CN108398616B - Alternating current line fault direction judging method based on direct current commutation failure detection - Google Patents

Alternating current line fault direction judging method based on direct current commutation failure detection Download PDF

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CN108398616B
CN108398616B CN201711445951.XA CN201711445951A CN108398616B CN 108398616 B CN108398616 B CN 108398616B CN 201711445951 A CN201711445951 A CN 201711445951A CN 108398616 B CN108398616 B CN 108398616B
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fault
commutation failure
current
judging
res
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CN108398616A (en
Inventor
王增超
刘玮
黄明辉
陈志光
曾耿晖
李一泉
王育学
刘琨
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Electric Power Dispatch Control Center of Guangdong Power Grid Co Ltd
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Electric Power Dispatch Control Center of Guangdong Power Grid Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/088—Aspects of digital computing
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • 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
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
    • 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
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention relates to an alternating current line fault direction judging method based on direct current commutation failure detection; firstly, detecting whether the inverter has phase commutation failure or not, and further judging the working state of a direction element; finally, judging the fault direction; if the direct current system has a commutation failure fault in a time period corresponding to the directional element, locking and protecting; the problem that the fault is enlarged due to the failure of commutation, which causes the failure or misoperation of the protection of the alternating current direction is solved.

Description

Alternating current line fault direction judging method based on direct current commutation failure detection
Technical Field
The invention relates to the technical field of line fault judgment, in particular to an alternating current line fault direction judgment method based on direct current commutation failure detection.
Background
At present, in an alternating current-direct current hybrid system, when a direct current inversion side alternating current system fails, phase change failure of a current conversion device may occur. When phase commutation fails, the direct current system injects a large amount of transient inter-harmonic components into the alternating current system, and the action behavior of alternating current protection depending on power frequency components is influenced. In the prior art, a directional element based on a power frequency quantity is most affected by phase commutation failure, which easily causes failure of protection of an alternating-current fault line and misoperation of protection of a non-fault line, so that the fault is expanded.
Disclosure of Invention
The invention provides an alternating current line fault direction judging method based on direct current commutation failure detection to overcome the defects.
In order to solve the technical problems, the invention adopts the technical scheme that:
a method for judging the fault direction of an AC line based on DC commutation failure detection comprises the following steps:
s1, detecting whether the inverter has phase commutation failure or not;
s2, judging the working state of the direction element;
s3, calculating the fault direction through a direction element;
s4, judging the fault direction according to the steps S2-S3;
the operation of step S3 can occur before step S1, between steps S1 and S2, or after step S2.
Preferably, the step S1 is as follows:
when the AC/DC system is in normal operation, the current I on the DC side of the converter valvedH、IdNAnd the valve side current I of the converter transformeracY、IacDEqual; the method is used as a basis for judging whether the inverter has phase commutation failure according to the following formula:
Ir>max(KresIres,Isetmin)
wherein, IrFor the operating current: i isr＝IdH-max(IacY,IacD) Or Ir＝IdN-max(IacY,IacD)；IresFor the braking current: i isres＝max(IacY,IacD)；KresIs the braking coefficient; i issetminIs a set minimum setting value; if the above formula is satisfied, determining that the commutation fails; otherwise, the reverse is carried out.
Preferably, the step S2 is as follows:
if a commutation failure fault occurs in the direct current system in a time period corresponding to the directional element, locking protection is carried out, and the directional protection enters a locking state; if the direct current system does not generate phase commutation failure fault in the time period corresponding to the directional element, the directional element is in a normal working state;
wherein, the corresponding time period is as follows: from 30ms to 40ms before the current time to the current time.
Preferably, the step S3 is as follows:
the direction of the fault is calculated using conventional relay protection direction elements.
Preferably, in step S4, based on steps S2 and S3, when the condition that the direction element is in the "normal operation state" and the calculation result of the direction element is the positive direction of the fault is satisfied, the relay protection device determines that the fault direction is the positive direction fault.
In the scheme, firstly, whether the inverter has phase commutation failure is detected, and then the working state of the direction element is further judged; finally, judging the fault direction; if the direct current system has a commutation failure fault in a time period corresponding to the directional element, locking and protecting; the problem that the fault is enlarged due to the failure of commutation, which causes the failure or misoperation of the protection of the alternating current direction is solved.
Compared with the prior art, the invention has the beneficial effects that: in the technical scheme, whether the inverter has phase commutation failure is detected, and then the working state of the directional element is further judged; finally, judging the fault direction; if the direct current system has a commutation failure fault in a time period corresponding to the directional element, locking and protecting; the problem that the fault is enlarged due to the failure of commutation, which causes the failure or misoperation of the protection of the alternating current direction is solved.
Drawings
Fig. 1 is a schematic diagram of an ac line fault direction determination method based on dc commutation failure detection.
Fig. 2 is a schematic diagram of the inverter side connection of the dc transmission system.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.
An ac line fault direction discrimination method based on dc commutation failure detection, a schematic diagram of which is shown in fig. 1:
the method comprises the following specific steps:
s1, detecting whether the inverter has phase commutation failure or not;
s2, judging the working state of the direction element;
s3, calculating the fault direction through a direction element;
s4, judging the fault direction according to the steps S2-S3;
wherein, the operation of the step S3 can occur before the step S1, between the steps S1 and S2, or after the step S2, respectively; for example, the sequence of steps performed includes S3-S1-S2-S4, S1-S3-S2-S4, S1-S2-S3-S4.
In the present embodiment, the determination diagram of step S1 is as shown in fig. 2:
current mutual inductor respectively measuring high-voltage direct current bus current IdHNeutral DC bus current IdNCurrent I at valve side of converter transformeracYAnd IacD。
When the AC/DC system is in normal operation, the current I on the DC side of the converter valvedH、IdNAnd the valve side current I of the converter transformeracY、IacDEqual; the method is used as a basis for judging whether the inverter has phase commutation failure according to the following formula:
Ir>max(KresIres,Isetmin)
wherein, IrFor the operating current: i isr＝IdH-max(IacY,IacD) Or Ir＝IdN-max(IacY,IacD)；IresFor the braking current: i isres＝max(IacY,IacD)；KresIs the braking coefficient; i issetminIs a set minimum setting value; if the above formula is satisfied, determining that the commutation fails; otherwise, the reverse is carried out.
In this embodiment, step S2 is specifically as follows:
if a commutation failure fault occurs in the direct current system in a time period corresponding to the directional element, locking protection is carried out, and the directional protection enters a locking state; if the direct current system does not generate phase commutation failure fault in the time period corresponding to the directional element, the directional element is in a normal working state;
wherein, the corresponding time period is as follows: from 30ms to 40ms before the current time to the current time.
In this embodiment, step S3 is specifically as follows:
the direction of the fault is calculated using conventional relay protection direction elements.
In this embodiment, in step S4, based on steps S2 and S3, when the direction element is "normal operation state" and the calculation result of the direction element is positive direction of the fault is satisfied, the relay protection device determines that the fault direction is positive direction fault.
In this embodiment, first, whether the inverter has failed in phase commutation is detected, and then, the operating state of the directional element is further determined; finally, judging the fault direction; if the direct current system has a commutation failure fault in a time period corresponding to the directional element, locking and protecting; the problem that the fault is enlarged due to the failure of commutation, which causes the failure or misoperation of the protection of the alternating current direction is solved.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (3)

