CN100367601C - Split-phase zero sequence braking method for preventing transformer protection from malfunction - Google Patents
Split-phase zero sequence braking method for preventing transformer protection from malfunction Download PDFInfo
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- CN100367601C CN100367601C CNB2004100847550A CN200410084755A CN100367601C CN 100367601 C CN100367601 C CN 100367601C CN B2004100847550 A CNB2004100847550 A CN B2004100847550A CN 200410084755 A CN200410084755 A CN 200410084755A CN 100367601 C CN100367601 C CN 100367601C
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- phase
- current
- transformer
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- malfunction
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Abstract
The present invention discloses a split-phase zero sequence braking method for preventing the malfunction of protection for transformers; a ratio braking element is composed of a phase electric current at the Y0 side of a transformer and a zero sequence electric current at the side; when a ratio value is smaller than a definite value, a braking signal of the phase is output to stop differential protection for corresponding phase transformer ratios. The application of the proposal only collects the ratio braking element composed of the three-phase electric current at the Y0 side where a power supply is arranged, and the zero sequence electric current, which can thoroughly avoid the malfunction of differential protection for transformers caused by an external grounding fault at the Y0 side when the errors of a three-phase electric current transformer are not consistent.
Description
Technical field
The present invention relates to a kind of relay protection method of power system, particularly a kind of split-phase zero-sequence braking method 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; Simultaneously,, promptly, discern magnetizing inrush current and overexcitation electric current, reach the purpose of differentiating internal fault by analyzing the waveform or the harmonic content of differential current by shoving and the overexcitation braking member.To Y
0The power transformer of/Δ wiring is for preventing Y
0Lateral areas external ground fault zero-sequence current causes the longitudinal difference protection malfunction, extensively adopts Y at present
0The side three-phase current carries out the method for conversion, eliminates the influence of zero-sequence current.But work as Y
0Side threephase current transformer error is inconsistent, and transformer is only at the Y that external area error takes place
0When side has power supply, can not eliminate Y by conventional method
0The influence of the zero-sequence current that lateral areas external ground fault causes; bigger differential unsymmetrical current will be had; the ratio brake element, shove and the overexcitation braking member can not reliably be braked this; especially very little even be under zero the situation at the transformer load electric current; 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.In number of patent application is 200410016305.8 " branch that prevents the transformer differential protection malfunction differs the stream method ", recently differentiate Y by differential current and zero-sequence current
0The method of lateral areas external ground fault can overcome above-mentioned defective, but differential current is gathered complexity.
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, and a kind of split-phase zero-sequence braking method that prevents malfunction for tranformer protection is provided, and uses transformer Y
0The phase current of side and this side zero-sequence current component ratio braking criterion when rate value during less than setting value, is exported the brake signal of this phase, and respective phase change depressor biased differential protection is braked.Advantage of the present invention is to rely on one-sided electric current and this side zero-sequence current component ratio to brake when avoiding the threephase current transformer error inconsistent fully Y
0The transformer differential protection malfunction that lateral areas external ground fault causes.
A kind of split-phase zero-sequence braking method that prevents malfunction for tranformer protection is characterized in that: use transformer Y
0A certain phase current in the side three-phase and this side zero-sequence current component ratio braking criterion during less than setting value K, is exported the brake signal of this phase divided by the rate value of this side zero-sequence current when described phase current, and this phase transformer biased differential protection is braked; The foundation of split-phase zero-sequence braking is:
I
x/3I
o＜K
I in the formula
xBe transformer Y
0Any phase current in the three-phase current of side, 3I
oBe this Y
0The side zero-sequence current, i.e. three-phase current sum, K is a setting value, setting value K is 0＜K＜2/3.
