CN114019293A - Method and device for analyzing three-circuit three-phase line breaking fault of same-pole four-circuit line - Google Patents

Method and device for analyzing three-circuit three-phase line breaking fault of same-pole four-circuit line Download PDF

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CN114019293A
CN114019293A CN202111069593.3A CN202111069593A CN114019293A CN 114019293 A CN114019293 A CN 114019293A CN 202111069593 A CN202111069593 A CN 202111069593A CN 114019293 A CN114019293 A CN 114019293A
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current
sequence
voltage
line
phase
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陆政君
杨嘉靖
石桂学
石怀强
汪凤月
李泳龙
童理
韦昌伟
庞泽
赵铎
覃正红
唐纬
黄宗启
覃雪梅
甘琦
唐广
杨超群
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Datang Hydropower Science and Technology Research Institute Co Ltd
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Datang Hydropower Science and Technology Research Institute 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
    • G01R31/081—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
    • 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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Abstract

The invention discloses a method, a device, equipment and a computer readable storage medium for analyzing three-phase line break faults of three circuit lines of a same-pole four-circuit line, wherein the method comprises the following steps: determining voltage constraint and current constraint according to boundary conditions of three-phase line breaking faults of three lines in four lines; drawing a composite sequence network diagram when the three-phase disconnection of the three circuit lines fails according to the relation between the voltage constraint and the current constraint middle-order component; determining each sequence voltage and each sequence current according to a composite sequence network diagram, voltage constraint and current constraint when three-loop three-phase disconnection faults occur; calculating the line break voltage and the normal phase current at the line break position according to the voltage of each sequence, the current of each sequence and the relation between the voltage and the current of each sequence at the line break position; analyzing the three-phase disconnection fault of the three-circuit line according to the disconnection voltage and the normal phase current at the disconnection position; the method effectively solves the problem of three-circuit three-phase line breaking faults of the same-pole four-circuit line, and makes up the vacancy of line breaking fault analysis of the same-pole four-circuit line.

Description

Method and device for analyzing three-circuit three-phase line breaking fault of same-pole four-circuit line
Technical Field
The invention relates to the technical field of power transmission, in particular to a method, a device, equipment and a computer readable storage medium for analyzing three-phase line breaking faults of three lines of a same-pole four-circuit line.
Background
With the application of four circuit lines on the same pole becoming more and more extensive, the technical problems are brought while the transmission capacity is improved and the construction cost is saved. The four circuit lines on the same pole are 12 lines in total, the coupling condition is complex, mutual inductance exists between lines besides phase-to-phase mutual inductance, the faults are various, line crossing faults can occur besides single circuit line faults, line breaking faults can occur besides short circuit faults, and difficulty is brought to relay protection configuration work. At present, a relatively mature symmetric component method and a six-sequence component method are widely applied to single-circuit and double-circuit fault analysis, and researches on fault phase selection, fault distance measurement, protection configuration and the like are greatly developed.
In recent years, the fault analysis of the same-pole multi-circuit transmission line is based on phase-mode transformation. The phase-mode transformation method for double-circuit lines on the same pole is a six-sequence component method. The phase-mode conversion method popularized by the symmetrical component method creates concepts of the same vector and the opposite vector, and therefore the inter-line decoupling is completed. According to the decoupling thought, a twelve-sequence component method for the same-pole four-loop line is provided. The method inherits the line-to-line decoupling thought of a six-sequence component method, reserves a group of same vectors, popularizes the inverse vectors into three groups of loop flows in a high-order modulus space, successfully completes line-to-line decoupling, and finally realizes fault analysis. However, the above researches only aim at short-circuit faults, but have different fault analysis methods for disconnection faults, fault sequence network diagrams, comprehensive electromotive force, composite sequence network diagrams and the like, and currently, corresponding researches are lacked, so that the method has important practical significance for filling the blank of disconnection fault analysis.
In summary, it can be seen that how to analyze the three-phase disconnection fault of the four circuit lines on the same pole by using the twelve-sequence component method is a problem to be solved at present.
Disclosure of Invention
The invention aims to provide a method, a device, equipment and a computer readable storage medium for analyzing three-circuit three-phase line breaking faults of a same-pole four-circuit line, so as to solve the problem to be solved in the line breaking fault analysis in the prior art.
In order to solve the technical problem, the invention provides a method for analyzing a three-phase disconnection fault of two lines of a same-pole four-line circuit, which comprises the following steps: determining voltage constraint and current constraint according to boundary conditions of three-circuit line three-phase disconnection faults in the four-circuit line; drawing a composite sequence network diagram when the three-circuit three-phase disconnection fault occurs according to the relation between the voltage constraint and the current constraint neutral component; determining each sequence voltage and each sequence current according to the composite sequence network diagram of the three-loop three-phase disconnection fault, the voltage constraint and the current constraint; calculating the line break voltage and the normal phase current at the line break position according to the relation among the voltage, the current and the voltage and the current at the line break position; and analyzing the three-loop three-phase line breakage fault according to the line breakage voltage and the normal phase current at the line breakage position.
