CN109119972A - A kind of blocking method and device for preventing balance winding CT broken string from leading to differential malfunction - Google Patents
A kind of blocking method and device for preventing balance winding CT broken string from leading to differential malfunction Download PDFInfo
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- CN109119972A CN109119972A CN201811093221.2A CN201811093221A CN109119972A CN 109119972 A CN109119972 A CN 109119972A CN 201811093221 A CN201811093221 A CN 201811093221A CN 109119972 A CN109119972 A CN 109119972A
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- balance winding
- phase current
- zero sequence
- protection
- winding
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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
- H02H7/04—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 transformers
- H02H7/045—Differential protection of transformers
-
- 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
- H02H3/02—Details
- H02H3/05—Details with means for increasing reliability, e.g. redundancy arrangements
Abstract
The present invention provides a kind of blocking methods and device for preventing balance winding CT broken string from leading to differential malfunction; its working method is: every phase winding electric current of acquisition series transformer balance winding; amplitude or virtual value to three-phase current are calculated in real time; the amplitude of each phase current or virtual value are compared with the phase current magnitude of other phases or virtual value respectively; when ratio is greater than locking definite value, it is latched zero sequence differential protection；When the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream is greater than locking definite value, locking zero sequence differential protection；The present invention is reliably prevented from protection because balancing winding CT broken string due to malfunction, can be widely applied to series transformer zero sequence differential protection.
Description
Technical field
The present invention relates to field of relay protection in power, prevent balance winding CT broken string from causing in particular to one kind
The blocking method and device of differential malfunction.
Background technique
Series transformer is novel FACTS (Flexible AC Transmission Systems, flexible AC transmission system
System) equipment one of core component, the core position that it is in straight-wavy valve and transmission line of alternation current is intercoursed.Work as series-transformer
When turn-to-turn fault occurs for device, zero-sequence current will occur in balance winding, configure the zero sequence differential protection based on magnetic balance, can be sensitive
Ground reflects such failure.
Winding not bringing onto load, three-phase symmetrical wiring are balanced, therefore balances winding current very little when transformer normal operation, such as
In fruit field application, there is balance winding CT broken string, when normal operation is indiscoverable.If uneven event outside burst region
Barrier, zero sequence differential protection will generate difference stream at this time, lead to zero sequence differential protection malfunction.
Existing zero sequence differential protection is generally based on the winding zero sequence differential protection of electric equilibrium, existing for disconnection problem
The emphasis of technical concerns is transformer neutral point zero sequence CT, this is single-phase CT, and correlation technique can not be applied to balance winding three-phase
In the polarity discriminating of CT.
Summary of the invention
In view of the deficiencies of the prior art, the present invention is intended to provide a kind of prevent balance winding CT broken string from leading to differential malfunction
Blocking method and device, to prevent balance winding CT broken string from leading to zero sequence differential protection malfunction.
In order to achieve the above objectives, the present invention takes technical solution below to realize.
A kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction, the method comprises the following steps:
(1) the three-phase phase current of the balance winding of series transformer is acquired, note balance winding A phase current is Ia, note balance
Winding B phase current is Ib, note balance winding C phase current is Ic；
(2) I is calculated separatelya、Ib、IcWith the amplitude or virtual value ratio of other biphase currents, when any phase current magnitude or
The ratio of any phase current magnitude or virtual value is less than locking definite value K in virtual value and other biphase currentsset1When, it is latched zero sequence
Differential protection.
In above scheme, the locking definite value Kset1Value range are as follows: 0.5~0.8.
In above scheme, the step 2 further include: the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream is calculated,
When the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream is greater than locking definite value Kset2, it is latched zero sequence differential protection.
In above scheme, the locking definite value Kset2Value range be 2~5.
In above scheme, the zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；Institute
It states longitudinal difference protection and poor circuit is constituted using net side CT, valve side CT.
