CN1545179A - Transformer differential protection difference stream and differential protection instantaneous TA abnormal state identification protecting method - Google Patents
Transformer differential protection difference stream and differential protection instantaneous TA abnormal state identification protecting method Download PDFInfo
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- CN1545179A CN1545179A CNA2003101064360A CN200310106436A CN1545179A CN 1545179 A CN1545179 A CN 1545179A CN A2003101064360 A CNA2003101064360 A CN A2003101064360A CN 200310106436 A CN200310106436 A CN 200310106436A CN 1545179 A CN1545179 A CN 1545179A
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- 230000002159 abnormal effect Effects 0.000 title claims abstract description 23
- 238000000034 method Methods 0.000 title claims abstract description 12
- 230000005856 abnormality Effects 0.000 claims abstract description 6
- 230000000903 blocking effect Effects 0.000 claims description 3
- 238000000819 phase cycle Methods 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 abstract 3
- 230000001052 transient effect Effects 0.000 abstract 2
- 230000004069 differentiation Effects 0.000 description 5
- 230000035945 sensitivity Effects 0.000 description 4
- 230000007257 malfunction Effects 0.000 description 2
- 230000002950 deficient Effects 0.000 description 1
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Abstract
The invention is a method of identifying and protecting differential protective difference current and differential protective transient TA abnormal state of a transformer. The differential abnormal alarming adopts ratio brake principle, the difference current abnormal alarming threshold value varies with the variation of load current of the transformer, when a phase difference current meets a condition, send out an abnormal alarming signal in no need of locking differential protection, the differential current initial value should be adjusted by avoiding the exciting current of the transformer, generally 0.03Ie, where Ie is rate current of the transformer, combine industrial frequency variation quantity voltage opening component and the current quantity, the distinguishing principle of differential protective loop transient TA breakage and short-circuit is allowable type, when differential protection starts and then meets conditions, consider it is a failure condition to open differential protection, and otherwise consider it is a start of differential protection caused by differential loop TA abnormality.
Description
One, technical field
The present invention relates to the method for transformer differential protection difference stream and the instantaneous TA abnormality of differential protection identification protecting, especially abnormalities such as the instantaneous TA broken string of differential protection that combines with the magnitude of current of the open element of ratio brake formula transformer differential loop difference unusual recognition principle of stream and power frequency variation voltage, short circuit are discerned new method.
Two, background technology
Present transformer differential loop commonly used difference stream abnormal alarm method of discrimination is: when arbitrary stream that differs flows warning definite value (I greater than difference
Bj_set) time send difference stream abnormal alarm signal, not Blocking Differential Protection when surpassing 10 seconds.Difference stream warning setting value should be avoided the maximum difference stream that on-load transformer tap changer does not produce when the centre, or issuable maximum difference stream during the other reasons operation.Therefore general poor stream warning fixed value adjusting is 0.2I
e(I
eBe the transformer rated current) about.It all is fixing threshold formula that at present existing transformer differential protection difference flows unusual recognition methods, has the low problem of sensitivity.
The instantaneous TA in present existing transformer differential protection loop (current transformer) broken string discrimination principles all adopts enclosed type, and only uses the magnitude of current.There is insecure problem in the differentiation of therefore instantaneous TA broken string; can not differentiate the short circuit or the mistake of differential protection TA secondary circuit bumps; can not differentiate problems such as the heterogeneous broken string of differential protection TA secondary circuit or many sides broken string; these problems usually can cause the malfunction of differential protection, have influenced the reliability and security of transformer differential protection.
Conventional transformer differential protection loop instantaneous TA broken string discrimination principles can be summarized as following:
When arbitrary phase differential current greater than 0.1I
e(I
eBe the transformer rated current) or arbitrary phase differential current greater than the differential protection starting value, carry out the instantaneous TA broken string of differential protection and differentiate, just think the TA broken string when it satisfies following condition:
(1) arbitrary phase no current in certain side three-phase current;
(2) other biphase current equates with the prestart electric current;
The shortcoming of therefore conventional transformer differential protection loop instantaneous TA broken string discrimination principles can be expressed as follows:
-can only differentiate the one-sided single-phase wire break in transformer differential protection loop.Heterogeneous broken string and many sides for one-sided loop break simultaneously and can not differentiate.
-can not differentiate certain phase current not reduce to zero situation, when for example certain phase current breaks, the situation that electric current does not disconnect fully.
