CN115524574A - Method and device for measuring distance between fault points - Google Patents

Method and device for measuring distance between fault points Download PDF

Info

Publication number
CN115524574A
CN115524574A CN202110712605.3A CN202110712605A CN115524574A CN 115524574 A CN115524574 A CN 115524574A CN 202110712605 A CN202110712605 A CN 202110712605A CN 115524574 A CN115524574 A CN 115524574A
Authority
CN
China
Prior art keywords
fault
current
point
impedance
voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202110712605.3A
Other languages
Chinese (zh)
Inventor
张洪喜
赵青春
徐晓春
谢华
戴光武
徐海洋
卜立之
黄涛
陆金凤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NR Electric Co Ltd
NR Engineering Co Ltd
Original Assignee
NR Electric Co Ltd
NR Engineering Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NR Electric Co Ltd, NR Engineering Co Ltd filed Critical NR Electric Co Ltd
Priority to CN202110712605.3A priority Critical patent/CN115524574A/en
Publication of CN115524574A publication Critical patent/CN115524574A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/088—Aspects of digital computing
    • 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

Abstract

The application provides a fault point distance measuring method and device. A method of measuring a distance to a fault point, comprising: calculating system impedance according to voltage and current change before and after the line fault of the protection point; calculating a fault current distribution coefficient according to the system impedance and the line impedance; calculating a fault current component according to the measured current before and after the line has a fault; calculating fault current of a fault point according to the fault current distribution coefficient and the fault current component; obtaining a measured impedance equation between the protection point and the fault point according to the measured voltage and the measured current; and calculating the distance between the fault point and the protection point according to the measured impedance equation. According to the fault point distance measuring method, the fault current distribution coefficient can be accurately calculated, and the influences of transition resistance and load current are considered.

