CN104158151A - Brake circuit and method for preventing transformer protection from malfunction - Google Patents
Brake circuit and method for preventing transformer protection from malfunction Download PDFInfo
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- CN104158151A CN104158151A CN201310464407.5A CN201310464407A CN104158151A CN 104158151 A CN104158151 A CN 104158151A CN 201310464407 A CN201310464407 A CN 201310464407A CN 104158151 A CN104158151 A CN 104158151A
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- transformer
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Abstract
Disclosed are a brake circuit and method for preventing transformer protection from malfunction. The circuit comprises an adder (1), a positive sequence current filter (2), a multiplier (3), a subtractor (4) and a comparator (5); the adder and the positive sequence current filter each have three input terminals for inputting effective values of three-phase currents (img file shown in the description) at a Y0 side of a transformer, and an output terminal of the adder is connected respectively to an input terminal of the multiplier and a positive input terminal of the subtractor; an output terminal of the positive sequence current filter is connected to a negative input terminal of the comparator; another input terminal of the multiplier inputs a set value K, and an output terminal of the multiplier is connected to a negative input terminal of the subtractor; an output terminal of the subtractor is connected to a positive input terminal of the comparator; and an output terminal of the comparator outputs a three-phase braking signal. The invention only requires collection of the three-phase currents at the Y0 side of the transformer to constitute the braking computing elements, and when an external fault occurs, a braking signal can be accurately sent to prevent transformer protection from malfunction due to inconsistent current transformer errors at the Y0 side of the transformer.
Description
Technical field
The present invention relates to a kind of relay protection method of power system, relate in particular to a kind of braking circuit that prevents malfunction for tranformer protection.The invention still further relates to the braking method that adopts described circuit to prevent malfunction for tranformer protection.
Background technology
Transformer is the indispensable important electrical of electric power system, will power supply reliability and system safety operation be brought and be had a strong impact on if it breaks down.Therefore, transformer relay protecting functional, reliable in action is very necessary.
In existing electric power system, extensively adopt the main protection of differential protection as transformer, to common employing Y, the differential protection input current of the three-phase transformer of the d11 mode of connection carries out vector, can be by Y
0side electric current subtracts each other through biphase current, offsets the zero-sequence current in former each phase current, eliminates the impact of zero-sequence current with this.
But in real system, under some single supply operational modes, because threephase current transformer exists error, Y after measuring by current transformer
0side electric current subtracts each other and can not offset each zero-sequence current in mutually completely through biphase current; in the time there is power supply lateral areas external ground fault; larger zero sequence short circuit current will be there is; cause the larger differential unsymmetrical current of generation in differential protection; and now transformer through current is very little; the unsymmetrical current causing because of current transformer error and the ratio of through current probably exceed the setting value of biased differential protection, and malfunction will occur tranformer protection.
Summary of the invention
First technical problem to be solved by this invention, is just to provide a kind of braking circuit that prevents malfunction for tranformer protection.
Second technical problem to be solved by this invention, is just to provide a kind of braking method that adopts foregoing circuit to prevent malfunction for tranformer protection.
Circuit of the present invention and method; can avoid three characteristics of the middle term current transformer to have error; under some single supply operational modes, the method for vector can not be eliminated the impact of zero-sequence current completely, and in the time there is power supply lateral areas external ground fault, tranformer protection will the problem of malfunction occur.
Solve above-mentioned first technical problem, the technical solution used in the present invention is:
A braking circuit that prevents malfunction for tranformer protection, is characterized in that: comprise adder 1, forward-order current pass filter 2, multiplier 3, subtracter 4 and comparator 5; Described adder 1 has three input input transformer Y
0the three-phase current of side
effective value, output is respectively to the input of multiplier 3, the positive input terminal of subtracter 4; Three inputs of forward-order current pass filter 2 input transformer Y respectively
0the three-phase current of side
output is connected with the negative input end of comparator 5; Another input input setting value K of multiplier 3, sets K=0.8, and output is connected with the negative input end of subtracter 4; The output of subtracter 4 is connected with the positive input terminal of comparator 5; The output output three-phase brake signal of comparator 5.