-can not differentiate the short-circuit conditions of differential protection TA secondary circuit, for example the secondary circuit generation short circuit of certain side biphase current or mistake are bumped, and this biphase current diminishes simultaneously.
-transformer differential protection loop instantaneous TA broken string discrimination principles all adopts enclosed type.Therefore just have defective promptly in principle: distinguishing speed is slow, misses locking etc. easily.
Three, summary of the invention
The present invention seeks to: the ratio brake principle is applied to transformer differential loop difference stream abnormal alarm differentiates, improve the sensitivity of protection, and can false alarm.(definition: current transformer) broken string is differentiated the new method that adopts the open element of power frequency variation voltage to combine with the magnitude of current to the instantaneous TA in transformer differential protection loop, can differentiate the heterogeneous broken string in one-sided loop, transformer differential protection loop or the situation that many sides break simultaneously; It is fast to propose a kind of distinguishing speed, the method that reliability is high.
The object of the present invention is achieved like this: the operation equation that it adopted is: differ time that stream satisfies following formula and send difference stream abnormal alarm signal, not Blocking Differential Protection when surpassing 10 seconds when arbitrary.Promptly poor stream abnormal alarm adopts the ratio brake principle, and its difference stream abnormal alarm threshold value changes with the load current of transformer, has broken through traditional fixedly threshold formula difference stream abnormal alarm mode.The initial definite value of difference stream warning should be adjusted by the exciting current of avoiding transformer.Therefore general poor stream warning fixed value adjusting is 0.03I
e(I
eBe the transformer rated current) about.Highly sensitive, and can false alarm.
Wherein k is a certain proportionality constant, I
1.......mBe respectively each side electric current of transformer, I
dBe differential current, I
rBe stalling current.
The open element of power frequency variation voltage is combined with the magnitude of current, and the instantaneous TA broken string in transformer differential protection loop adopts the permission formula with the short circuit discrimination principle.The various troubles inside the sample space of transformer when taking place in its principle, general equal action of the open element of power frequency variation voltage, and for low current fault (comprising slight turn-to-turn fault) in the various districts of transformer, the electric current that the electric current before the current ratio fault after the fault always has certain side phase can increase; And TA broken string and short circuit etc. appear in the transformer differential protection loop when unusual, the open element of power frequency variation voltage can not start, and electric current reduces; Therefore utilize These characteristics, the instantaneous TA broken string of novel transformer differential protection loop can be described below with the operation equation that the short circuit discrimination principle is adopted:
Differential protection starting back is satisfied following arbitrary condition and is thought failure condition, open differential protection, otherwise think the differential protection starting that difference loop TA causes unusually.
(1) the arbitrary alternate power frequency variation voltage component starting of either side;
(2) either side negative phase-sequence phase voltage is greater than 6V;
(3) the arbitrary phase current of starting back either side increases than prestart;
(4) starting back maximum phase current is greater than 1.1Ie.
Characteristics of the present invention:
-owing to adopt ratio-restrained characteristic, difference stream abnormal alarm operating characteristics can cooperate with difference stream unsymmetrical current preferably, and therefore poor stream abnormal alarm definite value can reduce safely, and sensitivity is greatly improved.
-because the instantaneous TA broken string in transformer differential protection loop adopts the permission formula with the short circuit discrimination principle.Therefore just exist distinguishing speed fast in principle, the advantage that reliability is high.
-because the new method that adopts the open element of power frequency variation voltage to combine with the magnitude of current can be differentiated the heterogeneous broken string in one-sided loop, transformer differential protection loop or the situation that many sides break simultaneously;
-because the new method that adopts the open element of power frequency variation voltage to combine with the magnitude of current can be differentiated the complex situations that the one-sided heterogeneous broken string in transformer differential protection loop or many sides break simultaneously; Also can differentiate simultaneously the short-circuit conditions of differential protection TA secondary circuit, for example the secondary circuit generation short circuit of certain side two-phase or three-phase current or mistake are bumped phenomenon.This in addition can solve the field operator when transformer belt bypass operational mode, corresponding TA secondary circuit is not switched, thereby may cause the problem of differential protection malfunction.
Therefore it is high effectively to solve in the past the ubiquitous differential circuit difference stream of transformer differential protection institute abnormal alarm sensitivity both at home and abroad at abnormality recognition principles such as the instantaneous TA broken string of differential protection that adopts ratio brake formula transformer differential loop difference unusual recognition principle of stream and the open element of power frequency variation voltage to combine with the magnitude of current, short circuits, the TA problems such as differentiation is unreliable that break.