The present invention proposes a kind of protective device for preventing balance winding CT broken string from leading to differential malfunction, described device simultaneously
Including sampling unit, locking judging unit, in which:
The sampling unit, acquires the three-phase phase current of the balance winding of series transformer, and note balance winding A phase current is
Ia, note balance winding B phase current is Ib, note balance winding C phase current is Ic；
The locking judging unit, for calculating separately Ia、Ib、IcWith the amplitude or virtual value ratio of other biphase currents,
When the ratio of any phase current magnitude or virtual value is less than locking in any phase current magnitude or virtual value and other biphase currents
Definite value Kset1When, it is latched zero sequence differential protection.
In above scheme, the locking definite value Kset1Value range are as follows: 0.5~0.8.
In above scheme, the locking judging unit further include: calculate zero sequence differential protection difference stream and longitudinal difference protection difference stream
Ratio, when the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream is greater than locking definite value Kset2, it is latched the differential guarantor of zero sequence
Shield.
In above scheme, the locking definite value Kset2Value range be 2~5.
In above scheme, the zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；Institute
It states longitudinal difference protection and poor circuit is constituted using net side CT, valve side CT.
Compared with prior art, the beneficial effect comprise that
The present invention provides a kind of blocking method and device for preventing balance winding CT broken string from leading to differential malfunction, work
Mode is: every phase winding electric current of acquisition series transformer balance winding, amplitude or virtual value to three-phase current carry out real-time
It calculates, the amplitude of each phase current or virtual value is compared with the phase current magnitude of other phases or virtual value respectively, work as ratio
When greater than locking definite value, it is latched zero sequence differential protection；It is closed when the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream is greater than
Lock value is latched zero sequence differential protection；The present invention is reliably prevented from differential protection and breaks due to malfunction because balancing winding CT, can
To be widely used in series transformer zero sequence differential protection.
Detailed description of the invention
Fig. 1 is the balance winding CT breakage lock device method flow diagram one of zero sequence differential protection；
Fig. 2 is the balance winding CT breakage lock device method flow diagram two of zero sequence differential protection；
Fig. 3 is the balance winding CT breakage lock device method flow diagram three of zero sequence differential protection；
Fig. 4 is the balance winding CT breakage lock device method flow diagram four of zero sequence differential protection
Fig. 5 is the mutual inductor schematic diagram for participating in series transformer pilot zero sequence differential protection and calculating.
Specific embodiment
The invention discloses a kind of blocking methods for preventing balance winding CT broken string from leading to differential malfunction, below with reference to attached
Figure, is described in detail technical solution of the present invention.
Embodiment one:
A kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction, comprising the following steps:
(1) the three-phase phase current of the balance winding of series transformer is acquired, note balance winding A phase current is Ia, note balance
Winding B phase current is Ib, note balance winding C phase current is Ic；
As shown in figure 5, zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；Longitudinal difference protection
Poor circuit is constituted using net side CT, valve side CT.When series transformer operates normally, winding not bringing onto load is balanced, winding is balanced
Three-phase current very little, i.e. Ia、Ib、IcVery little.When turn-to-turn fault occurs for series transformer, will be generated in balance three square ring of winding
Circulation, Ia、Ib、IcThree-phase current is equal in magnitude, direction is identical；
(2) I is calculated separatelya、Ib、IcWith the amplitude ratio of other biphase currents, when any phase current magnitude and other two-phases
The ratio of any phase current magnitude is less than locking definite value K in electric currentset1When, it is latched zero sequence differential protection, and provide warning message,
Kset1Value range are as follows: 0.5~0.8.
If there is the case where broken string in balance winding A, B, C three-phase, by taking A phase breaks as an example, in this case, when being
When singlephase earth fault occurs for system, balance winding A phase will adopt the electric current for less than electric current or only adopting very little, and B, C phase will adopt
Equal in magnitude, the identical electric current in direction.As shown in Figure 1, determining when A phase current is greater than locking with the current amplitude ratio of B phase or C phase
Value Kset1When, that is, it is judged to balance winding three-phase CT and there is exception, be latched zero sequence differential protection and simultaneously provide warning message.It is latched definite value
Kset1Value range it is general are as follows: 0.5~0.8.