Description

Fault point distance measuring method and device
Technical Field
The application relates to the power grid technology, in particular to a fault point distance measuring method and device.
Background
The transmission line of the power system is responsible for transmitting electric energy. And is the most prone to failure in the system. After the line breaks down, the fault point can be quickly and accurately found, the line can be timely repaired to ensure the power supply reliability, and meanwhile, the method has very important significance for the safe and stable operation of the power system.
At present, fault location methods are various and can be divided into an impedance analysis method and a traveling wave method according to a basic principle.
The traveling wave method is a distance measurement method realized according to a traveling wave theory, and the traveling wave method needs higher sampling frequency, so special software and hardware resources are needed, and the use cost is increased.
Impedance-based analysis methods include single-ended ranging and double-ended ranging.
The existing single-end distance measurement method cannot obtain the electric quantity of the opposite side, the algorithm of the method is based on certain hypothesis premise, and the distance measurement error is large when the fault of the transition resistor occurs.
The double-end ranging method requires strict synchronization of data on two sides, and requires transmission of electric quantities such as voltage, current and the like on the opposite side to the local side, so that large data transmission quantity is required. In addition, the double-end ranging generally adopts a zero sequence or negative sequence component method, and the ranging error is larger when the zero sequence or negative sequence component is smaller. In particular, a three-phase fault cannot employ the double-ended ranging principle.
Therefore, a method and an apparatus for measuring the distance between fault points are needed, which accurately calculate the fault current distribution coefficient by calculating the system impedance on both sides in real time and take the influence of the transition resistance and the load current into consideration. The method is based on strict theoretical derivation and mathematical modeling, and improves the ranging precision, particularly the ranging precision when passing through a transition resistance fault.
The above information disclosed in this background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.
Disclosure of Invention
The application aims to provide a fault point distance measuring method and device, which accurately calculate a fault current distribution coefficient by calculating system impedances at two sides in real time so as to adapt to different system operation modes. Meanwhile, the influence of the transition resistance and the load current on the distance measurement is considered, so that the purpose of improving the distance measurement precision is achieved.
According to an aspect of the present application, there is provided a method for measuring a distance to a fault point, including:
calculating system impedance according to the voltage and current variation before and after the line fault occurs at the protection point;
calculating a fault current distribution coefficient according to the system impedance and the line impedance;
calculating a fault current component according to the measured current before and after the line has a fault;
calculating fault point fault current according to the fault current distribution coefficient and the fault current component;
obtaining a measured impedance equation between the protection point and the fault point according to the measured voltage and the measured current;
and calculating the distance between the fault point and the protection point according to the measured impedance equation.
According to some embodiments, the calculating the system impedance according to the voltage and current changes before and after the line fault occurs at the protection point comprises:
subtracting the voltage before the fault from the voltage after the fault to obtain the voltage variation before and after the fault of the line
Figure BDA0003134291180000021
Subtracting the current before the fault from the current after the fault to obtain the current variation before and after the fault of the line
Figure BDA0003134291180000022
The voltage variation before and after the line failure
Figure BDA0003134291180000023
Dividing by the amount of current change before and after the line fault
Figure BDA0003134291180000024
Obtaining the system impedance Z S The calculation formula is as follows:
Figure BDA0003134291180000025
according to some embodiments, said calculating a fault current distribution coefficient from the system impedance and the line impedance comprises:
obtaining the system impedance Z of the local side SM And contralateral system impedance Z SN ；
Impedance Z of the contralateral system SN Transmitting to the local side through the communication equipment;
according to the system impedance Z S And line impedance Z L Calculating the fault current distribution coefficient C m The calculation formula is as follows;
Figure BDA0003134291180000026
k is the length coefficient from the protection point to the fault point.
In accordance with some embodiments of the present invention,the contralateral system impedance Z SN And then transmitted to the local side through the communication equipment.
According to some embodiments, the calculating the fault current component from the measured current before and after the line fault comprises:
calculating fault current component according to current variation before and after line fault
Figure BDA0003134291180000027
Said fault current component
Figure BDA0003134291180000028
Including a ground fault current component
Figure BDA0003134291180000029
And phase-to-phase fault current component
Figure BDA00031342911800000210
The ground fault current component
Figure BDA00031342911800000211
The calculation method is that the phase current before and after the line fault occurs
Figure BDA00031342911800000212
Minus zero sequence current
Figure BDA00031342911800000213
Is multiplied by
Figure BDA00031342911800000214
The calculation formula is as follows:
Figure BDA0003134291180000031
the phase-to-phase fault current component
Figure BDA0003134291180000032
The calculation method is that the inter-phase current before and after the line fault occurs
Figure BDA0003134291180000033
The calculation formula of the variation amount of (c) is as follows:
Figure BDA0003134291180000034
according to some embodiments, said calculating a fault point fault current from said fault current distribution coefficient and a fault component current comprises:
said fault current component
Figure BDA0003134291180000035
Divided by the fault current distribution coefficient C m Obtaining fault current of fault point
