CN100367615C - Transformer longitudinal error protecting element with multiple side zero sequence ratio brake - Google Patents
Transformer longitudinal error protecting element with multiple side zero sequence ratio brake Download PDFInfo
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- CN100367615C CN100367615C CNB2004100890086A CN200410089008A CN100367615C CN 100367615 C CN100367615 C CN 100367615C CN B2004100890086 A CNB2004100890086 A CN B2004100890086A CN 200410089008 A CN200410089008 A CN 200410089008A CN 100367615 C CN100367615 C CN 100367615C
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Abstract
The present invention discloses a longitudinal error protection element of a transformer with the multi-side zero sequence ratio brake. Three-phase brake current containing zero sequence current is formed by the method that brake current representing three-phase through current in the longitudinal error protection of the transformer carries out weighting summation with a weighting summation value of the zero sequence current at the grounding side of each neutral point of the transformer, and the three-phase brake current containing zero sequence current is used for forming a three-phase ratio brake element with differential current in a corresponding phase respectively. When the differential current is larger than the brake current containing zero sequence current and is larger than the minimum operation current, the condition that a ratio differential fold line does not pass through an original point is realized, and an operation signal of the ratio brake element in a corresponding phase is output. When the proposal is applied, a ratio brake coefficient can be changed by following a brake current; and the mis-operation of the differential protection of the transformer because of a grounding fault outside a Y0 side zone can be completely avoided under the condition that the errors of a three-phase current mutual inductor 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 multiple side 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 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 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 ratio brake element of traditional longitudinal difference protection, promptly do not have corresponding stalling current that it is braked in the ratio brake element, thereby may cause the transformer differential protection misoperation.
Summary of the invention
The technical problem to be solved in the present invention is the Y that exists in the existing transformer differential protection technology
0Side three-phase current transform method can not be eliminated the influence of zero-sequence current fully; a kind of transformer longitudinal error protecting element with multiple side zero sequence ratio brake is provided; the weighted sum value of the stalling current by representing the three-phase through current in the transformer differential protection and the zero-sequence current of each neutral ground side (or branch) of transformer 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 constitutes the rate of three phase flow braking member with corresponding differential current mutually respectively; when differential current during, export the actuating signal of corresponding phase ratio braking member greater than the stalling current that contains zero-sequence current and greater than minimum working current.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 multiple side zero sequence ratio brake is characterized in that: this element subtracts each other musical instruments used in a Buddhist or Taoist mass A11 by A, B subtracts each other musical instruments used in a Buddhist or Taoist mass B12, C subtracts each other musical instruments used in a Buddhist or Taoist mass C13, A phase multiplier A21, B phase multiplier B22, C phase multiplier C23, the first multiplier M2, A phase first adder A31, B phase first adder B32, C phase first adder C33, A phase second adder A41, B phase second adder B42, C phase second adder C43, the 3rd adder M1, A phase comparator A51, B phase comparator B52, C phase comparator C53 and n second multiplier 011,021,0n1 constitutes; Wherein A subtract each other musical instruments used in a Buddhist or Taoist mass A11, B subtract each other musical instruments used in a Buddhist or Taoist mass B12 and C subtract each other musical instruments used in a Buddhist or Taoist mass C13 positive input terminal separately respectively the input transformer longitudinal difference protection the representative through current through filtered A stalling current signal I mutually
Za, B phase stalling current signal I
ZbWith C stalling current signal I mutually
Zc, its negative input end separately is the braking keen current value I in the input transformer longitudinal difference protection all
Res0, its output separately connects A phase multiplier A21, a B phase multiplier B22 and C multiplier C23 input separately mutually respectively; A phase multiplier A21, B phase multiplier B22 and C multiplier C23 another input separately mutually import percentage differential broken line slope S, its output separately connect respectively A phase first adder A31, B phase first adder B32 and C mutually first adder C33 separately an input; A phase first adder A31, B phase first adder B32 and C first adder C33 another input separately mutually import minimum working current value I
Op.min, second adder A41, B phase second adder B42's its output separately are connected with a C phase second adder C43 input separately mutually with A respectively; Individual second multiplier 011,021 of n ... a 0n1 input separately is input transformer Y respectively
0Side is through filtered zero sequence current signal 3I
10, 3I
20... 3I
N0, its another input separately import respectively predefined weights k10, k20 ... kn0, its output separately connects each input of the 3rd adder M1 respectively; The input of the output termination first multiplier M2 of the 3rd adder M1; Another input input zero-sequence braking COEFFICIENT K of the first multiplier M2
0, second adder A41, B phase second adder B42's its output are connected with C phase second adder C43 another input separately mutually with A respectively; A phase comparator A51, B phase comparator B52, C phase comparator C53 positive input terminal are 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
DcIts negative input end separately respectively with A mutually second adder A41, B phase second adder B42 be connected with C phase second adder C43 output separately, A phase comparator A51, B phase comparator B52, C phase comparator C53 output are separately exported A phase, B respectively mutually and C percentage differential actuating signal mutually.Wherein n is transformer neutral point ground connection side number or branches; 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
0Setting range is 0＜K
0＜1/3, predefined weights k
10, k
20... k
N0Be 0＜k
I0＜1/3, wherein, i=1,2 ... n.When the differential current of a certain phase contained the stalling current of zero-sequence current mutually greater than this, comparator was exported the percentage differential actuating signal of this phase.