Embodiment two:
A kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction, comprising the following steps:
(1) the three-phase phase current of the balance winding of series transformer is acquired, note balance winding A phase current is Ia, note balance
Winding B phase current is Ib, note balance winding C phase current is Ic；
As shown in figure 5, zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；Longitudinal difference protection
Poor circuit is constituted using net side CT, valve side CT.When series transformer operates normally, winding not bringing onto load is balanced, winding is balanced
Three-phase current very little, i.e. Ia、Ib、IcVery little.When turn-to-turn fault occurs for series transformer, will be generated in balance three square ring of winding
Circulation, Ia、Ib、IcThree-phase current is equal in magnitude, direction is identical；
(2) I is calculated separatelya、Ib、IcWith the virtual value ratio of other biphase currents, when any phase current virtual value and other
The ratio of any phase current virtual value is less than locking definite value K in biphase currentset1When, it is latched zero sequence differential protection, and provide announcement
Warning message, Kset1Value range are as follows: 0.5~0.8.
If there is the case where broken string in balance winding A, B, C three-phase, by taking A phase breaks as an example, in this case, when being
When singlephase earth fault occurs for system, balance winding A phase will adopt the electric current for less than electric current or only adopting very little, and B, C phase will adopt
Equal in magnitude, the identical electric current in direction.As shown in Fig. 2, when A phase current and the current effective value ratio of B phase or C phase are greater than locking
Definite value Kset1When, that is, it is judged to balance winding three-phase CT and there is exception, be latched zero sequence differential protection and simultaneously provide warning message.Locking is fixed
Value Kset1Value range it is general are as follows: 0.5~0.8.
Embodiment three:
A kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction, comprising the following steps:
(1) the three-phase phase current of the balance winding of series transformer is acquired, note balance winding A phase current is Ia, note balance
Winding B phase current is Ib, note balance winding C phase current is Ic；
As shown in figure 5, zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；Longitudinal difference protection
Poor circuit is constituted using net side CT, valve side CT.When series transformer operates normally, winding not bringing onto load is balanced, winding is balanced
Three-phase current very little, i.e. Ia、Ib、IcVery little.When turn-to-turn fault occurs for series transformer, will be generated in balance three square ring of winding
Circulation, Ia、Ib、IcThree-phase current is equal in magnitude, direction is identical；
(2) I is calculated separatelya、Ib、IcWith the amplitude ratio of other biphase currents, when any phase current magnitude and other two-phases
The ratio of any phase current magnitude is less than locking definite value K in electric currentset1When, it is latched zero sequence differential protection, and provide warning message,
Kset1Value range are as follows: 0.5~0.8.The ratio for calculating zero sequence differential protection difference stream and longitudinal difference protection difference stream, when zero sequence is differential
The ratio of protection difference stream and longitudinal difference protection difference stream is greater than locking definite value Kset2, it is latched zero sequence differential protection., Kset2Value range
It is 2~5.
If there is the case where broken string in balance winding A, B, C three-phase, by taking A phase breaks as an example, in this case, when being
When singlephase earth fault occurs for system, balance winding A phase will adopt the electric current for less than electric current or only adopting very little, and B, C phase will adopt
Equal in magnitude, the identical electric current in direction.As shown in figure 3, determining when A phase current is greater than locking with the current amplitude ratio of B phase or C phase
Value Kset1When, that is, it is judged to balance winding three-phase CT and there is exception, be latched zero sequence differential protection and simultaneously provide warning message.It is latched definite value
Kset1Value range it is general are as follows: 0.5~0.8.
If balance winding A, B, C three-phase CT breaks, by taking singlephase earth fault outside system generating region as an example, zero sequence is differential
The poor stream of protection should be zero, but since balance winding three-phase CT breaks, zero sequence differential protection will calculate very big at this time
Difference stream, numerical value adjust 1 times of electric current close to source side winding；And longitudinal difference protection does not adopt balance winding current, when external area error, it is poor to indulge
Protection difference stream very little；Therefore, as shown in Figure 1, can use the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream to sentence
The poor circuit of other zero sequence differential protection is with the presence or absence of abnormal.It is latched definite value Kset2Range generally take: 2~5.