Figure BDA0003134291180000036
The calculation formula is as follows:
Figure BDA0003134291180000037
according to some embodiments, the obtaining a measured impedance equation between the protection point and the fault point from the measured voltage and current includes:
post-fault protection point measurement voltage
Figure BDA0003134291180000038
Equal to the measured current
Figure BDA0003134291180000039
Impedance k x Z from protection point to fault point L Voltage drop over plus fault current at fault point
Figure BDA00031342911800000310
At transition resistance R F The pressure drop over, the calculation is as follows:
Figure BDA00031342911800000311
according to some embodiments, the obtaining a measured impedance equation between the protection point and the fault point from the measured voltage and current comprises:
when earth fault occurs, the protection point measures voltage after fault
Figure BDA00031342911800000312
Is a phase voltage
Figure BDA00031342911800000313
Measuring current
Figure BDA00031342911800000314
The calculation formula is as follows:
Figure BDA00031342911800000315
Figure BDA00031342911800000316
in order to measure the current in a single phase,
Figure BDA00031342911800000317
for measuring zero sequence current;
K 0 for the zero sequence compensation coefficient, the calculation formula is as follows:
Figure BDA00031342911800000318
Z L0 is zero sequence impedance, Z L1 Is a positive sequence impedance.
According to some embodiments, the obtaining a measured impedance equation between the protection point and the fault point from the measured voltage and current includes:
measuring voltage during phase-to-phase fault
Figure BDA00031342911800000319
Is voltage between phases
Figure BDA00031342911800000320
Measuring current
Figure BDA0003134291180000041
Figure BDA0003134291180000042
The current is measured for the phases.
According to some embodiments, said calculating a distance between said fault point and said protection point according to said measured impedance equation comprises:
the measured impedance equation is a complex equation, and the real part and the imaginary part of the complex equation are separated to obtain a length coefficient k and a transition resistance R F A system of binary quadratic equations of (1);
solving a length coefficient k and eliminating a pseudo root;
multiplying the true value k by the line length parameter yields the fault location.
According to some embodiments, said finding the length coefficient k, rejecting the pseudo-root, comprises:
the impedance measurement equation is simplified into a quadratic equation with one element about a length coefficient k, and two equations are solved;
according to the length coefficient k belonging to (0, 1), removing roots smaller than 0 or larger than 1;
and if the two are both more than or equal to 0 and less than or equal to 1, eliminating false roots according to the principle that the sum of the length coefficients of the two sides is 1 by combining the roots calculated by the fault measurement impedance equation of the opposite side protection device.
According to an aspect of the present application, an apparatus based on a fault point distance measurement method is provided, including:
the receiving module is used for receiving the electric quantity data required in calculation;
the protection module is used for judging faults and fault types and selecting different calculation methods;
the calculation module is used for calculating the electrical quantity data according to a calculation formula to realize fault point distance measurement;
a communication module for transmitting the calculated system impedance Z S 。
According to an aspect of the present application, a power transmission line fault ranging apparatus is provided, including:
one or more processors;
storage means for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement the method as recited in any one of the preceding claims.
According to the fault point distance measuring method and device, the system impedances on two sides can be calculated in real time to accurately calculate the fault current distribution coefficient, and the method and device are suitable for different system operation modes. And meanwhile, the influence of the transition resistance and the load current on the distance measurement is considered. The method is based on strict mathematical modeling and theoretical derivation, and the distance measurement precision is improved. In particular, the accuracy of distance measurement when passing through a transition resistance fault is improved.
Drawings
The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings. The drawings described below are for illustrative purposes only of certain embodiments of the present application and are not intended to limit the present application.
FIG. 1 illustrates a two-node system single-phase transition resistance fault schematic in accordance with an exemplary embodiment;
FIG. 2 (a) illustrates a two node system post-fault status diagram in accordance with an exemplary embodiment;
FIG. 2 (b) is a diagram illustrating a normal load condition prior to a failure of a two node system in accordance with an illustrative embodiment;
FIG. 2 (c) illustrates a fault-plus-state component schematic diagram after a two-node system fault in accordance with an exemplary embodiment;
FIG. 3 illustrates a flow chart of a method of distance to failure measurement in accordance with an exemplary embodiment;
FIG. 4 illustrates a block diagram of an apparatus based fault point distance measurement method in accordance with an exemplary embodiment;
FIG. 5 illustrates a system fault type diagram in accordance with an exemplary embodiment;
FIG. 6 illustrates yet another embodiment of a schematic diagram of the type of system fault according to an example;
fig. 7 shows a block diagram of a power line fault ranging apparatus according to an example embodiment.
Detailed Description
Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals denote the same or similar parts in the drawings, and thus, a repetitive description thereof will be omitted.
The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the embodiments of the disclosure can be practiced without one or more of the specific details, or with other means, components, materials, devices, or the like. In such cases, well-known structures, methods, devices, implementations, materials, or operations are not shown or described in detail.
The flowcharts shown in the figures are illustrative only and do not necessarily include all of the contents and operations/steps, nor do they necessarily have to be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the actual execution sequence may be changed according to the actual situation.
The terms "first," "second," and the like in the description and claims of the present application and in the foregoing drawings are used for distinguishing between different objects and not for describing a particular sequential order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.
