CN102231570A - Control protection system and method of flexible AC transmission device - Google Patents

Control protection system and method of flexible AC transmission device Download PDF

Info

Publication number
CN102231570A
CN102231570A CN2011101923049A CN201110192304A CN102231570A CN 102231570 A CN102231570 A CN 102231570A CN 2011101923049 A CN2011101923049 A CN 2011101923049A CN 201110192304 A CN201110192304 A CN 201110192304A CN 102231570 A CN102231570 A CN 102231570A
Authority
CN
China
Prior art keywords
current
electrical quantities
measurement signal
respectively measuring
signal respectively
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN2011101923049A
Other languages
Chinese (zh)
Other versions
CN102231570B (en
Inventor
戴朝波
金雪芬
刘慧文
王宇红
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China Electric Power Research Institute Co Ltd CEPRI
China EPRI Science and Technology Co Ltd
Original Assignee
China Electric Power Research Institute Co Ltd CEPRI
China EPRI Science and Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by China Electric Power Research Institute Co Ltd CEPRI, China EPRI Science and Technology Co Ltd filed Critical China Electric Power Research Institute Co Ltd CEPRI
Priority to CN2011101923049A priority Critical patent/CN102231570B/en
Publication of CN102231570A publication Critical patent/CN102231570A/en
Application granted granted Critical
Publication of CN102231570B publication Critical patent/CN102231570B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/70—Smart grids as climate change mitigation technology in the energy generation sector
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/20—Systems supporting electrical power generation, transmission or distribution using protection elements, arrangements or systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/22—Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units

Landscapes

  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)

Abstract

The invention, which relates to the control protection field of the flexible AC transmission device, discloses a control protection system and a method of a flexible AC transmission device. The control protection system comprises a data acquisition device and a control protection device. The data acquisition device is used for collecting a signal of one-time electric quantity measurement of each measurement CT and transmitting the measuring signal to the control protection device. The control protection device is used for determining whether the signal of the one-time electric quantity measurement of the each measurement CT satisfies the Kirchhoff's current law; if so, the measuring signal is used as a credible one to complete the protection treatment of primary equipment of the flexible AC transmission device. According to the disclosed control protection system and the method based on the Kirchhoff's current law (KCL), the reliability of a control protection function of a series compensation apparatus/a fault current limiter apparatus can be improved, and the unnecessary withdrawal from operation of the series compensation apparatus can be prevented, wherein the unnecessary withdrawal from operation is caused by misoperation of protection of the series compensation apparatus.

