protect the recognition methods of public winding CT progress of disease exceptions.
Background technology
Protective relaying device requirement can reliably cut off faulty equipment in system jam, ensure that the safety of system is steady
Fixed operation, but harm caused by the incorrect operation (including tripping and malfunction) of protective device is also huge.
In recent years, repeatedly there is the phenomenon of main transformer point side differential protection malfunction during the air-drop of 330kV auto-transformers in scene.It is logical
The reason for crossing recording waveform when dropping main transformer to analyze, finding false protection is not that protection philosophy and CT saturations etc. are asked
Topic causes, but is caused extremely by public winding CT current amplitudes or the phase progress of disease.The reason for public winding CT progress of disease is abnormal with
The structure of main transformer and the CT arrangements of public winding are related.During normal operation, inside transformer leakage magnetic flux very little, public winding
CT being capable of the normal progress of disease；But when transformer drops, the magnetic flux of A, B, C three-phase windings cannot be completely counterbalanced by, internal leakage magnetic flux increase,
Coupling is superimposed to the couples magnetic flux of normal exciting current, causes the current amplitude of bis- sensings of public winding CT and the phase progress of disease different
Often.
The basic method for preventing main transformer point side false protection is to change the internal structure of three-phase integrated auto-transformer, makes public affairs
The influence of leakage magnetic flux when winding CT Transfer characteristics drop from main transformer altogether.But for the transformer to have put into operation, protection can be passed through
The public winding CT progress of disease is identified in device extremely, prevents main transformer from dropping time-division side differential protection malfunction.
The content of the invention
The object of the present invention is to provide the recognition methods that main transformer divides side differential protection public winding CT progress of disease exceptions, to solve
The problem of causing main transformer protection error action of device after public winding CT progress of disease exceptions.
To achieve the above object, main transformer of the present invention divides the recognition methods step of side differential protection public winding CT progress of disease exceptions
It is as follows：
Main transformer divides the recognition methods of side differential protection public winding CT progress of disease exceptions, it is characterised in that the step of this method
It is as follows：
(1) amplitude of public winding A, B, C three-phase current is calculated, judges public winding phase current magnitude whether more than no stream
Threshold, discriminant equation are：
|IΦ| ＞ 0.04IN
I in above formulaΦFor the amplitude of any phase current of public winding A, B, C, INFor the secondary rated current of public winding CT；
(2) public winding current waveform is subjected to differential, the differential equation is：
ΔiK=iK-iK-1
I in above formulaKFor current point sampled value, iK-1For former point sampled value, Δ iKFor the current sampling data after differential；
(3) the preceding half cycle of the public winding current waveform after differential and second half are subjected to symmetry comparison, waveform comparison
Discrimination formula is：
|I(k)+I(k+π)|/|I(k)-I(k+π)|≥0.5
Point sampling value, I (k+ π) are corresponding sampled value in second half before I (k) is taken in for preceding half cycle in above formula；
(4) number of the asymmetric point of waveform in the sampled point of half period is continuously compared, if number is more than setting value,
Judge that waveform is asymmetric.
When judging that waveform is asymmetric, this phase of locking divides side differential protection；When judging waveform symmetry, this open phase divides side differential
Protection.
In the step (1), when public winding phase current is less than without stream threshold, this open phase divides side differential protection.
The main transformer of the present invention divides the recognition methods of side differential protection public winding CT progress of disease exceptions to public winding current wave
The symmetry of shape is differentiated, due to there is point pair more than more than 1/4 cycle when the transformer air-drop public winding CT progress of disease is abnormal
Title property is unsatisfactory for, and public winding current waveform symmetry meets all the time during power transformer interior fault, therefore, can be by more public
The symmetry of winding current waveform identifies that failure and the CT progress of disease are abnormal altogether, make point side differential protection when main transformer normally drops not
Malfunction, quick acting when dropping failure transformer, the reliability of raising main transformer protection device.
Brief description of the drawings
Fig. 1 is auto-transformer high-pressure side air-drop current distributing figure.
Fig. 2 is a point recognition methods flow chart for side differential protection public winding CT progress of disease exceptions.
Fig. 3 is that public winding current symmetry differentiates sampling schematic diagram.
Embodiment
The recognition methods of main transformer point side differential protection public winding CT progress of disease exceptions is mainly used in the high pressure of intelligent grid
In protective relaying device, by differentiating in real time to the symmetry of auto-transformer public winding current waveform, prevent public
The winding CT progress of disease causes a point side differential protection malfunction extremely, to improve the reliability of main transformer protection device.Main transformer divides side differential guarantor
Shield electric current is derived from coupling high voltage side of transformer CT, medium voltage side CT and public winding CT, CURRENT DISTRIBUTION such as Fig. 1 institutes when high-pressure side is dropped
Show.
Main transformer divides the recognition methods of the side differential protection public winding CT progress of disease exceptions function module independent as one, collection
Into in main transformer protection device, which puts into all the time, its flow is as shown in Figure 2.After the function module uses differential
The sampled data of half cycle and second half carries out symmetry comparison point by point before public winding current waveform, as shown in Figure 3.Due to transformation
The device air-drop public winding CT progress of disease has point-symmetry property more than more than 1/4 cycle to be unsatisfactory for when abnormal, therefore, the function module energy
The reliable recognition public winding CT progress of disease is abnormal.
