CN107123974A - A kind of bus troubles inside the sample space CT saturations based on saturation mechanism open trip method - Google Patents
A kind of bus troubles inside the sample space CT saturations based on saturation mechanism open trip method Download PDFInfo
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- CN107123974A CN107123974A CN201710506485.5A CN201710506485A CN107123974A CN 107123974 A CN107123974 A CN 107123974A CN 201710506485 A CN201710506485 A CN 201710506485A CN 107123974 A CN107123974 A CN 107123974A
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- current
- spill current
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- spill
- sample space
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
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- Emergency Protection Circuit Devices (AREA)
Abstract
Trip method is opened the invention discloses a kind of bus troubles inside the sample space CT saturations based on saturation mechanism, is comprised the following steps：(1) spill current starts；Spill current and voltage or stalling current simultaneous mutation；(2) spill current zero passage [n is judged; 0] whether integration ratio brake coefficient is more than k1; continue to judge spill current zero passage [(n 1) if meeting; 1] whether integration ratio brake coefficient is more than k2; if met; and meet definite value without DC component, spill current, without other barring conditions when, directly open differential protection fast trip；(3) when k is more than at 1 after zero passage, calculate spill current zero passage interval [j, k] whether there is discontinuous point, if being then judged as external area error CT saturations, locking fast trip.The present invention can make full use of the correct progress of disease region internal difference electric current and the larger feature of stalling current ratio of spill current saturation waveform near zero-crossing point, and open differential protection fast trip cuts off troubles inside the sample space.
Description
Technical field
The present invention relates to field of relay protection in power, especially a kind of bus troubles inside the sample space CT based on saturation mechanism
Saturation opens trip method.
Background technology
With the raising of China's grid power transmission grade and capacity, TP (transient protection Transient protection) class
Current transformer (current transformer, CT) is widely used in power network, calculates and carries to relay protection of power system equipment
For initial data, safe operation of power system is ensured.Under normal circumstances, current transformer can accurately pass primary circuit electric current
Change to secondary circuit.When power system is broken down, primary circuit electric current is much larger than normal duty electric current, and there is substantial amounts of decline
When subtracting DC component, current transformer core can enter saturation state, and secondary loop current distorts.
Bus differential protecting is based on Kirchhoff's current law (KCL), and current transformer core enters saturation state and produces distortion electricity
Stream, causes bus during external area error maloperation outside spill current, easy generating region occur.It is full according to CT saturations genesis mechanism and CT
The characteristics of with rear secondary current waveform, Normal practice takes following technical proposal：
(1) although spill current wave distortion, the initial time period CT of failure will not saturation, spill current produces the moment and lags behind
Stalling current is mutated and busbar voltage mutation produces the moment；
(2) all there is several milliseconds of linear transform area in every cycle near zero-crossing point, and during external area error CT saturations, zero crossing is attached
Closely there is spill current waveform discontiguous area, this area difference current instantaneous value is zero；
(3) CT saturation deficits current waveform aperiodic component is higher.
When Normal practice has accomplished external area error CT saturations well, bus differential protecting can locking in time it is differential go out
Mouthful, prevent external malfunction, the accident of bus dead electricity.
When occurring bus troubles inside the sample space, because each line current all flows into bus, system short circuit capacity design and electric current
It ensure that spill current is substantially changed by sinusoidal rule in the type selecting of transformer, when being not in internal fault under normal circumstances
The mutation of CT saturation deficits stream becomes big situation.But because China's power network is complicated, design difficulty is big, and the method for operation is changeable, when because of certain
There is bus troubles inside the sample space in one reason, big power branch CT there is saturation and remaining branch current it is smaller or without when, bus therefore
Hinder phase spill current to present similar to external area error CT saturation characteristics, traditional technical scheme easily causes troubles inside the sample space and misses locking
Differential protection.Outlet tripping operation is opened for the bus differential protecting of such a phenomenon and prevents that lock-out scheme document is less by mistake.