Description

The control protection system and the method for flexible AC transmission equipment
Technical field
The present invention relates to the control protection field of flexible AC transmission equipment, relate in particular to the control protection system of flexible AC transmission equipment and the control protection system and the method for method.
Background technology
The series capacitor compensation technology of AC transmission system (being called for short string mends) is that power capacitor is series in the transmission line of alternation current, the part emotional resistance of compensation transmission line of alternation current, thus reach purposes such as increasing circuit transmission capacity, the raising stability of a system, the network loss that reduces, saving investment.In remote, large capacity transmission system, increase along with transmission distance, its conveying capacity is subjected to increasing restriction, and the string benefit is to address this problem, improve the ultra-high/extra-high voltage transmission line to send one of important means of electric energy power, have very huge economic, in the electric power system of countries in the world, received at present widely and used.
Thyristor controlled series capacitor compensation arrangement (abbreviation controlled series compensation) is regulated the equivalent impedance of fundamental frequency of controlled series compensation by the trigger angle that changes thyristor, realization is to the dynamic control of equivalent impedance of fundamental frequency, thereby can further improve stability of power system, increase the transmission capacity of transmission line, suppress low-frequency oscillation of electric power system and subsynchronous resonance.When the ultra-high/extra-high voltage transmission line was short-circuited fault, controlled series compensation changed thyristor bypass series capacitor pattern immediately over to, can reduce the short circuit current of system, improved the stability of electric power system.
Developing rapidly of electric power system, the load in unit and station capacity, substation capacity, city and the center of industry and the continuation of load density increase, and interconnected between the electric power system, cause the short circuit current level in the modern large power system electrical networks at different levels constantly to increase.Short circuit current exceeds standard becomes one of major issue that threatens the modern power systems safe operation.Except that changing electric network composition, series resonance-type fault current limiter device is to solve short circuit current the exceed standard new approaches and the new way of problem.2009, at East China Power Grid 500kV bottle kiln electric substation hanging net operation, this device was in the stage of applying to superhigh pressure fault current limiter device.
Fixed series capacitors compensation arrangement, thyristor controlled series capacitor compensation arrangement, series resonance-type fault current limiter device etc. all have the control protection system.Control mainly the acting as of protection system: detect in service various to installing disadvantageous failure condition, the relevant protection of correct operation, isolated fault timely and accurately, the safe and stable operation of assurance device, and cooperate route protection to come miscellaneous equipment in the protection system.In addition, the control protection system also have electrical quantities measurement and gather, functions such as monitoring running state, record ripple, man-machine interaction.In the station, should be able to realize supervision and control to all key equipment states such as bypass breaker, isolating switch, ground connection disconnecting links, should be able to be in dispatching office by the supervision of telecontrol equipment realization to key equipment state.
At present, the control protection system that string is mended device overlaps independently by two that system forms usually, and the configuration of two cover systems is identical, independently measures separately, data acquisition and control and protect.When a cover system need overhaul or because other reasons when out of service, what another set of system still can be stable works on, guarantee that string mends the normal operation of device.Two Redundant Control protection system outlet logic one generally be or relation, as long as one of them system satisfies the corresponding action condition, protection will trigger.
At present, the possibility of the protection malfunction of control protection system is bigger.
Summary of the invention
In view of this, the technical problem that the present invention will solve provides a kind of control protection system of flexible AC transmission equipment, can improve the reliability of control defencive function.
According to an aspect of the present invention, a kind of control protection system of flexible AC transmission equipment is provided, described control protection system comprises data acquisition unit, control protective device, described data acquisition unit is collected an electrical quantities measurement signal respectively measuring CT, and a described electrical quantities measurement signal respectively measuring CT is sent to described control protective device; Described control protective device judges whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); if a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), then the protection that a described electrical quantities measurement signal respectively measuring CT is finished described flexible AC transmission equipment primary equipment as believable measuring-signal is handled.
An embodiment of system according to the invention, described data acquisition unit is collected string and is mended a described electrical quantities measurement signal respectively measuring CT that is provided with in device or the fault current limiter; Described string is mended in device or the fault current limiter bypass breaker is set; Described control protective device receives the state information of described bypass breaker break-make; judge in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); if a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), then the protection that a described electrical quantities measurement signal respectively measuring CT is finished described flexible AC transmission equipment primary equipment as believable measuring-signal is handled.
