CN114720815B - A fault identification method suitable for power transmission line disconnection - Google Patents
A fault identification method suitable for power transmission line disconnection Download PDFInfo
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- CN114720815B CN114720815B CN202210268888.1A CN202210268888A CN114720815B CN 114720815 B CN114720815 B CN 114720815B CN 202210268888 A CN202210268888 A CN 202210268888A CN 114720815 B CN114720815 B CN 114720815B
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- 230000005540 biological transmission Effects 0.000 title claims abstract description 11
- 238000000638 solvent extraction Methods 0.000 claims abstract description 12
- 238000005192 partition Methods 0.000 claims description 31
- 230000035945 sensitivity Effects 0.000 abstract description 3
- 238000004364 calculation method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012850 discrimination method Methods 0.000 description 1
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
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
-
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/58—Testing of lines, cables or conductors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—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 involving signal transmission between at least two stations
- H02H7/262—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 involving signal transmission between at least two stations involving transmissions of switching or blocking orders
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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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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
本发明公开了一种适用于输电线路发生断线时的故障判别方法，利用故障序分量分区法识别故障区；根据识别出的故障区所对应回路的相电流值和无流条件，判定故障区是否满足单相或两相的断线条件；若满足断线条件，则根据线路的零序方向元件和负序方向元件确定故障方向。本发明充分利用线路双端信息，将故障序分量分区法、无流条件及零序方向元件和负序方向元件结合起来判断断线故障，提高了断线故障时保护的灵敏性并且从原理上消除了线路互感的影响。
The present invention discloses a fault identification method applicable to a power transmission line when a line is disconnected, which uses a fault sequence component partitioning method to identify a fault area; according to the phase current value and no-current condition of the circuit corresponding to the identified fault area, it is determined whether the fault area meets the single-phase or two-phase line disconnection condition; if the line disconnection condition is met, the fault direction is determined according to the zero-sequence direction element and the negative-sequence direction element of the line. The present invention makes full use of the line double-end information, combines the fault sequence component partitioning method, the no-current condition, the zero-sequence direction element and the negative-sequence direction element to judge the line disconnection fault, improves the sensitivity of the protection during the line disconnection fault, and eliminates the influence of the line mutual inductance in principle.
Description
Technical Field
The invention relates to a fault judging method suitable for a power transmission line when a broken line occurs, and belongs to the technical field of power systems.
Background
After the break fault occurs, as shown in fig. 3, the fault phase current disappears, the non-fault phase current slightly increases, damage to the power element is limited, and a large probability is converted to a ground fault. However, in actual operation, although a large fault current is not generated when a power system breaks, unbalanced zero sequence and negative sequence currents are generated in the system, the operation of a rotating motor is adversely affected, the zero sequence current protection in power grid protection is also affected, and the risk of override trip exists. Therefore, a fast and reliable fault removal is needed. However, the fault current is small when the line breaks, the sensitivity of the conventional fault direction judging element may not be enough, and the correctness of the protection action is affected.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a fault judging method suitable for a power transmission line when a broken line occurs, which is sensitive, reliable, fast and reliable, cuts off the broken line fault and ensures the safe and stable operation of a power system.
In order to achieve the above object, the present invention provides a fault discriminating method suitable for use when a transmission line breaks, comprising the steps of:
Identifying a fault area by using a fault sequence component partitioning method;
judging whether the fault area meets the single-phase or two-phase disconnection condition according to the phase current value and the no-current condition of the loop corresponding to the identified fault area;
If the line breaking condition is met, determining a fault direction according to the zero sequence direction element and the negative sequence direction element of the line.
Preferably, determining the fault direction further comprises:
if the fault direction meets the positive direction, sending a request permission command to the opposite side of the line;
and after receiving an allowable command on the opposite side of the line, tripping and locking the three phases for reclosing after a period of time, and cutting off the broken line.
Preferably, before the fault region is identified by using the fault sequence component partitioning method, calculating a zero sequence voltage, a zero sequence current, a negative sequence voltage and a negative sequence current by using the symmetric component method, including:
Acquiring three-phase voltages on two sides of a circuit and three-phase currents on two sides of the circuit, and calculating to acquire an A-phase voltage power frequency phasor, a B-phase voltage power frequency phasor, a C-phase voltage power frequency phasor, an A-phase current power frequency phasor, a B-phase current power frequency phasor and a C-phase current power frequency phasor on two sides of the circuit;
Calculating zero sequence voltage, zero sequence current, negative sequence voltage and negative sequence current:
where a=e j120°,a2＝ej240°, k=m or n, m represents the m side of the line, n represents the n side of the line, j is an imaginary unit, For the zero sequence voltages at both the line-side and line-side ends,For zero sequence currents at both the line side and the line side,For negative sequence voltages across the line side and line side,Negative sequence currents at two ends of the line side and the line opposite side;
Is the power frequency phasor of the A-phase voltage at two sides of the line, Is the power frequency phasor of B-phase voltage at two sides of the line,Is the power frequency phasor of the C-phase voltage at two sides of the line,Is the power frequency phasor of the A-phase current at two sides of the line,Is the power frequency phasor of B-phase current at two sides of the line,Is the power frequency phasor of the C-phase current at two sides of the line.