Bus troubles inside the sample space, big power branch CT there is saturation and remaining branch current it is smaller or without when, bus-bar fault
Phase spill current is mainly made up of the saturation waveform of big power branch, when the branch road saturation waveform has branch road CT saturations with external area error
Spill current feature it is similar, all there is discontiguous area.Difference is that spill current discontiguous area is the CT saturation moment during troubles inside the sample space,
Cross outside null range, CT secondary circuit output currents very little, close to zero.And spill current discontiguous area during external area error is CT
At the correct progress of disease moment, near zero passage, CT secondary circuits output current is normal progress of disease electric current.Prior art is based on finding
The spill current discontinuous point of zero crossings, in conjunction with remaining assistant criteria, decides whether that Blocking Differential Protection is exported.And for mistake
Whether zero crossings open differential protection outlet, do not do excessive measure.
The content of the invention
The technical problems to be solved by the invention are that there is provided a kind of bus troubles inside the sample space CT saturations based on saturation mechanism
Open trip method, can make full use of correct progress of disease region internal difference electric current and the braking of spill current saturation waveform near zero-crossing point
The larger feature of current ratio, open differential protection fast trip, cuts off troubles inside the sample space.
Opened in order to solve the above technical problems, the present invention provides a kind of bus troubles inside the sample space CT saturations based on saturation mechanism
Trip method, comprises the following steps：
(1) spill current starts；Spill current and voltage or stalling current simultaneous mutation；
(2) judge whether spill current zero passage [- n, 0] integration ratio brake coefficient is more than k1, continue to judge if meeting
Whether spill current zero passage [- (n-1), 1] integration ratio brake coefficient is more than k2, if it is satisfied, and full without DC component, spill current
Sufficient definite value, without other barring conditions when, directly open differential protection fast trip；
(3) when k is more than at 1 after zero passage, calculate spill current zero passage interval [- j, k] whether there is discontinuous point, if being then judged as
External area error CT saturations, locking fast trip.
It is preferred that, in step (2), judge whether spill current zero passage [- n, 0] integration ratio brake coefficient is more than k1 specific
For：Represent that be more than to forward direction n point interval integral ratio brake coefficients after zero passage at the 1st point
k1, the correct progress of disease region near anticipation spill current zero passage shows troubles inside the sample space feature；Wherein, icd(t) instantaneous poor electricity is represented
Stream, izd(t) instantaneous stalling current is represented, both ratios represent spill current ratio brake coefficient, k1For software inhouse spill current ratio
Rate restraint coefficient threshold.
It is preferred that, in step (2), judge whether spill current zero passage [- (n-1), 1] integration ratio brake coefficient is more than k2 tools
Body is：Represent after zero passage at the 2nd point to forward direction n point interval integral ratio brakes system
Number is more than k2, confirm that the correct progress of disease region near spill current zero passage continuously shows troubles inside the sample space feature；Wherein, icd(t) table
Show instantaneous spill current, izd(t) instantaneous stalling current is represented, both ratios represent spill current ratio brake coefficient, k2For in software
Portion's spill current ratio brake coefficient threshold.
It is preferred that, in step (3), calculating spill current zero passage interval [- j, k], which whether there is discontinuous point, is specially：
Represent that j points, to k points interval indifference stream discontinuous point after zero passage, take 3ms or so data window before zero passage；Wherein, fjd(t) represent whether there is
The function of discontinuous point.
It is preferred that, the calculating integrating range [- n, 0] of formula (1) and formula (2), [- (n-1), 1] are less than formula (3)
Integrating range [- j, k] is calculated, once formula (3) is met, locking bus differential protecting fast trip algorithm immediately.
Beneficial effects of the present invention are：The present invention can make full use of the correct biography of spill current saturation waveform near zero-crossing point
Become spill current and the larger feature of stalling current ratio in region, open differential protection fast trip cuts off troubles inside the sample space；Fully
Using existing ripe technical scheme, satisfied based on troubles inside the sample space CT in the correct progress of disease minizone of technical scheme superposition zero crossings
With open fast trip criterion, algorithm simply, is easily realized, more fully adapts to the complicated running environment of power network.