With prior art relatively, the invention has the beneficial effects as follows to have proposed first in traditional transformer differential protection, add a kind of transformer Y that uses
0The phase current of side and this side zero-sequence current component ratio braking criterion when rate value during less than setting value, is exported the brake signal of this phase, and respective phase change depressor biased differential protection is braked.Use this programme, only need to gather the Y that power supply is arranged
0The three-phase current of side and this side zero-sequence current component ratio braking member, in the time of just 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 situations the transformer differential protection misoperation that the differential unsymmetrical current that zero-sequence current causes causes.
Description of drawings
Below in conjunction with accompanying drawing to the specific embodiment of the present invention further detailed description.
Fig. 1 is for realizing a kind of circuit block diagram that prevents the split-phase zero-sequence braking element of malfunction for tranformer protection of the present invention.
Embodiment
Embodiment 1:
A kind of split-phase zero-sequence braking method that prevents the transformer differential protection malfunction, this method can be achieved by a kind of circuit block diagram of the split-phase zero-sequence braking element of malfunction for tranformer protection that prevents of Fig. 1.This element is made of filter 11～14, multiplier 2, comparator 31～33, and the input of its median filter 11～13 is input transformer Y respectively
0The three-phase current instantaneous value signal i of side
a, i
b, i
c, the input input transformer Y of filter 14
0Side zero-sequence current instantaneous value signal 3i
0, an input of its output termination multiplier 2; Another input input setting value K=0.5 of multiplier 2, the negative input end of comparator 31～33 is connected with the output of multiplier 2, its positive input terminal connects the output of filter 11～13 respectively, and comparator 31～33 is exported the brake signal of A, B, C phase respectively.Positive input terminal signal in comparator is less than the negative input end signal, and corresponding district's external ground fault that has is mutually declared in comparator output 0, exports corresponding phase brake signal, and the transformer ratio differential protection is braked, and prevents the transformer differential protection malfunction; Otherwise comparator output 1 allows corresponding phase differential protection action.Use this programme, only need to gather the Y that power supply is arranged
0Side three-phase current and this side zero-sequence current component ratio braking member, in the time of just 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 situations the transformer differential protection misoperation that the differential unsymmetrical current that zero-sequence current causes causes.
Claims (2)
1. a split-phase zero-sequence braking method that prevents malfunction for tranformer protection is characterized in that: use transformer Y
0A certain phase current in the side three-phase and this side zero-sequence current component ratio braking criterion during less than setting value, is exported the brake signal of this phase divided by the rate value of this side zero-sequence current when described phase current, and this phase transformer biased differential protection is braked; The foundation of split-phase zero-sequence braking is:
I
x/3I
o＜K
I in the formula
xBe transformer Y
0Any phase current in the three-phase of side, 3I
oBe this Y
0The side zero-sequence current, i.e. three-phase current sum, K is a setting value.
2. method according to claim 1 is characterized in that: the scope of setting value K is: 0＜K＜2/3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100847550A CN100367601C (en) | 2004-12-02 | 2004-12-02 | Split-phase zero sequence braking method for preventing transformer protection from malfunction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100847550A CN100367601C (en) | 2004-12-02 | 2004-12-02 | Split-phase zero sequence braking method for preventing transformer protection from malfunction |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1614843A CN1614843A (en) | 2005-05-11 |
| CN100367601C true CN100367601C (en) | 2008-02-06 |
Family
ID=34765969
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100847550A Expired - Fee Related CN100367601C (en) | 2004-12-02 | 2004-12-02 | Split-phase zero sequence braking method for preventing transformer protection from malfunction |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100367601C (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0833192A (en) * | 1994-07-21 | 1996-02-02 | Toshiba Corp | Relay controller |
| JPH09247845A (en) * | 1996-03-12 | 1997-09-19 | Meidensha Corp | Ratio differential 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 CNB2004100847550A patent/CN100367601C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0833192A (en) * | 1994-07-21 | 1996-02-02 | Toshiba Corp | Relay controller |
| JPH09247845A (en) * | 1996-03-12 | 1997-09-19 | Meidensha Corp | Ratio differential 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1614843A (en) | 2005-05-11 |
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|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080206 Termination date: 20101202 |