CN114002540B - Power distribution network line development fault protection method and system - Google Patents
Power distribution network line development fault protection method and system Download PDFInfo
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- CN114002540B CN114002540B CN202111111221.2A CN202111111221A CN114002540B CN 114002540 B CN114002540 B CN 114002540B CN 202111111221 A CN202111111221 A CN 202111111221A CN 114002540 B CN114002540 B CN 114002540B
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- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000009826 distribution Methods 0.000 title claims abstract description 19
- 238000002955 isolation Methods 0.000 claims abstract description 15
- 230000000750 progressive effect Effects 0.000 claims abstract description 13
- 230000008859 change Effects 0.000 claims abstract description 11
- 230000009471 action Effects 0.000 claims description 12
- 101150055297 SET1 gene Proteins 0.000 claims description 4
- 101150117538 Set2 gene Proteins 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 4
- 238000004891 communication Methods 0.000 claims description 3
- 230000001934 delay Effects 0.000 claims description 3
- 238000004590 computer program Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 230000006870 function Effects 0.000 description 4
- 238000003860 storage Methods 0.000 description 3
- 230000008033 biological extinction Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000016507 interphase Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
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Classifications
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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
-
- 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
-
- 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
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- 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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- General Physics & Mathematics (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a power distribution network line development fault protection method, which is characterized by comprising the following steps: collecting zero sequence voltage and three-phase current of a line; judging whether to start the progressive fault judgment according to the zero sequence voltage and the three-phase current signals; if the developmental fault is judged to be started, determining whether the developmental fault occurs according to the three-phase current change; the method for protecting the power distribution network line from the development faults can accurately identify the development faults after the single-phase grounding faults occur, and the fault isolation method is provided, so that the method can adapt to different use scenes and use purposes, realize reliable isolation of the development faults, prevent further expansion of accidents and reduce power grid loss.
Description
Technical Field
The invention belongs to the technical field of relay protection, and particularly relates to a power distribution network line development fault protection method.
Background
The power distribution network power supply system in China generally adopts a small-current grounding operation mode, has small fault current and symmetrical line voltage when single-phase grounding faults occur, cannot act when overcurrent protection does not meet the conditions, and can continue to operate. However, because the single-phase earth fault causes the rise of the system phase voltage, insulation breakdown of other lines is easy to cause, and further different-name phase faults among different lines are caused, at the moment, the existing interphase overcurrent protection action can only cut off one line, the overcurrent protection of the other line cannot be carried out due to the return of the interphase fault, the line can continue to operate with the single-phase earth fault, and further expansion of accidents can be possibly caused continuously. Considering that the current grounding line selection technology has low popularity and partial areas hope to continue to operate after single-phase grounding faults occur, the power distribution network line development fault protection method is required to accurately identify development faults and conduct fault isolation after single-phase grounding faults occur, further expansion of accidents is prevented, and power grid loss is reduced.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a power distribution network line development fault protection method which can accurately identify development faults and conduct fault isolation after single-phase grounding faults occur.
The technical problems to be solved by the invention are realized by the following technical scheme:
in a first aspect, a method for protecting a power distribution network line from a developing fault is provided, including:
Collecting zero sequence voltage and three-phase current of a line;
Judging whether to start the progressive fault judgment according to the zero sequence voltage and the three-phase current signals;
If the developmental fault is judged to be started, determining whether the developmental fault occurs according to the three-phase current change;
Isolating the developing faults that occur.
With reference to the first aspect, further, the judging whether to start the progressive fault according to the zero sequence voltage and the three-phase current signal includes:
When the collected line zero sequence voltage U 0 is larger than the overvoltage threshold U set, the three-phase currents are smaller than the overcurrent threshold I set, and the time duration exceeds the time threshold T set1, the progressive fault judgment is started.
With reference to the first aspect, further, the determining whether a developing fault occurs according to the three-phase current change includes:
If a certain phase current in the three-phase currents has a change process from being smaller than the overcurrent threshold I set to being larger than the overcurrent threshold I set, the phase circuit is judged to have a developing fault.