It should be understood by those skilled in the art that the drawings are merely schematic representations of exemplary embodiments, and that the blocks or flowchart illustrations in the drawings are not necessarily required to practice the present application and, therefore, should not be considered to limit the scope of the present application.
The technical solution of the present application will be described in detail below with reference to the accompanying drawings.
Fig. 1 illustrates a two-node system single-phase transition resistance fault schematic according to an exemplary embodiment.
As shown in the figure 1 of the drawings,
Figure BDA0003134291180000061
for the two-sided system potential, the left side of the fault point F is defined as the home side, the right side of the point F is defined as the opposite side, Z SM Is the line local side system impedance, Z SN As the impedance of the contralateral system,
Figure BDA0003134291180000062
as the amount of voltage after the fault on the present side,
Figure BDA0003134291180000063
for the amount of voltage after the fault on the opposite side,
Figure BDA0003134291180000064
for the amount of current after the fault on the present side,
Figure BDA0003134291180000065
for the amount of post-contralateral fault current, Z L The total line impedance is shown as the total line impedance, where M is the protection point at the side, N is the protection point at the opposite side, F is the fault point, the total line length is 1, and the length from the protection point M to the fault point F is shown asThe number is k, and the length coefficient k belongs to (0, 1), the impedance from the local protection point M to the fault point F is k × Z L The impedance from the side protection point N to the fault point F is (1-k). Times.Z L ，R F In order to be the transition resistance, the resistance,
Figure BDA0003134291180000066
for fault current at fault point, the electric quantities are voltage and current in line, and the line local system impedance Z for transmission operation of communication equipment SM And contralateral system impedance Z SN The protection devices M and N are used for receiving current and voltage electrical quantity data, judging faults and fault types and carrying out fault point distance measurement.
According to some embodiments, after the protection device detects a fault and determines the type of the fault, the whole calculation method is calculated according to different fault types.
Fig. 2 (a) shows a schematic diagram of a fault state after a failure of a two-node system according to an exemplary embodiment.
FIG. 2 (b) illustrates a diagram of a normal load condition before a failure of a two node system, according to an exemplary embodiment.
Fig. 2 (c) shows a fault-added status component schematic after a two-node system fault according to an example embodiment.
The post-fault condition of fig. 2 (a) is decomposed into the pre-fault normal load condition of fig. 2 (b) and the fault-added condition of fig. 2 (c), see fig. 2, according to the superposition principle.
As shown in fig. 2, fig. 2 (a) is a schematic diagram of a fault state after a fault of a two-node system, fig. 2 (a) is an exploded schematic diagram of fig. 1,
Figure BDA0003134291180000067
as the amount of voltage after the fault on the present side,
Figure BDA0003134291180000068
for the amount of current after the fault on this side, downwards
Figure BDA0003134291180000069
For adding potential to the fault, upwards
Figure BDA00031342911800000610
The equivalent potential before the F point fault is equal in size and opposite in direction.
As shown in fig. 2, fig. 2 (b) is a schematic diagram of a normal load state before a failure of the two-node system, and the difference between fig. 2 (b) and fig. 1 is shown in that,
Figure BDA00031342911800000611
as the amount of voltage before the fault on the present side,
Figure BDA00031342911800000612
for amount of current before fault on this side, upwards
Figure BDA00031342911800000613
Is the equivalent potential before the F point fault.
As shown in fig. 2, fig. 2 (c) is a schematic diagram of the fault additional status component after the two-node system fault. Wherein the content of the first and second substances,
Figure BDA00031342911800000614
the fault voltage in the fault additional state is obtained by the voltage variation before and after the fault of the line, and the calculation method is the voltage variation after the fault
Figure BDA0003134291180000071
Subtracting the pre-fault voltage magnitude
Figure BDA0003134291180000072
For the fault current in the fault-added state, the fault current is obtained by the current variation before and after the fault of the line, and the calculation method is that the current amount after the fault is obtained
Figure BDA0003134291180000073
Subtracting the amount of pre-fault current
Figure BDA0003134291180000074
Downwards facing
Figure BDA0003134291180000075
A potential is added for the fault.
Fig. 3 shows a flow chart of a method of measuring a distance to a point of failure according to an exemplary embodiment.
According to some embodiments, when the method is implemented, the system impedance is calculated according to the voltage and current change amount before and after the line fault occurs at the protection point; calculating a fault current distribution coefficient according to the system impedance and the line impedance; calculating a fault current component according to the measured current before and after the line has a fault; calculating fault point fault current according to the fault current distribution coefficient and the fault current component; obtaining a measurement impedance equation between the protection point and the fault point according to the measurement voltage and the measurement current; and calculating the distance between the fault point and the protection point according to the measured impedance equation.
Referring to fig. 3, at S310, the system impedance is calculated.
And calculating the system impedance according to the voltage and current change quantity before and after the line fault occurs at the protection point.
Referring to fig. 2 (a), 2 (b) and 2 (c), the fault voltage in the fault-added state
Figure BDA0003134291180000076
The voltage variation before and after the line fault is obtained by calculating the voltage variation after the fault
Figure BDA0003134291180000077
Subtracting the pre-fault voltage magnitude
Figure BDA0003134291180000078
Fault current in fault attach state
Figure BDA0003134291180000079
Obtained by the current variation before and after the line fault, and calculated by the current amount after the fault
Figure BDA00031342911800000710
Subtracting the amount of pre-fault current
Figure BDA00031342911800000711
System impedance Z S By the amount of voltage change before and after a line fault
