CN113589099A - Method for realizing fault location in power distribution system with multi-branch transmission line - Google Patents

Method for realizing fault location in power distribution system with multi-branch transmission line Download PDF

Info

Publication number
CN113589099A
CN113589099A CN202110787805.5A CN202110787805A CN113589099A CN 113589099 A CN113589099 A CN 113589099A CN 202110787805 A CN202110787805 A CN 202110787805A CN 113589099 A CN113589099 A CN 113589099A
Authority
CN
China
Prior art keywords
node
fault
branch
nodes
area
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.)
Granted
Application number
CN202110787805.5A
Other languages
Chinese (zh)
Other versions
CN113589099B (en
Inventor
胡冉
康文韬
邓世聪
叶枫舒
陈昆
尚龙龙
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.)
Shenzhen Power Supply Bureau Co Ltd
Original Assignee
Shenzhen Power Supply Bureau 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 Shenzhen Power Supply Bureau Co Ltd filed Critical Shenzhen Power Supply Bureau Co Ltd
Priority to CN202110787805.5A priority Critical patent/CN113589099B/en
Publication of CN113589099A publication Critical patent/CN113589099A/en
Application granted granted Critical
Publication of CN113589099B publication Critical patent/CN113589099B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • G01R31/081—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
    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Locating Faults (AREA)

Abstract

The invention provides a method for realizing fault positioning in a power distribution system with a plurality of branch transmission lines, which divides system nodes into T-shaped nodes and non-T-shaped nodes by establishing a directed graph after a power distribution network fault. Dividing the system into a plurality of areas according to the T-shaped nodes, calculating the voltage of the T-shaped nodes in each area by using a loop voltage equation so as to determine a fault area, and combining non-fault areas so as to reduce the fault area and further perform fault positioning. The method can be used for positioning the faults of the actual power distribution network on line, and when the system has faults, the faults are positioned and removed in time, so that the further development of the faults is prevented, the power supply recovery is ensured, and the safety and the stability of the system are improved. The method provided by the invention has a simple principle, is easy to realize, and is not influenced by the scale of the system.

