CN100461572C - Floating threshold and current ratio brake combined turn-to-turn protection method for electric generator - Google Patents
Floating threshold and current ratio brake combined turn-to-turn protection method for electric generator Download PDFInfo
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- CN100461572C CN100461572C CNB021381690A CN02138169A CN100461572C CN 100461572 C CN100461572 C CN 100461572C CN B021381690 A CNB021381690 A CN B021381690A CN 02138169 A CN02138169 A CN 02138169A CN 100461572 C CN100461572 C CN 100461572C
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Abstract
When the high sensitive protection between turns of longitudinal zero sequence voltage being utilized, the longitudinal zero sequence voltage is setup at the TV open triangle specific for generator exit, serving as the protection of the short circuit between turns of the stator coil. The new criterion of the rated current braking is as follows. (1) The increasing amount of the current is as the braking amount, if the fault current increases a lot, but the longitudinal zero sequence voltage increase less; (2) the increasing amount of the current and the negative sequence current are as the braking amount, if the negative sequence current appears. The floating threshold technique includes the technique is used, if the unbalance value of the zero sequence voltage is increased.
Description
One, technical field
The present invention relates to a kind of method of relaying protection, especially floating threshold and current ratio are braked the method for the inter-turn protection of generator that combines.
Two, background technology
Protective relaying device is the vitals that electrical network comprises large-scale plant safe operation such as generator, and existing at present inter-turn protection of generator exists sensitivity low, the problem that the malfunction rate is high:
1. the longitudinal zero-sequence over-voltage interturn protection of negative sequence direction locking
-negative-sequence direction component externally may malfunction in the three-phase shortcircuit transient process and during the frequency departure rated value;
-when adopting the negative sequence power direction as action element, sensitivity is not high;
2. the second harmonic formula interturn short circuit protection of negative sequence direction locking
-for generating set, outside unbalanced fault also can produce second harmonic current, needs negative sequence direction locking, therefore also has above-mentioned shortcoming;
3. third-harmonic component locking longitudinal zero-sequence over-voltage interturn protection
When-dynamic model and actual set fault do not confirm external area error in the longitudinal zero-sequence over-voltage third-harmonic component can increase.
Three, summary of the invention
The objective of the invention is: a kind of brand-new inter-turn protection method for power generator is provided, improves the sensitivity of interturn protection, can malfunction under situations such as district's external symmetry, unbalanced fault and frequency shift (FS).
The inter-turn protection method for power generator that floating threshold of the present invention and current ratio braking combine is realized in the highly sensitive horizontal poor interturn protection two cover protections respectively in highly sensitive longitudinal zero-sequence over-voltage interturn protection.
The method of the inter-turn protection of generator that floating threshold and current ratio braking combine, during highly sensitive longitudinal zero-sequence over-voltage interturn protection: longitudinal zero-sequence over-voltage is installed on the special-purpose TV open delta of generator outlet, as the protection of the turn-to-turn short circuit of generator unit stator winding; Current ratio braking principle and floating threshold technology are incorporated into the protection of turn-to-turn longitudinal zero-sequence over-voltage, the wherein new criterion of dynamo current ratio brake:
1) fault current increases during outside three-phase fault, and longitudinal zero-sequence over-voltage increases, and power taking stream recruitment is made the braking amount;
2) electric current increases during outside unbalanced fault, occur negative-sequence current simultaneously, and longitudinal zero-sequence over-voltage has increase slightly, and power taking stream recruitment and negative-sequence current are made the braking amount;
The floating threshold technology:
1) under the operating modes such as different loads, voltage rising, loss of excitation fault, the increase of residual voltage unbalanced value adopts floating threshold to escape unbalance voltage;
2) when the generator dedicated potential transformer once breaks, the protection of locking interturn in stator windings longitudinal zero-sequence over-voltage;
Longitudinal zero-sequence over-voltage interturn protection uneven fundamental voltage when escaping normal operation is adjusted; Greatly reduce than traditional protection definite value;
Operation equation of the present invention is as follows: U
O(1+k
0* (dI+I
2)/I
Ezd) * U
Ozd
In the formula: Uozd: the residual voltage definite value
DI: dynamo current increment
I
2: generator machine end negative-sequence current
Iezd: the rated current of generator
Ko: restraint coefficient, U
0: generator turn-to-turn longitudinal zero-sequence over-voltage.