An embodiment of system according to the invention, described control protective device comprises data summarization unit, judging unit, protected location; Wherein, described data summarization unit, be used to receive from described data acquisition unit described and respectively measure the electrical quantities measurement signal of CT and the state information of bypass breaker break-make, respectively measure electrical quantities measurement signal of CT and the state information of bypass breaker break-make sends to described judging unit described; Described judging unit, be used to receive the state information of bypass breaker break-make, judge in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), if satisfy, then a described electrical quantities measurement signal respectively measuring CT sent to described protected location; Described protected location receives a described electrical quantities measurement signal respectively measuring CT, according to described electrical quantities measurement signal execute protection algorithm and the control strategy of respectively measuring CT, output protection action command.
The string benefit circuit that an embodiment of system according to the invention, described string mend in device or the fault current limiter is provided with capacitor and the metal oxide pressure-limiting device MOV in parallel with described capacitor; In the device main circuit that comprises described metal oxide pressure-limiting device MOV and capacitor etc., select electric current to converge node A, described judging unit judges in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), be specially: when described bypass breaker is in open mode, whether described judgment unit judges all flow into the absolute value of algebraical sum of electric current that described electric current converges node A less than δ, and duration T; Wherein, δ, T are threshold value.
An embodiment of system according to the invention; when bypass breaker is in closure state; then described judging unit does not carry out the signal true and false and judges; a described electrical quantities measurement signal respectively measuring CT is sent to described protected location, and described protection is single uses described electrical quantities measurement signal execute protection algorithm and the control strategy of respectively measuring CT.
An embodiment of system according to the invention, a described electrical quantities measurement signal packet vinculum road current i respectively measuring CT 1ine, the platform current i Pf, condenser current i c, MOV branch current i MOV1And i MOV2, the GAP current i GAP Described judging unit judges in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), be specially: if bypass breaker is in open mode, whether described judgment unit judges satisfies:
| i Line+ i Pf+ i c+ i MOV1+ i MOV2+ i GAP|＜δ, and duration T;
Wherein, described line current i 1ine, the platform current i Pf, condenser current i c, MOV branch current i MOV1And i MOV2, the GAP current i GAPAll electric currents that converge node A for inflow current.
An embodiment of system according to the invention, when bypass breaker is in open mode, when
Figure BDA0000074819230000041
And during lasting long period T1 (escaping single-pole reclosing), the measurement CT of then described judgment unit judges line current and the measurement CT of capacitor are unusual; Perhaps, when bypass breaker is in open mode, the platform current i Pf=0, MOV branch current i MOV1=0, i MOV2=0, the GAP current i GAP=0, and
Figure BDA0000074819230000042
And during lasting short period T2, the measurement CT of the described circuit of then described judgment unit judges and the measurement CT of described capacitor are unusual;
Wherein, described
Figure BDA0000074819230000043
For the electric current of circuit, described Be the electric current on the capacitor, ζ, T1, T2 are judgment threshold, and described
Figure BDA0000074819230000045
The platform current i Pf, MOV branch current i MOV1And i MOV2, the GAP current i GAPAll electric currents that converge node A for inflow current.
An embodiment of system according to the invention, described judging unit is deployed in the described protected location, and perhaps described judging unit is deployed in the described data summarization unit.
System of the present invention adopts Kirchhoff's current law (KCL) to judge to the current signal of measuring CT, has effectively prevented the generation of protection misoperation.
Another technical problem that the present invention will solve provides the control guard method of flexible AC transmission equipment, can improve the reliability of control defencive function.
According to an aspect of the present invention, provide a kind of control guard method of flexible AC transmission equipment, collect an electrical quantities measurement signal respectively measuring CT; Judge whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); if a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), then the protection that a described electrical quantities measurement signal respectively measuring CT is finished described flexible AC transmission equipment primary equipment as believable measuring-signal is handled.
According to an embodiment of the inventive method, collect string and mend a described electrical quantities measurement signal respectively measuring CT that is provided with in device or the fault current limiter; Described string is mended in device or the fault current limiter bypass breaker is set; Receive the state information of described bypass breaker break-make; judge in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); if a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), then the protection that a described electrical quantities measurement signal respectively measuring CT is finished described flexible AC transmission equipment primary equipment as believable measuring-signal is handled.
The string benefit circuit that an embodiment of system according to the invention, described string mend in device or the fault current limiter is provided with capacitor and the metal oxide pressure-limiting device MOV in parallel with described capacitor; Comprise described metal oxide pressure-limiting device MOV and capacitor etc. the device main circuit in select electric current to converge node A, described judging unit judges in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), be specially: when described bypass breaker is in open mode, whether described judgment unit judges all flow into the absolute value of algebraical sum of electric current that described electric current converges node A less than δ, and duration T; Wherein, δ, T are threshold value.
An embodiment of system according to the invention, when bypass breaker is in open mode, when
Figure BDA0000074819230000051
And during lasting long period T1 (escaping single-pole reclosing), the measurement CT of then described judgment unit judges line current and the measurement CT of capacitor are unusual; Perhaps, when bypass breaker is in open mode, the platform current i Pf=0, MOV branch current i MOV1=0, i MOV2=0, the GAP current i GAP=0, and And during lasting short period T2, the measurement CT of the described circuit of then described judgment unit judges and the measurement CT of described capacitor are unusual; Wherein, described
Figure BDA0000074819230000053
