CN111884346B - Low-voltage distribution network protection method and medium based on wide-area measurement information - Google Patents

Low-voltage distribution network protection method and medium based on wide-area measurement information Download PDF

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CN111884346B
CN111884346B CN202010825809.3A CN202010825809A CN111884346B CN 111884346 B CN111884346 B CN 111884346B CN 202010825809 A CN202010825809 A CN 202010825809A CN 111884346 B CN111884346 B CN 111884346B
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matrix
fault
distribution network
power distribution
measurement
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CN111884346A (en
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李世龙
张华�
龙呈
高艺文
苏学能
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Electric Power Research Institute of State Grid Sichuan Electric Power Co Ltd
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Electric Power Research Institute of State Grid Sichuan Electric Power Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
    • 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
    • G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
    • H02J13/00036—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers
    • H02J13/0004—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers involved in a protection system
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • 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
    • Y04S10/20—Systems supporting electrical power generation, transmission or distribution using protection elements, arrangements or systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

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  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)

Abstract

The invention discloses a low-voltage distribution network protection method and medium based on wide-area measurement information, and relates to the field of electric power systems and automation thereof. Aiming at the defects of fault identification and positioning of the existing power distribution network, the technical problem that the existing power distribution network online monitoring and protecting method is insufficient in reliability is solved by using a current differential principle. The method comprises the steps of constructing a topological structure incidence relation matrix R, a measuring unit remote control function switching matrix B, a transformer transmission coefficient correction matrix D, a measured voltage matrix U and a measured current matrix I, forming a fault position studying and judging criterion, positioning a fault position on an element, determining a fault phase, and constructing a fault-caused incidence breaker tripping strategy based on the remote control function switching matrix B. The method can accurately judge the fault position in the power distribution network and improve the operation and maintenance level of the power distribution network.

Description

Low-voltage distribution network protection method and medium based on wide-area measurement information
Technical Field
The invention relates to the field of power systems and automation thereof, in particular to a low-voltage distribution network protection method and medium based on wide-area measurement information.
Background
The power distribution network with the voltage class of 35kV or below is a power supply system for most of urban and rural power and plays a vital role in guaranteeing production of various industries and life of people. At present, a power distribution system has large power supply loss, low automation degree and slow fault processing and recovery, and the power supply reliability is seriously influenced. In addition, with the continuous maturity of power electronic technology and new energy power generation technology, more and more distributed power sources are connected into the power distribution network, and the complexity of the power distribution network system is greatly increased. The traditional power distribution network is a single-power unidirectional radial power supply structure, and a protection system of the traditional power distribution network generally comprises three parts, namely three-section current protection at a line appearing position of a transformer substation, an automatic reclosing device on a main feeder line and a fuse of a branch line. However, the access of the distributed power supply and the increasing complexity of the grid structure change the tide distribution and the current characteristics after the fault in the power distribution network, and the traditional power distribution network protection mode is not applicable any more.
With the continuous perfection of the distribution automation system, a large number of FTUs, DTUs, TTUs, RTUs and residual current protection devices are configured in the power distribution network, and available measurement information in the power distribution network is more and more abundant. The FTU (feeder Terminal Unit) is a feeder remote Terminal and is used for measuring three-phase parameters of a feeder, monitoring and protecting the feeder in a power distribution system, communicating with a power distribution automation main station, providing information to a power distribution monitoring main station system, and executing adjustment and control of the main station on the feeder and Terminal equipment thereof. The DTU (distribution Terminal Unit) is a power distribution Terminal unit and is used for multi-loop data acquisition, communication and management of an open-close station, a ring main unit and a substation. The TTU (transducer Terminal Unit) is a remote Terminal of the distribution transformer, is used for collecting and controlling information of the distribution transformer, monitors the operation condition of the distribution transformer in real time, protects the safe operation of the transformer, adjusts reactive compensation, and can transmit the collected information to a main station or other intelligent devices to provide data required by the operation control and management of a distribution system. An RTU (remote Terminal Unit) remote Terminal unit, which is generally used for monitoring and controlling field signals and electric power equipment. The RTU generally has superior communication capabilities and greater storage capacity, is suitable for use in more hostile temperature and humidity environments, and provides more computing functionality. The residual current protection device (simply called leakage protection) is an important measure for effectively preventing electric leakage accidents of a power grid (organism electric shock accidents or equipment electric leakage accidents), is widely used and popularized in rural low-voltage power grids in recent years, and also has the functions of electric quantity acquisition and information transmission, and part of residual current protection devices even have the function of fault recording. The data acquired by the system is not effectively applied to the monitoring level and the protection performance improvement of the power distribution network.