In an embodiment of the present invention, the boundary conditions of the three-wire three-phase disconnection fault in the four-wire line are as follows:
Figure BDA0003259619420000021
wherein,
Figure BDA0003259619420000022
is a return line A phase current at the broken line,
Figure BDA0003259619420000023
is a return line B phase current at the broken line,
Figure BDA0003259619420000024
is a return line C phase current at the broken line,
Figure BDA0003259619420000025
the phase A current of the two return wires at the broken wire position,
Figure BDA0003259619420000026
the B-phase current of the two return wires at the broken wire position,
Figure BDA0003259619420000027
the phase C current of the two return wires at the broken wire position,
Figure BDA0003259619420000028
three return wires of phase A current at the broken wire position,
Figure BDA0003259619420000029
three return wires at the broken line are used for B-phase current,
Figure BDA00032596194200000210
three return wires of phase C current at the broken wire position,
Figure BDA00032596194200000211
for the phase A voltage drop of the four-circuit line at the broken line,
Figure BDA00032596194200000212
for the voltage drop of the phase B of the four-circuit line at the broken line,
Figure BDA00032596194200000213
the voltage drop of the phase C of the four-circuit line at the broken line is shown.
In an embodiment of the present invention, the step of drawing a composite sequence grid diagram of the three-wire three-phase disconnection fault according to the relation between the voltage constraint and the current constraint neutral component includes:
determining a relationship of the voltage constraint and a neutral component of the current constraint according to the voltage constraint and the current constraint;
analyzing the series-parallel connection relation among the sequences according to the relation between the voltage constraint and the current constraint intermediate-sequence component, and calculating the impedance relation among the sequences;
and drawing a composite sequence network diagram when the three-circuit three-phase disconnection fault occurs according to the series-parallel connection among the sequences and the impedance relation among the sequences.
In one embodiment of the present invention, the relationship of the voltage constraint and the current constraint neutral-order component is:
Figure BDA0003259619420000031
wherein,
Figure BDA0003259619420000032
is the current of the sequence e0,
Figure BDA0003259619420000033
is the current of the sequence e1,
Figure BDA0003259619420000034
is the current of the sequence e2,
Figure BDA0003259619420000035
is the current of the sequence f0,
Figure BDA0003259619420000036
is the current of the sequence f1,
Figure BDA0003259619420000037
is the current of the sequence f2,
Figure BDA0003259619420000038
is the current of the sequence g0,
Figure BDA0003259619420000039
is the current of the sequence g1,
Figure BDA00032596194200000310
is the current of the sequence g2,
Figure BDA00032596194200000311
is the current of the h0 series,
Figure BDA00032596194200000312
is the current of the h1 series,
Figure BDA00032596194200000313
is the current of the h2 series,
Figure BDA00032596194200000314
is the voltage of the sequence e0 and,
Figure BDA00032596194200000315
is e1 series voltage，
Figure BDA00032596194200000316
Is the voltage of the sequence e2 and,
Figure BDA00032596194200000317
is the voltage of the sequence h0,
Figure BDA00032596194200000318
is the voltage of the sequence h1,
Figure BDA00032596194200000319
is h2 series voltage.
In an embodiment of the present invention, the analyzing the series-parallel relationship between the sequences according to the relationship between the voltage constraint and the current constraint neutral component, and calculating the impedance relationship between the sequences includes:
voltage in relation to the voltage constraint and the current constraint neutral component
Figure BDA00032596194200000320
Figure BDA00032596194200000321
Determining the e1 sequence and the h1 sequence as a parallel relation;
current in a relationship according to the voltage constraint and the current constraint neutral component
Figure BDA00032596194200000322
Figure BDA00032596194200000323
Calculating the impedance of the h1 order to be 3Z by combining U with Z multiplied by Ih1；
Wherein U is voltage, Z is impedance, I is current, and Z ish1Is an h1 series impedance.
In an embodiment of the present invention, the determining the sequence voltages and the sequence currents according to the composite sequence diagram, the voltage constraints and the current constraints when the three-circuit three-phase disconnection fault occurs includes:
determining the e1 sequence voltage by using a composite sequence network diagram during the three-circuit three-phase disconnection fault
Figure BDA00032596194200000324
Calculating sequence voltages of f1 sequence, g1 sequence and h1 sequence and the sequence currents according to the voltage constraint and the voltage constraint;
wherein Z ish1Is h1 order impedance, Ze1Is an e 1-sequence impedance,
Figure BDA00032596194200000325
the comprehensive electromotive force is seen into the system at the broken line.
In an embodiment of the present invention, the analyzing the three-wire three-phase disconnection fault according to the disconnection voltage at the disconnection point and the normal phase current comprises:
identifying a broken line fault line according to the broken line voltage and the normal phase current at the broken line position;
and judging the specific position of the line break fault according to the line break pre-sequence voltage and post-sequence voltage of the line break fault line and the change of the normal phase current, and cutting off the line break fault.