Solve above-mentioned second technical problem, the technical solution used in the present invention is:
Adopt foregoing circuit to prevent a braking method for malfunction for tranformer protection, comprise the following steps:
S1 is by transformer Y
0side three-phase current obtains forward-order current;
S2 is by forming braking computing element with three-phase current;
S3 is in the time that calculated value is greater than setting value, and output three-phase brake signal, brakes transformer differential protection; The braking of forward-order current and three-phase current is according to being:
In formula:
transformer Y
0the forward-order current of side;
transformer Y
0the a phase current of side;
transformer Y
0the b phase current of side;
transformer Y
0the c phase current of side;
K: setting value 3/4<K<1.
for transformer Y
0the effective value of the forward-order current of side;
for transformer Y
0the effective value of side three-phase current vector sum.
Feature of the present invention is:
Only need to gather transformer Y
0the three-phase current of side, forms braking computing element, in the time there is external area error, can accurately send brake signal, prevents because of transformer Y
0the inconsistent malfunction for tranformer protection causing of side current transformer error.
Brief description of the drawings
Accompanying drawing is the circuit block diagram of the braking method that prevents malfunction for tranformer protection of the present invention.
In figure: 1-adder, 2-forward-order current pass filter, 3-multiplier, 4-subtracter, 5-comparator.
Embodiment
Below in conjunction with drawings and Examples, the present invention is further described.
As shown in drawings, the embodiment of the braking circuit that prevents malfunction for tranformer protection of the present invention is made up of adder 1, forward-order current pass filter 2, multiplier 3, subtracter 4, comparator 5.Wherein, three of adder 1 input input transformer Y
0the three-phase current of side
effective value, output is connected with the input of multiplier 3, the positive input terminal of subtracter 4; Three inputs of forward-order current pass filter 2 input transformer Y respectively
0the three-phase current of side
output is connected with the negative input end of comparator 5; An input input setting value K of multiplier 3, sets K=0.8, another input input transformer Y
0the forward-order current effective value of side, output is connected with the negative input end of subtracter 4; The output of subtracter 4 is connected with the positive input terminal of comparator 5; The output output three-phase brake signal of comparator 5.
In the time that the positive input terminal signal of comparator 5 is greater than negative input end signal, comparator 5 exports 1, is judged to be external area error, exports corresponding brake signal, and transformer ratio differential protection is braked, and prevents malfunction for tranformer protection; Otherwise comparator 5 exports 0, is judged to be troubles inside the sample space, allow the action of transformer ratio differential protection.
Only need to gather transformer Y
0the three-phase current of side, forms braking computing element, in the time there is external area error, can accurately send brake signal, prevents because of transformer Y
0the inconsistent malfunction for tranformer protection causing of side current transformer error.
Adopt foregoing circuit to prevent the braking method of malfunction for tranformer protection, comprise the following steps:
S1 is by transformer Y
0side three-phase current obtains forward-order current;
S2 is by forming braking computing element with three-phase current;
S3 is in the time that calculated value is greater than setting value, and output three-phase brake signal, brakes transformer differential protection; The braking of forward-order current and three-phase current is according to being:
In formula:
transformer Y
0the forward-order current of side;
transformer Y
0the a phase current of side;
transformer Y
0the b phase current of side;
transformer Y
0the c phase current of side;
K: setting value 3/4<K<1.
for transformer Y
0the effective value of the forward-order current of side;
for transformer Y
0the effective value of side three-phase current vector sum.
Claims (5)
1. a braking circuit that prevents malfunction for tranformer protection, is characterized in that: comprise adder (1), forward-order current pass filter (2), multiplier (3), subtracter (4) and comparator (5); Described adder has three input input transformer Y
0the three-phase current of side
effective value, output is respectively to the input of multiplier, the positive input terminal of subtracter; Three inputs of forward-order current pass filter input transformer Y respectively
0the three-phase current of side
output is connected with the negative input end of comparator; Another input input setting value K of multiplier, output is connected with the negative input end of subtracter; The output of subtracter is connected with the positive input terminal of comparator; The output output three-phase brake signal of comparator.