1. A method for judging the fault direction of an AC line based on DC commutation failure detection is characterized in that: the method comprises the following specific steps:
s1, detecting whether the inverter has phase commutation failure or not;
s2, judging the working state of the direction element;
s3, calculating the fault direction through a direction element;
s4, judging the fault direction according to the steps S2-S3;
wherein, the operation of the step S3 can occur before the step S1, between the steps S1 and S2, or after the step S2, respectively;
the step S1 is specifically as follows:
when the AC/DC system is in normal operation, the current I on the DC side of the converter valvedH、IdNAnd the valve side current I of the converter transformeracY、IacDEqual; the method is used as a basis for judging whether the inverter has phase commutation failure according to the following formula:
Ir＞max(KresIres,Isetmin)
wherein, IrFor the operating current: i isr＝IdH-max(IacY,IacD) Or Ir＝IdN-max(IacY,IacD)；IresFor the braking current: i isres＝max(IacY,IacD)；KresIs the braking coefficient; i issetminIs a set minimum setting value; if the formula is met, determining that the commutation fails; otherwise, the process is reversed;
if a commutation failure fault occurs in the direct current system in a time period corresponding to the directional element, locking protection is carried out, and the directional protection enters a locking state; if the direct current system does not generate phase commutation failure fault in the time period corresponding to the directional element, the directional element is in a normal working state;
wherein the corresponding time period is: from 30ms to 40ms before the current time to the current time.
2. The ac line fault direction discrimination method based on dc commutation failure detection according to claim 1, wherein: the step S3 is specifically as follows:
the direction of the fault is calculated using conventional relay protection direction elements.
3. The ac line fault direction discrimination method based on dc commutation failure detection according to claim 1 or 2, wherein: in the step S4, based on the steps S2 and S3, when the direction element is "normal operation state" and the calculation result of the direction element is positive direction of the fault, the relay protection device determines that the fault direction is positive direction fault.
CN201711445951.XA 2017-12-27 2017-12-27 Alternating current line fault direction judging method based on direct current commutation failure detection Active CN108398616B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0819168A (en) * 1994-06-30 1996-01-19 Mitsubishi Electric Corp Method and apparatus for protective relaying of dc transmission line
JPH09308253A (en) * 1996-05-20 1997-11-28 Fuji Electric Co Ltd Control of power converting apparatus
CN100574032C (en) * 2005-06-15 2009-12-23 许继集团有限公司 Back-to-back differential protection method in high-voltage DC power transmission system
CN102590655B (en) * 2012-01-11 2014-04-23 西安交通大学 Failure direction judgment element and judgment method for direct current transmission line
CN105226620B (en) * 2015-10-28 2018-02-13 许继电气股份有限公司 A kind of implementation method of bipolar commutation failure protection
CN107482594B (en) * 2017-07-11 2019-04-12 昆明理工大学 The three-phase time sequence of coincidence setting method of direction protection malfunction rate in a kind of reduction ac and dc systems

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