CN2687919Y - Positive sequence synthetic brake device for preventing multi-branch differential protection from being malfunction - Google Patents
Positive sequence synthetic brake device for preventing multi-branch differential protection from being malfunction Download PDFInfo
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- CN2687919Y CN2687919Y CN 200420020120 CN200420020120U CN2687919Y CN 2687919 Y CN2687919 Y CN 2687919Y CN 200420020120 CN200420020120 CN 200420020120 CN 200420020120 U CN200420020120 U CN 200420020120U CN 2687919 Y CN2687919 Y CN 2687919Y
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- transformer
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- differential protection
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- 230000007257 malfunction Effects 0.000 title claims description 13
- 230000007935 neutral effect Effects 0.000 claims abstract description 14
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
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Abstract
The utility model relates to a positive sequence synthetic brake device for preventing multi-branch differential protection from being false action. The device comprises a ratio braking element through using the positive sequence current of the base wave of three phase difference motion current in a transformer differential protection device and the maximum value of the zero sequence current of each neutral point earthing side (or branch) of the transformer. When the signal of the positive input terminal of a comparator 5 is smaller than the signal of the negative input terminal, the comparator 5 exports 0. The situation is judged as an outer region earthing fault, and a three phase difference motion protecting outlet is closed. Otherwise, the comparator 5 exports 1 and permits the three phase difference motion protection device to do action. The advantages of the utility model are : the utility model can completely avoid the false action of the transformer differential protection device which the outer region earthing fault of the neutral point earthing side induces when the error of the three-phase current transformers is inconsistent.
Description
Technical field
The utility model relates to a kind of protection equipment for transformer, particularly a kind of synthetic brake apparatus of positive sequence that prevents the malfunction of multiple-limb transformer differential 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 utility model provides a kind of synthetic brake apparatus of positive sequence that prevents the malfunction of multiple-limb transformer differential protection, by with the maximum component ratio braking member in the zero-sequence current of the fundamental positive sequence electric current of the three-phase differential current in the transformer differential protection and each neutral ground side (or branch) of transformer, when rate value during less than setting value K, be judged to district's external ground fault, output three-phase phase brake signal, the outlet of locking rate of three phase flow differential protection; The utility model has the advantages that, 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.
A kind of synthetic brake apparatus of positive sequence that prevents the malfunction of multiple-limb transformer differential protection; this device circuit constitutes as shown in Figure 1; it is characterized in that: this device by filter 01,02 ... 0n, fundamental positive sequence pass filter 1, filter 2, maximizing circuit 3, multiplier 4, comparator 5 constitute, its median filter 01,02 ... the input of 0n is the zero-sequence current instantaneous value signal 3i of each neutral ground side (or branch) of input transformer respectively
10, 3i
20... 3i
N0Its output connects the input of maximizing circuit 3 respectively; an input of multiplier 4 is connected with the output of maximizing circuit 3; its another input input setting value K; the negative input end of comparator 5 connects the output of multiplier 4, and three inputs of fundamental positive sequence pass filter 1 are imported the three-phase differential current instantaneous value signal i that obtains respectively from transformer differential protection
Da, i
Db, i
Dc, the input of its output termination filter 2, the positive input terminal of the output of filter 2 and comparator 5 joins, comparator 5 output three-phase brake signals.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, and n is a transformer neutral point ground connection side number (or branches).When comparator 5 positive input terminal signals less than the negative input end signal, comparator 5 output 0 is judged to district's external ground fault, the outlet of locking rate of three phase flow differential protection; Otherwise comparator 5 outputs 1 allow the action of three-phase differential protection.
With prior art relatively; the utility model has the advantages that proposed first in traditional multiple-limb transformer differential protection, to have added a kind of by with the maximum component ratio braking member in the zero-sequence current of the fundamental positive sequence electric current of the three-phase differential current in the transformer differential protection and each neutral ground side (or branch) of transformer; when rate value during less than setting value K; be judged to district's external ground fault, the outlet of locking rate of three phase flow 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 positive sequence of multiple-limb transformer differential protection malfunction.
Embodiment
Embodiment 1
The synthetic brake apparatus of a kind of positive sequence that prevents the malfunction of multiple-limb transformer differential protection, its circuit structure as shown in Figure 1, transformer neutral point ground connection side is counted n=3.When comparator 5 positive input terminal signals less than the negative input end signal, comparator 5 output 0 is judged to district's external ground fault, the differential outlet of locking rate of three phase flow; Otherwise comparator 5 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 gets 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.
Claims (2)
1. a positive sequence that prevents the malfunction of multiple-limb transformer differential protection is synthesized brake apparatus; it is characterized in that: this device by filter (01,02 ... 0n), fundamental positive sequence pass filter (1), filter (2), maximizing circuit (3), multiplier (4), comparator (5) constitute, its median filter (01,02 ... input 0n) is the zero-sequence current instantaneous value signal (3i of each neutral ground side (or branch) of input transformer respectively
10, 3i
20... 3i
N0); its output is connected with the input of maximizing circuit (3) respectively; the output of an input termination maximizing circuit (3) of multiplier (4); its another input input setting value (K); the negative input end of comparator (5) connects the output of multiplier (4), and three inputs of fundamental positive sequence pass filter (1) are imported the three-phase differential current instantaneous value signal (i that obtains respectively from transformer differential protection
Da, i
Db, i
Dc), the input of its output termination filter (2), the positive input terminal of the output of filter (2) and comparator (5) joins, and comparator (5) output three-phase brake signal (n) is transformer neutral point ground connection side number (or branches).
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 |
|---|---|---|---|
| CN 200420020120 CN2687919Y (en) | 2004-02-13 | 2004-02-13 | Positive sequence synthetic brake device for preventing multi-branch differential protection from being malfunction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420020120 CN2687919Y (en) | 2004-02-13 | 2004-02-13 | Positive sequence synthetic brake device for preventing multi-branch differential protection from being malfunction |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2687919Y true CN2687919Y (en) | 2005-03-23 |
Family
ID=34669249
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200420020120 Expired - Fee Related CN2687919Y (en) | 2004-02-13 | 2004-02-13 | Positive sequence synthetic brake device for preventing multi-branch differential protection from being malfunction |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2687919Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105071346A (en) * | 2015-08-27 | 2015-11-18 | 南京国电南自电网自动化有限公司 | Positive-sequence current cross brake method for preventing transformer homodyne protection misoperation |
-
2004
- 2004-02-13 CN CN 200420020120 patent/CN2687919Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105071346A (en) * | 2015-08-27 | 2015-11-18 | 南京国电南自电网自动化有限公司 | Positive-sequence current cross brake method for preventing transformer homodyne protection misoperation |
| CN105071346B (en) * | 2015-08-27 | 2017-11-21 | 南京国电南自电网自动化有限公司 | A kind of forward-order current for preventing restricted earth protection malfunction intersects braking method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |