CN100350698C - Positive sequence synthesized brake device for preventing multiple-branch voltage transformer differential protection unwanted operation by utilizing fault components - Google Patents
Positive sequence synthesized brake device for preventing multiple-branch voltage transformer differential protection unwanted operation by utilizing fault components Download PDFInfo
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- CN100350698C CN100350698C CNB2004100162981A CN200410016298A CN100350698C CN 100350698 C CN100350698 C CN 100350698C CN B2004100162981 A CNB2004100162981 A CN B2004100162981A CN 200410016298 A CN200410016298 A CN 200410016298A CN 100350698 C CN100350698 C CN 100350698C
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Abstract
The present invention relates to a positive sequence synthesized braking device for preventing the unwanted operation of differential protection for the multiple-branch transformers by utilizing fault components; ratio braking elements are composed of positive sequence abrupt qualities of a basal wave of a three-phase differential electric current in differential protection for transformers and the maximum value of the abrupt qualities of a zero-sequence electric current at each neutral point grounding side (or branch) of the transformer; when a signal at the positive input end of a comparator 9 is weaker than a signal at the negative end, the comparator outputs 0; an external grounding fault is judged; a three-phase differential protection outlet is locked; or the comparator 7 outputs 1; the three-phase differential protection is allowed to act. The application of the proposal can thoroughly avoid the unwanted operation of differential protection for transformers caused by the external grounding fault at a y<o> side when the errors of a three-phase electric current transformer are not same.
Description
Technical field
The present invention relates to a kind of protection equipment for transformer, particularly a kind of synthetic brake apparatus of fault component positive sequence that prevents malfunction for tranformer protection.
Background technology
Existing power transformer differential protection device by the ratio brake element, promptly by the ratio of differential current and through current, is discerned external area error and troubles inside the sample space; By shoving and the overexcitation braking member, promptly, discern magnetizing inrush current and overexcitation electric current simultaneously, reach the purpose of differentiating internal fault by analyzing the waveform or the harmonic content of differential current.To both sides being arranged or being the power transformer of neutral-point solid ground more than the both sides, when a ground connection side generating region external ground fault, may big earth fault zero-sequence current appear many sides.For preventing that this zero-sequence current from causing differential protection malfunction, extensively adopt the method that ground connection side three-phase current is carried out conversion at present, eliminate the influence of zero-sequence current.But it is inconsistent to work as ground connection side threephase current transformer error; and transformer is only when the neutral ground side that external area error takes place has power supply; can not eliminate the influence of the zero-sequence current that external ground fault in neutral ground lateral areas causes by conventional method; bigger differential unsymmetrical current will be had; the ratio brake element; the braking member that shoves can not reliably be braked this; especially very little even be under zero the situation at the transformer load electric current; the ratio brake element; the braking member that shoves can not be braked this; as long as error current surpasses threshold, transformer differential protection is with malfunction.
Summary of the invention
The purpose of this invention is to provide a kind of synthetic brake apparatus of fault component positive sequence that prevents malfunction for tranformer protection; the maximum component ratio braking member of the fundamental positive sequence sudden change amount by the three-phase differential current in the transformer differential protection and the zero-sequence current sudden change amount of each neutral ground side of transformer or branch; when rate value during less than setting value K; be judged to district's external ground fault, the outlet of locking three-phase differential protection.Advantage of the present invention is, in the time of can avoiding the threephase current transformer error inconsistent fully, and the transformer differential protection malfunction that external ground fault in neutral ground lateral areas causes.
A kind of synthetic brake apparatus of fault component positive sequence that prevents malfunction for tranformer protection, this device circuit constitutes as shown in Figure 1.It is characterized in that: this device by memory 11～13, subtracter 21～23, fundamental positive sequence pass filter 31, filter 32, memory 41,42 ... 4n, subtracter 51,52 ... 5n, filter 61,62 ... 6n, maximizing circuit 71, multiplier 72, comparator 8 constitute, wherein the three-phase differential current instantaneous value signal i of the positive input terminal of the input of memory 11～13 and subtracter 21～23 difference input transformer differential protection formation
Da, i
Db, i
DcThe negative input end of subtracter 21～23 connects the output of memory 11～13 respectively, the output of subtracter 21～23 connects three inputs of fundamental positive sequence pass filter 31 respectively, the output of the input termination fundamental positive sequence pass filter 31 of filter 32, the output of filter 32 is connected with the positive input terminal of comparator 8; Memory 41,42 ... the input of 4n and subtracter 51,52 ... positive input terminal difference each the neutral ground side of input transformer of 5n or the zero-sequence current instantaneous value signal 3i of branch
10, 3i
20... 3i
N0Subtracter 51,52, the negative input end of 5n connects memory 41 respectively, 42, the output of 4n, subtracter 51,52, the output of 5n connects filter 61 respectively, 62, the input of 6n, the input of maximizing circuit 71 connects filter 61 respectively, 62, the output of 6n, n is transformer neutral point ground connection side number or branches, an input of the output of maximizing circuit 71 and multiplier 72 joins, another input input setting value K of multiplier 72, the negative input end of the output termination comparator 8 of multiplier 72, comparator 8 output three-phase brake signals; When the signal of comparator 8 positive input terminals less than the negative input end signal, comparator 8 outputs 0 are judged to district's external ground fault, locking three-phase differential protection outlet, otherwise comparator 8 outputs 1 allow the action of three-phase differential protection; Arrive under the same side, the same no-load voltage ratio situation in differential current and zero-sequence current reduction, setting value K is 0＜K＜1.