Brief description of the drawings
Fig. 1 is the system model structural representation of the present invention.
Fig. 2 is the method flow schematic diagram of the present invention.
Fig. 3 is the simulation result recording schematic diagram of the present invention.
Embodiment
As shown in Fig. 2 a kind of bus troubles inside the sample space CT saturations based on saturation mechanism open trip method, including following step
Suddenly：
(1) spill current starts；Spill current and voltage or stalling current simultaneous mutation；
(2) judge whether spill current zero passage [- n, 0] integration ratio brake coefficient is more than k1, continue to judge if meeting
Whether spill current zero passage [- (n-1), 1] integration ratio brake coefficient is more than k2, if it is satisfied, and full without DC component, spill current
Sufficient definite value, without other barring conditions when, directly open differential protection fast trip；
(3) when k is more than at 1 after zero passage, calculate spill current zero passage interval [- j, k] whether there is discontinuous point, if being then judged as
External area error CT saturations, locking fast trip.
As shown in figs. 1 and 3, system model is bus scheme with one and half breaker mode, totally two strings.Bus differential protecting is installed
In BUS1, Brk1 and Brk3 corresponding current transformer secondary sides rated current is 1A.The middle breaker of the 2nd string is in disconnected before failure
Open state, remaining breaker is in position state of closing, and system is in heavy condition.K1 points generation B phases are grounded metallicity failure in area,
There is saturation in Brk1 current transformers.
When K1 points break down in area because second string in the middle of breaker disconnect, Infinite bus system by Brk4, Brk2,
Brk1 provides trouble power to trouble point K1, and #2 units provide trouble power through Brk3 to trouble point K1, because #2 units are compared
Infinite bus system capacity is smaller, and Brk1 fault current is far longer than Brk3, and BUS1 bus protections spill current is mainly carried by Brk1
For.Because saturation occur in Brk1 current transformers, therefore BUS1 bus protection spill currents are mainly reflected in the full of Brk1 current transformers
And waveform.Recording figure is as shown in figure 3, in figure, IdB is the instantaneous spill current of B phases and stalling current with IfB.As seen from Figure 3, failure
After generation, the saturation waveform of B phases spill current and Brk1 current transformers is very close to theoretical foundation of the present invention is set up.
Brk1 fault currents are larger, CT saturations, and fault moment Brk3 electric currents are reduced on the contrary, the main body of bus B phase spill currents
It is now Brk1 saturation waveforms.Analyzed according to aforementioned techniques, the present invention is calculated in bus spill current zero crossings minizone in real time
Spill current and stalling current ratio brake coefficient, with reference to other assistant criterias, troubles inside the sample space feature is substantially then quick to open bus
Differential protection is exported.Criterion is as follows：
In above-mentioned formula, icd(t) instantaneous spill current, i are representedzd(t) instantaneous stalling current is represented, both ratios represent poor
Current ratio restraint coefficient.k1、k2For software inhouse spill current ratio brake coefficient threshold.fjd(t) represent whether there is discontinuous point
Function.
Formula (1) represent zero passage after the 1st point to forward direction n point interval integrals ratio brake coefficient be more than k1, anticipation spill current
Correct progress of disease region near zero passage shows troubles inside the sample space feature.Formula (2) represent after zero passage the 2nd point it is interval to forward direction n points
Integrate ratio brake coefficient and be more than k2, confirm that the correct progress of disease region near spill current zero passage continuously shows troubles inside the sample space special
Levy.Formula (3) represents that j points, to k points interval indifference stream discontinuous point after zero passage, take 3ms or so data window before zero passage.Other routines
Criterion judges comprising difference current and voltage or stalling current simultaneous mutation, DC component and spill current reaches action threshold etc.
No longer list.
