CN100394658C - Transformer longitudinal error protective element with zero sequence ratio brake - Google Patents
Transformer longitudinal error protective element with zero sequence ratio brake Download PDFInfo
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- CN100394658C CN100394658C CNB2004100890067A CN200410089006A CN100394658C CN 100394658 C CN100394658 C CN 100394658C CN B2004100890067 A CNB2004100890067 A CN B2004100890067A CN 200410089006 A CN200410089006 A CN 200410089006A CN 100394658 C CN100394658 C CN 100394658C
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- 230000001681 protective effect Effects 0.000 title description 2
- 238000000034 method Methods 0.000 abstract description 3
- 230000009699 differential effect Effects 0.000 abstract 1
- 238000005303 weighing Methods 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 4
- 230000007257 malfunction Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 2
- 101100459998 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) NDJ1 gene Proteins 0.000 description 1
- 101100205955 Schizosaccharomyces pombe (strain 972 / ATCC 24843) tam1 gene Proteins 0.000 description 1
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Abstract
The present invention discloses a longitudinal-error protection element of a transformer with the zero-sequence ratio brake. A three-phase brake current with a zero sequence current is formed by the method that a three-phase brake current representing a crossing current in the differential protection of the present transformer carries out the weighing sum respectively with zero sequence currents at the Y0 side of the transformer, and the three-phase brake current with the zero sequence current form differential elements with corresponding phase ratios respectively with three phases of differential currents in the differential protection of the transformer; when the differential currents are larger than the brake current with the zero sequence current, the differential action signals of the corresponding phase ratios are output. When the proposal is applied, a situation that a ratio differential fold line is not beyond an initial point can be achieved, and a ratio braking coefficient is changed following the brake current change; furthermore, when errors of a three-phase current transformer are inconsistent, the longitudinal-error protection misoperation of the transformer because of a ground fault outside of the Y0 side zone can be totally avoided.
Description
Technical field
The present invention relates to a kind of protection equipment for transformer, particularly a kind of transformer longitudinal error protecting element with zero sequence ratio brake.
Background technology
Present Power Transformer Longitudinal Differential Protection is made of elements such as differential quick-break, percentage differential, magnetizing inrush current detection, overexcitation detections; according to the DL/T 684-1999 in People's Republic of China's power industry standard " the high-rating generator transformer relay protecting is adjusted and is calculated guide rule "; the transformer differential protection block diagram as shown in Figure 1, Differential Current Protection Principle wiring example is as shown in Figure 2.Usually utilize current transformer to Y
0The side three-phase current carries out the conversion of Y/ Δ, to eliminate the influence of zero-sequence current.Obviously, after the conversion, each electric current has not comprised the zero-sequence component in the primary current, these electric currents are behind intermediate current instrument transformer TAM1～TAM6 balancing, each phase current addition of the same name obtains the three-phase differential current, Wd is a differential coil, and phase current of the same name carries out the alternate manner combination and obtains the three-phase system streaming current, and Wres1～Wres3 is each side restraining coil.As seen, differential current that obtains thus and stalling current all do not comprise the zero-sequence component in the primary current.
When implementing longitudinal difference protection, also there is Y
0The side current transformer is the situation of complete star-like wiring, at this moment, often in protective device to Y
0Side three-phase secondary current carries out the conversion of Y/ Δ, perhaps with Y
0Side three-phase secondary current deducts zero-sequence current I respectively
0Simultaneously Δ side secondary current is carried out Δ/Y conversion, eliminate the influence of zero-sequence current by above-mentioned conversion.After these conversion, carry out differential current that balancing obtains with famous prime minister's addition again and do not comprise zero-sequence component in the primary current equally by the stalling current that other combination obtains.As: the vector by calculating phase current of the same name with obtain this differential current mutually; Maximum by asking for phase current of the same name or obtain this phase stalling current by the weighted sum of calculating phase current magnitude of the same name, its stalling current can only be represented the size of through current.
When transformer at Y
0Side generating region external ground fault and when having only this side that power supply is arranged, Y
0Very big zero-sequence fault electric current will appear in side, but the fault-free electric current passes through transformer.At this moment, work as Y
0When side threephase current transformer error was inconsistent, the zero-sequence current that equates at the primary side three-phase was after the threephase current transformer conversion, and secondary current is unequal, above-mentioned traditional Y
0Side three-phase current transform method can not be eliminated the influence of zero-sequence current fully, will produce unsymmetrical current at differential circuit.Because this moment, the fault-free electric current passed through transformer, the stalling current that obtains by above-mentioned conventional method is very little, can not surpass the preceding stalling current of fault, as long as differential unsymmetrical current surpasses differential threshold, transformer differential protection is with malfunction.Obviously, by Y
0Side zero-sequence fault electric current causes that unsymmetrical current has been left in the basket in the biased differential protection of traditional longitudinal difference protection, promptly do not have corresponding stalling current that it is braked in the percentage differential element, thereby make the transformer differential protection misoperation.