Figure BDA00031342911800000712
Divided by the amount of current change before and after a line fault
Figure BDA00031342911800000713
The calculation formula is obtained as follows:
Figure BDA00031342911800000714
calculating the impedance Z of the local side system of the circuit SM And contralateral system impedance Z SN And will impedance the contralateral system Z SN And then transmitted to the local side through the communication equipment.
Local side system impedance Z SM The calculation formula is as follows:
Figure BDA00031342911800000715
Figure BDA00031342911800000716
the voltage variation before and after the line of the side breaks down is taken as the voltage variation of the side;
Figure BDA00031342911800000717
the current variation before and after the line fault occurs on the current side.
Impedance of contralateral system Z SN The calculation formula is as follows:
Figure BDA0003134291180000081
Figure BDA0003134291180000082
the voltage variation before and after the fault of the opposite side on the line;
Figure BDA0003134291180000083
the current variation before and after the fault of the opposite side line.
At S320, a fault current distribution coefficient is calculated.
And calculating the fault current distribution coefficient according to the system impedance and the line impedance.
Setting total impedance of line as Z L And the length coefficient from the protection point to the fault point is k, and the length coefficient k belongs to (0, 1), the impedance from the protection point to the fault point on the side is k multiplied by Z L Then the impedance to the fault point from the side protection point is (1-k). Times.Z L 。
According to an example embodiment, two-sided system impedance and line impedance Z are utilized L Calculating the fault current distribution coefficient, distribution coefficient C m The calculation formula is as follows:
Figure BDA0003134291180000084
at S330, a fault current component is calculated.
The fault current component is calculated from the measured currents before and after the line fault.
According to some embodiments, the fault current component
Figure BDA0003134291180000085
Calculating including a ground fault current component
Figure BDA0003134291180000086
And phase-to-phase fault current component
Figure BDA0003134291180000087
Selecting a ground fault current component based on the fault condition
Figure BDA0003134291180000088
Or phase-to-phase fault current component
Figure BDA0003134291180000089
As a component of fault current
Figure BDA00031342911800000810
According to some embodiments, the ground fault current component
Figure BDA00031342911800000811
The calculation method is that the phase current before and after the line fault occurs
Figure BDA00031342911800000812
Minus zero sequence current
Figure BDA00031342911800000813
Is multiplied by
Figure BDA00031342911800000814
The calculation formula is as follows:
Figure BDA00031342911800000815
according to some embodiments, the phase-to-phase fault current component
Figure BDA00031342911800000816
The calculation method is that the phase current before and after the line fault occurs
Figure BDA00031342911800000817
The variable quantity is calculated by the formula:
Figure BDA00031342911800000818
at S340, a fault point fault current is calculated.
And calculating fault current of a fault point according to the fault current distribution coefficient and the fault current component.
According to some embodiments, the method comprisesBarrier current distribution coefficient C m And fault current component
Figure BDA00031342911800000819
Calculating fault current at fault point
Figure BDA0003134291180000091
Will be fault current component
Figure BDA0003134291180000092
Divided by the fault current distribution coefficient C m Obtaining fault current of fault point
Figure BDA0003134291180000093
The calculation formula is as follows:
Figure BDA0003134291180000094
at S350, a measured impedance equation is obtained.
And obtaining a measured impedance equation between the protection point and the fault point according to the measured voltage and the measured current.
According to some embodiments, referring to FIG. 1, the post-fault protection point measures voltage according to kirchhoff's voltage law
Figure BDA0003134291180000095
Equal to the measured current
Figure BDA0003134291180000096
Impedance k x Z from protection point to fault point L Voltage drop over plus fault current at fault point
Figure BDA0003134291180000097
At the transition resistance R F The pressure drop over, the calculation is as follows:
Figure BDA0003134291180000098
in accordance with some embodiments of the present invention,measuring voltage during earth fault
Figure BDA0003134291180000099
Is a phase voltage
Figure BDA00031342911800000910
Measuring current
Figure BDA00031342911800000911
Figure BDA00031342911800000912
In order to measure the current in a single phase,
Figure BDA00031342911800000913
to measure zero sequence current; the zero sequence compensation coefficient calculation method comprises
Figure BDA00031342911800000914
Z L0 Is zero sequence impedance, Z L1 Is a positive sequence impedance.
According to some embodiments, the voltage is measured at phase-to-phase failure
Figure BDA00031342911800000915
As a voltage between phases
Figure BDA00031342911800000916
Measuring current
Figure BDA00031342911800000917
At S360, the distance between the failure point and the protection point is obtained.
And calculating the distance between the fault point and the protection point according to the measured impedance equation.
According to some embodiments, the measured impedance equation is a complex equation, which is divided into a real part and an imaginary part, resulting in a length coefficient k and a transition resistance R F A system of binary quadratic equations. By simplification, a quadratic equation of unity for k is finally obtained. The equation has two roots, eliminating false roots.
According to some embodiments, the method of rejecting the pseudo-root is: and removing roots smaller than 0 or larger than 1 according to the length coefficient k belonging to (0, 1), if both roots are larger than or equal to 0 and smaller than or equal to 1, calculating the root of the fault location equation of the opposite side protection device by the same method, and removing the pseudo-root according to the principle that the sum of the fault location coefficients at the two sides is 1. Multiplying the true value k by the line length parameter yields the fault location.
The method comprises a grounding and phase-to-phase distance measurement method, wherein the method is determined to adopt a grounding or phase-to-phase distance measurement method for distance measurement calculation according to a fault phase selection result of a protection device during fault, the grounding distance measurement method is adopted during single-phase grounding fault, the phase-to-phase distance measurement method is adopted during phase-to-phase fault, and the phase-to-phase fault distance measurement method is adopted during phase-to-phase grounding fault and three-phase fault.