Preferably, identifying the fault region using fault sequence component partitioning comprises:
Calculating zero sequence current Phase and negative sequence current of (a)Is a phase of (2);
according to zero sequence current And negative sequence currentThe phase relationship between them determines three phase-selective partitions:
a partition A area;
a partition B area;
A partition C area;
Identifying a fault region:
(1) If the subarea falls into the area A, determining that the subarea is broken, or the subarea is broken;
(2) If the subarea falls into the B area, determining that the B phase is broken, or the CA phase is broken;
(3) If the subarea falls into the C area, the subarea is determined to be a C-phase broken line or an AB-phase broken line.
Preferentially, according to the phase current value and the no-current condition of the loop corresponding to the identified fault area, judging whether the fault area meets the single-phase or two-phase line breaking condition, including:
If the partition falls into the A region and only the A phase current I ma meets the no-current condition I ma＜0.04In,In as the rated current, judging that the A phase breaks;
If the partition falls into the A area, I ma＞0.04In, B phase current I mb and C phase current I mc are smaller than 0.04I n, judging that the BC phase is broken;
If the partition falls into the B region and only the B phase current I mb meets the no-current condition I mb＜0.04In, judging that the B phase is broken;
If the partition falls into the B area, and the I mb＞0.04In,Ima and the C-phase current I mc are smaller than 0.04I n, judging that the CA phase is broken;
if the partition falls into the C area and only the C-phase current I mc meets the no-current condition I mc＜0.04In, judging that the C-phase is broken;
If the partition falls into the C area, and both I mc＞0.04In,Ima and I mb are smaller than 0.04I n, the AB phase line is judged to be broken.
Preferentially, determining the fault direction from the zero sequence direction element and the negative sequence direction element of the line comprises:
If it is AndIf the two faults are satisfied, judging the positive direction fault, otherwise judging the negative direction fault,Is the zero-sequence voltage,Is a zero-sequence current,Is a negative sequence voltage, and is a voltage with a negative sequence,Is a negative sequence current.
The invention has the beneficial effects that:
(1) The invention combines the fault sequence component partitioning method, the no-current condition, the zero sequence direction element and the negative sequence direction element to judge the broken line fault, thereby improving the protection sensitivity in the broken line fault;
(2) The invention fully utilizes the double-end information of the line to judge the broken line phase, is accurate and reliable, and is convenient to implement;
(3) The invention eliminates the influence of the mutual inductance of the line in principle, has simple calculation and reliable principle, and is suitable for lines with voltage levels of 110kV and above.
Drawings
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a schematic diagram of a fault sequence component partitioning method of the present invention;
Fig. 3 is a schematic diagram of a broken line fault.
Detailed Description
The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
The fault distinguishing method for the broken transmission line of the invention is shown in fig. 1, and specifically comprises the following steps:
The first step, three-phase voltage and three-phase current at two ends of a line are obtained, and power frequency phasors of the voltages at the two ends are obtained through calculation of a Fourier algorithm Sum current power frequency phasorWhere k=m, n.
Second, calculating the zero sequence voltages at two ends of the line by using a symmetrical component methodZero sequence currentNegative sequence voltageAnd negative sequence current
Wherein a=e j120°,a2＝ej240°, k=m, n, m represents the m side of the line, n represents the n side of the line, j is an imaginary unit;
Third, fault region is selected by fault sequence component partitioning method, and zero sequence current is calculated by taking line head end m side as an example And negative sequence currentAccording to the zero sequence currentAnd negative sequence currentThe different phase relationships between them determine three phase-selective partitions, as shown in fig. 2:
a partition A area;
a partition B area;
partition C.
(1) If the subarea falls into the area A, determining that the subarea is broken, or the subarea is broken;
(2) If the subarea falls into the B area, the subarea can be determined as a B phase disconnection or a CA phase disconnection;
(3) If the partition falls into the C area, the partition can be determined as a C-phase broken line or an AB-phase broken line.