Summary of the invention
The technical problem to be solved in the present invention is to adopt Y at the transformer differential protection that exists in the prior art
0The method of side three-phase current conversion provides a kind of transformer longitudinal error protecting element with zero sequence ratio brake; can not eliminate the influence of zero-sequence current fully to second difference unbalance dynamic electric current, the three-phase system streaming current by representing through current in the present transformer differential protection respectively with transformer Y
0The side zero-sequence current is weighted summation and constitutes the stalling current that three-phase contains zero-sequence current; the stalling current that contains zero-sequence current with this three-phase respectively with transformer differential protection in the three-phase differential current constitute corresponding phase ratio difference element; when differential current when containing the stalling current of zero-sequence current, export the percentage differential actuating signal of corresponding phase.Advantage of the present invention is, in the time of can avoiding the threephase current transformer error inconsistent fully, and Y
0The transformer differential protection malfunction that lateral areas external ground fault causes.
A kind of transformer longitudinal error protecting element with zero sequence ratio brake is characterized in that: this element by first to the 3rd subtracter A1, B1, C1, first group first to the 3rd multiplier A2, B2, C2, second group of multiplier 01, first group first constitute to the 3rd adder A3, B3, C3, second group first to the 3rd adder A4, B4, C4 and first to the 3rd comparator A5, B5, C5; Wherein the representative through current of the positive input terminal of first to the 3rd subtracter A1, B1, C1 difference input transformer longitudinal difference protection is through filtered stalling current signal I
Za, I
Zb, I
Zc, the braking keen current value Ires0 in its negative input end difference input transformer longitudinal difference protection, its output connects first group of first input to the 3rd multiplier A2, B2, C2 respectively; First group of first another input to the 3rd multiplier A2, B2, C2 imported percentage differential broken line slope S respectively, and its output connects first group of first input to the 3rd adder A3, B3, C3 respectively; First group of first another input to the 3rd adder A3, B3, C3 imported minimum working current value Iop.min respectively, and its output is connected with second group of first input to the 3rd adder A4, B4, C4 respectively; An input input transformer Y of second group of multiplier 01
0Side is through filtered zero sequence current signal 3I
0, another input input zero-sequence braking COEFFICIENT K
0, its output connects second group of first another input to the 3rd adder A4, B4, C4 respectively; The positive input terminal of first to the 3rd comparator A5, B5, C5 is imported respectively through filtered three-phase differential current signal I
Da, I
Db, I
Dc, its negative input end is connected with second group of first output to the 3rd adder A4, B4, C4 respectively, and the output of first to the 3rd comparator A5, B5, C5 is exported the percentage differential actuating signal of A phase, B phase, C phase respectively.The value of percentage differential broken line slope S is 0＜S＜0.8.Arrive under the situation of the same side the zero-sequence braking COEFFICIENT K at zero-sequence current and three-phase differential current, the reduction of three-phase system streaming current
0Be 0＜K
0＜1/3.When differential current when containing the stalling current of zero-sequence current, export the percentage differential actuating signal of corresponding phase.
With prior art relatively, the invention has the beneficial effects as follows and proposed first in the stalling current of the percentage differential element of traditional transformer differential protection, to add the zero-sequence braking electric current.By the table through current the three-phase system streaming current respectively with transformer Y
0The side zero-sequence current is weighted summation and constitutes the stalling current that three-phase contains zero-sequence current; the stalling current that contains zero-sequence current with this three-phase respectively with transformer differential protection in the three-phase differential current constitute corresponding phase ratio difference element; when differential current when containing the stalling current of zero-sequence current, export the percentage differential actuating signal of corresponding phase.Use this programme, can realize the only situation of initial point of percentage differential broken line, the coefficient of ratio changes with stalling current; In the time of also can avoiding the threephase current transformer error inconsistent fully, Y
0The transformer differential protection malfunction that lateral areas external ground fault causes; also can prevent under other non-internal fault situation; the transformer differential protection misoperation that the vertical poor unsymmetrical current that zero-sequence current causes causes, and the correct operation of longitudinal difference protection under the zone of influence internal fault situation not.
Description of drawings
Below in conjunction with accompanying drawing to the specific embodiment of the present invention further detailed description.
Fig. 1 is existing transformer differential protection block diagram.
Fig. 2 is existing transformer differential protection key wiring diagram.
Fig. 3 is for realizing the circuit block diagram of a kind of fault component transformer longitudinal error protecting element with zero sequence ratio brake of the present invention.
Embodiment
Embodiment 1:
A kind of transformer longitudinal error protecting element, this element with zero sequence ratio brake can be by Fig. 3 a kind of circuit of the transformer longitudinal error protecting element with zero sequence ratio brake be achieved.Percentage differential broken line slope S=0.5 wherein.Arrive under the situation of the same side the zero-sequence braking COEFFICIENT K at zero-sequence current and three-phase differential current, the reduction of three-phase system streaming current
0Be 0.3.Braking keen current I in the transformer differential protection
Reso=1.2*I
n, I
nFor converting the transformer rated current of this side, minimum working current I
Op.min=0.4*I
n, when differential current when containing the stalling current of zero-sequence current, comparator is exported the percentage differential actuating signal of corresponding phase.Use this programme, can realize the only situation of initial point of percentage differential broken line, ratio brake coefficient changes with stalling current; In the time of also can avoiding the threephase current transformer error inconsistent fully, Y
0The transformer differential protection malfunction that lateral areas external ground fault causes; also can prevent under other non-internal fault situation; the transformer differential protection misoperation that the vertical poor unsymmetrical current that zero-sequence current causes causes, and the correct operation of longitudinal difference protection under the zone of influence internal fault situation not.