Fig. 4 shows a block diagram of a fault point distance measurement based method apparatus according to an example embodiment.
As shown in fig. 4, the fault point distance measurement method-based device may include: a communication module 410, a receiving module 420, a protection module 430, and a calculation module 440.
Referring to fig. 4 and with reference to the previous description, the communication module 410, the system impedance Z for the transmission operation S 。
The receiving module 420 is configured to receive electrical quantity data required in the calculation.
And the protection module 430 is configured to determine a fault and a fault type and select different calculation methods.
And the calculating module 440 is configured to calculate the electrical quantity data according to a calculation formula, so as to implement distance measurement of a fault point.
The device performs functions similar to those of the method provided above, and other functions can be referred to above, and will not be described again here.
FIG. 5 illustrates a system fault type diagram in accordance with an exemplary embodiment.
Referring to fig. 5 and in view of the foregoing description, fig. 5 illustrates a phase-to-phase fault.
According to some embodiments, the phase-to-phase fault current component
Figure BDA0003134291180000101
The calculation method is that the inter-phase current before and after the line fault occurs
Figure BDA0003134291180000102
The variable quantity is calculated by the formula:
Figure BDA0003134291180000103
according to some embodiments, the voltage is measured at phase-to-phase failure
Figure BDA0003134291180000104
As a voltage between phases
Figure BDA0003134291180000105
Measuring current
Figure BDA0003134291180000106
FIG. 6 illustrates yet another embodiment of a system fault type schematic according to an example.
Referring to fig. 6 and with reference to the foregoing description, fig. 6 illustrates a phase-to-phase fault.
According to some embodiments, the ground fault current component
Figure BDA0003134291180000107
The calculation method is that the phase current before and after the line fault occurs
Figure BDA0003134291180000108
Minus zero sequence current
Figure BDA0003134291180000109
Is multiplied by
Figure BDA00031342911800001010
The calculation formula is as follows:
Figure BDA00031342911800001011
according to some embodiments, the voltage is measured at ground fault
Figure BDA00031342911800001012
Is a phase voltage
Figure BDA00031342911800001013
Measuring current
Figure BDA00031342911800001014
Figure BDA00031342911800001015
In order to measure the current for a single phase,
Figure BDA00031342911800001016
for measuring zero sequence current; the zero sequence compensation coefficient calculation method comprises
Figure BDA00031342911800001017
Z L0 Is a zero sequence impedance, Z L1 Is a positive sequence impedance.
Fig. 7 shows a block diagram of a power line fault location apparatus according to an example embodiment.
A power line fault location apparatus 200 according to this embodiment of the present application is described below with reference to fig. 7. The power line fault ranging apparatus 200 shown in fig. 7 is only an example, and should not bring any limitation to the function and the range of use of the embodiment of the present application.
As shown in fig. 7, the power line fault ranging device 200 is in the form of a general purpose computing device. The components of the power line fault ranging device 200 may include, but are not limited to: at least one processing unit 210, at least one memory unit 220, a bus 230 connecting different system components (including the memory unit 220 and the processing unit 210), a display unit 240, and the like.
Wherein the storage unit stores program code that can be executed by the processing unit 210, so that the processing unit 210 executes the methods according to various exemplary embodiments of the present application described herein. For example, processing unit 210 may perform a method as shown in fig. 3.
The storage unit 220 may include readable media in the form of volatile storage units, such as a random access memory unit (RAM) 2201 and/or a cache memory unit 2202, and may further include a read only memory unit (ROM) 2203.
The storage unit 220 can also include a program/utility 2204 having a set (at least one) of program modules 2205, such program modules 2205 including, but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which, or some combination thereof, may comprise an implementation of a network environment.
Bus 230 may be one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.
Powerline fault ranging device 200 can also communicate with one or more external devices 300 (e.g., keyboard, pointing device, bluetooth device, etc.), one or more devices that enable a user to interact with powerline fault ranging device 200, and/or any device (e.g., router, modem, etc.) that enables powerline fault ranging device 200 to communicate with one or more other computing devices. Such communication may occur via an input/output (I/O) interface 250. Also, powerline fault ranging device 200 can communicate with one or more networks (e.g., a Local Area Network (LAN), a Wide Area Network (WAN), and/or a public network such as the internet) via network adapter 260. Network adapter 260 may communicate with other modules of power line fault ranging device 200 via bus 230. It should be understood that although not shown in the figures, other hardware and/or software modules may be used in conjunction with power line fault location apparatus 200, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, to name a few.
It should be clearly understood that this application describes how to make and use particular examples, but the application is not limited to any details of these examples. Rather, these principles can be applied to many other embodiments based on the teachings of the present disclosure.
Furthermore, it should be noted that the above-mentioned figures are only schematic illustrations of the processes involved in the method according to exemplary embodiments of the present application, and are not intended to be limiting. It will be readily understood that the processes shown in the above figures are not intended to indicate or limit the chronological order of the processes. In addition, it is also readily understood that these processes may be performed, for example, synchronously or asynchronously in multiple modules.
Exemplary embodiments of the present application are specifically illustrated and described above. It is to be understood that the application is not limited to the details of construction, arrangement or method of operation set forth herein; on the contrary, the application is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims (13)