Formula (1) and formula (2) are used to determine whether bus troubles inside the sample space, in difference current and voltage or stalling current
Simultaneous mutation, DC component are not influenceed on the basis of criterion and spill current reach action threshold, and formula (1) and formula (2) are together
When meet open tripping operation outlet immediately；Formula (3) is used to determine whether bus external area error CT saturations, meets condition then locking
Tripping operation outlet, formula (3) in big power branch CT saturation times section because the improper progress of disease of CT, secondary output current very little, very
Condition may be met, external area error CT saturations, Blocking Differential Protection outlet is mistaken for.In order to ensure formula (1) and formula (2) energy
Enough quick open tripping operations, and not by formula (3) to locking by mistake, the calculating integrating range [- n, 0] of formula (1) and formula (2), [-
(n-1), 1] it is less than the calculating integrating range [- j, k] of formula (3), once formula (3) is met, locking bus differential is protected immediately
Protect fast trip algorithm.
After spill current starts, first determine whether whether spill current zero passage [- n, 0] integration ratio brake coefficient is more than k1, such as
Fruit, which meets, then to continue to judge whether spill current zero passage [- (n-1), 1] integration ratio brake coefficient is more than k2, if it is satisfied, and nothing
DC component, spill current meet definite value, without other barring conditions when, directly open differential protection fast trip.K is (big after zero passage
When 1) putting, calculate spill current zero passage [- j, k] whether there is discontinuous point, if being then judged as external area error CT saturations, locking is quick
Tripping operation.
The present invention makes full use of existing ripe technical scheme, small based on the technical scheme superposition correct progress of disease of zero crossings
Troubles inside the sample space CT saturations open fast trip criterion in interval, and algorithm is simple, easily realizes, can more fully adapt to power network and answer
Miscellaneous running environment.
Although the present invention is illustrated and described with regard to preferred embodiment, it is understood by those skilled in the art that
Without departing from scope defined by the claims of the present invention, variations and modifications can be carried out to the present invention.
Claims (5)
1. a kind of bus troubles inside the sample space CT saturations based on saturation mechanism open trip method, it is characterised in that including following step
Suddenly：
(1) spill current starts；Spill current and voltage or stalling current simultaneous mutation；
(2) judge whether spill current zero passage [- n, 0] integration ratio brake coefficient is more than k1, continue to judge difference electricity if meeting
Flow through whether zero [- (n-1), 1] integrations ratio brake coefficient is more than k2, if it is satisfied, and meeting fixed without DC component, spill current
Value, without other barring conditions when, direct opening differential protection fast trip；
(3) when k is more than at 1 after zero passage, calculate spill current zero passage interval [- j, k] whether there is discontinuous point, if being then judged as outside area
Failure CT saturations, locking fast trip.
2. the bus troubles inside the sample space CT saturations based on saturation mechanism open trip method as claimed in claim 1, its feature exists
In, in step (2), judge spill current zero passage [- n, 0] integration ratio brake coefficient whether be specially more than k1：Represent zero passage after the 1st point to forward direction n point interval integrals ratio brake coefficient be more than k1,
Correct progress of disease region near anticipation spill current zero passage shows troubles inside the sample space feature；Wherein, icd(t) instantaneous spill current is represented,
izd(t) instantaneous stalling current is represented, both ratios represent spill current ratio brake coefficient, k1For software inhouse spill current ratiometric
Dynamic coefficient threshold.
3. the bus troubles inside the sample space CT saturations based on saturation mechanism open trip method as claimed in claim 1, its feature exists
In, in step (2), judge spill current zero passage [- (n-1), 1] integration ratio brake coefficient whether be specially more than k2：Represent big to forward direction n-1 point interval integral ratio brake coefficients after zero passage at the 2nd point
In k2, confirm that the correct progress of disease region near spill current zero passage continuously shows troubles inside the sample space feature；Wherein, icd(t) wink is represented
When spill current, izd(t) instantaneous stalling current is represented, both ratios represent spill current ratio brake coefficient, k2It is poor for software inhouse
Current ratio restraint coefficient threshold.