With reference to the first aspect, further, isolating the developing fault is:
After the protection device receives protection device action signals of other circuits, when the phase current of the protection device is changed from being larger than an overcurrent threshold I set to being smaller than an overcurrent threshold I set and the zero sequence voltage U 0 is always larger than an overvoltage threshold U set, the protection device sends a tripping command to realize fault removal.
With reference to the first aspect, further, isolating the occurred developing fault may further be: when the phase current of the protection deviceThe protection device sends a tripping command to realize fault removal when the zero sequence voltage U 0>Uset is changed from being larger than the overcurrent threshold I set to being smaller than the overcurrent threshold I set.
With reference to the first aspect, further, isolating the occurred developing fault may further be: and after the protection device delays by T set2, a tripping command is sent out to realize fault removal.
In combination with the first aspect, further, the action signals of the protection devices of any other line may be obtained by connecting the action signal hard contacts of all the protection devices in parallel and then switching in the access device, or by means of communication.
In a second aspect, there is also provided a power distribution network line-developing fault protection system, including:
the acquisition module is used for acquiring zero sequence voltage and three-phase current of the line;
the fault judging module is used for judging whether to start the progressive fault judgment according to the zero sequence voltage and the three-phase current signals;
If the developmental fault is judged to be started, determining whether the developmental fault occurs according to the three-phase current change;
And the isolation module is used for isolating the developed faults.
The invention has the beneficial effects that: the power distribution network line development fault protection method can accurately identify development faults after single-phase earth faults occur, and provides a fault isolation method which can adapt to different use scenes and use purposes, so that reliable isolation of the development faults is realized, further expansion of accidents is prevented, and power grid loss is reduced.
Drawings
Fig. 1 is a flowchart of a power distribution network line development fault protection method provided by the invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In order to better understand the present invention, the following describes related technologies in the technical solution of the present invention.
Example 1
The invention relates to a power distribution network line development fault protection method, which can accurately identify and isolate development faults, and the working flow is shown in a figure 1 and comprises the following steps:
Step 1: the developing fault protection starts. When the zero sequence voltage U 0 collected by line protection is larger than the threshold U set, the three-phase currents (Ia, ib and Ic) are smaller than the overcurrent threshold I set, and the duration exceeds T set1, the progressive fault judgment is started, and the step 2 is entered.
Step 2: and determining the development faults. If any phase current in the three-phase currentThere is a change from less than threshold I set to greater than threshold I set, and a determination is made that a line has failed. Step 3 is entered.
Step 3: developed fault isolation. After the protection device receives the protection action signal of any other line, the phase currentFrom greater than threshold I set to less than threshold I set, and zero sequence voltage U 0 is always greater than U set, the device trips to remove the fault. If the duration of the developing fault is not long, the self-arc extinction becomes a single-phase earth fault, and the circuit can not trip because other circuit protection is not operated at this time, so that the operation can be continued. The protection action signal of any other line can be obtained by connecting action signal hard joints of all devices in parallel and then switching in the devices, or by communication.
The fault isolation of the development can also not judge the action signals of other circuit protection, at the moment, the device trips to isolate faults after the current is smaller than a threshold, the matching time with the next-stage circuit is reserved, if the next-stage circuit trips first and successfully cuts off the faults, the zero sequence voltage returns, and the device is not tripped any more. If the duration of the developing fault is not long, the self-arc extinction becomes a single-phase grounding fault, and the fault line can still trip and cut off the fault.
The progressive fault isolation can also be directly accelerated to trip through short delay T set2 (recommended value 100 ms), and the rapid fault isolation is realized without considering the cooperation with the next-stage line.