For the electric current of circuit, described
Figure BDA0000074819230000054
Be the electric current on the capacitor, ζ, T1, T2 are judgment threshold, and described
Figure BDA0000074819230000055
The platform current i Pf, MOV branch current i MOV1And i MOV2, the GAP current i GAPAll electric currents that converge node A for inflow current.
According to an embodiment of the inventive method, described string is mended device or fault current limiter comprises: fixed series capacitors compensation arrangement, thyristor controlled series capacitor compensation arrangement, series resonance-type fault current limiter device.
The inventive method adopts the KCL law to judge to the current signal of measuring CT, has effectively prevented the generation of protection misoperation.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, to do one to the accompanying drawing of required use in embodiment or the description of the Prior Art below introduces simply, apparently, accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the schematic diagram that the string of one embodiment of the invention is mended control protection system in the device;
Fig. 2 A is the schematic diagram of the control protection system of one embodiment of the invention;
Fig. 2 B is the schematic diagram of another control protection system of one embodiment of the invention;
Fig. 2 C is the schematic diagram of another control protection system of one embodiment of the invention;
Fig. 3 is the single-phase schematic diagram of the fixed series compensation of one embodiment of the present of invention;
Fig. 4 is the flow chart according to an embodiment of the control guard method of flexible AC transmission equipment of the present invention;
Fig. 5 is the flow chart that carries out the embodiment of KCL judgement in the control guard method according to flexible AC transmission equipment of the present invention;
Fig. 6 is the flow chart that carries out another embodiment of KCL judgement in the control guard method according to flexible AC transmission equipment of the present invention;
Fig. 7 is the flow chart that carries out another embodiment of KCL judgement in the control guard method according to flexible AC transmission equipment of the present invention;
Embodiment
With reference to the accompanying drawings the present invention is described more fully, exemplary embodiment of the present invention wherein is described.Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.
According to one embodiment of present invention; for CT is measured in the installing of current delivery equipment; the measuring-signal of measuring CT is judged by Kirchhoff's current law (KCL) KCL; if measuring-signal satisfies the KCL law; then measuring-signal is used for follow-up protection control as credible measuring-signal; guarantee the reliability of measuring-signal as far as possible, prevent to control the protection system malfunction, improve the reliability of control protection system.
Below in conjunction with each figure and embodiment technical scheme of the present invention is carried out many-sided description.
Fig. 1 is the schematic diagram that the string of one embodiment of the invention is mended control protection system in the device.String is mended configuration control protection system system 12 in the device, also can independently measure protection system system 12 redundant configuration control system, 13, two cover control protection system independent operatings, data acquisition and control protects.With system 12 is example, and data acquisition unit 121 is measured the CT11 acquired signal from each, and each electrical quantities measurement signal measuring CT is sent to control protective device 122; Control protective device 122 judges whether an electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); satisfy Kirchhoff's current law (KCL) if respectively measure the electrical quantities measurement signal of CT, an electrical quantities measurement signal then each being measured CT is finished the protection processing of flexible AC transmission equipment primary equipment as believable measuring-signal.If judge when fault is arranged, 122 pairs of circuit breakers of control protective device/switch operation mechanism 14 sends relevant protection action command, as triggering GAP15, closing bypass breaker 16, DD17, GD18 etc.
According to one embodiment of present invention, data acquisition unit 121 is collected string and is mended an electrical quantities measurement signal respectively measuring CT11 that is provided with in device or the fault current limiter; String is mended in device or the fault current limiter bypass breaker is set; Control protective device 122 receives the state information of bypass breaker break-make; judge in conjunction with the state information of bypass breaker break-make whether an electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); satisfy Kirchhoff's current law (KCL) if respectively measure the electrical quantities measurement signal of CT, an electrical quantities measurement signal then each being measured CT is finished the protection processing of flexible AC transmission equipment primary equipment as believable measuring-signal.
The current signal of measuring CT is judged by the KCL theorem, carried out corresponding primary equipment protection calculating again, thereby effectively prevent the generation of misoperation.
Fig. 2 A is the schematic diagram for the control protection system of one embodiment of the invention.Data acquisition unit 22 is from measuring CT21....; acquired signal among the n; convert light signal to and send to control protective device 23; 23 pairs of these digital signals of control protective device are carried out KCL and are judged; with judging the protection algorithm that comes the finishing device primary equipment for genuine signal; monitor relevant switching value information simultaneously, when the system failure or plant failure, provide relevant protection action command.
According to one embodiment of present invention, data acquisition unit 22 comprises: EMI filter 221, and the transmission that is used on the filtering measurement CT transmission line is disturbed; Signal condition unit 222 is used for current signal is adjusted, and makes its demand that satisfies A/D unit 223, also plays the effect that realizes once more electrical isolation simultaneously; A/D unit 223 is used for received signal with analog signal and be converted to digital signal, imports control protective device 23 into by light path.