Four, embodiment
(1) the transformer differential loop of ratio brake principle difference stream abnormal alarm is differentiated.Its operation equation specifically describes as follows:
Wherein k is a certain proportionality constant, generally is taken as 0.18 in this example, I
1.......mBe respectively each side electric current of transformer, I
dBe differential current, I
rBe stalling current, I
Bj_setFor difference stream abnormal alarm definite value, generally be taken as 0.03I in this example
e(I
eBe the transformer rated current) about.By above-mentioned operation equation as can be seen, when the transformer load electric current increased, the threshold of difference stream abnormal alarm raise automatically, and reduces automatically at the threshold value of light load situation difference stream abnormal alarm, and therefore poor stream abnormal alarm is highly sensitive, and can false alarm.
(2) the instantaneous TA broken string in transformer differential protection loop specifically describes as follows with the short circuit discrimination principle:
The open element of power frequency variation voltage is combined with the magnitude of current; the instantaneous TA broken string in transformer differential protection loop adopts the permission formula with short circuit discrimination; differential protection starting back is satisfied following arbitrary condition and is thought failure condition; open differential protection, otherwise think the differential protection starting that difference loop TA causes unusually.
1. the arbitrary alternate power frequency variation voltage component starting of either side; Promptly
Δ U
Nn＞kU
N+ Δ U
T, (k is a certain proportionality constant in the formula, is taken as 0.05 in this example, U
NBe rated voltage, Δ U
TBe the unsteady door of voltage).Above-mentioned alternate power frequency variation voltage component guarantees can start when the variation of 0.2 rated voltage is arranged, and guaranteeing can sensitive action message when system's generation generic failure.
2. either side negative phase-sequence phase voltage is greater than 6V; Promptly
3U
2〉=6V, negative sequence voltage element guarantee can start when system's generation unbalanced fault, do not carry out the differentiation of TA broken string.
3. the arbitrary phase current of starting back either side increases than prestart; Promptly the arbitrary phase current of starting back either side increases by 3% than prestart:
For low current fault (comprising slight turn-to-turn fault) in the various districts of transformer, the electric current that the electric current before the current ratio fault after the fault always has certain side phase can increase; And TA broken string and short circuit etc. appear in the transformer differential protection loop when unusual, the open element of power frequency variation voltage can not start, and electric current reduces.Therefore above-mentioned electric current increases criterion and guarantees that low current fault in the various districts of transformer (comprising slight turn-to-turn fault) does not carry out the differentiation of TA broken string.
4. starting back maximum phase current promptly under the situation of transformer overload, does not carry out the differentiation of TA broken string greater than 1.1Ie.
Claims (1)
1, the method for transformer differential protection difference stream and the instantaneous TA abnormality of differential protection identification protecting; it is characterized in that the operation equation that is adopted is: difference stream abnormal alarm adopts the ratio brake principle; its difference stream abnormal alarm threshold value changes with the load current of transformer; differ time that stream satisfies following formula and send difference stream abnormal alarm signal when surpassing 10 seconds when arbitrary; Blocking Differential Protection not; the initial definite value of difference stream warning should be adjusted by the exciting current of avoiding transformer, and general poor stream warning fixed value adjusting is 0.03I
e, I
eBe the transformer rated current,
Wherein k is a certain proportionality constant, I
1......mBe respectively each side electric current of transformer, I
dBe differential current, I
rBe stalling current;
The open element of power frequency variation voltage is combined with the magnitude of current; the instantaneous TA broken string in transformer differential protection loop adopts the permission formula with the short circuit discrimination principle; differential protection starting back is satisfied following arbitrary condition and is thought failure condition; open differential protection, otherwise think the differential protection starting that difference loop TA causes unusually:
(1) the arbitrary alternate power frequency variation voltage component starting of either side;
(2) either side negative phase-sequence phase voltage is greater than 6V;
