CN100367608C - Transformer longitudinal error protecting element with maximum zero sequence ratio brake - Google Patents
Transformer longitudinal error protecting element with maximum zero sequence ratio brake Download PDFInfo
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- CN100367608C CN100367608C CNB2004100847669A CN200410084766A CN100367608C CN 100367608 C CN100367608 C CN 100367608C CN B2004100847669 A CNB2004100847669 A CN B2004100847669A CN 200410084766 A CN200410084766 A CN 200410084766A CN 100367608 C CN100367608 C CN 100367608C
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- phase
- current
- buddhist
- multiplier
- transformer
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- Emergency Protection Circuit Devices (AREA)
Abstract
The present invention discloses a transformer longitudinal error protection element with the maximum side zero sequence ratio brake. A three-phase brake current with a zero sequence current is formed by the method that the three-phase brake current representing a crossing current in the present transformer differential protection carries out the weighting sum respectively with the maximal value in the zero sequence current of each neutral point earthing side (or branch), and corresponding phase ratio brake elements are formed by a brake current with the zero sequence current and each of three phases of differential currents in the transformer differential protection. When the differential currents are more than the brake current with the zero sequence current, a ratio differential action signal of a corresponding phase is output; when the proposal is adopted, the unwanted operation of the differential protection of the transformer because of an earthing fault outside of a Y0 side region can be completely avoided when errors of a three-phase current transformer are inconsistent.
Description
Technical field
The present invention relates to a kind of relay protection of power system element, particularly a kind of transformer longitudinal error protecting element with the maximum zero sequence current 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 respectively and simultaneously Δ side secondary current is carried out Δ/Y conversion, eliminates the influence of zero-sequence current by above-mentioned conversion.By these conversion and behind each side balancing, the stalling current that obtains by the differential current that obtains with famous prime minister's addition and by other combination does not comprise the zero-sequence component in the primary current equally.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 certain Y
0Side generation external area error and when having only this side that power supply is arranged, this Y
0Very big zero-sequence fault electric current will appear in side, but the fault-free electric current passes through transformer.At this moment, as this 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.As seen, by Y
0Side zero-sequence fault electric current causes that unsymmetrical current has been left in the basket in traditional biased differential protection.
Summary of the invention
The object of the present invention is to provide a kind of transformer longitudinal error protecting element with the maximum zero sequence current ratio brake; three-phase system streaming current by representing through current in the present transformer differential protection respectively with the zero-sequence current of each neutral ground side (or branch) in maximum be weighted summation and constitute the stalling current that three-phase contains zero-sequence current; with this stalling current that contains zero-sequence current respectively with transformer differential protection in the three-phase differential current constitute corresponding phase ratio braking member; 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 the maximum zero sequence current ratio brake is characterized in that: this element is by maximizing circuit 01, A phase multiplier A
1, B phase multiplier B
1, C phase multiplier C
1, first multiplier 02, A addition musical instruments used in a Buddhist or Taoist mass A
3, B addition musical instruments used in a Buddhist or Taoist mass B
3, C addition musical instruments used in a Buddhist or Taoist mass C
3, A phase comparator A
4, B phase comparator B
4With C phase comparator C
4Constitute; Wherein the input of maximizing circuit 01 difference each neutral ground side of input transformer or ground connection branch are through filtered zero sequence current signal 3I
10, 3I
20... 3I
N0, its output is connected with an input of first multiplier 02; Another input input zero-sequence braking COEFFICIENT K of first multiplier 02
0, its output meets A addition musical instruments used in a Buddhist or Taoist mass A respectively
3, B addition musical instruments used in a Buddhist or Taoist mass B
3With C addition musical instruments used in a Buddhist or Taoist mass C
3An input separately; A phase multiplier A
1, B phase multiplier B
1With C multiplier C mutually
1Input separately represent in the input transformer differential protection respectively through current through filtered A phase stalling current signal I
Za, B phase stalling current signal I
ZbWith C stalling current signal I mutually
Zc, its another input is separately all imported ratio brake coefficient K
ZA addition musical instruments used in a Buddhist or Taoist mass A
3, B addition musical instruments used in a Buddhist or Taoist mass B
3With C addition musical instruments used in a Buddhist or Taoist mass C
3Another input separately meets A phase multiplier A respectively
1, B phase multiplier B
1With C multiplier C mutually
1Output separately, A addition musical instruments used in a Buddhist or Taoist mass A
3, B addition musical instruments used in a Buddhist or Taoist mass B
3With C addition musical instruments used in a Buddhist or Taoist mass C
3Output separately respectively with A phase comparator A
4, B phase comparator B
4With C phase comparator C
4Negative input end separately is connected; A phase comparator A
4, B phase comparator B
4With C phase comparator C
4Positive input terminal is separately imported respectively through filtered A phase differential current signal I
Da, B phase differential current signal I
DbWith C differential current signal I mutually
Dc, its output is separately exported A phase, B phase and C percentage differential actuating signal mutually respectively; Wherein n is transformer neutral point ground connection side number or ground connection branches.Ratio brake coefficient K
ZBe 0＜K
Z＜1.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, comparator is exported the percentage differential actuating signal of corresponding phase.