According to one embodiment of present invention, data summarization unit 231 receiving optical signals change into the signal of telecommunication with it, and therefrom parse sampled data, and the measuring-signal that will measure CT by predetermined data format sends to judging unit 234 then; Judging unit 234 obtains bypass breaker position signalling S BCB, bypass breaker position signalling S BCBExpression on off operating mode (for example, value is 0 or 1).Judging unit 234 judges in conjunction with the state information of bypass breaker break-make whether an electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), satisfy Kirchhoff's current law (KCL) if respectively measure the electrical quantities measurement signal of CT, measuring-signal is sent to protected location 235; Protected location 235 receives believable measuring-signal, execute protection algorithm and control strategy, output protection action command.
According to one embodiment of present invention, selectable, judging unit 234 can obtain bypass breaker position signalling S BCB, and judge in conjunction with the state information of bypass breaker break-make whether an electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL).
According to one embodiment of present invention, control protective device 23 can also comprise wave record playback unit 232, under fault or situation about manually booting, and record current demand signal amount and switching signal amount, and realize playback to history record ripple file or self-defined file; Communications management unit 233 is finished information interaction, and with the information interaction of device such as background monitoring and information remote transmitting interface, function when issuing guidance command, school.
Fig. 2 B is the schematic diagram for another control protection system of one embodiment of the invention.As shown in the figure, alternatively, judging unit 234 is deployed in the data summarization unit 231, and data summarization unit 231 can be obtained bypass breaker position signalling S BCB, judging unit 234 gathers the electrical quantities measurement signal respectively measuring CT that unit 231 receives in conjunction with the state information judgment data of bypass breaker break-make and whether satisfies Kirchhoff's current law (KCL).
Fig. 2 C is the schematic diagram for another control protection system of one embodiment of the invention.As shown in the figure, alternatively, judging unit 234 is deployed in the protected location 235, and protected location 235 can obtain bypass breaker position signalling S BCB, judging unit 234 judges in conjunction with the state information of bypass breaker break-make whether the electrical quantities measurement signal respectively measuring CT from data summarization unit 231 satisfies Kirchhoff's current law (KCL).
Fig. 3 is the single-phase schematic diagram of the fixed series compensation of one embodiment of the present of invention, below in conjunction with Fig. 3, judging unit 234 is judged whether an electrical quantities measurement signal respectively measuring CT satisfies the Kirchhoff's current law (KCL) detailed description of making comparisons.
Only adopting the fixed series capacitors compensation arrangement of single H bridge type wiring with capacitor herein is example, and this string is mended each main equipment of device and all install and measure CT except that bypass breaker; As shown in Figure 3, the damping circuit 33, platform 34, capacitor 35, the bus 36 that comprise bypass breaker 31, spark gap 32 in the power circuit system, form by resistance R 331 and MOV332, dispose on the line and measure CT1-7, be used for the current value on the different circuits in the measuring system respectively, wherein, the MOV branch road comprises MOVA and MOVB.The capacitor two ends that the string of string benefit device or fault current limiter is mended in the circuit are respectively high potential and electronegative potential, all measurement CT are installed in low potential side, select electric current to converge node A at the low potential side that string is mended in the circuit, make the electric current of measurement CT of the electric current of measurement CT of capacitor and metal oxide pressure-limiting device MOV can flow into described node A.
According to Kirchhoff's current law (KCL), " in lumped-circuit, in any moment, to arbitrary node, all flow into the algebraical sum identically vanishing of the branch current of node ".
For node A, line current i 1ine, the platform current i Pf, condenser current i c, the MOV current i MOV1And i MOV2, the GAP current i GAP, the bypass breaker current i BCBSum is zero.That is:
i line+i pf+i c+i MOV1+i MOV2+i GAP+i BCB＝0 (1)
Because measure the difference of CT measure error, modulate circuit, the factors such as error of AD conversion, following formula can not equal zero on the stricti jurise, approaches zero value but should be one, and in certain scope δ.Formula (1) is in practice
|i line+i pf+i c+i MOV1+i MOV2+i GAP+i BCB|＜δ (2)
According to formula (2) signal value of each sampling instant is carried out pointwise and calculates, can according to experimental data or in the past the corresponding recorder data of engineering choose suitable δ, and lasting regular hour T is to prevent erroneous judgement.
Because bypass breaker does not does not install and measure CT, can't record i BCB, and the folding condition of bypass breaker is available, so in criterion, introduce bypass breaker mode bit S BCB(S BCB=0 expression bypass breaker is in open mode, S BCB=1 expression bypass breaker is in closure state), S BCB=0 o'clock, bypass breaker current i just BCB=0 o'clock, employing formula (2) was carried out the judgement of the signal true and false, is fashionable at the bypass breaker state, did not carry out the signal true and false and judged.
In addition, when the string revisal often moves, have only circuit and capacitor to flow through electric current, concerning node A, phasor satisfies
I · line + I · c - - - ( 3 )
Same, following formula can not equal zero on the stricti jurise, approaches zero value but also should be one, and in certain scope ζ.Formula (3) is in practice:
| I · line + I · c | > ζ - - - ( 4 )
Owing to calculate the algorithm of power frequency component itself certain anti-interference is arranged, therefore, desirable relatively littler of deviation ζ, and can be with judging that the duration extend, so that escape the single-pole reclosing time; Perhaps combine, select the shorter duration with other branch currents.This criterion only is used to judge that line current is measured CT and whether condenser current CT is unusual, is not used in the rejecting misdata.
Sum up above-mentioned judgement, can draw:
1, S BCB=0 and | i Line+ i Pf+ i c+ i MOV1+ i MOV2+ i GAP|＜δ, duration T, promptly work as bypass breaker and be in open mode, and all are flowed into the absolute value of electric current algebraic value summation of node A less than δ, and duration T, then judge described measuring-signal as believable measuring-signal, use described measuring-signal execute protection algorithm and control strategy, otherwise signal is deleted;
2, work as S BCB=0, and the string revisal is when often moving, and the electric current on the circuit is
Figure BDA0000074819230000103
Electric current on the described capacitor is