The invention also provides a device for analyzing the three-phase line-breaking fault of the same-pole four-circuit line and three-circuit line, which comprises the following components:
the determining and restraining module is used for determining voltage restraint and current restraint according to boundary conditions of three-phase line breaking faults of three lines in the four lines;
the sequence network diagram drawing module is used for drawing a composite sequence network diagram of the three-loop three-phase disconnection fault according to the relation between the voltage constraint and the current constraint sequence component;
the sequence voltage and current calculation module is used for determining each sequence voltage and each sequence current according to a composite sequence network diagram of the three-loop three-phase disconnection fault, the voltage constraint and the current constraint;
the line break voltage and current calculation module is used for calculating the line break voltage and the normal phase current at the line break position according to the voltage of each sequence, the current of each sequence and the relation between the voltage and the current of each sequence at the line break position;
and the fault analysis module is used for analyzing the three-loop three-phase line break fault according to the line break voltage at the line break position and the normal phase current.
The invention also provides equipment for analyzing the three-phase line break fault of the same-pole four-circuit line three-circuit line, which comprises the following components:
a memory for storing a computer program; and the processor is used for realizing the steps of the same-pole four-circuit line three-phase disconnection fault analysis method when executing the computer program.
The invention also provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and when the computer program is executed by a processor, the steps of the method for analyzing the three-circuit three-phase line breaking fault of the same-pole four-circuit line are realized.
The invention provides a method for analyzing the three-circuit three-phase wire break fault of a same-pole four-circuit line, which comprises the steps of firstly determining voltage constraint and current constraint according to the boundary conditions of the three-circuit three-phase wire break fault, then determining the relation of components of each sequence in the voltage constraint and the current constraint, then determining the series-parallel relation and the impedance relation among the sequences, drawing a composite sequence network diagram when the three-circuit three-phase wire break fault occurs, determining the voltage and the current of each sequence according to the composite sequence network diagram, the voltage constraint and the current constraint of each sequence, calculating the wire break voltage and the normal phase current at the wire break according to the voltage, the current of each sequence and the relation between the voltage and the current of each sequence at the wire break, and finally analyzing the three-circuit three-phase wire break fault of the same-pole four-circuit three-circuit based on the composite sequence network diagram, the method provides a basic theory for analyzing the electrical quantity characteristic when the same-pole four-circuit three-circuit line is broken, provides an effective tool for the research of protection action characteristics and system stability, and makes up the defect of the same-pole four-circuit line fault in broken line fault analysis.
Drawings
In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
Fig. 1 is a flowchart of a three-phase disconnection fault analysis method for a same-pole four-circuit line three-circuit line in accordance with a first embodiment of the present invention;
fig. 2 is a flowchart of a three-phase disconnection fault analysis method for three circuit lines on the same pole with four circuit lines according to a second embodiment of the present invention;
FIG. 3 is a diagram of impedance structure of four loops on the same pole;
FIG. 4a is a generic positive sequence diagram;
FIG. 4b is an e-sequence diagram;
FIG. 5 is a 12-order fault component sequence diagram;
wherein, FIG. 5a is a net-ordering diagram of e1 and e 2;
FIG. 5b is a net view of e 0;
FIG. 5c is a net graph of sequences f1, g1, h1, f2, g2, h 2;
FIG. 5d is a net view of f0, g0, h 0;
FIG. 6 is a composite sequence diagram of three-circuit three-phase simultaneous power failure;
fig. 7 is a block diagram of a device for analyzing a three-phase disconnection fault of a same-pole four-circuit line and a three-circuit line according to an embodiment of the present invention.
Detailed Description
The core of the invention is to provide a method, a device, equipment and a computer readable storage medium for analyzing three-circuit three-phase line break faults of a same-pole four-circuit line, and the problem of two-circuit three-phase line break faults is effectively solved.
In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a flowchart illustrating a three-phase disconnection fault analysis method for three circuit lines of a four-circuit line on the same tower according to a first embodiment of the present invention; the specific operation steps are as follows:
step S101: determining voltage constraint and current constraint according to boundary conditions of two-loop three-phase disconnection faults in four loops on the same pole;
step S102: drawing a composite sequence network diagram when the two-loop three-phase disconnection fault occurs according to the relation between the voltage constraint and the current constraint middle-sequence component;
step S103: determining each sequence voltage and each sequence current according to a composite sequence network diagram, the voltage constraint and the current constraint when the two-loop three-phase disconnection fault occurs;
step S104: calculating the line break voltage and the normal phase current at the line break position according to the relation among the voltage, the current and the voltage and the current at the line break position;
step S105: and analyzing the two-circuit three-phase disconnection fault according to the disconnection voltage at the disconnection position and the normal phase current.
In the method provided by the embodiment, voltage constraint and current constraint are determined according to the boundary condition of the two-loop three-phase disconnection fault, a composite sequence network diagram is drawn according to the sequence component relation in the constraint condition, then, the voltage and the current of each sequence are calculated according to the composite sequence network diagram, and then, the disconnection voltage and the normal phase current at the disconnection position are calculated for fault analysis; the method carries out deep research on the same-pole four-circuit line disconnection fault analysis, researches a calculation and analysis method of the same-pole four-circuit line disconnection fault, makes up for the same-pole four-circuit line disconnection fault analysis, and has important significance for perfecting the same-pole four-circuit line disconnection fault analysis.