Example IV:
A kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction, comprising the following steps:
(1) the three-phase phase current of the balance winding of series transformer is acquired, note balance winding A phase current is Ia, note balance
Winding B phase current is Ib, note balance winding C phase current is Ic；
As shown in figure 5, zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；Longitudinal difference protection
Poor circuit is constituted using net side CT, valve side CT.When series transformer operates normally, winding not bringing onto load is balanced, winding is balanced
Three-phase current very little, i.e. Ia、Ib、IcVery little.When turn-to-turn fault occurs for series transformer, will be generated in balance three square ring of winding
Circulation, Ia、Ib、IcThree-phase current is equal in magnitude, direction is identical；
(2) I is calculated separatelya、Ib、IcWith the virtual value ratio of other biphase currents, when any phase current virtual value and other
The ratio of any phase current virtual value is less than locking definite value K in biphase currentset1When, it is latched zero sequence differential protection, and provide announcement
Warning message, Kset1Value range are as follows: 0.5~0.8.
If there is the case where broken string in balance winding A, B, C three-phase, by taking A phase breaks as an example, in this case, when being
When singlephase earth fault occurs for system, balance winding A phase will adopt the electric current for less than electric current or only adopting very little, and B, C phase will adopt
Equal in magnitude, the identical electric current in direction.As shown in figure 4, when A phase current and the current effective value ratio of B phase or C phase are greater than locking
Definite value Kset1When, that is, it is judged to balance winding three-phase CT and there is exception, be latched zero sequence differential protection and simultaneously provide warning message.Locking is fixed
Value Kset1Value range it is general are as follows: 0.5~0.8.
If balance winding A, B, C three-phase CT breaks, by taking singlephase earth fault outside system generating region as an example, zero sequence is differential
The poor stream of protection should be zero, but since balance winding three-phase CT breaks, zero sequence differential protection will calculate very big at this time
Difference stream, numerical value adjust 1 times of electric current close to source side winding；And longitudinal difference protection does not adopt balance winding current, when external area error, it is poor to indulge
Protection difference stream very little；Therefore, as shown in Figure 1, can use the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream to sentence
The poor circuit of other zero sequence differential protection is with the presence or absence of abnormal.It is latched definite value Kset2Range generally take: 2~5.
The present invention proposes a kind of protective device for preventing balance winding CT broken string from leading to differential malfunction, described device simultaneously
Including sampling unit, locking judging unit, in which:
The sampling unit, acquires the three-phase phase current of the balance winding of series transformer, and note balance winding A phase current is
Ia, note balance winding B phase current is Ib, note balance winding C phase current is Ic；
The locking judging unit, for calculating separately Ia、Ib、IcWith the amplitude or virtual value ratio of other biphase currents,
When the ratio of any phase current magnitude or virtual value is less than locking in any phase current magnitude or virtual value and other biphase currents
Definite value Kset1When, it is latched zero sequence differential protection.
Wherein, the locking definite value Kset1Value range are as follows: 0.5~0.8.
Wherein, the locking judging unit further include: the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream is calculated,
When the ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream is greater than locking definite value Kset2, it is latched zero sequence differential protection.
Wherein, the locking definite value Kset2Value range be 2~5.
Wherein, the zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；The vertical difference
Protection constitutes poor circuit using net side CT, valve side CT.
The above examples only illustrate the technical idea of the present invention, and this does not limit the scope of protection of the present invention, all
According to the technical idea provided by the invention, any changes made on the basis of the technical scheme each falls within the scope of the present invention
Within.
Claims (10)
1. a kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction, which is characterized in that the method step is such as
Under:
(1) the three-phase phase current of the balance winding of series transformer is acquired, note balance winding A phase current is Ia, note balance winding B
Phase current is Ib, note balance winding C phase current is Ic；
(2) I is calculated separatelya、Ib、IcWith the amplitude or virtual value ratio of other biphase currents, when any phase current magnitude or effectively
Value is less than locking definite value K with the ratio of any phase current magnitude or virtual value in other biphase currentsset1When, locking zero sequence is differential
Protection.
2. a kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction as described in claim 1, feature exist
In the locking definite value Kset1Value range are as follows: 0.5~0.8.