Figure BDA0000074819230000104
And And lasting long period T (as 1s);
Perhaps work as S BCB=0, and the string revisal has only on capacitor and the circuit electric current is arranged, be i.e. i when often moving Pf=0, i MOV1=0, i MOV2=0, i GAP=0, judge this moment
Figure BDA0000074819230000106
And lasting short period T judges that line current is measured CT and condenser current CT is unusual, sends line current and measures CT and condenser current CT abnormality alarming signal.
3, work as S BCB=1 o'clock, then do not carry out the signal true and false and judge, directly signal arrangement back is sent to protected location by the agreement of making an appointment, the protection algorithm of finishing device primary equipment.
In the criterion, the value of δ, ζ, T is chosen according to the recorder data of experimental data or former engineering in the above.
In the foregoing description; judge by measuring-signal being carried out the KCL theorem; the measuring-signal that satisfies the consistency judgement is used for follow-up protection to be handled; can reduce the possibility of MOV current protection and MOV unbalance protection generation malfunction, thereby improve the reliability that string is mended the control defencive function of device/fault current limiter device.
Fig. 4 is the flow chart according to an embodiment of the control guard method of flexible AC transmission equipment of the present invention.As shown in Figure 4, step 402 is collected the measuring-signal of measuring CT;
Step 403, the measuring-signal of measuring CT adopts Kirchhoff's current law (KCL) to judge;
Step 404 is judged if measuring-signal satisfies Kirchhoff's current law (KCL), then measuring-signal is handled as believable measuring-signal.
Judge measuring-signal by the use Kirchhoff's current law (KCL), and will judge that believable measuring-signal is used for follow-up protection and handles, can reduce the possibility of MOV current protection and MOV unbalance protection generation malfunction.
According to one embodiment of present invention, string is mended in device or the fault current limiter bypass breaker is set; According to the state of described bypass breaker break-make, adopt Kirchhoff's current law (KCL) to judge whether the measuring-signal of measuring CT is believable measuring-signal.
Fig. 5 is the flow chart according to an embodiment of the control guard method of flexible AC transmission equipment of the present invention.The string benefit circuit that string is mended in device or the fault current limiter is provided with capacitor and the metal oxide pressure-limiting device MOV in parallel with capacitor;
Step 502, the state of judgement bypass breaker break-make;
If bypass breaker is an open mode, then execution in step 503, select electric current to converge node A, wherein in comprising the device main circuit of metal oxide pressure-limiting device MOV and capacitor, select the A node, and make the electric current of measurement CT of the electric current of measurement CT of capacitor and metal oxide pressure-limiting device MOV can flow into described node A;
Step 504 flows into the electric current algebraic value summation of node A to all;
Step 505, the absolute value of summed result is less than δ, and duration T, then judges measuring-signal as believable measuring-signal, and wherein, δ, T are judgment threshold;
Step 506 is used measuring-signal execute protection algorithm and control strategy, otherwise signal is deleted
An embodiment in according to the present invention, when bypass breaker is in closure state, then execution in step 507, do not carry out the signal true and false and judge, use measuring-signal execute protection algorithm and control strategy.
Fig. 6 is another embodiment according to the control guard method of flexible AC transmission equipment of the present invention.The string benefit circuit that string is mended in device or the fault current limiter is provided with capacitor.
Step 602, bypass breaker is in open mode, and
Figure BDA0000074819230000121
And duration T 1; Be the electric current of circuit,
Figure BDA0000074819230000123
Be the electric current on the capacitor, ζ, T1 are judgment threshold;
Step 603, the measurement CT of judgement circuit and the measurement CT of capacitor are unusual;
Fig. 7 is another embodiment according to the control guard method of flexible AC transmission equipment of the present invention.The string benefit circuit that string is mended in device or the fault current limiter is provided with capacitor.
Step 702, bypass breaker is in open mode, and the string revisal often move, have only capacitor and with circuit on electric current is arranged, and
Figure BDA0000074819230000124
And duration T 1;
Figure BDA0000074819230000125
Be line current,
Figure BDA0000074819230000126
Be the electric current on the capacitor, ζ, T2 are judgment threshold;
Step 703, the measurement CT of judgement circuit and the measurement CT of capacitor are unusual;
According to one embodiment of present invention, establish
Figure BDA0000074819230000127
Be line current,
Figure BDA0000074819230000128
Be the electric current on the capacitor, ζ, T1, T2 are judgment threshold,
Figure BDA0000074819230000129
The platform current i Pf, MOV branch current i MOV1And i MOV2, the GAP current i GAPAll electric currents that converge node A for inflow current.
When bypass breaker is in open mode, i Pf=0, i MOV1=0, i MOV2=0, i GAP=0, and
Figure BDA00000748192300001210
And during duration T 2, judge that then the measurement CT of the measurement CT of circuit and capacitor is unusual.
According to one embodiment of present invention, wherein T1 can be for bigger value, and as 1S, T2 can select less value for use.
Embodiment from above as can be seen, embodiments of the invention adopt the KCL theorem to judge to the current signal of measuring CT, weed out rub-out signal, carry out corresponding protection again and calculate, thereby improved the reliability that string is mended the control defencive function of device/fault current limiter device; Improve the environment tolerance of measuring system indirectly, guaranteed the stability of measuring system and the reliability of image data; And can prevent to go here and there and mend unnecessary out of service of device that the unit protection misoperation causes, thereby significantly improve the availability factor and the utilance of package unit.
Description of the invention provides for example with for the purpose of describing, and is not exhaustively or limit the invention to disclosed form.Many modifications and variations are obvious for the ordinary skill in the art.Selecting and describing embodiment is for better explanation principle of the present invention and practical application, thereby and makes those of ordinary skill in the art can understand the various embodiment that have various modifications that the present invention's design is suitable for special-purpose.