Description

Method for realizing fault location in power distribution system with multi-branch transmission line
Technical Field
The invention relates to the technical field of fault location of a power distribution network, in particular to a method for realizing fault location in a power distribution system with a plurality of branch transmission lines.
Background
With the gradual development of power distribution networks, multi-branch overhead lines are widely applied to the power distribution networks due to the economy and flexibility of the multi-branch overhead lines. When the multi-branch overhead line fails, accidents such as power failure and unstable voltage generally cause huge economic loss, and the longer the accident time is, the greater the loss of the power grid is, and meanwhile, the safe and stable operation of the system is seriously threatened. In order to ensure the normal operation of the power grid, faults need to be removed in time. The fault location of the power distribution network is the basis of fault elimination and power supply recovery, and is also important content for improving the safety and the power supply reliability of the power distribution network. However, the multi-branch overhead line has a complicated structure and many branch lines, and fault diagnosis needs to be performed on each branch line one by one, so that fault location of the multi-branch overhead line is difficult. In addition, the mixed characteristics of the overhead line and the cable greatly increase the positioning difficulty.
The electric energy is an important guarantee for the healthy and stable development of national economy, and for electric power enterprises, the electric energy guarantees the stability and safety of power supply and improves the quality of power supply service, and is a primary problem to be solved in new situation. The service quality of a power supply enterprise can be influenced by the fault of the power distribution network. Accurate fault location is the key point for ensuring the power supply reliability of users, provides basis for fault isolation and power supply recovery of non-fault areas and effectively improves the power supply recovery efficiency. How to locate the fault of the multi-branch overhead line is a hot point of research in electric power work at home and abroad.
At present, the fault location of a multi-branch overhead line is mainly divided into a traveling wave method and an impedance method, and the traveling wave method judges the fault position according to the propagation speed and time of fault traveling waves. The impedance method firstly determines a fault branch by using state variables such as system voltage and current, and then establishes a fault distance measurement equation by using the relationship between the voltage and the current of a network circuit in the subsequent fault and the line impedance, thereby determining the fault distance.
However, the traveling wave method requires a large number of devices with high sampling rate, so that the economic cost is high, and meanwhile, the method depends on waveform identification, and the accuracy of identification will affect the accuracy of fault location.
The existing impedance method mainly utilizes the phenomenon that the phase of a ranging function before and after a fault branch is suddenly changed to judge the fault branch, the method is complex in derivation equation and complicated in implementation process, and when the scale of a power distribution network is large, the method is large in calculated amount and poor in universality and flexibility.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for realizing fault location in a power distribution system with a multi-branch transmission line, which overcomes the problem that the fault branch of the multi-branch overhead line is difficult to check and measure the distance and can quickly and accurately realize the fault location.
In one aspect of the present invention, a method for implementing fault location in a power distribution system having multiple branch transmission lines is provided, which includes the following steps:
step S1, determining a detailed topological structure of the current power distribution system with a plurality of branch transmission lines, equivalently, a directed graph containing nodes and branches, numbering the nodes and the branches, and obtaining a node branch incidence matrix of the power distribution system;
step S2, obtaining sampling values of voltage and current of each node measured by a Power Management Unit (PMU) arranged in the power distribution system;
step S3, calculating and obtaining the current value of each branch by combining the node branch incidence matrix according to the current sampling value of each node;
step S4, dividing the node into T-type and non-T-type nodes according to the number of branches connected with the node, and determining the T-type node nearest to the root node as the current reference T-type node,
step S5, dividing the system into three areas including two single-branch areas and one multi-branch area according to the current reference T-shaped node; calculating the voltage of the current reference T-shaped node in the three regions respectively through a loop voltage equation, and judging a fault region according to the magnitude relation among the three calculated voltages;
step S6, when the fault occurs in the single branch area, calculating to obtain the fault position; when the fault occurs in the multi-branch area, combining the non-fault areas, establishing a new power distribution system, updating the voltage and current sampling values measured by the power management unit PMU, and repeating the steps until an accurate fault position is obtained.
Preferably, the step S1 further includes:
the method comprises the steps of (1) enabling a distribution network system to be equivalent to a directed graph containing nodes and branches, wherein the nodes correspond to a bus, and the branches correspond to a transmission line, a transformer, series compensation, a voltage regulator, a circuit breaker and other equipment;
and obtaining a node branch incidence matrix T of the distribution network systemN×b(I, J), wherein for a distribution network system with N nodes and B branches, the number of a root node is the largest, the farther the root node is, the smaller the number of the node is, and the branch number points to the node with the larger number from the node with the smaller number; if the branch J is on the road I, T (I, J) is 1, otherwise T (I, J) is 0;