With prior art relatively, advantage of the present invention is to have proposed first to add the zero-sequence braking electric current in the stalling current of the percentage differential element of traditional transformer differential protection.Three-phase system streaming current by representing through current respectively with the zero-sequence current of each neutral ground side (or branch) in maximum be weighted summation and constitute the stalling current that three-phase contains zero-sequence current; with this stalling current that contains zero-sequence current respectively with transformer differential protection in the three-phase differential current constitute corresponding phase ratio braking member; when differential current when containing the stalling current of zero-sequence current, export the percentage differential actuating signal of corresponding phase.Use this programme, in the time of can avoiding the threephase current transformer error inconsistent fully, with the Y of unique power supply
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 differential unsymmetrical current that zero-sequence current causes causes, and the correct operation of differential 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 a kind of circuit block diagram of the transformer longitudinal error protecting element with the maximum zero sequence current ratio brake
Embodiment
Embodiment 1:
A kind of transformer longitudinal error protecting element with the maximum zero sequence current ratio brake can be achieved by the circuit block diagram of Fig. 3.This element is by maximizing circuit 01, multiplier A
1, B
1, C
1, 02, adder A
3, B
3, C
3With comparator A
4, B
4, C
4Constitute.Wherein n=3 is a transformer neutral point ground connection side number (or branches), the ratio brake coefficient K in the existing biased differential protection
ZBe 0.5, the zero-sequence braking COEFFICIENT K
0Be 0.3.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, in the time of can avoiding the threephase current transformer error inconsistent fully, with the Y of unique power supply
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 differential unsymmetrical current that zero-sequence current causes causes, and the correct operation of differential protection under the zone of influence internal fault situation not.
Claims (3)
1. transformer longitudinal error protecting element with the maximum zero sequence current ratio brake, it is characterized in that: this element is by maximizing circuit (01), A phase multiplier (A
1), B phase multiplier (B
1), C phase multiplier (C
1), first multiplier (02), A addition musical instruments used in a Buddhist or Taoist mass (A
3), B addition musical instruments used in a Buddhist or Taoist mass (B
3), C addition musical instruments used in a Buddhist or Taoist mass (C
3), A phase comparator (A
4), B phase comparator (B
4) and C phase comparator (C
4) constitute; Wherein the input of maximizing circuit (01) difference each neutral ground side of input transformer or ground connection branch are through filtered zero sequence current signal 3I
10, 3I
20... 3I
N0, its output is connected with an input of first multiplier (02); Another input input zero-sequence braking COEFFICIENT K of first multiplier (02)
0, its output meets A addition musical instruments used in a Buddhist or Taoist mass (A respectively
3), B addition musical instruments used in a Buddhist or Taoist mass (B
3) and C addition musical instruments used in a Buddhist or Taoist mass (C
3) separately an input; A phase multiplier (A
1), B phase multiplier (B
1) with C multiplier (C mutually
1) separately input represent in the input transformer differential protection respectively through current through filtered A phase stalling current signal I
Za, B phase stalling current signal I
ZbWith C stalling current signal I mutually
Zc, its another input is separately all imported ratio brake coefficient K
ZA addition musical instruments used in a Buddhist or Taoist mass (A
3), B addition musical instruments used in a Buddhist or Taoist mass (B
3) and C addition musical instruments used in a Buddhist or Taoist mass (C
3) separately another input meets A phase multiplier (A respectively
1), B phase multiplier (B
1) with C multiplier (C mutually
1) separately output, A addition musical instruments used in a Buddhist or Taoist mass (A
3), B addition musical instruments used in a Buddhist or Taoist mass (B
3) and C addition musical instruments used in a Buddhist or Taoist mass (C
3) separately output respectively with A phase comparator (A
4), B phase comparator (B
4) and C phase comparator (C
4) separately negative input end is connected; A phase comparator (A
4), B phase comparator (B
4) and C phase comparator (C
4) separately positive input terminal imports respectively through filtered A phase differential current signal I
Da, B phase differential current signal I
DbWith C differential current signal I mutually
Dc, its output is separately exported A phase, B phase and C percentage differential actuating signal mutually respectively; Wherein n is transformer neutral point ground connection side number or ground connection branches.
2. element according to claim 1 is characterized in that: ratio brake coefficient K
ZValue be 0＜K
Z＜1.
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 |
|---|---|---|---|
| CNB2004100847669A CN100367608C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protecting element with maximum zero sequence ratio brake |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100847669A CN100367608C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protecting element with maximum zero sequence ratio brake |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1783616A CN1783616A (en) | 2006-06-07 |
| CN100367608C true CN100367608C (en) | 2008-02-06 |
Family
ID=36773489
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100847669A Expired - Fee Related CN100367608C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protecting element with maximum zero sequence ratio brake |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100367608C (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1141097A (en) * | 1994-01-06 | 1997-01-22 | 施耐德电器公司 | Device for differentially protecting a power transformer |
| US6356421B1 (en) * | 1999-11-29 | 2002-03-12 | Schweitzer Engineering Labs., Inc. | System for power transformer differential protection |
| 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 CNB2004100847669A patent/CN100367608C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1141097A (en) * | 1994-01-06 | 1997-01-22 | 施耐德电器公司 | Device for differentially protecting a power transformer |
| US6356421B1 (en) * | 1999-11-29 | 2002-03-12 | Schweitzer Engineering Labs., Inc. | System for power transformer differential protection |
| 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1783616A (en) | 2006-06-07 |
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| PB01 | Publication | ||
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| C14 | Grant of patent or utility model | ||
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Granted publication date: 20080206 Termination date: 20101202 |