Fourth, after the fault sequence component is partitioned, judging whether the fault region belongs to a single-phase or two-phase disconnection condition according to whether the phase current value of the loop corresponding to the identified fault region meets the no-current condition or not:
Taking the partition falling into the A area as an example, if only the A-phase current I ma meets the no-flow condition I ma＜0.04In, judging as the A-phase broken line, and if the A-phase current I ma does not meet the no-flow condition, namely I ma＞0.04In, and the B-phase current I mb and the C-phase current I mc both meet the no-flow condition, namely (I mb＜0.04In)&&(Imc＜0.04In), judging as the BC-phase broken line.
If the partition falls into the B region and only the B phase current I mb meets the no-current condition I mb＜0.04In, judging that the B phase is broken;
If the partition falls into the B area, and the I mb＞0.04In,Ima and the C-phase current I mc are smaller than 0.04I n, judging that the CA phase is broken;
if the partition falls into the C area and only the C-phase current I mc meets the no-current condition I mc＜0.04In, judging that the C-phase is broken;
If the partition falls into the C area, and both I mc＞0.04In,Ima and I mb are smaller than 0.04I n, the AB phase line is judged to be broken.
I n is rated current, and is generally 1A or 5A according to the type of the current transformer;
And fifthly, determining the fault direction according to the zero sequence direction element and the negative sequence direction element of the line after the line breaking condition is met, and sending an allowable command to the opposite side if the positive direction condition is met.
In order to eliminate the influence of line mutual inductance, the fault direction is determined by adopting the relationship between a zero sequence direction element and a negative sequence direction element and a gate, and when the angle difference between the zero sequence voltage and the zero sequence current and the angle difference between the negative sequence voltage and the negative sequence current are all within 175 o～325o, namely:
it is determined as a positive direction fault and a request permission command is sent to the line opposite side.
Sixthly, when the line side meets the line breaking condition, the zero sequence direction element and the negative sequence direction element are both positive directions, and an allowable command of the opposite side of the line is received, and three phases trip and lock and reclose after 500-1000 ms, so that the line breaking line is cut off;
The invention combines the fault sequence component partitioning method, the no-flow condition, the zero sequence direction element and the negative sequence direction element to judge the broken line fault, fully utilizes the double-end information of the line, eliminates the influence of the mutual inductance of the line in principle, and has simple calculation and reliable principle.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present invention, and such modifications and variations should also be regarded as being within the scope of the invention.
Claims (4)
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101038316A (en) * | 2007-04-23 | 2007-09-19 | 国电南京自动化股份有限公司 | Circuit protection order component phase selectiing method using both end information |
| CN104198884A (en) * | 2014-08-06 | 2014-12-10 | 国网山东省电力公司 | Differential principle based large-scale power grid intelligent trouble diagnosis method |
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| US4795983A (en) * | 1988-03-07 | 1989-01-03 | Westinghouse Electric Corp. | Method and apparatus for identifying a faulted phase |
| US5808845A (en) * | 1997-05-30 | 1998-09-15 | Schweitzer Engineering Laboratories Inc. | System for preventing sympathetic tripping in a power system |
| CN100581020C (en) * | 2007-04-24 | 2010-01-13 | 北京四方继保自动化股份有限公司 | Method for realizing line high-resistance fast trip using zero-sequence loop fuction |
| CN102769279B (en) * | 2012-07-23 | 2014-10-08 | 国电南瑞科技股份有限公司 | High-resistance grounding phase selection method for longitudinal zero-sequence protection of line protection device |
| US10132853B2 (en) * | 2015-04-10 | 2018-11-20 | Washington State University | Wide area fault detection method using PMU data |
| CN106997019A (en) * | 2017-05-17 | 2017-08-01 | 国家电网公司 | A kind of monitoring method for earth-free power system single-phase wire break |
| RU2744035C1 (en) * | 2020-07-16 | 2021-03-02 | Общество с ограниченной ответственностью "Релематика" | DEVICE FOR DETECTING DAMAGED SECTION OF OVERHEAD ELECTRIC LINE WITH SUBBRANCES IN 6-35 kV DISTRIBUTION NETWORK |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101038316A (en) * | 2007-04-23 | 2007-09-19 | 国电南京自动化股份有限公司 | Circuit protection order component phase selectiing method using both end information |
| CN104198884A (en) * | 2014-08-06 | 2014-12-10 | 国网山东省电力公司 | Differential principle based large-scale power grid intelligent trouble diagnosis method |
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