During the high sensitivity transverse differential protection method: be installed in the transverse differential protection on two neutral point lines of generator; the main protection of snapping fault and phase fault as turn-to-turn short circuit, the branch of generator unit stator winding: current ratio braking principle and floating threshold technology are introduced transverse differential protection, the floating threshold technology:
1) different loads, voltage are raise or the loss of excitation fault condition, the increase of transverse differential current unbalanced value adopts floating threshold to escape unsymmetrical current;
2) when generator transverse differential current instrument transformer once breaks, the locking transverse differential protection.
Transverse differential protection current ration unsymmetrical current when escaping normal operation is adjusted, and operation equation is as follows:
I
hc>(1+k
hc×dI/I
ezd)×I
hczd
In the formula:
Ihczd: transverse differential current definite value
DI: maximum phase current added value
Iezd: rated current of generator khc: restraint coefficient, Ihc: transverse differential current.
Four, description of drawings
Fig. 1 is the sensitive vertically zero sequence interturn protection logic diagram of the present invention
Fig. 2 is the sensitive horizontal poor interturn protection logic diagram of the present invention
Five, embodiment
1. highly sensitive longitudinal zero-sequence over-voltage interturn protection
As shown in Figure 1; longitudinal zero-sequence over-voltage is installed on the special-purpose TV open delta of generator outlet; be used as the protection of the turn-to-turn short circuit of generator unit stator winding: the present invention is incorporated into the protection of turn-to-turn longitudinal zero-sequence over-voltage with current ratio braking principle and floating threshold technology first; improve the sensitivity of troubles inside the sample space, prevented the misoperation of external area error.
The new criterion of dynamo current ratio brake:
1) the fault current increase is very big during outside three-phase fault, and that longitudinal zero-sequence over-voltage increases is less, and power taking stream recruitment is made the braking amount, and protection can reliably be braked.
2) electric current increases during outside unbalanced fault, occur negative-sequence current simultaneously, and longitudinal zero-sequence over-voltage has increase slightly, and power taking stream recruitment and negative-sequence current are made the braking amount, and protection can reliably be braked.
3) the longitudinal zero-sequence over-voltage increase is bigger during the slight turn-to-turn fault of stator winding, and electric current does not almost change, and very high action sensitivity is arranged.
The floating threshold technology:
1) to (different loads, voltage rising, loss of excitation fault etc.) under other operating modes, the increase of residual voltage unbalanced value adopts floating threshold to escape unbalance voltage.
2) frequency-tracking combines with digital filter, and during frequency shift (FS), the triple-frequency harmonics filtration ratio is still greater than 100.
3) when the generator dedicated potential transformer once breaks, the protection of locking interturn in stator windings longitudinal zero-sequence over-voltage.
Owing to taked above measure, the longitudinal zero-sequence over-voltage interturn protection only needs when escaping normal operation uneven fundamental voltage to adjust, and greatly reduces than traditional protection definite value, and sensitivity has obtained large increase, and troubles inside the sample space is sensitive to move, and external area error is reliably braked.
Operation equation of the present invention such as above-mentioned corresponding person logic diagram of the present invention.
2. highly sensitive transverse differential protection
Be installed in the transverse differential protection on two neutral point lines of generator, the main protection of snapping fault and phase fault as turn-to-turn short circuit, the branch of generator unit stator winding.The present invention is incorporated into transverse differential protection with current ratio braking principle and floating threshold technology first, has improved the sensitivity of troubles inside the sample space, has prevented the misoperation of external area error.
The function of phase current ratio brake:
(1) increase of fault phase current is very big during external fault, and that transverse differential current increases is less, therefore can reliably brake.
(2) the transverse differential current increase is bigger during the slight turn-to-turn fault of stator winding, and that phase current changes is little, and very high action sensitivity is arranged.