With prior art relatively; advantage of the present invention is the ratio brake element that proposes to set up a kind of fundamental positive sequence sudden change amount with maximum formation of the zero-sequence current sudden change amount of each neutral ground side (or branch) of transformer by the three-phase differential current in the transformer differential protection first in traditional transformer differential protection; when rate value during less than setting value; be judged to district's external ground fault, the outlet of locking three-phase differential protection.Use this programme; in the time of can avoiding the threephase current transformer error inconsistent fully; the transformer differential protection malfunction that external ground fault in neutral ground lateral areas causes; also can prevent under other non-internal fault situations; 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
Fig. 1 is the circuit block diagram that prevents the synthetic brake apparatus of fault component positive sequence of malfunction for tranformer protection.
Embodiment
Embodiment 1
A kind of synthetic brake apparatus of fault component positive sequence that prevents malfunction for tranformer protection, its circuit constitutes as shown in Figure 1, and transformer neutral point ground connection side is counted n=3.When the signal of comparator 8 positive input terminals during less than the negative input end signal, comparator 8 outputs 0 are judged to district's external ground fault, the outlet of locking three-phase differential protection; Otherwise comparator 8 outputs 1 allow the action of three-phase differential protection.When differential current and zero-sequence current reduction under the same side, same no-load voltage ratio situation, setting value K is 0.8.The advantage of this device is, in the time of can avoiding the threephase current transformer error inconsistent fully, and the transformer differential protection malfunction that external ground fault in neutral ground lateral areas causes, and the correct operation of differential protection under the zone of influence internal fault situation not.
Claims (2)
1. a fault component positive sequence that prevents malfunction for tranformer protection is synthesized brake apparatus; it is characterized in that: this device is by memory (11～13); subtracter (21～23); fundamental positive sequence pass filter (31); filter (32); memory (41; 42; 4n); subtracter (51; 52; 5n); filter (61; 62; 6n); maximizing circuit (71); multiplier (72); comparator (8) constitutes, wherein the three-phase differential current instantaneous value signal (i of the positive input terminal of the input of memory (11～13) and subtracter (21～23) difference input transformer differential protection formation
Da, i
Db, i
Dc), the negative input end of subtracter (21～23) connects the output of memory (11～13) respectively, the output of subtracter (21～23) connects three inputs of fundamental positive sequence pass filter (31) respectively, the output of the input termination fundamental positive sequence pass filter (31) of filter (32), the output of filter (32) is connected with the positive input terminal of comparator (8); Memory (41,42 ... input 4n) and subtracter (51,52 ... positive input terminal difference each the neutral ground side of input transformer 5n) or the zero-sequence current instantaneous value signal (3i of branch
10, 3i
20... 3i
N0), subtracter (51,52, negative input end 5n) connects memory (41 respectively, 42, output 4n), subtracter (51,52, output 5n) connects filter (61 respectively, 62, input 6n), the input of maximizing circuit (71) connects filter (61 respectively, 62, output 6n), n is transformer neutral point ground connection side number or branches, an input of the output of maximizing circuit (71) and multiplier (72) joins, another input input setting value K of multiplier (72), the negative input end of the output termination comparator (8) of multiplier (72), comparator (8) output three-phase brake signal; When the signal of comparator (8) positive input terminal less than the negative input end signal, comparator 8 outputs 0 are judged to district's external ground fault, the outlet of locking three-phase differential protection.
2. brake apparatus according to claim 1 is characterized in that: under the same side, same no-load voltage ratio situation, setting value K is 0＜K＜1 in differential current and zero-sequence current reduction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100162981A CN100350698C (en) | 2004-02-13 | 2004-02-13 | Positive sequence synthesized brake device for preventing multiple-branch voltage transformer differential protection unwanted operation by utilizing fault components |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100162981A CN100350698C (en) | 2004-02-13 | 2004-02-13 | Positive sequence synthesized brake device for preventing multiple-branch voltage transformer differential protection unwanted operation by utilizing fault components |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1558504A CN1558504A (en) | 2004-12-29 |
| CN100350698C true CN100350698C (en) | 2007-11-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100162981A Expired - Fee Related CN100350698C (en) | 2004-02-13 | 2004-02-13 | Positive sequence synthesized brake device for preventing multiple-branch voltage transformer differential protection unwanted operation by utilizing fault components |
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| CN (1) | CN100350698C (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1047887C (en) * | 1994-01-06 | 1999-12-29 | 施耐德电器公司 | Device for differentially protecting a power transformer |
| 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 |
| CN1402900A (en) * | 1999-11-29 | 2003-03-12 | 施魏策尔工程实验公司 | System for power transformer differential protection |
| 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 |
| CN2711963Y (en) * | 2004-02-13 | 2005-07-20 | 浙江大学 | Fault component positive sequence synthetic brake for preventing transformer protection from error action |
-
2004
- 2004-02-13 CN CNB2004100162981A patent/CN100350698C/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1047887C (en) * | 1994-01-06 | 1999-12-29 | 施耐德电器公司 | Device for differentially protecting a power transformer |
| CN1402900A (en) * | 1999-11-29 | 2003-03-12 | 施魏策尔工程实验公司 | 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 |
| 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 |
| CN2711963Y (en) * | 2004-02-13 | 2005-07-20 | 浙江大学 | Fault component positive sequence synthetic brake for preventing transformer protection from error action |
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| Publication number | Publication date |
|---|---|
| CN1558504A (en) | 2004-12-29 |
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Granted publication date: 20071121 Termination date: 20100213 |