Claims (3)
1. transformer longitudinal error protecting element with zero sequence ratio brake is characterized in that: this element by first to the 3rd subtracter (A1, B1, C1), first group first to the 3rd multiplier (A2, B2, C2), second group of multiplier (01), first group first to the 3rd adder (A3, B3, C3), second group first constitute to the 3rd adder (A4, B4, C4) and first to the 3rd comparator (A5, B5, C5); Wherein the representative through current of the positive input terminal of first to the 3rd subtracter (A1, B1, C1) difference input transformer longitudinal difference protection is through filtered stalling current signal I
Za, I
Zb, I
Zc, the braking keen current value I in its negative input end difference input transformer longitudinal difference protection
Res0, its output connects first group of first input to the 3rd multiplier (A2, B2, C2) respectively; First group of first another input to the 3rd multiplier (A2, B2, C2) imported percentage differential broken line slope S respectively, and its output connects first group of first input to the 3rd adder (A3, B3, C3) respectively; First group of first another input to the 3rd adder (A3, B3, C3) imported minimum working current value I respectively
Op.min, its output is connected with second group of first input to the 3rd adder (A4, B4, C4) respectively; An input input transformer Y of second group of multiplier (01)
0Side is through filtered zero sequence current signal 3I
0, another input input zero-sequence braking COEFFICIENT K
0, its output connects second group of first another input to the 3rd adder (A4, B4, C4) respectively; The positive input terminal of first to the 3rd comparator (A5, B5, C5) is imported respectively through filtered three-phase differential current signal I
Da, I
Db, I
Dc, its negative input end is connected with second group of first output to the 3rd adder (A4, B4, C4) respectively, and the output of first to the 3rd comparator (A5, B5, C5) is exported the percentage differential actuating signal of A phase, B phase, C phase respectively.
2. element according to claim 1 is characterized in that: the value of percentage differential broken line slope S is 0＜S＜0.8.
3. element according to claim 1 is characterized in that: in zero-sequence current and three-phase differential current, the reduction of three-phase system streaming current under the situation of the same side, the zero-sequence braking COEFFICIENT K
0Be 0＜K
0＜1/3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100890067A CN100394658C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protective element with zero sequence ratio brake |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100890067A CN100394658C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protective element with zero sequence ratio brake |
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| Publication Number | Publication Date |
|---|---|
| CN1783624A CN1783624A (en) | 2006-06-07 |
| CN100394658C true CN100394658C (en) | 2008-06-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100890067A Expired - Fee Related CN100394658C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protective element with zero sequence ratio brake |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104852354A (en) * | 2015-06-04 | 2015-08-19 | 南京南瑞继保电气有限公司 | Adaptive-slope transformer zero-sequence differential protection method and device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6356421B1 (en) * | 1999-11-29 | 2002-03-12 | Schweitzer Engineering Labs., Inc. | System for power transformer differential protection |
| JP2002186169A (en) * | 2000-12-11 | 2002-06-28 | Toshiba Corp | Transformer protection relay |
| CN1402400A (en) * | 2002-08-26 | 2003-03-12 | 南京南瑞继保电气有限公司 | Variable slope differential ratio protection method |
-
2004
- 2004-12-02 CN CNB2004100890067A patent/CN100394658C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6356421B1 (en) * | 1999-11-29 | 2002-03-12 | Schweitzer Engineering Labs., Inc. | System for power transformer differential protection |
| JP2002186169A (en) * | 2000-12-11 | 2002-06-28 | Toshiba Corp | Transformer protection relay |
| CN1402400A (en) * | 2002-08-26 | 2003-03-12 | 南京南瑞继保电气有限公司 | Variable slope differential ratio protection method |
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| Publication number | Publication date |
|---|---|
| CN1783624A (en) | 2006-06-07 |
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Assignee: Sanbian Sci-Tech Co., Ltd. Assignor: Zhejiang University Contract fulfillment period: 2007.6.15 to 2017.6.14 contract change Contract record no.: 2008330002007 Denomination of invention: Transformer longitudinal error protective element with zero sequence ratio brake Granted publication date: 20080611 License type: Exclusive license Record date: 20081114 |
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Free format text: EXCLUSIVE LICENSE; TIME LIMIT OF IMPLEMENTING CONTACT: 2007.6.15 TO 2017.6.14; CHANGE OF CONTRACT Name of requester: SANBIAN SCIENCE CO., LTD. Effective date: 20081114 |
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Granted publication date: 20080611 Termination date: 20161202 |
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| CF01 | Termination of patent right due to non-payment of annual fee |