Main transformer divides the step of side differential protection public winding CT progress of disease anomalous identification modules as follows：
(1) amplitude of public winding A, B, C three-phase current is calculated, public winding phase current magnitude should be greater than without stream threshold,
Discriminant equation is：
|IΦ| ＞ 0.04IN (1)
I in above formulaΦFor the amplitude of any phase current of public winding A, B, C, INFor the secondary rated current of public winding CT.
(2) public winding current waveform is subjected to differential, the differential equation is：
ΔiK=iK-iK-1 (2)
I in above formulaKFor current point sampled value, iK-1For former point sampled value, Δ iKFor the current sampling data after differential.
(3) the preceding half cycle of the public winding current waveform after differential and second half are subjected to symmetry comparison, waveform comparison
Discrimination formula is：
|I(k)+I(k+π)|/|I(k)-I(k+π)|≥0.5 (3)
Point sampling value, I (k+ π) are corresponding sampled value (preceding half cycle in second half before I (k) is taken in for preceding half cycle in above formula
With poor half of the cycle of second half).
(4) continuously relatively the sampled point (12 points, sample per cycle at 24 points) of half period, the asymmetric points of waveform are more than
5, then it is judged to waveform asymmetry.
Main transformer divides the recognition methods of side differential protection public winding CT progress of disease exceptions to the symmetrical of public winding current waveform
Property split-phase differentiated that this phase of locking divides side differential protection when public winding phase current waveform is asymmetric, not locking is other
Phase divides side differential protection.When public winding phase current is less than without stream threshold, gives tacit consent to this phase current waveform symmetrically and open this phase
Divide side differential protection, the differentiation of the step (2), step (3) and step (4) is no longer carried out, to mitigate the calculating of protective device
Workload.
Claims (2)
1. main transformer divides the recognition methods of side differential protection public winding CT progress of disease exceptions, it is characterised in that the step of this method such as
Under：
(1) amplitude of public winding A, B, C three-phase current is calculated, judges whether public winding phase current magnitude is more than without stream door
Sill, discriminant equation are：
|IΦ| ＞ 0.04IN
I in above formulaΦFor the amplitude of any phase current of public winding A, B, C, INFor the secondary rated current of public winding CT；
(2) when public winding phase current magnitude is more than without stream threshold, public winding current waveform is subjected to differential, the differential equation
For：
ΔiK=iK-iK-1
I in above formulaKFor current point sampled value, iK-1For former point sampled value, Δ iKFor the current sampling data after differential；
(3) the preceding half cycle of the public winding current waveform after differential and second half are subjected to symmetry comparison, waveform comparison differentiates
Formula is：
|I(k)+I(k+π)|/|I(k)-I(k+π)|≥0.5
In above formula I (k) be the public winding current waveform after differential preceding half cycle be taken in before after point sampling value, I (k+ π) be differential
Public winding current waveform second half on corresponding sampled value；
(4) continuously compare the number of the asymmetric point of waveform in the sampled point of half period, if number is more than setting value, judge
Waveform is asymmetric, and the setting value is 5；
When judging that waveform is asymmetric, this phase of locking divides side differential protection；When judging waveform symmetry, this open phase divides side differential guarantor
Shield.
2. main transformer according to claim 1 divides the recognition methods of side differential protection public winding CT progress of disease exceptions, its feature
It is：In the step (1), when public winding phase current is less than without stream threshold, this open phase divides side differential protection.
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| CN201410523955.5A CN104362590B (en) | 2014-10-08 | 2014-10-08 | Main transformer divides the recognition methods of side differential protection public winding CT progress of disease exceptions |
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| CN104362590B true CN104362590B (en) | 2018-05-04 |
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| CN108539716B (en) * | 2018-03-20 | 2019-07-23 | 许继集团有限公司 | A kind of protection starting method and apparatus based on transient |
| CN113267698A (en) * | 2021-06-02 | 2021-08-17 | 南京国电南自电网自动化有限公司 | Method, system and storage medium for distinguishing main transformer CT saturation |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103675415A (en) * | 2012-08-31 | 2014-03-26 | 西门子公司 | Excitation surge current detection method, excitation surge current brake method and excitation surge current detection device |
| CN104319735A (en) * | 2014-09-30 | 2015-01-28 | 许继集团有限公司 | Excitation inrush identification method for longitudinal differential protection of auto transformer |
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| CN104078934B (en) * | 2014-07-15 | 2017-01-18 | 国家电网公司 | Transformer differential current protection device mis-operation preventing relay protection method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103675415A (en) * | 2012-08-31 | 2014-03-26 | 西门子公司 | Excitation surge current detection method, excitation surge current brake method and excitation surge current detection device |
| CN104319735A (en) * | 2014-09-30 | 2015-01-28 | 许继集团有限公司 | Excitation inrush identification method for longitudinal differential protection of auto transformer |
Non-Patent Citations (2)
| Title |
|---|
| 三相一体自耦变压器公共绕组TA传变异常分析;雷明，等;《电力系统自动化》;20090225;第33卷(第4期);第104-107页 * |
| 几种波形对称法变压器差动保护原理的比较研究;林湘宁，等;《电工技术学报》;20010831;第16卷(第4期);第46页 * |
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