Example 2
There is also provided a power distribution network line-developing fault protection system comprising:
the acquisition module is used for acquiring zero sequence voltage and three-phase current of the line;
the fault judging module is used for judging whether to start the progressive fault judgment according to the zero sequence voltage and the three-phase current signals;
If the developmental fault is judged to be started, determining whether the developmental fault occurs according to the three-phase current change;
And the isolation module is used for isolating the developed faults.
In summary, the power distribution network line development fault protection method can accurately identify development faults after single-phase earth faults occur, and 3 fault isolation methods are provided, so that the power distribution network line development fault protection method can adapt to different use scenes and use purposes, achieves reliable isolation of the development faults, prevents further expansion of accidents, reduces power grid loss, and has good application prospects.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Claims (3)
1. A method for protecting a power distribution network line from a developing fault, comprising:
Collecting zero sequence voltage and three-phase current of a line;
Judging whether to start the progressive fault according to the zero sequence voltage and the three-phase current signals, including: when the collected line zero sequence voltage U 0 is larger than the overvoltage threshold U set, the three-phase currents are smaller than the overcurrent threshold I set, and after the duration exceeds the time threshold T set1, the progressive fault judgment is started;
if the developmental fault is judged to be started, determining whether the developmental fault occurs according to the three-phase current change comprises the following steps: if a certain phase current in the three-phase currents has a change process from being smaller than an overcurrent threshold I set to being larger than an overcurrent threshold I set, judging that the phase line has a developing fault;
isolating an occurrence of a developing fault, comprising:
After the protection device receives protection device action signals of other circuits, when the phase current of the protection device is changed from being larger than an overcurrent threshold I set to smaller than an overcurrent threshold I set and the zero sequence voltage U 0 is always larger than an overvoltage threshold U set, the protection device sends a tripping command to realize fault removal;
When the phase current I φ of the protection device is changed from being larger than the overcurrent threshold I set to being smaller than the overcurrent threshold I set, and the zero sequence voltage U 0 is larger than the overvoltage threshold U set, the protection device sends a tripping command to realize fault removal;
The zero sequence voltage U 0 is always larger than the overvoltage threshold U set, and the protection device delays T set2 to send out a tripping command to realize fault removal.
2. A method of power distribution network line progressive fault protection as claimed in claim 1, wherein: the action signals of the protection devices of any other line can be obtained by connecting the action signal hard joints of all the protection devices in parallel and then switching in the access device, or by a communication mode.
3. A power distribution network line-developing fault protection system, comprising:
the acquisition module is used for acquiring zero sequence voltage and three-phase current of the line;
the fault judging module is used for judging whether to start the progressive fault judgment according to the zero sequence voltage and the three-phase current signals, and comprises the following steps: when the collected line zero sequence voltage U 0 is larger than the overvoltage threshold U set, the three-phase currents are smaller than the overcurrent threshold I set, and after the duration exceeds the time threshold T set1, the progressive fault judgment is started;
If the development fault is judged to be started, determining whether the development fault occurs according to the three-phase current change, wherein the step of judging that the development fault occurs in the phase line comprises the steps of if a certain phase current in the three-phase current has a change process from being smaller than an overcurrent threshold I set to being larger than an overcurrent threshold I set;
The isolation module is used for isolating the developed faults and sending a tripping command to realize fault removal when the phase current of the protection device is changed from being larger than an overcurrent threshold I set to smaller than an overcurrent threshold I set and the zero sequence voltage U 0 is always larger than an overvoltage threshold U set after the protection device receives protection device action signals of other lines;
When the phase current I φ of the protection device is changed from being larger than the overcurrent threshold I set to being smaller than the overcurrent threshold I set, and the zero sequence voltage U 0 is larger than the overvoltage threshold U set, the protection device sends a tripping command to realize fault removal;
The zero sequence voltage U 0 is always larger than the overvoltage threshold U set, and the protection device delays T set2 to send out a tripping command to realize fault removal.
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| CN202111111221.2A CN114002540B (en) | 2021-09-23 | 2021-09-23 | Power distribution network line development fault protection method and system |
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