Based on the above embodiment, in this embodiment, the above embodiment is described in more detail, first, a 12-sequence component method is used to decouple a four-circuit matrix on the same pole, and a disconnected fault analysis is performed by using the decoupled matrix, please refer to fig. 2, where fig. 2 is a flowchart of a second specific embodiment of a three-circuit three-phase disconnected fault analysis method for a four-circuit line on the same pole provided by the present invention; the method provided by the embodiment specifically comprises the following operation steps:
step S201: decoupling the same-pole four-loop matrix by using a 12-sequence component algorithm;
as shown in FIG. 3, the structure of the same pole four-wire loop is that the self-impedance of the line is set to ZsThe mutual impedances of the lines are respectively equal and are ZmThe mutual impedances of different loops are also equal, denoted as Zx。
In the same-pole four-loop shown in the above figure, the phase voltage and the phase current of the four-loop have a matrix equation (1-1) between them:
Figure BDA0003259619420000071
it is briefly described as
Figure BDA0003259619420000072
Wherein
Figure BDA0003259619420000073
Is the voltage drop of the three phases of the first loop,
Figure BDA0003259619420000074
Figure BDA0003259619420000075
is the voltage drop of the three phases of the second loop,
Figure BDA0003259619420000076
is the voltage drop of the three phases of the third loop,
Figure BDA0003259619420000077
voltage drop of three phases of the fourth circuit is achieved;
Figure BDA0003259619420000078
the phase currents for the three phases of the first loop,
Figure BDA0003259619420000079
the phase currents of the three phases of the second return line,
Figure BDA00032596194200000710
the phase currents of three phases of the third circuit are returned,
Figure BDA00032596194200000711
the phase current of the three phases of the fourth circuit is shown.
Figure BDA00032596194200000712
For the same pole four-circuit line voltage drop,
Figure BDA00032596194200000713
phase current column vector of four loops on the same pole, [ Z ]]The impedance matrix of four loops is shown, the elements on the diagonal line represent the self-impedance of each phase, and the elements on the non-diagonal line represent the inter-phase mutual impedance of each phase on the single loop and the inter-line mutual impedance of each loop respectively. Because mutual inductance exists between 12 electrical quantities of the ABC three phases of the four loops on the same pole, decoupling needs to be researched firstly when the four loops are researched, namely the mutual inductance is eliminated. The decoupling is carried out in two steps: and the mutual inductance between the outside lines of the loops is eliminated, and then the mutual inductance between the phases inside the loops is eliminated. The impedance matrix is transformed into a diagonal matrix, namely, other elements except the diagonal are zero, 12 electrical quantities are decoupled into independent 12-sequence components, and mutual inductance does not exist any more.
Let the decoupling matrix be:
Figure BDA0003259619420000081
wherein a ═ ej120°
The decoupled voltage and current matrix is:
Figure BDA0003259619420000083
the two-loop phase-mode transformation is noted as:
Figure BDA0003259619420000091
wherein,
Figure BDA0003259619420000092
is a sequence voltage of a 12-sequence component,
Figure BDA0003259619420000093
is the voltage of the sequence e0 and,
Figure BDA0003259619420000094
is the voltage of the sequence f0,
Figure BDA0003259619420000095
is the voltage of the sequence g0 and,
Figure BDA0003259619420000096
is the voltage of the sequence h0,
Figure BDA0003259619420000097
is the voltage of the sequence e1 and,
Figure BDA0003259619420000098
is the voltage of the sequence f1,
Figure BDA0003259619420000099
is the voltage of the sequence g1 and,
Figure BDA00032596194200000910
is the voltage of the sequence h1,
Figure BDA00032596194200000911
is the voltage of the sequence f2,
Figure BDA00032596194200000912
is the voltage of the sequence f2,
Figure BDA00032596194200000913
is the voltage of the sequence g2 and,
Figure BDA00032596194200000914
h2 series voltage;
Figure BDA00032596194200000915
is a sequence current of a 12-sequence component,
Figure BDA00032596194200000916
is the current of the sequence e0,
Figure BDA00032596194200000917
is the current of the sequence e1,
Figure BDA00032596194200000918
is the current of the sequence e2,
Figure BDA00032596194200000919
is the current of the sequence f0,
Figure BDA00032596194200000920
is the current of the sequence f1,
Figure BDA00032596194200000921
is the current of the sequence f2,
Figure BDA00032596194200000922
is the current of the sequence g0,
Figure BDA00032596194200000923
is the current of the sequence g1,
Figure BDA00032596194200000924
is the current of the sequence g2,
Figure BDA00032596194200000925
is the current of the h0 series,
Figure BDA00032596194200000926
is the current of the h1 series,
Figure BDA00032596194200000927
is h2 series current.
From equation (1-2), one can deduce:
Figure BDA00032596194200000928
unfolding the formula (1-3) to obtain:
Figure BDA0003259619420000101
wherein z ise0＝zs+2zm+9zx，zf0＝zg0＝zho＝zs+2zm-3zx，
ze1＝zf1＝zg1＝zh1＝ze2＝zf2＝zg2＝zh2＝zs-zm。
ze0Is an e0 series impedance, zf0Is f0 order impedance, zg0Is the g0 series impedance; z is a radical ofh0Is h0 order impedance, ze1Is an e0 series impedance, zf1Is f0 order impedance, zg1Is the g0 series impedance; z is a radical ofh1Is h0 order impedance, ze2Is an e0 series impedance, zf2Is f0 order impedance, zg2Is the g0 series impedance; z is a radical ofh2Is an h0 series impedance.