(3) the arbitrary phase current of starting back either side increases than prestart;
(4) starting back maximum phase current is greater than 1.1Ie.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2003101064360A CN100433486C (en) | 2003-11-27 | 2003-11-27 | Transformer differential protection difference stream and differential protection instantaneous TA abnormal state identification protecting method |
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|---|---|---|---|
| CNB2003101064360A CN100433486C (en) | 2003-11-27 | 2003-11-27 | Transformer differential protection difference stream and differential protection instantaneous TA abnormal state identification protecting method |
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| CN1545179A true CN1545179A (en) | 2004-11-10 |
| CN100433486C CN100433486C (en) | 2008-11-12 |
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ID=34334165
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101192748B (en) * | 2007-12-12 | 2010-06-09 | 北京四方继保自动化股份有限公司 | Differential protection differential current reducing method for digital transformer |
| CN102222876A (en) * | 2011-06-09 | 2011-10-19 | 重庆新世纪电气有限公司 | Breakage blocking differential protection method and breakage blocking differential protection system based on current transformer |
| CN102916404A (en) * | 2011-12-27 | 2013-02-06 | 许继集团有限公司 | Differential protection method of regional power grid network change range |
| CN104635085A (en) * | 2015-02-04 | 2015-05-20 | 南京南瑞继保电气有限公司 | Method for distinguishing load from fault |
| CN107546718A (en) * | 2017-08-02 | 2018-01-05 | 许继集团有限公司 | A kind of recognition methods of TA abnormalities in protection positioned at multiple differential and device |
| CN107579506A (en) * | 2017-08-02 | 2018-01-12 | 许继集团有限公司 | The recognition methods of TA abnormalities in multiple differential protection and device |
| CN107706890A (en) * | 2016-08-09 | 2018-02-16 | 西门子电力自动化有限公司 | The line differential protection method and device of power system |
| CN110299692A (en) * | 2019-07-10 | 2019-10-01 | 许昌许继软件技术有限公司 | A kind of converter power transformer differential protecting method and device |
| CN113363939A (en) * | 2021-05-12 | 2021-09-07 | 北京四方继保工程技术有限公司 | Differential protection method without excitation inrush current locking based on transformer state identification |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100424955C (en) * | 2002-08-26 | 2008-10-08 | 南京南瑞继保电气有限公司 | Variable slope differential ratio protection method |
| CN1419327A (en) * | 2002-10-24 | 2003-05-21 | 南京南瑞继保电气有限公司 | Generator industrial-frequency variation equantity rate difference protection method |
-
2003
- 2003-11-27 CN CNB2003101064360A patent/CN100433486C/en not_active Expired - Lifetime
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101192748B (en) * | 2007-12-12 | 2010-06-09 | 北京四方继保自动化股份有限公司 | Differential protection differential current reducing method for digital transformer |
| CN102222876A (en) * | 2011-06-09 | 2011-10-19 | 重庆新世纪电气有限公司 | Breakage blocking differential protection method and breakage blocking differential protection system based on current transformer |
| CN102222876B (en) * | 2011-06-09 | 2014-02-12 | 重庆新世纪电气有限公司 | Breakage blocking differential protection method and breakage blocking differential protection system based on current transformer |
| CN102916404A (en) * | 2011-12-27 | 2013-02-06 | 许继集团有限公司 | Differential protection method of regional power grid network change range |
| CN102916404B (en) * | 2011-12-27 | 2015-01-07 | 许继电气股份有限公司 | Differential protection method of regional power grid network change range |
| CN104635085A (en) * | 2015-02-04 | 2015-05-20 | 南京南瑞继保电气有限公司 | Method for distinguishing load from fault |
| CN107706890B (en) * | 2016-08-09 | 2019-04-26 | 西门子电力自动化有限公司 | The line differential protection method and device of electric system |
| CN107706890A (en) * | 2016-08-09 | 2018-02-16 | 西门子电力自动化有限公司 | The line differential protection method and device of power system |
| CN107579506A (en) * | 2017-08-02 | 2018-01-12 | 许继集团有限公司 | The recognition methods of TA abnormalities in multiple differential protection and device |
| CN107546718A (en) * | 2017-08-02 | 2018-01-05 | 许继集团有限公司 | A kind of recognition methods of TA abnormalities in protection positioned at multiple differential and device |
| CN110299692A (en) * | 2019-07-10 | 2019-10-01 | 许昌许继软件技术有限公司 | A kind of converter power transformer differential protecting method and device |
| CN110299692B (en) * | 2019-07-10 | 2022-01-04 | 许昌许继软件技术有限公司 | Converter transformer differential protection method and device |
| CN113363939A (en) * | 2021-05-12 | 2021-09-07 | 北京四方继保工程技术有限公司 | Differential protection method without excitation inrush current locking based on transformer state identification |
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|---|---|
| CN100433486C (en) | 2008-11-12 |
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Granted publication date: 20081112 |