Claims (13)

1. the control protection system of a flexible AC transmission equipment, described control protection system comprise data acquisition unit, control protective device, it is characterized in that:
Described data acquisition unit is collected an electrical quantities measurement signal respectively measuring CT, and a described electrical quantities measurement signal respectively measuring CT is sent to described control protective device;
Described control protective device judges whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); if a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), then the protection that a described electrical quantities measurement signal respectively measuring CT is finished described flexible AC transmission equipment primary equipment as believable measuring-signal is handled.
2. the system as claimed in claim 1 is characterized in that: a described electrical quantities measurement signal respectively measuring CT that is provided with in described data acquisition unit collection string benefit device or the fault current limiter; Described string is mended in device or the fault current limiter bypass breaker is set;
Described control protective device receives the state information of described bypass breaker break-make; judge in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); if a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), then the protection that a described electrical quantities measurement signal respectively measuring CT is finished described flexible AC transmission equipment primary equipment as believable measuring-signal is handled.
3. system as claimed in claim 2 is characterized in that: described control protective device comprises data summarization unit, judging unit, protected location;
Wherein, described data summarization unit is used to receive the described electrical quantities measurement signal respectively measuring CT from described data acquisition unit, and a described electrical quantities measurement signal respectively measuring CT is sent to described judging unit;
Described judging unit, be used to receive the state information of bypass breaker break-make, judge in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), if satisfy, then a described electrical quantities measurement signal respectively measuring CT sent to described protected location;
Described protected location receives a described electrical quantities measurement signal respectively measuring CT, according to described electrical quantities measurement signal execute protection algorithm and the control strategy of respectively measuring CT, output protection action command.
4. system as claimed in claim 3 is characterized in that:
The string benefit circuit that described string is mended in device or the fault current limiter is provided with capacitor and the metal oxide pressure-limiting device MOV in parallel with described capacitor; In the device main circuit that comprises described metal oxide pressure-limiting device MOV and capacitor, select electric current to converge node (A), make the electric current of measurement CT of the electric current of measurement CT of described capacitor and described metal oxide pressure-limiting device MOV can flow into described electric current and converge node (A);
Described judging unit judges in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL) and be specially:
When described bypass breaker was in open mode, whether described judgment unit judges all flowed into the algebraical sum absolute value of electric current that described electric current converges node (A) less than δ, and duration T;
Wherein, δ, T are threshold value.
5. system as claimed in claim 4; it is characterized in that; when bypass breaker is in closure state; then described judging unit does not carry out the signal true and false and judges; a described electrical quantities measurement signal respectively measuring CT is sent to described protected location, and described protection is single uses described electrical quantities measurement signal execute protection algorithm and the control strategy of respectively measuring CT.
6. system as claimed in claim 3 is characterized in that,
A described electrical quantities measurement signal packet vinculum road current i respectively measuring CT 1ine, the platform current i Pf, condenser current i c, MOV branch current i MOV1And i MOV2, the GAP current i GAP
Described judging unit judges that in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), is specially:
If bypass breaker is in open mode, whether described judgment unit judges satisfies:
| i Line+ i Pf+ i c+ i MOV1+ i MOV2+ i GAP|＜δ, and duration T;
Wherein, described line current i 1ine, the platform current i Pf, condenser current i c, MOV branch current i MOV1And i MOV2, the GAP current i GAPAll electric currents that converge node (A) for inflow current.
7. system as claimed in claim 3 is characterized in that,
When bypass breaker is in open mode, when
Figure FDA0000074819220000021
And during lasting long period T1, the measurement CT of then described judgment unit judges line current and the measurement CT of capacitor are unusual;
Perhaps,
Perhaps, when bypass breaker is in open mode, the platform current i Pf=0, MOV branch current i MOV1=0, i MOV2=0, the GAP current i GAP=0, and
Figure FDA0000074819220000031
And during lasting short period T2, the measurement CT of the described circuit of then described judgment unit judges and the measurement CT of described capacitor are unusual; Wherein, described For the electric current of circuit, described
Figure FDA0000074819220000033
Be the electric current on the capacitor, ζ, T1, T2 are judgment threshold, and described
Figure FDA0000074819220000034
The platform current i Pf, MOV branch current i MOV1And i MOV2, the GAP current i GAPAll electric currents that converge node (A) for inflow current.
8. as system as described in the claim 3, it is characterized in that: described judging unit is deployed in the described protected location, and perhaps described judging unit is deployed in the described data summarization unit.
9. the control guard method of a flexible AC transmission equipment is characterized in that:
Collect an electrical quantities measurement signal respectively measuring CT;
Judge whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); if a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), then the protection that a described electrical quantities measurement signal respectively measuring CT is finished described flexible AC transmission equipment primary equipment as believable measuring-signal is handled.
10. as method as described in the claim 9, it is characterized in that:
Collect string and mend a described electrical quantities measurement signal respectively measuring CT that is provided with in device or the fault current limiter; Described string is mended in device or the fault current limiter bypass breaker is set;
Receive the state information of described bypass breaker break-make; judge in conjunction with the state information of described bypass breaker break-make whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL); if a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL), then the protection that a described electrical quantities measurement signal respectively measuring CT is finished described flexible AC transmission equipment primary equipment as believable measuring-signal is handled.
11. method as claimed in claim 10 is characterized in that:
The string benefit circuit that described string is mended in device or the fault current limiter is provided with capacitor and the metal oxide pressure-limiting device MOV in parallel with described capacitor; In the device main circuit that comprises described metal oxide pressure-limiting device MOV and capacitor, select electric current to converge node (A), make the electric current of measurement CT of the electric current of measurement CT of described capacitor and described metal oxide pressure-limiting device MOV can flow into described electric current and converge node (A);
Describedly judge whether a described electrical quantities measurement signal respectively measuring CT satisfies Kirchhoff's current law (KCL) and be specially:
When described bypass breaker is in open mode, judge that whether all flow into the algebraical sum absolute value of electric current that described electric current converges node (A) less than δ, and duration T;
Wherein, δ, T are threshold value.
12. method as claimed in claim 10 further comprises:
When bypass breaker is in open mode, when
Figure FDA0000074819220000041
And during lasting long period T1, the measurement CT of then described judgment unit judges line current and the measurement CT of capacitor are unusual;
Perhaps, when bypass breaker is in open mode, the platform current i Pf=0, MOV branch current i MOV1=0, i MOV2=0, the GAP current i GAP=0, and And during lasting short period T2, the measurement CT of the described circuit of then described judgment unit judges and the measurement CT of described capacitor are unusual; Wherein, described
Figure FDA0000074819220000043
For the electric current of circuit, described
Figure FDA0000074819220000044
Be the electric current on the capacitor, ζ, T1, T2 are judgment threshold, and described
Figure FDA0000074819220000045
The platform current i Pf, MOV branch current i MOV1And i MOV2, the GAP current i GAPAll electric currents that converge node (A) for inflow current.
13. method as claimed in claim 10 is characterized in that:
Described string is mended device or fault current limiter comprises: fixed series capacitors compensation arrangement, thyristor controlled series capacitor compensation arrangement, series resonance-type fault current limiter device.
CN2011101923049A 2011-07-11 2011-07-11 Control protection system and method of flexible AC transmission device Active CN102231570B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2011101923049A CN102231570B (en) 2011-07-11 2011-07-11 Control protection system and method of flexible AC transmission device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN2011101923049A CN102231570B (en) 2011-07-11 2011-07-11 Control protection system and method of flexible AC transmission device