It can be seen from the inverse matrix of M that the e-sequence component reflects the co-current of the four lines, and the f-sequence component, g-sequence component and h-sequence component reflect the loop current in the four lines on the same pole. The f-sequence component, the g-sequence component and the h-sequence component only circulate in the same pole four-circuit line and do not flow out of the same pole four-circuit line, so that the voltages of the sequence components f, g and h on the buses at two ends of the same pole four-circuit line are zero, and only e-sequence voltage and current exist outside the same pole four-circuit line.
The connection between the four-circuit line on the same pole and the external system is embodied by the e-sequence component, but the e-sequence component is not directly connected with the positive sequence network of the external system but needs to be correspondingly processed. From the inverse matrix of M:
Figure BDA0003259619420000111
wherein, (i ═ 0,1, 2).
As can be seen from the equation, the e1 sequence voltage is equal to the positive sequence voltage of the four-circuit line divided by 4, i.e., the average value. Referring to the positive sequence (012) diagram of fig. 4, since the four lines are all connected to the line left end bus M, the positive sequence voltages of the four lines are equal, and thus the voltage at bus M, e1 is equal to the normal positive sequence voltage. For current, the e1 current flowing through the system impedance is equal to the sum of the positive sequence currents of the four-circuit line divided by 4, whereas the positive sequence current flowing through the system impedance in a normal positive sequence network is the sum of the positive sequence currents of the four-circuit line, so the e1 sequence current is 1/4 of the normal positive sequence current. According to ohm's law, the left system impedance in the e1 sequence net diagram should be corrected to 4 times the value of the system impedance of the normal positive sequence net. The same applies to the e0 procedure and the e2 procedure, and the N-side system impedance correction method is the same as the M-side. The common positive net-ordering diagram and the e-net-ordering diagram of the four-circuit line on the same pole can be seen in fig. 4.
Step S202: drawing each sequence network diagram of the broken line fault according to each sequence network diagram of the short circuit fault, and determining the relation between each sequence voltage and current at the broken line;
according to the sequence network diagrams of the short-circuit faults, the sequence network diagrams of the broken line faults can be drawn, but when the broken line faults are different from the short-circuit faults, the sequence impedance is in a series relation when the broken line faults are seen from the broken port. A 12-order fault component sequence net diagram is shown in fig. 5.
From the 12-sequence component method, only the e1 sequence is an active network, and the other sequence components are passive networks. The voltage and current equations at the line break are as follows:
Figure BDA0003259619420000121
Figure BDA0003259619420000122
respectively, the voltage components of each sequence at the broken line,
Figure BDA0003259619420000123
for the combined electromotive force of the broken wire looking into the system, wherein
Figure BDA0003259619420000124
E is the equivalent electromotive force on both sides of the line, delta is the phase angle between the electromotive forces on both sides of the line,
Figure BDA0003259619420000125
(i is 0,1,2) is the current component of each sequence at the broken line,
Figure BDA0003259619420000126
Figure BDA0003259619420000127
respectively, the impedance of each sequence looking into the system from the broken line.
Step S203: determining voltage constraint and current constraint according to boundary conditions of three-phase disconnection faults of two lines of a four-line circuit;
taking three-phase line breaking faults of I, II and III loops as an example, the boundary conditions are as follows:
Figure BDA0003259619420000128
wherein,
Figure BDA0003259619420000129
is a return line A phase current at the broken line,
Figure BDA00032596194200001210
is a return line B phase current at the broken line,
Figure BDA00032596194200001211
is a return line C phase current at the broken line,
Figure BDA00032596194200001212
the phase A current of the two return wires at the broken wire position,
Figure BDA00032596194200001213
the B-phase current of the two return wires at the broken wire position,
Figure BDA00032596194200001214
the phase C current of the two return wires at the broken wire position,
Figure BDA00032596194200001215
three return wires of phase A current at the broken wire position,
Figure BDA00032596194200001216
three return wires at the broken line are used for B-phase current,
Figure BDA00032596194200001217
three return wires of phase C current at the broken wire position,
Figure BDA00032596194200001218
for the phase A voltage drop of the four-circuit line at the broken line,
Figure BDA00032596194200001219
for the voltage drop of the phase B of the four-circuit line at the broken line,
Figure BDA00032596194200001220
the voltage drop of the phase C of the four-circuit line at the broken line is shown.