4. the bus troubles inside the sample space CT saturations based on saturation mechanism open trip method as claimed in claim 1, its feature exists
In in step (3), calculating spill current zero passage interval [- j, k], which whether there is discontinuous point, is specially：Represent zero passage
Preceding j points take 3ms or so data window to k points interval indifference stream discontinuous point after zero passage；Wherein, fjd(t) represent whether there is discontinuous point
Function.
5. the bus troubles inside the sample space CT saturations based on saturation mechanism open trip method as claimed in claim 1, its feature exists
In the calculating integrating range [- n, 0] of formula (1) and formula (2), [- (n-1), 1] are less than the calculating integrating range of formula (3)
[- j, k], once formula (3) is met, locking bus differential protecting fast trip algorithm immediately.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110492444A (en) * | 2019-09-10 | 2019-11-22 | 许昌许继软件技术有限公司 | Substation bus bar differential protecting method and device |
| CN111797699A (en) * | 2020-06-10 | 2020-10-20 | 积成软件有限公司 | Method for identifying fault-removal CT trailing waveform |
| CN113964799A (en) * | 2020-07-20 | 2022-01-21 | 南京南瑞继保电气有限公司 | Method and device for preventing differential protection unwanted operation at two ends of T area |
| CN115566651A (en) * | 2022-10-25 | 2023-01-03 | 上海山源电子科技股份有限公司 | Coal mine power supply quick-break protection method based on CT saturation judgment |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105071356A (en) * | 2015-07-15 | 2015-11-18 | 南京国电南自电网自动化有限公司 | Method for preventing sampling channel AD over-limit differential misoperation |
| CN105140893A (en) * | 2015-07-27 | 2015-12-09 | 许继集团有限公司 | Differential protection current transformer (CT) saturation recognition method |
| SE1651571A1 (en) * | 2016-11-30 | 2016-11-30 | Abb Schweiz Ag | Open current circuit detection |
-
2017
- 2017-06-28 CN CN201710506485.5A patent/CN107123974B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105071356A (en) * | 2015-07-15 | 2015-11-18 | 南京国电南自电网自动化有限公司 | Method for preventing sampling channel AD over-limit differential misoperation |
| CN105140893A (en) * | 2015-07-27 | 2015-12-09 | 许继集团有限公司 | Differential protection current transformer (CT) saturation recognition method |
| SE1651571A1 (en) * | 2016-11-30 | 2016-11-30 | Abb Schweiz Ag | Open current circuit detection |
Non-Patent Citations (2)
| Title |
|---|
| 刘益青等: "基于差电流半周积分特征的电流互感器饱和识别方法", 《电网技术》 * |
| 黄继东等: "母线差动保护区外转区内故障再动作判据", 《电力系统自动化》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110492444A (en) * | 2019-09-10 | 2019-11-22 | 许昌许继软件技术有限公司 | Substation bus bar differential protecting method and device |
| CN110492444B (en) * | 2019-09-10 | 2022-04-05 | 许昌许继软件技术有限公司 | Transformer substation bus differential protection method and device |
| CN111797699A (en) * | 2020-06-10 | 2020-10-20 | 积成软件有限公司 | Method for identifying fault-removal CT trailing waveform |
| CN113964799A (en) * | 2020-07-20 | 2022-01-21 | 南京南瑞继保电气有限公司 | Method and device for preventing differential protection unwanted operation at two ends of T area |
| CN113964799B (en) * | 2020-07-20 | 2024-01-02 | 南京南瑞继保电气有限公司 | Method and device for preventing differential protection misoperation at two ends of T region |
| CN115566651A (en) * | 2022-10-25 | 2023-01-03 | 上海山源电子科技股份有限公司 | Coal mine power supply quick-break protection method based on CT saturation judgment |
| CN115566651B (en) * | 2022-10-25 | 2023-06-02 | 上海山源电子科技股份有限公司 | Coal mine power supply quick-break protection method based on CT saturation judgment |
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