1. A method of measuring distance to a fault point, comprising:
calculating system impedance according to the voltage and current variation before and after the line fault occurs at the protection point;
calculating a fault current distribution coefficient according to the system impedance and the line impedance;
calculating a fault current component according to the measured current before and after the line has a fault;
calculating fault point fault current according to the fault current distribution coefficient and the fault current component;
obtaining a measured impedance equation between the protection point and the fault point according to the measured voltage and the measured current;
and calculating the distance between the fault point and the protection point according to the measured impedance equation.
2. The method for measuring according to claim 1, wherein the calculating system impedance according to the voltage and current variation before and after the line fault occurs at the protection point comprises:
subtracting the voltage before the fault from the voltage after the fault to obtain the voltage variation before and after the fault of the line
Figure FDA0003134291170000011
Subtracting the current before the fault from the current after the fault to obtain the current variation before and after the fault of the line
Figure FDA0003134291170000012
The voltage variation before and after the line failure
Figure FDA0003134291170000013
Dividing by the amount of current change before and after the line fault
Figure FDA0003134291170000014
Obtaining the system impedance Z S The calculation formula is as follows:
Figure FDA0003134291170000015
3. the method of measurement according to claim 2, wherein said calculating a fault current distribution coefficient from the system impedance and the line impedance comprises:
obtaining the system impedance Z of the local side SM And contralateral system impedance Z SN ；
According to the system impedance Z S And line impedance Z L Calculating the fault current distribution coefficient C m The calculation formula is as follows;
Figure FDA0003134291170000016
k is the length coefficient from the protection point to the fault point.
4. A measuring method according to claim 3, characterized in that:
the contralateral system impedance Z SN And then transmitted to the local side through the communication equipment.
5. The method of measurement according to claim 3, wherein said calculating a fault current component from measured currents before and after a fault in a line comprises:
calculating fault current component according to current variation before and after line fault
Figure FDA0003134291170000021
Said fault current component
Figure FDA0003134291170000022
Including a ground fault current component
Figure FDA0003134291170000023
And phase-to-phase fault current component
Figure FDA0003134291170000024
The ground fault current component
Figure FDA0003134291170000025
The calculation method is that the phase current before and after the line fault occurs
Figure FDA0003134291170000026
Minus zero sequence current
Figure FDA0003134291170000027
Is multiplied by
Figure FDA0003134291170000028
Calculation formula asThe following:
Figure FDA0003134291170000029
the phase-to-phase fault current component
Figure FDA00031342911700000210
The calculation method is that the phase current before and after the line fault occurs
Figure FDA00031342911700000211
The calculation formula of the variation amount of (c) is as follows:
Figure FDA00031342911700000212
6. the method of measurement according to claim 5, wherein said calculating a fault point fault current from said fault current distribution factor and a fault component current comprises:
said fault current component
Figure FDA00031342911700000213
Divided by the fault current distribution coefficient C m Obtaining fault current of fault point
Figure FDA00031342911700000214
The calculation formula is as follows:
Figure FDA00031342911700000215
7. the method of measurement according to claim 6, wherein the deriving a measured impedance equation between the protection point and the fault point from the measured voltage and current comprises:
post-fault protection point measurement voltage
Figure FDA00031342911700000216
Equal to the measured current
Figure FDA00031342911700000217
Impedance k x Z from protection point to fault point L Voltage drop over plus fault current at fault point
Figure FDA00031342911700000218
At the transition resistance R F The pressure drop over, the calculation is as follows:
Figure FDA00031342911700000219
8. the method of measurement according to claim 7, wherein the obtaining a measured impedance equation between the protection point and the fault point from the measured voltage and current comprises:
when earth fault occurs, the protection point measures voltage after fault
Figure FDA00031342911700000220
Is a phase voltage
Figure FDA00031342911700000221
Measuring current
Figure FDA0003134291170000031
The calculation formula is as follows:
Figure FDA0003134291170000032
Figure FDA0003134291170000033
in order to measure the current in a single phase,
Figure FDA0003134291170000034
to measure zero sequence current;
K 0 for the zero sequence compensation coefficient, the calculation formula is as follows:
Figure FDA0003134291170000035
Z L0 is zero sequence impedance, Z L1 Is a positive sequence impedance.
9. The method of measurement according to claim 7, wherein the obtaining a measured impedance equation between the protection point and the fault point from the measured voltage and current comprises:
measuring voltage during phase-to-phase fault
Figure FDA0003134291170000036
Is voltage between phases
Figure FDA0003134291170000037
Measuring current
Figure FDA0003134291170000038
Figure FDA0003134291170000039
The current is measured for the phases.
10. The method of measurement according to claim 7, wherein said calculating a distance between the fault point and the protection point according to the measured impedance equation comprises:
the measured impedance equation is a complex equation, and the real part and the imaginary part of the equation are separated to obtain a length coefficient k and a transition resistance R F A system of binary quadratic equations of (c);
solving a length coefficient k and eliminating a pseudo root;
multiplying the true value k by the line length parameter yields the fault location.
11. The method of claim 10, wherein the finding the length coefficient k, and the removing the pseudo-root, comprises:
the impedance measurement equation is simplified into a quadratic equation with one element about a length coefficient k, and two equations are solved;
according to the length coefficient k belonging to (0, 1), removing roots smaller than 0 or larger than 1;
and if the two are both more than or equal to 0 and less than or equal to 1, eliminating false roots according to the principle that the sum of the length coefficients of the two sides is 1 by combining the roots calculated by the fault measurement impedance equation of the opposite side protection device.
12. An apparatus based on a fault point distance measurement method, comprising:
the receiving module is used for receiving the electric quantity data required in calculation;
the protection module is used for judging faults and fault types and selecting different calculation methods;
the calculation module is used for calculating the electrical quantity data according to a calculation formula to realize fault point distance measurement;
a communication module for transmitting the calculated system impedance Z S 。
13. A power transmission line fault location apparatus, comprising:
one or more processors;
storage means for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement the method of any one of claims 1-11.
CN202110712605.3A 2021-06-25 2021-06-25 Method and device for measuring distance between fault points Pending CN115524574A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110712605.3A CN115524574A (en) 2021-06-25 2021-06-25 Method and device for measuring distance between fault points