By substituting the above formula (2-1) for the formula (1-2), the relationship of the respective sequence components can be obtained as follows:
Figure BDA0003259619420000131
through simplification, the method can obtain:
Figure BDA0003259619420000132
wherein a ═ ej120°，
Figure BDA0003259619420000133
Is the current of the sequence e0,
Figure BDA0003259619420000134
is the current of the sequence e1,
Figure BDA0003259619420000135
is the current of the sequence e2,
Figure BDA0003259619420000136
is the current of the sequence f0,
Figure BDA0003259619420000137
is the current of the sequence f1,
Figure BDA0003259619420000138
is the current of the sequence f2,
Figure BDA0003259619420000139
is the current of the sequence g0,
Figure BDA00032596194200001310
is the current of the sequence g1,
Figure BDA00032596194200001311
is the current of the sequence g2,
Figure BDA00032596194200001312
is the current of the h0 series,
Figure BDA00032596194200001313
is the current of the h1 series,
Figure BDA00032596194200001314
is the current of the h2 series,
Figure BDA00032596194200001315
is the voltage of the sequence e0 and,
Figure BDA00032596194200001316
is the voltage of the sequence e1 and,
Figure BDA00032596194200001317
is the voltage of the sequence e2 and,
Figure BDA00032596194200001318
is the voltage of the sequence h0,
Figure BDA00032596194200001319
is the voltage of the sequence h1,
Figure BDA00032596194200001320
is h2 series voltage.
Step S204: analyzing the series-parallel relation among the sequences according to the relation between the voltage constraint and the current constraint medium sequence component, calculating the impedance relation among the sequences, and drawing a composite sequence network diagram when the three-circuit three-phase disconnection fault occurs;
according to the voltage constraint and the current constraint conditions, a composite sequence network diagram of the three-phase disconnection fault of the I, II and III loop lines can be drawn, and as shown in fig. 6, the specific analysis is as follows:
except the sequence e1, the other 11-sequence components are passive networks, the sequence component which has no direct relation with the sequence e1 is 0 according to the relation between voltage and current, and the sequence components except the sequences e1, f1, g1 and h1 are all 0.
According to voltage relation
Figure BDA0003259619420000141
The e1 and h1 sequences can be set in parallel.
According to the current relation
Figure BDA0003259619420000142
The e1 order and the h1 order are connected in parallel. By comprehensively considering the voltage relation and the current relation, the e1 and g1 sequence voltage proportionality coefficients are 1, while the sequence current proportionality coefficients are not 1, and the h1 sequence impedance needs to be corrected. Hold h1 order current
Figure BDA0003259619420000143
Constant, hold sequence voltage
Figure BDA0003259619420000144
The constant h1 order impedance is corrected to 3Zh1；
Wherein Z ish1Is an h1 series impedance.
Step S205: determining each sequence voltage and each sequence current according to a composite sequence network diagram, the voltage constraint and the current constraint when the three-circuit three-phase disconnection fault occurs;
from FIG. 6, it can be quickly deduced
Figure BDA0003259619420000145
Equation (2-4):
Figure BDA0003259619420000146
the h 1-series voltage can be calculated by the following equation (2-3):
Figure BDA0003259619420000147
according to the e1 and f1 sequence current relationship in the formula (2-3)
Figure BDA0003259619420000148
The e1 and f1 sequence voltage relationships (2-5) can be obtained:
Figure BDA0003259619420000149
according to the relation between e1 and g1 sequence currents in the formula (2-3)
Figure BDA00032596194200001410
The voltage relationships of e1 and g1 can be obtained (2-6):
Figure BDA00032596194200001411
after e1, f1, g1 and h1 sequence voltages are obtained, the sequence currents can be calculated through (1-5);
wherein Z ish1Is h1 order impedance, Ze1Is an e1 series impedance, Zf1Is an impedance of the order of f1,
Figure BDA0003259619420000151
the comprehensive electromotive force is seen into the system at the broken line.
Step S206: calculating the line break voltage and the normal phase current at the line break position according to the relation among the voltage, the current and the voltage and the current at the line break position;
using the above-obtained e1, f1, g1 and h1 series voltages and e1, f1, g1 and h1 series currents according to the formula (1-2)
Figure BDA0003259619420000152
And calculating the voltage between the two points of the broken line and the normal phase current.
Step S207: and analyzing the two-circuit three-phase disconnection fault according to the disconnection voltage at the disconnection position and the normal phase current.
The ungrounded fault is generated after the light load line is broken, and the fault component is difficult to collect and distinguish due to the fact that the light load line has no obvious fault characteristics, and the fault is difficult to process. The invention researches the electric quantity characteristic when the same-pole four-circuit line three-circuit line is broken, provides an effective tool for the research of protection action characteristic and system stability, and can reliably judge whether the line breaking fault occurs, the type of the line breaking fault and the section where the break point is located according to the change rule of each phase current of the fault line and each phase voltage of the power supply side and the load side. The criterion based on the phase current and the phase voltage is convenient to realize, the influence of abnormal conditions such as line break of the mutual inductor, non-full-phase operation, system asymmetry and the like can be better overcome, and the line break fault of the light and no-load line can be correctly judged.
The method provided by the embodiment of the invention comprises the steps of calculating a matrix of four circuit lines on the same pole by using a 12-sequence component method to obtain a decoupled matrix, determining voltage and current constraints according to boundary conditions of three-phase disconnection faults of three circuit lines, analyzing the voltage and current relations among the sequences, drawing a composite sequence network diagram, calculating e1 sequence voltage with only one unknown quantity by using the composite sequence network diagram, calculating other sequence voltage and sequence current according to the voltage constraint and current constraint relations, and calculating disconnection voltage and normal phase current at the disconnection position by using the sequence voltage and the sequence current, wherein the method provided by the invention analyzes the three-phase disconnection faults of the three circuit lines by using the 12-sequence component method, reduces the calculation difficulty, improves the calculation precision, compensates the disconnection fault calculation and analysis of the four circuit lines on the same pole, and provides a method for analyzing the disconnection faults of three circuit lines on the same pole and three circuit lines simultaneously based on the composite sequence network diagram, a basic theory is provided for analyzing the electrical quantity characteristic when the same pole four-circuit line three-circuit line is broken, and an effective tool is provided for the research of the protection action characteristic and the system stability; the method has important significance for perfecting fault analysis of four circuit lines on the same pole.