Disclosure of Invention
Aiming at the defects of fault identification and positioning of the existing power distribution network, the invention provides a low-voltage power distribution network protection method and medium based on wide-area measurement information based on wide-area measurement data of a power distribution automation platform and by utilizing a current differential principle, and aims to solve the technical problem that the existing power distribution network on-line monitoring and protection method is insufficient in reliability.
The invention is realized by the following technical scheme:
the low-voltage distribution network protection method based on the wide area measurement information comprises the following steps:
step 1: constructing an element incidence relation matrix in the power distribution network:
constructing a topological structure incidence relation matrix R according to the connection relation of different elements and electric quantity measuring units in the power distribution network;
constructing a remote control function switching matrix of a measuring unit:
establishing a remote control function switching matrix B of each measuring unit according to the condition whether the remote control brake-separating function of each measuring unit is switched on or not;
constructing a transmission coefficient correction matrix of the transformer:
considering the correction effect D of the transformer transmission characteristics on the electrical quantity for all the measurement units connected with the transformer, and generating a transmission coefficient correction matrix;
constructing a measuring electrical quantity matrix:
respectively constructing a measurement voltage matrix U and a measurement current matrix I by using the electric quantity acquired by each measurement unit;
step 2: forming a fault position studying and judging criterion by using the matrix constructed in the step 1, positioning the fault position on an element, and determining a fault phase;
and step 3: and (3) for the fault condition of the step (2), constructing a related breaker tripping strategy after the fault based on the remote control function switching matrix constructed in the step (1).
Further, the topological structure incidence relation matrix R is used for reflecting the connection relation between each electrical element in the power distribution network and the electrical quantity measurement unit, where the electrical element includes a transformer, a distribution line, and a bus in the power distribution network;
the number of rows of the topological structure incidence relation matrix R is the same as the number of elements in the power distribution network, the row and column serial numbers of the topological structure incidence relation matrix R respectively correspond to the voltage grades of the elements and the measuring units in the power distribution network from high to low from small to large, and the elements and the electric quantity measuring units with the same voltage grade in the topological structure incidence relation matrix R are numbered in a centralized manner;
in the topological structure incidence relation matrix R, the positive direction of the electric quantity is positive when a bus points to a line or a transformer, the element in the matrix R is Rmn, m represents a protected element m, n represents a measuring unit n, Rmn represents the incidence relation between the protected element m and the measuring unit n, and for the protected element, if the measuring unit is directly connected with the protected element and the direction points to the element, Rmn is 1; if the measuring unit is directly connected with the measuring unit and the direction is opposite to the element, Rmn is equal to-1; if the measurement unit is not directly connected to it, Rmn is 0.
Furthermore, the number of rows of the remote control function switching matrix B is 1, the number of columns is the same as the number of measuring units, and if the measuring units have a switching-off function and the switching-off function is switched on, the corresponding element B1n is 1; if the measurement unit switching-off function is not activated or is not provided, the corresponding element B1n is equal to 0.
Further, the method also comprises the step of correcting the primary and secondary electric quantities of the transformer by using the transformer transmission coefficient correction matrix D.
Further, the fault starting criterion is constructed as follows:
the measurement voltage matrix U is:
U＝[U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11 U12]T
the measurement current matrix I is:
I＝[I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 I11 I12]T
when the voltage or current out-of-limit condition occurs in the power distribution network, starting a fault discrimination algorithm, and obtaining a voltage threshold value matrix U at each measurement pointsetComprises the following steps:
Uset
＝[Uset1 Uset2 Uset3 Uset4 Uset5 Uset6 Uset7 Uset8 Uset9 Uset10 Uset11 Uset12]T
matrix I of voltage threshold values at measurement pointssetComprises the following steps:
Iset＝[Iset1 Iset2 Iset3 Iset4 Iset5 Iset6 Iset7 Iset8 Iset9 Iset10 Iset11 Iset12]T
the fault starting criterion is as follows:
In＞Isetn∩Un＜Usetn
Infor measuring the n-th column value of the current matrix I, UnIn order to measure the nth column number of the voltage matrix U, when the voltage or current of a certain electrical quantity measuring element in the system is out of limit, a fault positioning algorithm is started.