wherein, the node number is 1,2, K … N-2, N, the branch number is B1,B2…BN-2,BN-1。
Preferably, the step S3 further includes:
will branch into the incidence matrix TN×bDivision into sub-matrices T1And T2Respectively representing the relationship between branches, branches and roads, wherein T1Is an upper triangular matrix, T2Is an empty matrix;
calculating the current I of each branch according to the following formulab：
Figure BDA0003159657960000031
Wherein, INThe current at each node is sampled.
Preferably, the step S4 further includes:
the nodes of the distribution network system with the multi-branch transmission lines are divided into T-shaped nodes and non-T-shaped nodes, wherein the T-shaped nodes are numbered as 3, K +1, K +3, …, N-1 and N.
Preferably, the step S5 further includes:
according to the current reference T-type node N-1, the system is divided into three regions including two single-branch regions and one multi-branch region, the region between the root node N and the current reference T-type node N-1 is determined as a first region S1, the region between the current reference T-type node N-1 and the branch node N-2 is determined as a second region S2, and the region between the current reference T-type node and the next T-type node until the end node is taken as a third region S3.
Preferably, the step S5 further includes:
in the first region S1, the voltage of the current reference T-type node N-1 is calculated by the following equation:
VN-1(S1)＝VN-ZB(N-1)·IN·LB(N-1) (14)
in the formula, VNAnd INMeasured by a PMU device; zB(N-1)Is the system positive sequence impedance;
in the second region S1, the voltage of the current reference T-type node N-1 is calculated by the following equation:
VN-1(S2)＝VN-2-ZB(N-2)·IB(N-2)·LB(N-2) (15)
in a second region S1, a road having a T-node and an end node with PMU measurement is selected to establish a loop voltage equation, and in this system, B is selected1,B3,BK+1,BK+3,BK+5,BN-3And BN-1And solving to obtain the voltage of the current reference T-shaped node N-1 according to the following formula:
Figure BDA0003159657960000041
preferably, in step S5, the determining the fault region according to the magnitude relationship between the three calculated voltages further includes:
when | VN-1(S1)-VN-1(S2)|>|VN-1(S2)-VN-1(S3)I, and I VN-1(S1)-VN-1(S3)|>|VN-1(S2)-VN-1(S3)If l, it is determined that the failure has occurred in the first area S1.
When | VN-1(S2)-VN-1(S1)|>|VN-1(S1)-VN-1(S3)I, and I VN-1(S2)-VN-1(S3)|>|VN-1(S1)-VN-1(S3)If l, it is determined that the failure has occurred in the second area S2.
When | VN-1(S3)-VN-1(S1)|>|VN-1(S2)-VN-1(S1)I, and I VN-1(S3)-VN-1(S2)|>|VN-1(S2)-VN-1(S1)When | the failure is determined to occur in the third area S3.
Preferably, in the step S6, if the fault occurs in the first area or the second area, the fault location x is obtained by calculating according to the following formula:
Figure BDA0003159657960000042
wherein, Vm1And Vn1Is the positive sequence voltage of the two end nodes during the fault in the fault area; i ism1、In1Respectively representing positive sequence currents at the end nodes; zmnRepresenting the positive sequence impedance per unit length of the transmission line.
Preferably, in the step S6, if the fault occurs in the first area or the second area, the fault location x is obtained by calculating according to the following formula:
Figure BDA0003159657960000051
I'm1＝Im1-jwCm1Vm1 (8)
I'n1＝In1-jwCn1Vn1 (9)
wherein, Vm1And Vn1In the fault area, twoPositive sequence voltage of the end node during fault; i ism1、In1Respectively representing positive sequence currents at the end nodes; zmnPositive sequence impedance, C, representing a unit length of the transmission linem1And Cn1Respectively representing the grounded capacitances of the two end node sides.
The implementation of the invention has the following beneficial effects:
the invention provides a method for realizing fault positioning in a power distribution system with a plurality of branch transmission lines, which divides system nodes into T-shaped nodes and non-T-shaped nodes by establishing a directed graph after a power distribution network fault. Dividing the system into a plurality of areas according to the T-shaped nodes, calculating the voltage of the T-shaped nodes in each area by using a loop voltage equation so as to determine a fault area, and combining non-fault areas so as to reduce the fault area and further perform fault positioning. The method can be used for the online fault location of the actual power distribution network, when the system has a fault, the fault is located and removed in time, further development of the fault is prevented, power supply recovery is guaranteed, and the safety and stability of the system are improved.
The method provided by the invention has the advantages of simple principle, easy realization and no influence of system scale.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.
Fig. 1 is a schematic flow chart illustrating one embodiment of a method for fault location in an electrical distribution system having multiple branch transmission lines according to the present invention;
fig. 2 is a diagram of an exemplary distribution network topology as referenced in fig. 1;
FIG. 3 is a schematic diagram of the fault referenced in FIG. 1 occurring in a main branch of a multi-branch transmission line distribution network system;
FIG. 4 is a schematic diagram of the fault referenced in FIG. 1 occurring at a branch of a multi-branch transmission line distribution network system;
FIG. 5 is a schematic view of the partition referred to in FIG. 1;
FIG. 6 is a schematic diagram of the positive sequence component of the exemplary dual-port transmission line distribution network system of FIG. 1;
fig. 7 is a schematic diagram of the merged distribution network system referred to in fig. 1;
FIG. 8 is a topological diagram of an actual power distribution network system employed for validation in the present invention;
fig. 9 is a directed graph corresponding to fig. 8.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
First, several technical terms are introduced herein as follows:
fault positioning: determining the position of the power distribution network fault;
a Power Management Unit (PMU) is a microcontroller that controls the Power functions of a digital platform;