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110712605.3A CN115524574A (en) 2021-06-25 2021-06-25 Method and device for measuring distance between fault points

Publications (1)

Publication Number Publication Date
CN115524574A true CN115524574A (en) 2022-12-27

Family

ID=84694716

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110712605.3A Pending CN115524574A (en) 2021-06-25 2021-06-25 Method and device for measuring distance between fault points

Country Status (1)

Country Link
CN (1) CN115524574A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113687184A (en) * 2021-08-25 2021-11-23 国网重庆市电力公司电力科学研究院 Fault location method for overcoming influence of transition resistance

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113687184A (en) * 2021-08-25 2021-11-23 国网重庆市电力公司电力科学研究院 Fault location method for overcoming influence of transition resistance

Similar Documents

Publication Publication Date Title
Salim et al. Further improvements on impedance-based fault location for power distribution systems
Wang et al. A new node voltage stability index based on local voltage phasors
Abur et al. Power system state estimation: theory and implementation
US8849614B2 (en) System and method for monitoring and managing three-phase power flows in electrical transmission and distribution networks
Çapar et al. A performance oriented impedance based fault location algorithm for series compensated transmission lines
Wu et al. Modeling and testing of a digital distance relay MATLAB/SIMULINK
CN103236691B (en) Method of three-phase unbalance load flow calculation based on complex affine mathematical theory
Cui et al. Voltage stability assessment based on improved coupled single‐port method
CN111141995B (en) Line double-end steady-state distance measuring method and system based on amplitude comparison principle
CN102967779B (en) Identifying method of distribution parameters of transmission line
CN105375484A (en) PMU-based electric power system distributed dynamic-state estimation method
Mrehel et al. Implementation and Evaluation a SIMULINK Model of a Distance Relay in MATLAB/SIMULINK
Leite et al. Development of a smart grid simulation environment, Part I: Project of the electrical devices simulator
Claeys et al. Optimal power flow in four-wire distribution networks: Formulation and benchmarking
CN115524574A (en) Method and device for measuring distance between fault points
JP5490166B2 (en) Distributed power distribution system and power flow failure analysis method thereof
Watitwa et al. A review on active distribution system state estimation
CN102938010A (en) Parallel circuit unbalance degree analysis method
Ghaedi et al. Modified WLS three-phase state estimation formulation for fault analysis considering measurement and parameter errors
Naidu et al. Parameter estimation, selective auto‐reclosing and fault location for three‐terminal mixed transmission lines using synchronised data
CN112526396A (en) Multi-loop line ground fault analysis method and device, electronic equipment and storage medium
CN114137360B (en) Power distribution network fault positioning method, device and storage medium
CN102798751B (en) A kind of Novel voltage stability detection method
Bockarjova et al. Statistical algorithms for fault location on power transmission lines
Hebling et al. Sparse and orthogonal method for fast bad data processing in distribution system state estimation

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination