CN107887891B - Preventing ac voltage measurement circuit extremely leads to the virtual AC voltage method of direct current locking - Google Patents
Preventing ac voltage measurement circuit extremely leads to the virtual AC voltage method of direct current locking Download PDFInfo
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- CN107887891B CN107887891B CN201710949072.4A CN201710949072A CN107887891B CN 107887891 B CN107887891 B CN 107887891B CN 201710949072 A CN201710949072 A CN 201710949072A CN 107887891 B CN107887891 B CN 107887891B
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- voltage
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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
- H02H7/268—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 for dc systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
- H02H1/003—Fault detection by injection of an auxiliary voltage
Abstract
The abnormal virtual electricity exchange pressure method for causing direct current to be latched of alternating voltage sampling is prevented the invention discloses a kind of, when judging ac voltage measurement circuit exception, virtual voltage is generated using former normal voltage amplitude and phase and replaces virtual voltage, aberrant continuation cutting system after a certain period of time.This method is applicable in for customary DC and flexible direct current.It can identify and be spaced apart false tripping, be spaced apart the failures such as poor contact.
Description
Technical field
The present invention relates to allocated transmission electro-technical fields, and in particular to one kind, which prevents ac voltage measurement circuit extremely, to be caused directly
Flow the virtual AC voltage method of locking.
Background technique
Customary DC convertor unit based on thyristor and the flexible direct current convertor unit based on wholly-controled devices such as IGBT
Often by capacitance type mutual inductor (CVT) measurement alternating voltage (such as Fig. 1,2), which is sent to DC control by PT terminal box and is protected
Screen, direct current protecting screen, filter protection screen, failure wave-recording screen, AC harmonic monitor screen are controlled in shield screen cabinet, such as pole.Alternating voltage
, generally containing being spaced apart, cause ac voltage measurement circuit disconnected if being spaced apart the reasons such as tripping on PT terminal box and screen cabinet inlet wire in circuit
Line is spaced apart dynamic/static contact poor contact and leads to electric voltage exception, may result in direct-current commutation failure or locking.2013-2014
Between, a lot of control system erroneous judgement commutation failures, which occur, for Xingan's direct current Bao'an converter station causes to protect incorrect response events.Through dividing
Analysis test, PT terminal box are spaced apart the unstable alternating voltage that results in of performance and sample exception.
The general dual of HVDC protection equipment or two from three configuration, the single loop fault of single element do not cause generally
Direct current locking, and for DC control, due to that can not judge that PT broken string (judges what PT broken string needed by being spaced apart auxiliary contact in time
Time is longer, is spaced apart reliability reduction), redundant system is switched to after judging PT broken string, whole process may trip.
A solution is, using being spaced apart with auxiliary contact, will to be spaced apart position signal and be respectively fed to control and protect.
In operational process, auxiliary contact signal is sent into protective device after being spaced apart tripping, is latched related protection (correlation protection does not export)；It is auxiliary
Contact signal is helped to be sent into control device, cutting system.The program can judge to be spaced apart tripping failure, sentence the disadvantage is that being spaced apart auxiliary contact
The disconnected time is longer, and reliability is lower.In addition, the program can only judge to be spaced apart broken string, can not judge to be spaced apart the failures such as poor contact.
Summary of the invention
In view of the deficiencies of the prior art, the purpose of the present invention is to provide one kind to prevent ac voltage measurement circuit from leading extremely
The virtual AC voltage method for causing direct current locking carries out abnormal judgement to ac voltage measurement circuit and adopts remedial measures.
To achieve the goals above, the technical solution adopted by the present invention is that:
A kind of virtual AC voltage method for preventing ac voltage measurement circuit extremely and causing direct current to be latched, feature exist
In, comprising steps of
The ac voltage measurement circuit of direct-flow controlling device on duty and the acquisition of spare direct-flow controlling device and clearing house access
Alternating voltage, judge two sets of ac voltage measurement circuits with the presence or absence of abnormal further according to the otherness of two groups of alternating voltages:
K1=max (| Ua1-Ua2|,|Ub1-Ub2|,|Uc1-Uc2|)<δ1}
Ua1、Ub1、Uc1Indicate the alternating voltage of direct-flow controlling device acquisition on duty, Ua2、Ub2、Uc2Indicate spare DC control
The alternating voltage of device acquisition, δ1For the threshold value of two groups of alternating voltage differences, which is not more than 0.3pu, K1=1 indicates two sets
Ac voltage measurement circuit is without exception, K1=0 indicates that two sets of ac voltage measurement circuits have exception；
Direct-flow controlling device on duty and spare direct-flow controlling device execute the ac voltage measurement circuit accessed respectively
Judge below:
K2=max (| Ua|,|Ub|,|Uc|) < δ2}&&{max(|Ia|,|Ib|,|Ic|) < δ3}
K3=| Ua+Ub+Uc|>δ4}
Ua、Ub、Uc、Ia、Ib、IcRespectively indicate the alternating voltage and alternating current in current ac voltage measurement circuit；δ2For
Judge the threshold value that alternating voltage falls, which is not more than under-voltage protection fixed value adjusting, δ3To judge that alternating current does not occur
Unexpected raised threshold value, the threshold value are adjusted according to current power value and alternating voltage amplitude；K2=1 indicates that current alternating voltage is surveyed
It is abnormal to measure circuit three-phase；δ4For the judgment threshold that ac voltage measurement circuit is single-phase or two-phase is abnormal, K3=1 indicates current exchange
Voltage measurement circuit is single-phase or two-phase is abnormal；
If K1=0, and K2=1 or K3=1, and direct current component incoming breaker is that (only incoming breaker is to close to coincidence
Position, voltage judgement are just significant), then it is abnormal to determine that current ac voltage measurement circuit exists；
When direct current component is in the unlocked state, if spare direct-flow controlling device determines that the ac voltage measurement of its access returns
There is exception in road, then issue alarm；If it is abnormal that direct-flow controlling device on duty determines that the ac voltage measurement circuit of its access exists,
Virtual AC voltage is then generated according to the following formula, using the virtual AC voltage as the alternating voltage at current time:
F indicates power frequency 50Hz, tn+1Indicate current time, ac voltage measurement circuit is determined in the presence of abnormal, t at this timenTable
Show last moment, at this point, ac voltage measurement circuit is no abnormal, tn+1-tn=T, T indicate the sampling period of alternating voltage,Indicate tnThe phase of moment a phase alternating voltage, UA(tn) indicate tnMoment, calculated a phase alternating current was pressed with valid value；Ua
(tn+1) indicate current time calculated a phase alternating voltage virtual value, the calculation method of b phase and c phase alternating voltage virtual value with
A phase is similarly.
Compared with prior art, the beneficial effects of the present invention are:
The present invention generates virtual hand over when judging ac voltage measurement circuit exception, using former normal voltage amplitude and phase
Galvanic electricity pressure replaces virtual voltage, aberrant continuation cutting system after a certain period of time.This method is suitable for customary DC and flexible direct current
With can identify and be spaced apart false tripping, be spaced apart the failures such as poor contact.
Detailed description of the invention
Fig. 1 is the customary DC unit ac voltage measurement circuit diagram of thyristor valves；
Fig. 2 is the flexible direct current unit ac voltage measurement circuit diagram based on converter valve during full control；
Fig. 3 is the logical box that the present invention prevents the abnormal virtual AC voltage method for causing direct current to be latched of alternating voltage sampling
Figure.
Specific embodiment
The present invention is further illustrated With reference to embodiment.
1. ac voltage measurement circuit abnormality mark position judges
By redundancy communication network, current direct-flow controlling device obtains the ac voltage measurement data of another set of flow directing device
(general every set direct-flow controlling device accesses the ac voltage measurement circuit of an absolute coil, if current direct-flow controlling device is
Direct-flow controlling device on duty, then another set of direct-flow controlling device is spare direct-flow controlling device, if current direct-flow controlling device is
Spare direct-flow controlling device, then another set of direct-flow controlling device is direct-flow controlling device on duty), and adopted with this direct-flow controlling device
The alternating voltage of collection compares, and compares the otherness of two groups of alternating voltages:
Therefore K is defined1For ac voltage measurement circuit abnormality mark position:
K1={ max (Ua1-Ua2,Ub1-Ub2,Uc1-Uc2) < δ 1
δ1For the threshold value of alternating voltage difference, 0.3pu should not exceed, recommend value 0.1pu.K1=1 indicate measurement circuit without
It is abnormal, K1=0 to indicate that ac voltage measurement circuit exists abnormal, but can not judge be direct-flow controlling device access on duty exchange
The ac voltage measurement circuit of voltage measurement circuit exception or the access of spare direct-flow controlling device is abnormal.
2. ac voltage measurement circuit judges extremely
(1) three-phase judges extremely
If exception occurs in ac voltage measurement circuit three-phase, alternating voltage is reduced to smaller value, but alternating current without
It significantly increases, therefore can be using the following conditions as criterion:
max(|Ua|, | Ub|, | Uc|) < δ 2&&max (| Ia|, | Ib|, | Ic|) < δ 3
Ua、Ub、Uc、Ia、Ib、IcRespectively indicate the alternating voltage and alternating current in current ac voltage measurement circuit；δ2For
Judge the threshold value that three-phase alternating voltage falls, be not more than under-voltage protection fixed value adjusting, recommends value 0.3pu；δ3It can be according to working as
Preceding power and the adjusting of alternating voltage amplitude, consider overload, should be greater than 1.2 times of calculated value, can use 1.3pu.
Define K2For ac voltage measurement circuit three-phase abnormality mark position.
K2=max (| Ua1|,|Ub1|,|Uc1|) < δ2}&&{max(|Ia1|,|Ib1|,|Ic1|) < δ3}
K2=1 indicates that ac voltage measurement is low, but alternating current does not increase suddenly, indicates that three-phase measures loop fault, such as
The three-phase of isolation is spaced apart disparate normal tripping on circuit.
(2) single-phase or two-phase judges extremely
When ac voltage measurement circuit is single-phase or two-phase is abnormal, | Ua+Ub+Uc| > δ4。
Define K3For single-phase or abnormal two-phase flag bit, then have:
K3=| Ua1+Ub1+Uc1|>δ4}
δ4For the judgment threshold that alternating voltage is single-phase or two-phase is abnormal, K3=1 indicates that ac voltage measurement circuit is single-phase or two
It is mutually abnormal, it is spaced apart disconnection Ru single-phase.When K3 should escape direct current component incoming breaker divide-shut brake caused by open-phase operation in short-term
Residual voltage, δ4Desirable 0.5pu.
In addition, ac voltage measurement circuit is abnormal only significant when direct current component incoming breaker is coincidence,
As shown in figure 3, if K1=1, and K2=1 or K3=1, and direct current component incoming breaker is coincidence, then determines current
Ac voltage measurement circuit exists abnormal.
3. virtual AC voltage generates
Direct-flow controlling device generally has phaselocked loop, and exchange is calculated after can filtering according to the three-phase alternating voltage of acquisition
Voltage effective value U and phase(only consider periodic component, therefore default f=50HZ) calculates virtual further according to sampling period T
Alternating voltage and the alternating voltage that it is regarded to next sampling period.
Specifically, when direct current component is in the unlocked state, if spare direct-flow controlling device determines the exchange of its access
There is exception in voltage measurement circuit, then issue alarm；If direct-flow controlling device on duty determines that the ac voltage measurement of its access returns
There is exception in road, then virtual AC voltage is generated according to the following formula, using the virtual AC voltage as the alternating voltage at current time
(by taking a phase as an example, b phase is analogized with c phase):
F indicates power frequency 50Hz, tn+1Indicate current time, ac voltage measurement circuit is determined in the presence of abnormal, t at this timenTable
Show last moment, at this point, ac voltage measurement circuit is no abnormal, tn+1-tn=T, T indicate the sampling period of alternating voltage,Indicate tnThe phase of moment a phase alternating voltage, UA(tn) indicate tnMoment calculated a phase alternating current be pressed with valid value (Not according to tnOne moment calculates, but is calculated according to preamble multiple moment by low-pass filtering)；Ua(tn+1) table
Show a phase alternating voltage virtual value at current time.
4. system switches
(adjusting as needed) if whithin a period of time, direct-flow controlling device on duty persistently judges the alternating current of its access
There is exception in pressure measurement circuit, then direct-flow controlling device on duty is cut OFF, spare direct-flow controlling device switches to state on duty.
5. overall logic
Fig. 3 is general logical block diagram, it can be seen that this method selects the virtual AC voltage of upper period generation to replace
The alternating voltage in this period, and if only if detect ac voltage measurement exception, and direct current component incoming breaker be in coincidence,
It just comes into force when direct current component is in the unlocked state, this control device is in state on duty.
Above-listed detailed description is illustrating for possible embodiments of the present invention, and the embodiment is not to limit this hair
Bright the scope of the patents, all equivalence enforcements or change without departing from carried out by the present invention, is intended to be limited solely by the scope of the patents of this case.