Further, the fault location is evaluated:
after the fault positioning algorithm is started, firstly, whether the measurement result of the measurement unit is normal is judged, and the algorithm error starting caused by the fault of the measurement unit is eliminated:
unbalanced current matrix I of measuring elements associated with each elementunCan be expressed as:
Iun＝(R·D)×I
unbalanced current threshold matrix I of measuring element associated with each elementthCan be expressed as:
Figure GDA0003209918720000031
wherein
Figure GDA0003209918720000032
And
Figure GDA0003209918720000033
respectively representing absolute values of all elements in the matrix R and the matrix I, wherein K is a proportionality coefficient;
when an unbalanced current I corresponding to a certain elementunmGreater than its unbalance current threshold value IthmNamely:
Iunm＞Ithm
a fault is determined to be within range of the element.
A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 6.
Further, a computer-readable storage medium, in which a computer program is stored, which computer program, when being executed by a processor, carries out the steps of the method. The specific use of the method relies on a large number of calculations and it is therefore preferred that the above calculation is performed by a computer program, so any computer program and its storage medium containing the steps protected in the method also fall within the scope of the present application.
The invention has the following advantages and beneficial effects:
the method can accurately judge the fault position in the power distribution network and improve the operation and maintenance level of the power distribution network.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
fig. 1 is an exemplary diagram of a topology and numbering of a power distribution network according to the present invention.
Fig. 2 is a performance verification model constructed by using the PSCAD electromagnetic transient simulation software according to the present invention.
Fig. 3 is a diagram of an incidence relation matrix R corresponding to the power distribution network topology and the number thereof shown in fig. 1 in the present invention.
Fig. 4 is a matrix D diagram of the power distribution network topology shown in fig. 1 in the present invention.
Detailed Description
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any inventive changes, are within the scope of the present invention.
The low-voltage distribution network protection method based on the wide area measurement information comprises the following steps:
step 1: constructing an element incidence relation matrix in the power distribution network:
constructing a topological structure incidence relation matrix R according to the connection relation of different elements and electric quantity measuring units in the power distribution network;
constructing a remote control function switching matrix of a measuring unit:
establishing a remote control function switching matrix B of each measuring unit according to the condition whether the remote control brake-separating function of each measuring unit is switched on or not;
constructing a transmission coefficient correction matrix of the transformer:
considering the correction effect D of the transformer transmission characteristics on the electrical quantity for all the measurement units connected with the transformer, and generating a transmission coefficient correction matrix;
constructing a measuring electrical quantity matrix:
respectively constructing a measurement voltage matrix U and a measurement current matrix I by using the electric quantity acquired by each measurement unit;
step 2: forming a fault position studying and judging criterion by using the matrix constructed in the step 1, positioning the fault position on an element, and determining a fault phase;
and step 3: and (3) for the fault condition of the step (2), constructing a related breaker tripping strategy after the fault based on the remote control function switching matrix constructed in the step (1).
The detailed steps of the method are as follows:
constructing an element incidence relation matrix in the power distribution network:
and constructing a topological structure incidence relation matrix R according to the connection relation of different elements and electric quantity measuring units in the power distribution network. The matrix can reflect the connection relation between each electrical element and an electrical quantity measuring unit in the power distribution network, wherein the elements comprise a transformer, a distribution line and a bus in the power distribution network. The number of rows of the matrix is the same as the number of elements in the power distribution network, and the number of columns of the matrix is the same as the number of the electric quantity measuring units. The row and column serial numbers of the matrix are from small to large and correspond to the voltage grades of the elements and the measuring units in the power distribution network from high to low, and the elements and the electric quantity measuring units with the same voltage grade are numbered in a concentrated mode. The distribution network topology shown in fig. 1 and the incidence relation matrix R corresponding to the number thereof are shown in fig. 3.
The positive direction of the specified electrical quantity is positive when the bus points to the line or the transformer. The elements in the R matrix are Rmn. Meaning the relationship between the protected element m and the measurement unit n. For the protected element, if the measurement unit is directly connected with the protected element and the direction of the protected element points to the element, Rmn is equal to 1; if the measuring unit is directly connected with the measuring unit and the direction is opposite to the element, Rmn is equal to-1; if the measurement unit is not directly connected to it, Rmn is 0.