Publications (2)

Publication Number Publication Date
CN102231570A true CN102231570A (en) 2011-11-02
CN102231570B CN102231570B (en) 2013-12-25

Family

ID=44844114

Family Applications (1)

Application Number Title Priority Date Filing Date
CN2011101923049A Active CN102231570B (en) 2011-07-11 2011-07-11 Control protection system and method of flexible AC transmission device

Country Status (1)

Country Link
CN (1) CN102231570B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102522825A (en) * 2011-12-27 2012-06-27 中电普瑞科技有限公司 Control and protection system for flexible alternating-current power transmission device
CN110632412A (en) * 2019-08-23 2019-12-31 中国南方电网有限责任公司超高压输电公司南宁局 Test method of series compensation protection device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101577417A (en) * 2009-06-11 2009-11-11 西安交通大学 Method for current differential protection of direct current electric transmission line
CN101789602A (en) * 2010-01-13 2010-07-28 中国电力科学研究院 Dynamic simulation device of extra-high, ultrahigh voltage thyristor controlled series compensation device and test method thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101577417A (en) * 2009-06-11 2009-11-11 西安交通大学 Method for current differential protection of direct current electric transmission line
CN101789602A (en) * 2010-01-13 2010-07-28 中国电力科学研究院 Dynamic simulation device of extra-high, ultrahigh voltage thyristor controlled series compensation device and test method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
鲍伟: "福双线路加设TCSC对继电保护装置的影响分析", 《华东电力》 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102522825A (en) * 2011-12-27 2012-06-27 中电普瑞科技有限公司 Control and protection system for flexible alternating-current power transmission device
CN102522825B (en) * 2011-12-27 2014-08-27 中电普瑞科技有限公司 Control and protection system for flexible alternating-current power transmission device
CN110632412A (en) * 2019-08-23 2019-12-31 中国南方电网有限责任公司超高压输电公司南宁局 Test method of series compensation protection device
CN110632412B (en) * 2019-08-23 2022-08-02 中国南方电网有限责任公司超高压输电公司南宁局 Test method of series compensation protection device

Also Published As

Publication number Publication date
CN102231570B (en) 2013-12-25

Similar Documents

Publication Publication Date Title
Sarangi et al. Distributed generation hybrid AC/DC microgrid protection: A critical review on issues, strategies, and future directions
US10823777B2 (en) Detection and location of broken conductors for transmission lines
CN107210603B (en) Fault protection in converter-based DC power distribution systems
US9784781B2 (en) Islanding detection reliability in electricity distribution network
CN102231515B (en) Control protection method, device and system for series capacitor device
O'Brien et al. Catching falling conductors in midair—detecting and tripping broken distribution circuit conductors at protection speeds
CN106655120A (en) Intelligent ground protection method and system for neutral point of power distribution network
Sharafi et al. Transmission system wide-area back-up protection using current phasor measurements
CN101304170A (en) System debug method for high voltage direct current transmission project
CN103606909A (en) Protecting system and method for power distribution network circuit
US11721975B2 (en) System and method for use with microgrids having inverter-based distributed generators
CN107561408B (en) Method for improving accuracy rate of small current ground fault line selection
Ikhide et al. Fault detection in multi-terminal modular multilevel converter (MMC) based high voltage DC (HVDC) transmission system
KR102099568B1 (en) Fault management device for distribution network interconnected with distributed generator and method thereof
CN106959403B (en) A kind of distributed generation resource access distribution net work earthing fault detection method
CN102231569B (en) Control protection system and method for metal oxide varistor (MOV) branch circuit
CN107872049A (en) Method and apparatus for controlling the breaker in power supply network
CN102244379B (en) Method, device and system for controlling and protecting serial capacitors
CN103545798A (en) Distance protection method of fault opening elements in swing block
CN104319743A (en) Method and device for quick backup protection of high-voltage side of main transformer based on station region information
CN102231570B (en) Control protection system and method of flexible AC transmission device
CN108469557A (en) High voltage direct current transmission device Fault Locating Method based on transverter differential protection
CN108710040A (en) Shunt capacitor is protected and monitoring integration method
Aboelezz et al. Efficient fault detection, localization, and isolation in MT-HVDC systems based on distance protection and LoRaWAN communication
Elkhatib et al. Protection of Renewable-dominated Microgrids: Challenges and Potential Solutions.

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
CB03 Change of inventor or designer information

Inventor after: Dai Chaobo

Inventor after: Jin Xuefen

Inventor after: Qiu Yufeng

Inventor after: Wang Shaowu

Inventor after: Liu Huiwen

Inventor after: Wang Yuhong

Inventor before: Dai Chaobo

Inventor before: Jin Xuefen

Inventor before: Liu Huiwen

Inventor before: Wang Yuhong

COR Change of bibliographic data