Claims (3)
1. a kind of virtual AC voltage method for preventing ac voltage measurement circuit extremely and causing direct current to be latched, which is characterized in that
Comprising steps of
The friendship in the ac voltage measurement circuit of direct-flow controlling device on duty and the acquisition of spare direct-flow controlling device and clearing house access
Galvanic electricity pressure judges two sets of ac voltage measurement circuits with the presence or absence of abnormal further according to the otherness of two groups of alternating voltages:
K1=max (| Ua1-Ua2|,|Ub1-Ub2|,|Uc1-Uc2|)<δ1}
Ua1、Ub1、Uc1Indicate the alternating voltage of direct-flow controlling device acquisition on duty, Ua2、Ub2、Uc2Indicate spare direct-flow controlling device
The alternating voltage of acquisition, δ1For two groups of alternating voltage deviation thresholds；K1=1 indicates that two sets of ac voltage measurement circuits are without exception,
K1=0 indicates that two sets of ac voltage measurement circuits have exception；
Direct-flow controlling device on duty and spare direct-flow controlling device execute the ac voltage measurement circuit accessed following respectively
Judgement:
K2=max (| Ua|,|Ub|,|Uc|) < δ2}&&{max(|Ia|,|Ib|,|Ic|) < δ3}
K3=| Ua+Ub+Uc|>δ4}
Ua、Ub、Uc、Ia、Ib、IcRespectively indicate the alternating voltage and alternating current in current ac voltage measurement circuit；δ2It is handed over for judgement
The threshold value of Voltage Drop is flowed, which is not more than under-voltage protection fixed value adjusting, δ3To judge that rising suddenly does not occur in alternating current
High threshold value, the threshold value are adjusted according to current power value and alternating voltage amplitude；K2=1 indicates current ac voltage measurement circuit
Three-phase is abnormal；δ4For the judgment threshold that ac voltage measurement circuit is single-phase or two-phase is abnormal, K3=1 indicates that current alternating voltage is surveyed
Amount circuit is single-phase or two-phase is abnormal；
If K1=0, K2=1 or K3=1, and direct current component incoming breaker is coincidence, then determines current ac voltage measurement circuit
There are exceptions；
When direct current component is in the unlocked state, if spare direct-flow controlling device determines that the ac voltage measurement circuit of its access is deposited
In exception, then alarm is issued；If it is abnormal that direct-flow controlling device on duty determines that the ac voltage measurement circuit of its access exists, press
Virtual AC voltage is generated according to following formula, using the virtual AC voltage as the alternating voltage at current time:
F indicates power frequency 50Hz, tn+1Indicate current time, ac voltage measurement circuit is determined in the presence of abnormal, t at this timenIn expression
One moment, at this point, ac voltage measurement circuit is no abnormal, tn+1-tn=T, T indicate the sampling period of alternating voltage,Table
Show tnThe phase of moment a phase alternating voltage, UA(tn) indicate tnMoment, calculated a phase alternating current was pressed with valid value；Ua(tn+1) indicate
The calculation method of current time calculated a phase alternating voltage virtual value, b phase and c phase alternating voltage virtual value with a phase similarly.
2. the virtual AC voltage side according to claim 1 for preventing ac voltage measurement circuit extremely and causing direct current to be latched
Method, which is characterized in that further comprise the steps of:
If it is abnormal that direct-flow controlling device on duty persistently determines that the ac voltage measurement circuit of its access exists in the given time,
Application status switching, direct-flow controlling device on duty switch to shutdown status, and spare direct-flow controlling device switches to state on duty.
3. the virtual AC voltage side according to claim 1 for preventing ac voltage measurement circuit extremely and causing direct current to be latched
Method, which is characterized in that
δ1Value 0.1pu；δ2Value 0.3pu, δ3Take 1.3pu, δ4Take 0.5pu.
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| KR101324744B1 (en) * | 2012-09-13 | 2013-11-05 | 부산대학교 산학협력단 | Apparatus for detectiing open-switch fault in the three-phase npc ac/dc converter |
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2017
- 2017-10-12 CN CN201710949072.4A patent/CN107887891B/en active Active
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|---|---|---|---|---|
| US8278934B2 (en) * | 2009-02-13 | 2012-10-02 | Bae Systems Controls Inc. | Robust AC chassis fault detection using PWM sideband harmonics |
| KR101324744B1 (en) * | 2012-09-13 | 2013-11-05 | 부산대학교 산학협력단 | Apparatus for detectiing open-switch fault in the three-phase npc ac/dc converter |
| CN106877698A (en) * | 2015-12-10 | 2017-06-20 | 特变电工新疆新能源股份有限公司 | A kind of flexible direct current power transmission system topological structure |
| CN105655879A (en) * | 2016-01-19 | 2016-06-08 | 国网福建省电力有限公司泉州供电公司 | Voltage arranging mode of bus merging unit double configuration of 110 kV system in intelligent substation double-bus wiring mode |
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| Title |
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