Constructing a remote control function switching matrix of a measuring unit:
and establishing a switching matrix B of the remote control function of the measuring units according to whether the remote control brake-separating function of each measuring unit is switched on or not. The number of rows of the matrix B is 1, and the number of columns is the same as the number of measurement units. If the measuring unit has the switching-off function and the switching-off function is put into use, the corresponding element B1n is equal to 1; if the measurement unit switching-off function is not activated or is not provided, the corresponding element B1n is equal to 0. Taking the topology shown in fig. 1 as an example, if all the measurement units have the switching-off function and the switching-off function is activated, the switching-on/off matrix B can be represented as:
B＝[1 1 1 1 1 1 1 1 1 1 1 1]
constructing a transmission coefficient correction matrix of the transformer:
for all measuring units connected to the transformer, the correcting effect of the transformer transmission characteristic on the electrical quantity needs to be considered. Through the transformation of the transformer, the amplitude and the phase of the electric quantity of the primary side and the secondary side of the transformer are changed. And correcting the primary and secondary electric quantities of the transformer by using the transformer transmission coefficient correction matrix D. Taking the topology shown in FIG. 1 as an example, the element 1 and the element 3 are transformers, and the transmission correction coefficients are respectively
Figure GDA0003209918720000051
And
Figure GDA0003209918720000052
by transmission correction factor of element 1
Figure GDA0003209918720000053
For example, the meaning can be expressed as:
Figure GDA0003209918720000054
wherein
Figure GDA0003209918720000055
The measurement currents of the measurement unit 1 and the measurement unit 2, respectively. Taking the power distribution network topology shown in fig. 1 as an example, the matrix D may be represented as shown in fig. 4.
Constructing a measuring electrical quantity matrix:
each electrical quantity measuring unit measures the voltage and current phasor at the position thereof, taking the topological structure shown in fig. 1 as an example, wherein the measuring voltage matrix U is:
U＝[U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11 U12]T
similarly, the measurement current matrix I is:
I＝[I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 I11 I12]T
the fault starting criterion structure comprises the following steps:
when the voltage or current out-of-limit condition occurs in the power distribution network, the fault discrimination algorithm can be started. Taking the topology shown in FIG. 1 as an example, the voltage threshold value matrix U at each measurement pointsetComprises the following steps:
Uset
＝[Uset1 Uset2 Uset3 Uset4 Uset5 Uset6 Uset7 Uset8 Uset9 Uset10 Uset11 Uset12]T
matrix I of voltage threshold values at measurement pointssetComprises the following steps:
Iset＝[Iset1 Iset2 Iset3 Iset4 Iset5 iset6 iset7 Iset8 Iset9 Iset10 Iset11 Iset12]T
the fault starting criterion is as follows:
In＞Isetn∩Un＜Usetn
when the voltage or current of a certain electrical quantity measuring element in the system is out of limit, the fault positioning algorithm can be started.
And (3) studying and judging fault positions:
after the fault location algorithm is started, whether the measurement result of the measurement unit is normal or not is judged firstly, namely, the algorithm is prevented from being started by mistake due to the fault of the measurement unit.
Unbalanced current matrix I of measuring elements associated with each elementunCan be expressed as:
Iun＝(R·D)×I
unbalanced current threshold matrix I of measuring element associated with each elementthCan be expressed as:
Figure GDA0003209918720000061
wherein
Figure GDA0003209918720000071
And
Figure GDA0003209918720000072
respectively representing the absolute value of all elements in the matrix R and the matrix I, and K is a proportionality coefficient.
Taking the topology shown in FIG. 1 as an example, IunAnd IthAll are 7-row and 1-column matrices, and the number of rows of the matrices is the same as the number of elements in the network.
When an unbalanced current I corresponding to a certain elementunmGreater than its unbalance current threshold value IthmNamely:
Iunm＞Ithm
it can be determined that the fault is within the range of this element.
And (3) fault handling:
and (3) forming a tripping strategy by utilizing the incidence relation between the element of the row where the fault element is positioned in the incidence relation matrix and the measuring device and the remote control function switching matrix B in the step (2). Taking the short-circuit fault inside the element 3 shown in fig. 1 as an example, the forming process of the tripping and closing strategy is as follows:
the incidence relation between the element 3 and the measurement unit in the incidence relation matrix R is as follows:
R(3，：)＝[0 0 1 1 0 0 0 0 0 0 0 0]
the trip strategy T may be expressed as:
T＝R(3，：)·B
and the breaker corresponding to the element of 1 in T is tripped, so that the fault removal can be realized.
Taking the topology structure of the power distribution network shown in fig. 1 as an example, the power distribution network fault monitoring and protecting method provided by the patent is verified by using PSCAD/EMTDC, and a simulation model is shown in fig. 2. After the elements 1 to 7 respectively have faults, the fault simulation results judged by the method of the invention show that the fault position in the power distribution network can be accurately judged, and the operation and maintenance level of the power distribution network is improved.