(3) the transverse differential current increase is very big during the stator winding phase-to phase fault, and the phase current increase is also bigger, only brakes with little ratio phase current increment, has guaranteed the transverse differential protection action message.
The floating threshold technology:
1) to (different loads, voltage rising, loss of excitation fault etc.) under other operating modes, the increase of transverse differential current unbalanced value adopts floating threshold to escape unsymmetrical current.
2) frequency-tracking combines with digital filter, and during frequency shift (FS), the triple-frequency harmonics filtration ratio is still greater than 100.
3) when generator transverse differential current instrument transformer once breaks, the locking transverse differential protection.
Owing to adopted above measure; the transverse differential protection current ration only needs when escaping normal operation unsymmetrical current to adjust; greatly reduce than conventional elements part transverse differential protection definite value, thereby the sensitivity when having improved the inner turn-to-turn short circuit of generator, the malfunction of external area error prevented.
Operation equation of the present invention such as above-mentioned, corresponding logic diagram of the present invention.
Conclusion: the present invention is incorporated into floating threshold technology and current ratio braking principle in the inter-turn protection of generator first; the microcomputer generator protection that utilizes this principle and criterion to realize has greatly reduced the definite value of traditional protection; the sensitivity of having protected when therefore having improved the generator turn-to-turn fault; the use of technology of frequency tracking, floating threshold simultaneously can prevent external area error, the malfunction that causes under the unusual service conditions such as frequency shift (FS).
Claims (2)
1. floating threshold and current ratio are braked the method for the inter-turn protection of generator that combines; when it is characterized in that the longitudinal zero-sequence over-voltage protection: longitudinal zero-sequence over-voltage is installed on the generator outlet dedicated potential transformer TV open delta; be used as the protection of the turn-to-turn short circuit of generator unit stator winding: current ratio braking principle and floating threshold technology are incorporated into the protection of turn-to-turn longitudinal zero-sequence over-voltage, the wherein new criterion of dynamo current ratio brake:
Fault current increases during outside three-phase fault, and longitudinal zero-sequence over-voltage also increases, and power taking stream recruitment is made the braking amount;
Electric current increases during outside unbalanced fault, occur negative-sequence current simultaneously, and longitudinal zero-sequence over-voltage increases, and power taking stream recruitment and negative-sequence current are made the braking amount;
The floating threshold method:
Under different loads, voltage rising or loss of excitation fault condition, the increase of residual voltage unbalanced value adopts floating threshold to escape unbalance voltage;
When the generator dedicated potential transformer once breaks, the protection of locking interturn in stator windings longitudinal zero-sequence over-voltage;
Longitudinal zero-sequence over-voltage interturn protection uneven fundamental voltage when escaping normal operation is adjusted;
Operation equation is as follows: U
O(1+k
0* (dI+I
2)/I
Ezd) * U
Ozd
In the formula: Uozd: the residual voltage definite value
DI: dynamo current increment
I
2: generator machine end negative-sequence current
Iezd: the rated current of generator
Ko: restraint coefficient, U
0: generator turn-to-turn longitudinal zero-sequence over-voltage.