2. the braking circuit that prevents malfunction for tranformer protection according to claim 1, is characterized in that: described K=0.8.
3. one kind adopts braking circuit as claimed in claim 1 or 2 to prevent malfunction for tranformer protection
Braking method, is characterized in that: comprise the following steps:
S1 is by transformer Y
0side three-phase current obtains forward-order current;
S2 is by forming braking computing element with three-phase current;
S3 is in the time that calculated value is greater than setting value, and output three-phase brake signal, brakes transformer differential protection; The braking of forward-order current and three-phase current is according to being:
In formula:
transformer Y
0the forward-order current of side;
transformer Y
0the a phase current of side;
transformer Y
0the b phase current of side;
transformer Y
0the c phase current of side;
K: setting value 3/4<K<1;
for transformer Y
0the effective value of the forward-order current of side;
for transformer Y
0the effective value of side three-phase current vector sum.
4. the braking method that prevents malfunction for tranformer protection according to claim 3, is characterized in that: described
for transformer Y
0the effective value of the forward-order current of side;
for transformer Y
0the effective value of side three-phase current vector sum.
5. the braking method that prevents malfunction for tranformer protection according to claim 4, is characterized in that: setting value 3/4<K<1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310464407.5A CN104158151B (en) | 2013-10-08 | 2013-10-08 | Prevent the braking circuit and method of malfunction for tranformer protection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310464407.5A CN104158151B (en) | 2013-10-08 | 2013-10-08 | Prevent the braking circuit and method of malfunction for tranformer protection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104158151A true CN104158151A (en) | 2014-11-19 |
| CN104158151B CN104158151B (en) | 2017-07-18 |
Family
ID=51883594
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310464407.5A Active CN104158151B (en) | 2013-10-08 | 2013-10-08 | Prevent the braking circuit and method of malfunction for tranformer protection |
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| Country | Link |
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| CN (1) | CN104158151B (en) |
Cited By (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 (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10257667A (en) * | 1997-03-07 | 1998-09-25 | Mitsubishi Electric Corp | Power system protector |
| CN1614850A (en) * | 2004-12-02 | 2005-05-11 | 浙江大学 | Positive and zero sequence fault component braking method for preventing transformer protection from malfunction |
| CN1614848A (en) * | 2004-12-02 | 2005-05-11 | 浙江大学 | Positive sequence and zero sequence braking method for preventing transformer protection from malfunction |
| CN203504149U (en) * | 2013-10-08 | 2014-03-26 | 广东电网公司电力科学研究院 | Braking circuit for preventing misoperation of transformer protection |
-
2013
- 2013-10-08 CN CN201310464407.5A patent/CN104158151B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10257667A (en) * | 1997-03-07 | 1998-09-25 | Mitsubishi Electric Corp | Power system protector |
| CN1614850A (en) * | 2004-12-02 | 2005-05-11 | 浙江大学 | Positive and zero sequence fault component braking method for preventing transformer protection from malfunction |
| CN1614848A (en) * | 2004-12-02 | 2005-05-11 | 浙江大学 | Positive sequence and zero sequence braking method for preventing transformer protection from malfunction |
| CN203504149U (en) * | 2013-10-08 | 2014-03-26 | 广东电网公司电力科学研究院 | Braking circuit for preventing misoperation of transformer protection |
Cited By (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 |
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| Publication number | Publication date |
|---|---|
| CN104158151B (en) | 2017-07-18 |
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Address after: 510080 water Donggang 8, Dongfeng East Road, Yuexiu District, Guangzhou, Guangdong. Patentee after: ELECTRIC POWER RESEARCH INSTITUTE, GUANGDONG POWER GRID CO., LTD. Address before: 510080 water Donggang 8, Dongfeng East Road, Yuexiu District, Guangzhou, Guangdong. Patentee before: Electrical Power Research Institute of Guangdong Power Grid Corporation |
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