Preferably, a computer-readable storage medium stores a computer program which, when executed by a processor, implements the steps of the method. The specific use of the method relies on a large number of calculations and it is therefore preferred that the above calculation is performed by a computer program, so any computer program and its storage medium containing the steps protected in the method also fall within the scope of the present application.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (5)

1. The low-voltage distribution network protection method based on wide-area measurement information is characterized by comprising the following steps of:
step 1: constructing an element incidence relation matrix in the power distribution network:
constructing a topological structure incidence relation matrix R according to the connection relation of different elements and electric quantity measuring units in the power distribution network;
constructing a remote control function switching matrix of a measuring unit:
establishing a remote control function switching matrix B of each measuring unit according to the condition whether the remote control brake-separating function of each measuring unit is switched on or not;
constructing a transmission coefficient correction matrix of the transformer:
considering the correction effect D of the transformer transmission characteristics on the electrical quantity for all the measurement units connected with the transformer, and generating a transmission coefficient correction matrix;
constructing a measuring electrical quantity matrix:
respectively constructing a measurement voltage matrix U and a measurement current matrix I by using the electric quantity acquired by each measurement unit;
step 2: forming a fault position studying and judging criterion by using the matrix constructed in the step 1, positioning the fault position on an element, and determining a fault phase;
and step 3: for the fault condition of the step 2, constructing a tripping strategy of the associated breaker after the fault based on the remote control function switching matrix constructed in the step 1;
and (3) constructing fault starting criteria:
the measurement voltage matrix U is:
U＝[U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11 U12]T
the measurement current matrix I is:
I＝[I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 I11 I12]T
when the voltage or current out-of-limit condition occurs in the power distribution network, starting a fault discrimination algorithm, and obtaining a voltage threshold value matrix U at each measurement pointsetComprises the following steps:
Uset
＝[Uset1 Uset2 Uset3 Uset4 Uset5 Uset6 Uset7 Uset8 Uset9 Uset10 Uset11 Uset12]T
matrix I of voltage threshold values at measurement pointssetComprises the following steps:
Iset＝[Iset1 Iset2 Iset3 Iset4 Iset5 Iset6 Iset7 Iset8 Iset9 Iset10 Iset11 Iset12]T
the fault starting criterion is as follows:
In＞Isetn∩Un＜Usetn
Infor measuring the n-th column value of the current matrix I, UnIn order to measure the nth column value of the voltage matrix U, when the voltage or current of a certain electrical quantity measuring element in the system is out of limit, starting a fault positioning algorithm;
and (3) judging the fault position:
after the fault positioning algorithm is started, firstly, whether the measurement result of the measurement unit is normal is judged, and the algorithm error starting caused by the fault of the measurement unit is eliminated:
unbalanced current matrix I of measuring elements associated with each elementunCan be expressed as:
Iun＝(R·D)×I
unbalanced current threshold matrix I of measuring element associated with each elementthCan be expressed as:
Figure FDA0003209918710000021
wherein
Figure FDA0003209918710000022
And
Figure FDA0003209918710000023
respectively representing absolute values of all elements in the matrix R and the matrix I, wherein K is a proportionality coefficient;
when an unbalanced current I corresponding to a certain elementunmGreater than its unbalance current threshold value IthmNamely:
Iunm＞Ithm
a fault is determined to be within range of the element.
2. The method according to claim 1, wherein the method comprises:
the topological structure incidence relation matrix R is used for reflecting the connection relation between each electrical element in the power distribution network and an electrical quantity measuring unit, and the electrical elements comprise transformers, distribution lines and buses in the power distribution network;
the number of rows of the topological structure incidence relation matrix R is the same as the number of elements in the power distribution network, the row and column serial numbers of the topological structure incidence relation matrix R respectively correspond to the voltage grades of the elements and the measuring units in the power distribution network from high to low from small to large, and the elements and the electric quantity measuring units with the same voltage grade in the topological structure incidence relation matrix R are numbered in a centralized manner;
in the topological structure incidence relation matrix R, the positive direction of the electric quantity is positive when a bus points to a line or a transformer, the element in the matrix R is Rmn, m represents a protected element m, n represents a measuring unit n, Rmn represents the incidence relation between the protected element m and the measuring unit n, and for the protected element, if the measuring unit is directly connected with the protected element and the direction points to the element, Rmn is 1; if the measuring unit is directly connected with the measuring unit and the direction is opposite to the element, Rmn is equal to-1; if the measurement unit is not directly connected to it, Rmn is 0.
3. The method according to claim 1, wherein the method comprises:
the number of rows of the remote control function switching matrix B is 1, the number of columns is the same as the number of the measuring units, and if the measuring units have a switching-off function and the switching-off function is switched on, the corresponding element B1n is 1; if the measurement unit switching-off function is not activated or is not provided, the corresponding element B1n is equal to 0.
4. The method according to claim 1, wherein the method comprises:
and correcting the primary and secondary electrical quantities of the transformer by using the transformer transmission coefficient correction matrix D.
5. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 4.
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