2. floating threshold and current ratio are braked the method for the inter-turn protection of generator that combines; when it is characterized in that transverse differential protection method: be installed in the transverse differential protection on two neutral point lines of generator; the main protection of snapping fault and phase fault as turn-to-turn short circuit, the branch of generator unit stator winding: current ratio braking principle and floating threshold method are introduced transverse differential protection, and the floating threshold method is:
Different loads, voltage are raise or the loss of excitation fault condition, and the increase of transverse differential current unbalanced value adopts floating threshold to escape unsymmetrical current;
When generator transverse differential current instrument transformer once breaks, the locking transverse differential protection;
Transverse differential protection current ration unsymmetrical current when escaping normal operation is adjusted, and operation equation is as follows:
I
hc>(1+k
hc×dI/I
ezd)×I
hczd
In the formula:
Ihczd: transverse differential current definite value
DI: maximum phase current added value
Iezd: rated current of generator k
Hc: restraint coefficient, I
Hc: transverse differential current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021381690A CN100461572C (en) | 2002-08-26 | 2002-08-26 | Floating threshold and current ratio brake combined turn-to-turn protection method for electric generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021381690A CN100461572C (en) | 2002-08-26 | 2002-08-26 | Floating threshold and current ratio brake combined turn-to-turn protection method for electric generator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1402401A CN1402401A (en) | 2003-03-12 |
| CN100461572C true CN100461572C (en) | 2009-02-11 |
Family
ID=4749325
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021381690A Expired - Lifetime CN100461572C (en) | 2002-08-26 | 2002-08-26 | Floating threshold and current ratio brake combined turn-to-turn protection method for electric generator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100461572C (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100399663C (en) * | 2005-01-14 | 2008-07-02 | 北京四方继保自动化股份有限公司 | Negative sequence direction inter-turn protection with fault component start-up and steady state component preservation |
| CN100424956C (en) * | 2005-01-25 | 2008-10-08 | 北京四方继保自动化股份有限公司 | Fault tolerant re-judging negative sequence direction locking type longitudinal zero voltage inter-turn protection for generator |
| CN100428604C (en) * | 2005-04-08 | 2008-10-22 | 南京南瑞继保电气有限公司 | Turns protection method of composite zero sequence voltage in generator |
| CN100428605C (en) * | 2005-12-15 | 2008-10-22 | 南京南瑞继保电气有限公司 | Magnetic-loss protection method for salient-pole generator |
| CN101505051B (en) * | 2009-03-17 | 2011-04-13 | 国电南端科技股份有限公司 | Turn-to-turn short circuit protection method for generator stator based on negative sequence distribution |
| CN102882185B (en) * | 2011-07-14 | 2014-08-06 | 湖北省电力公司电力科学研究院 | Comprehensive relay protection method for single element zero sequence transverse differential current of large generator |
| CN104808105B (en) * | 2014-01-27 | 2017-10-13 | 南京南瑞继保电气有限公司 | The online method of discrimination of generator terminal voltage transformer turn-to-turn short circuit |
| CN110609195B (en) * | 2019-08-20 | 2021-12-28 | 国电南瑞科技股份有限公司 | Method and system for identifying grounding and phase-to-phase faults of micro-grid |
| CN111404118B (en) * | 2020-03-27 | 2022-04-05 | 南京国电南自维美德自动化有限公司 | Longitudinal zero sequence voltage synthesis algorithm and turn-to-turn protection method and device |
| CN111812574A (en) * | 2020-06-18 | 2020-10-23 | 许昌许继软件技术有限公司 | Discrimination method for preventing disconnection and mistaken tripping of segments of heavy-load current transformer |
| CN112332371B (en) * | 2020-10-19 | 2022-06-03 | 西安工程大学 | Generator differential protection method based on stator double-layer winding model |
| CN113097983B (en) * | 2021-04-15 | 2021-12-14 | 攀钢集团西昌钢钒有限公司 | Zero sequence protection method, device and medium |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2052974U (en) * | 1989-04-27 | 1990-02-14 | 付建忠 | Three phase power contactless switch protector |
| CN2099983U (en) * | 1991-08-21 | 1992-03-25 | 双鸭山矿务局机电总厂 | Portable inter-turn voltage tester for high-voltage motor |
| US5777833A (en) * | 1996-02-02 | 1998-07-07 | Schneider Electric Sa | Electronic relay for calculating the power of a multiphase electric load based on a rectified wave signal and a phase current |
-
2002
- 2002-08-26 CN CNB021381690A patent/CN100461572C/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2052974U (en) * | 1989-04-27 | 1990-02-14 | 付建忠 | Three phase power contactless switch protector |
| CN2099983U (en) * | 1991-08-21 | 1992-03-25 | 双鸭山矿务局机电总厂 | Portable inter-turn voltage tester for high-voltage motor |
| US5777833A (en) * | 1996-02-02 | 1998-07-07 | Schneider Electric Sa | Electronic relay for calculating the power of a multiphase electric load based on a rectified wave signal and a phase current |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1402401A (en) | 2003-03-12 |
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Granted publication date: 20090211 |
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