Referring to fig. 7, fig. 7 is a block diagram of a device for analyzing a three-phase disconnection fault of two lines on a same-pole four-line circuit according to an embodiment of the present invention; the specific device may include:
the determining and restraining module 100 is used for determining voltage restraint and current restraint according to boundary conditions of three-circuit line three-phase line break faults in four circuit lines;
a net-sequencing graph drawing module 200, configured to draw a composite net-sequencing graph of the three-loop three-phase disconnection fault according to a relationship between the voltage constraint and a neutral component in the current constraint;
the sequence voltage and current calculation module 300 is configured to determine each sequence voltage and each sequence current according to a composite sequence network diagram of the three-loop three-phase disconnection fault, the voltage constraint and the current constraint;
a line break voltage and current calculation module 400, configured to calculate a line break voltage and a normal phase current at a line break according to the voltage of each sequence, the current of each sequence, and a relationship between the voltage of each sequence and the current at the line break;
and the fault analysis module 500 is configured to analyze the three-loop three-phase disconnection fault according to the disconnection voltage at the disconnection point and the normal phase current.
The apparatus for analyzing a three-phase wire break fault of a same-pole four-circuit line three-circuit line in this embodiment is used to implement the aforementioned method for analyzing a three-phase wire break fault of a same-pole four-circuit line three-circuit line, so specific embodiments in the apparatus for analyzing a three-phase wire break fault of a same-pole four-circuit line three-circuit line in the same-pole four-circuit line three-phase wire break fault may be found in the embodiments of the method for analyzing a three-phase wire break fault of a same-pole four-circuit line three-circuit line in the foregoing, for example, the constraint determining module 100, the sequence diagram drawing module 200, the sequence voltage and current calculating module 300, the wire break voltage and current calculating module 400, and the fault analyzing module 200 are respectively used to implement steps S101, S102, S103, S104, and S105 in the method for analyzing a three-phase wire break fault of a same-pole four-circuit line three-phase wire break fault.
The specific embodiment of the present invention further provides a device for analyzing a three-phase disconnection fault of a three-circuit line of a four-circuit line on the same pole, including: a memory for storing a computer program; and the processor is used for realizing the steps of the same-pole four-circuit line three-phase disconnection fault analysis method when executing the computer program.
The specific embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method for analyzing the three-phase line break fault of the same-pole four-circuit line three-circuit line are implemented.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The method, the device, the equipment and the computer readable storage medium for analyzing the three-phase line breaking fault of the same-pole four-circuit line three-circuit line provided by the invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims (10)

1. A three-circuit three-phase line break fault analysis method for a same-pole four-circuit line is characterized by comprising the following steps:
determining voltage constraint and current constraint according to boundary conditions of three-circuit line three-phase disconnection faults in the four-circuit line;
drawing a composite sequence network diagram when the three-circuit three-phase disconnection fault occurs according to the relation between the voltage constraint and the current constraint neutral component;
determining each sequence voltage and each sequence current according to the composite sequence network diagram of the three-loop three-phase disconnection fault, the voltage constraint and the current constraint;
calculating the line break voltage and the normal phase current at the line break position according to the relation among the voltage, the current and the voltage and the current at the line break position;
and analyzing the three-loop three-phase line breakage fault according to the line breakage voltage and the normal phase current at the line breakage position.
2. The method of claim 1, wherein the boundary conditions of a three-wire three-phase disconnection fault in the four-wire line are as follows:
Figure FDA0003259619410000011
wherein,
Figure FDA0003259619410000012
is a return line A phase current at the broken line,
Figure FDA0003259619410000013
is a return line B phase current at the broken line,
Figure FDA0003259619410000014
is a return line C phase current at the broken line,
Figure FDA0003259619410000015
the phase A current of the two return wires at the broken wire position,
Figure FDA0003259619410000016
the B-phase current of the two return wires at the broken wire position,
Figure FDA0003259619410000017
the phase C current of the two return wires at the broken wire position,
Figure FDA0003259619410000018
three loops at the broken lineThe phase of the line a phase current,
Figure FDA0003259619410000019
three return wires at the broken line are used for B-phase current,
Figure FDA00032596194100000110
three return wires of phase C current at the broken wire position,
Figure FDA00032596194100000111
for the phase A voltage drop of the four-circuit line at the broken line,
Figure FDA00032596194100000112
for the voltage drop of the phase B of the four-circuit line at the broken line,
Figure FDA00032596194100000113
the voltage drop of the phase C of the four-circuit line at the broken line is shown.