3. such as a kind of described in any item blocking methods for preventing balance winding CT broken string from leading to differential malfunction of claims 1 or 2,
It is characterized in that, the step 2 further include: the ratio for calculating zero sequence differential protection difference stream and longitudinal difference protection difference stream, when zero sequence is poor
The ratio of dynamic protection difference stream and longitudinal difference protection difference stream is greater than locking definite value Kset2, it is latched zero sequence differential protection.
4. a kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction as claimed in claim 3, feature exist
In the locking definite value Kset2Value range be 2~5.
5. a kind of blocking method for preventing balance winding CT broken string from leading to differential malfunction as claimed in claim 3, feature exist
In the zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；The longitudinal difference protection uses net
Side CT, valve side CT constitute poor circuit.
6. a kind of protective device for preventing balance winding CT broken string from leading to differential malfunction, which is characterized in that described device includes adopting
Sample unit, locking judging unit, in which:
The sampling unit acquires the three-phase phase current of the balance winding of series transformer, and note balance winding A phase current is Ia, note
Balance winding B phase current is Ib, note balance winding C phase current is Ic；
The locking judging unit, for calculating separately Ia、Ib、IcWith the amplitude or virtual value ratio of other biphase currents, when appoint
The ratio of any phase current magnitude or virtual value is less than locking definite value in one phase current magnitude or virtual value and other biphase currents
Kset1When, it is latched zero sequence differential protection.
7. a kind of protective device for preventing balance winding CT broken string from leading to differential malfunction as claimed in claim 6, feature exist
In the locking definite value Kset1Value range are as follows: 0.5~0.8.
8. such as a kind of described in any item protective devices for preventing balance winding CT broken string from leading to differential malfunction of claim 6 or 7,
It is characterized in that, the locking judging unit further include: the ratio for calculating zero sequence differential protection difference stream and longitudinal difference protection difference stream, when
The ratio of zero sequence differential protection difference stream and longitudinal difference protection difference stream is greater than locking definite value Kset2, it is latched zero sequence differential protection.
9. a kind of protective device for preventing balance winding CT broken string from leading to differential malfunction as claimed in claim 8, feature exist
In the locking definite value Kset2Value range be 2~5.
10. a kind of protective device for preventing balance winding CT broken string from leading to differential malfunction as claimed in claim 8, feature exist
In the zero sequence differential protection constitutes poor circuit using net side CT, valve side CT, balance winding CT；The longitudinal difference protection uses net
Side CT, valve side CT constitute poor circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811093221.2A CN109119972B (en) | 2018-09-19 | 2018-09-19 | Locking method and device for preventing differential misoperation caused by CT (current transformer) disconnection of balance winding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811093221.2A CN109119972B (en) | 2018-09-19 | 2018-09-19 | Locking method and device for preventing differential misoperation caused by CT (current transformer) disconnection of balance winding |
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| Publication Number | Publication Date |
|---|---|
| CN109119972A true CN109119972A (en) | 2019-01-01 |
| CN109119972B CN109119972B (en) | 2020-03-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811093221.2A Active CN109119972B (en) | 2018-09-19 | 2018-09-19 | Locking method and device for preventing differential misoperation caused by CT (current transformer) disconnection of balance winding |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111521951A (en) * | 2020-04-14 | 2020-08-11 | 南京国电南自电网自动化有限公司 | Method and device for preventing misjudgment of CT (current transformer) broken line caused by grounding fault of control winding side of valve-controlled reactor and storage medium |
| CN116365456A (en) * | 2023-04-03 | 2023-06-30 | 南京国电南自电网自动化有限公司 | Cross-interval protection data anomaly identification and intelligent processing method |
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| CN116365456A (en) * | 2023-04-03 | 2023-06-30 | 南京国电南自电网自动化有限公司 | Cross-interval protection data anomaly identification and intelligent processing method |
| CN116365456B (en) * | 2023-04-03 | 2024-02-09 | 南京国电南自电网自动化有限公司 | Cross-interval protection data anomaly identification and intelligent processing method |
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| CN109119972B (en) | 2020-03-20 |
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