With prior art relatively; advantage of the present invention is that a kind of transformer longitudinal error protecting element with multiple side zero sequence ratio brake is provided first; the weighted sum value of the stalling current by representing the three-phase through current in the transformer differential protection and the zero-sequence current of each neutral ground side (or branch) of transformer 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 constitutes the rate of three phase flow braking member with corresponding differential current mutually respectively; when differential current during, export the actuating signal of corresponding phase ratio braking member greater than the stalling current that contains zero-sequence current and greater than minimum working current.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.
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 protective device with zero sequence ratio brake of the present invention.
Embodiment
Embodiment 1:
A kind of transformer longitudinal error protecting element, this element with multiple side zero sequence ratio brake can be by Fig. 3 a kind of circuit block diagram of the transformer longitudinal error protecting element with multiple side zero sequence ratio brake be achieved.This element by subtracter A11, B12, C13, multiplier A21, B22, C23, M2,011,021 ... 0n1, adder A31, B32, C33, A41, B42, C43, M 1 and comparator A51, B52, C53 constitute; The braking keen current I in the transformer differential protection wherein
Reso=1.2 * I
n, I
nFor converting the transformer rated current of this side, have the percentage differential broken line slope S in the biased differential protection now, its value is 0.4; Minimum working current I
Op.min=0.4 * I
nThe zero-sequence braking COEFFICIENT K
0=0.2, predefined weights k10, k20 ... kn0, its value is 0.3; N=3 is a transformer neutral point ground connection side number (or branches).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 (4)
1. transformer longitudinal error protecting element with multiple side zero sequence ratio brake, it is characterized in that: this element subtracts each other musical instruments used in a Buddhist or Taoist mass (A11) by A, B subtracts each other musical instruments used in a Buddhist or Taoist mass (B12), C subtracts each other musical instruments used in a Buddhist or Taoist mass (C13), A phase multiplier (A21), B phase multiplier (B22), C phase multiplier (C23), first multiplier (M2), A phase first adder (A31), B phase first adder (B32), C phase first adder (C33), A phase second adder (A41), B phase second adder (B42), C phase second adder (C43), the 3rd adder (M1), A phase comparator (A51), B phase comparator (B52), C phase comparator (C53) and n the second multiplier (O11, O21, On1) constitute; Wherein A subtract each other musical instruments used in a Buddhist or Taoist mass (A11), B subtract each other musical instruments used in a Buddhist or Taoist mass (B12) and C subtract each other musical instruments used in a Buddhist or Taoist mass (C13) positive input terminal separately respectively the input transformer longitudinal difference protection the representative through current through filtered A stalling current signal I mutually
Za, B phase stalling current signal I
ZbWith C stalling current signal I mutually
Zc, its negative input end separately is the braking keen current value I res0 in the input transformer longitudinal difference protection all, and its output separately connects A phase multiplier (A21), B phase multiplier (B22) and C multiplier (C23) input separately mutually respectively; A phase multiplier (A21), B phase multiplier (B22) and C multiplier (C23) another input separately mutually import percentage differential broken line slope S, its output separately connect respectively A phase first adder (A31), B phase first adder (B32) and C mutually first adder (C33) separately an input; A phase first adder (A31), B phase first adder (B32) and C first adder (C33) another input separately mutually import minimum working current value I op.min, its output separately respectively with A mutually second adder (A41), B phase second adder (B42) and C phase second adder (C43) input separately be connected; Individual second multiplier of n (O11, O21 ... On1) an input difference input transformer Y separately
0Side is through filtered zero sequence current signal 3I
10, 3I
20... 3I
N0, its another input separately import respectively predefined weights k10, k20 ... kn0, its output separately connects each input of the 3rd adder (M1) respectively; An input of output termination first multiplier (M2) of the 3rd adder (M1); Another input input zero-sequence braking COEFFICIENT K of first multiplier (M2)
0, second adder (A41), B phase second adder (B42) and C phase second adder (C43) another input separately are connected its output mutually with A respectively; A phase comparator (A51), B phase comparator (B52), C phase comparator (C53) positive input terminal are 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
DcIts negative input end separately respectively with A mutually second adder (A41), B phase second adder (B42) and C phase second adder (C43) output separately be connected, A phase comparator (A51), B phase comparator (B52), C phase comparator (C53) output are separately exported A phase, B respectively mutually and C percentage differential actuating signal mutually; Wherein n is transformer neutral point ground connection side number or branches; When the differential current of a certain phase contained the stalling current of zero-sequence current mutually greater than this, comparator was exported the percentage differential actuating signal of this phase.
2. element according to claim 1 is characterized in that: percentage differential broken line slope S, its value are 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, predefined weights k10, k20 ... kn0 is 0＜k
I0＜1/3, wherein, i=1,2 ... n.
4. 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
0Setting range is 0＜K
0＜1/3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100890086A CN100367615C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protecting element with multiple side zero sequence ratio brake |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100890086A CN100367615C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protecting element with multiple side zero sequence ratio brake |
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| Publication Number | Publication Date |
|---|---|
| CN1783626A CN1783626A (en) | 2006-06-07 |
| CN100367615C true CN100367615C (en) | 2008-02-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100890086A Expired - Fee Related CN100367615C (en) | 2004-12-02 | 2004-12-02 | Transformer longitudinal error protecting element with multiple side zero sequence ratio brake |
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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 CNB2004100890086A patent/CN100367615C/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 |
Non-Patent Citations (1)
| Title |
|---|
| 差动保护比率制动整定中动作电流与制动系数等关系分析. 庄伟民.继电器，第28卷第9期. 2000 * |
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| CN1783626A (en) | 2006-06-07 |
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