3. The method of claim 1, wherein said plotting a composite net graph of said three loop three phase open fault from said voltage constraint versus said current constraint neutral component comprises:
determining a relationship of the voltage constraint and a neutral component of the current constraint according to the voltage constraint and the current constraint;
analyzing the series-parallel connection relation among the sequences according to the relation between the voltage constraint and the current constraint intermediate-sequence component, and calculating the impedance relation among the sequences;
and drawing a composite sequence network diagram when the three-circuit three-phase disconnection fault occurs according to the series-parallel connection among the sequences and the impedance relation among the sequences.
4. The method of claim 1, wherein the voltage constraint and the current constraint have a relationship of a neutral-order component:
Figure FDA0003259619410000021
wherein,
Figure FDA0003259619410000022
is the current of the sequence e0,
Figure FDA0003259619410000023
is the current of the sequence e1,
Figure FDA0003259619410000024
is the current of the sequence e2,
Figure FDA0003259619410000025
is the current of the sequence f0,
Figure FDA0003259619410000026
is the current of the sequence f1,
Figure FDA0003259619410000027
is the current of the sequence f2,
Figure FDA0003259619410000028
is the current of the sequence g0,
Figure FDA0003259619410000029
is the current of the sequence g1,
Figure FDA00032596194100000210
is the current of the sequence g2,
Figure FDA00032596194100000211
is the current of the h0 series,
Figure FDA00032596194100000212
is the current of the h1 series,
Figure FDA00032596194100000213
is the current of the h2 series,
Figure FDA00032596194100000214
is the voltage of the sequence e0 and,
Figure FDA00032596194100000215
is the voltage of the sequence e1 and,
Figure FDA00032596194100000216
is the voltage of the sequence e2 and,
Figure FDA00032596194100000217
is the voltage of the sequence h0,
Figure FDA00032596194100000218
is the voltage of the sequence h1,
Figure FDA00032596194100000219
is h2 series voltage.
5. The method of claim 3, wherein analyzing series-parallel relationships between sequences according to relationships of the voltage constraint and the current constraint neutral component and calculating impedance relationships between the sequences comprises:
voltage in relation to the voltage constraint and the current constraint neutral component
Figure FDA00032596194100000220
Figure FDA00032596194100000221
Determining the e1 sequence and the h1 sequence as a parallel relation;
current in a relationship according to the voltage constraint and the current constraint neutral component
Figure FDA00032596194100000222
Figure FDA00032596194100000223
Calculating the impedance of the h1 order to be 3Z by combining U with Z multiplied by Ih1；
Wherein U is voltage, Z is impedance, I is current, and Z ish1Is an h1 series impedance.
6. The method of claim 1, wherein determining the sequence voltages and the sequence currents according to the composite sequence grid map, the voltage constraints and the current constraints at the time of the three-wire three-phase disconnection fault comprises:
determining the e1 sequence voltage by using a composite sequence network diagram during the three-circuit three-phase disconnection fault
Figure FDA00032596194100000224
Calculating sequence voltages of f1 sequence, g1 sequence and h1 sequence and the sequence currents according to the voltage constraint and the voltage constraint;
wherein Z ish1Is h1 order impedance, Ze1Is an e 1-sequence impedance,
Figure FDA0003259619410000031
the comprehensive electromotive force is seen into the system at the broken line.
7. The method of claim 1, wherein analyzing the three-wire, three-phase line break fault based on the line break voltage at the line break and the normal phase current comprises:
identifying a broken line fault line according to the broken line voltage and the normal phase current at the broken line position;
and judging the specific position of the line break fault according to the line break pre-sequence voltage and post-sequence voltage of the line break fault line and the change of the normal phase current, and cutting off the line break fault.
8. The utility model provides a device of three-phase broken string fault analysis of three return wires of four circuit lines on same pole which characterized in that includes:
the determining and restraining module is used for determining voltage restraint and current restraint according to boundary conditions of three-phase line breaking faults of three lines in the four lines;
the sequence network diagram drawing module is used for drawing a composite sequence network diagram of the three-loop three-phase disconnection fault according to the relation between the voltage constraint and the current constraint sequence component;
the sequence voltage and current calculation module is used for determining each sequence voltage and each sequence current according to a composite sequence network diagram of the three-loop three-phase disconnection fault, the voltage constraint and the current constraint;
the line break voltage and current calculation module is used for calculating the line break voltage and the normal phase current at the line break position according to the voltage of each sequence, the current of each sequence and the relation between the voltage and the current of each sequence at the line break position;
and the fault analysis module is used for analyzing the three-loop three-phase line break fault according to the line break voltage at the line break position and the normal phase current.
9. The utility model provides a three-circuit line three-phase disconnection fault analysis's of four circuit lines on same pole equipment which characterized in that includes:
a memory for storing a computer program;
a processor for implementing the steps of the method for analyzing the three-phase line break fault of the same-pole four-circuit line three-circuit line as claimed in any one of claims 1 to 7 when executing the computer program.
10. A computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and when executed by a processor, the computer program implements the steps of the method for analyzing the three-circuit three-phase disconnection fault of the four-circuit line on the same pole according to any one of claims 1 to 7.
CN202111069593.3A 2021-09-13 2021-09-13 Method and device for analyzing three-circuit three-phase line breaking fault of same-pole four-circuit line Pending CN114019293A (en)

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