positive sequence network: a computing network determined by a power system positive sequence network topology and positive sequence parameters of the elements.
As shown in fig. 1, a main flow diagram of an embodiment of a method for fault location in an electrical distribution system having multiple branch transmission lines according to the present invention is shown; referring to fig. 2 and 7 together, in the present embodiment, the method includes the following steps:
step S1, determining a detailed topological structure of the current power distribution system with a plurality of branch transmission lines, equivalently, a directed graph containing nodes and branches, numbering the nodes and the branches, and obtaining a node branch incidence matrix of the power distribution system;
preferably, the step S1 further includes:
the method comprises the steps of (1) enabling a distribution network system to be equivalent to a directed graph containing nodes and branches, wherein the nodes correspond to a bus, and the branches correspond to a transmission line, a transformer, series compensation, a voltage regulator, a circuit breaker and other equipment; therefore, the distribution network system can be analyzed by adopting a loop analysis method in graph theory. It is understood that in the loop analysis method, the road of a node is a set of branches of the node along the tree to the root. For a given tree, the roads of the node are unique, consisting of only branches. Fig. 2 shows a typical distribution network topology, in which numbers in circles indicate node numbers, and arrows and numbers on each branch indicate branch numbers and directions.
Thereby obtaining the node branch incidence matrix T of the distribution network systemN×b(I, J), wherein for a distribution network system with N nodes and B branches, the number of a root node is the largest, the farther the root node is, the smaller the number of the node is, and the branch number points to the node with the larger number from the node with the smaller number; known as TN×b(I, J) is an n × b matrix, where the number of channels is n and the number of branches is b. The direction of the branch and the road are the same, and if the branch J is on the road I, T (I, J) is 1, otherwise, T (I, J) is 0;
a node branch incidence matrix T is established for the typical distribution network system shown in fig. 2, as shown in formula (1):
Figure BDA0003159657960000071
step S2, obtaining sampling values of voltage and current of each node measured by a Power Management Unit (PMU) arranged in the power distribution system;
step S3, calculating and obtaining the current value of each branch by combining the node branch incidence matrix according to the current sampling value of each node;
preferably, the step S3 further includes:
will branch into the incidence matrix TN×bDivision into sub-matrices T1And T2Respectively representing the relationship between branches, branches and roads, wherein T1Is an upper triangular matrix, T2Is an empty matrix;
calculating the current I of each branch according to the following formulab：
Figure BDA0003159657960000072
Wherein, INThe current at each node is sampled.
Specifically, the formula (2) may be represented as the following formula (3) corresponding to the correlation matrix of formula 1:
Figure BDA0003159657960000081
step S4, dividing the node into T-type and non-T-type nodes according to the number of branches connected with the node, and determining the T-type node nearest to the root node as the current reference T-type node,
it will be appreciated that the structural models of the multi-branch transmission lines in the power distribution system are shown in fig. 3 and 4, which represent the occurrence of faults in the main branch and the branch, respectively. Where the transmission line parameters are known, the PMU device may collect the voltage and current at the measurement point.
As shown in fig. 3 and 4, the system nodes and tributaries are numbered by loop analysis. The node is numbered as 1,2, K … N-2, N, the branch is numbered as B1,B2…BN-2,BN-1。
Preferably, the step S4 further includes:
the nodes of the distribution network system with the multi-branch transmission lines are divided into T-shaped nodes and non-T-shaped nodes, wherein the T-shaped nodes are numbered as 3, K +1, K +3, …, N-1 and N.
Step S5, dividing the system into three areas including two single-branch areas and one multi-branch area according to the current reference T-shaped node; calculating the voltage of the current reference T-shaped node in the three regions respectively through a loop voltage equation, and judging a fault region according to the magnitude relation among the three calculated voltages;
the voltage and current collected by the PMU are as shown in equations (11) and (12):
Vp＝[V1 V2 Vk+1 Vk+3 Vk+5...VN-4 VN-2 VN]T (11)
Ip＝[IB1 IB2 IB(k)IB(k+2)IB(k+4)...IB(N-2)IB(N-1)]T (12)
partial elements in the node branch incidence matrix of the system are shown as the formula (13):
Figure BDA0003159657960000091
the T-node may divide the system into multiple regions. For the current reference T-node N-1, as shown in fig. 5, the system may be divided into three regions of S1, S2, and S3. Specifically, the system is divided into three regions including two single-branch regions and one multi-branch region according to the current reference T-type node N-1, the region between the root node N and the current reference T-type node N-1 is determined as a first region S1, the region between the current reference T-type node N-1 and the branch node N-2 is determined as a second region S2, and the region between the current reference T-type node and the next T-type node up to the end node is determined as a third region S3.
Preferably, the step S5 further includes:
in the first region S1, the voltage of the current reference T-type node N-1 is calculated by the following equation:
VN-1(S1)＝VN-ZB(N-1)·IN·LB(N-1) (14)
in the formula, VNAnd INMeasured by a PMU device; zB(N-1)Is the system positive sequence impedance;
in the second region S1, the voltage of the current reference T-type node N-1 is calculated by the following equation:
VN-1(S2)＝VN-2-ZB(N-2)·IB(N-2)·LB(N-2) (15)
in the second regionIn the domain S1, a road with a T-node and an end node with PMU measurement is selected to establish a loop voltage equation, and in this system B is selected1,B3,BK+1,BK+3,BK+5,BN-3And BN-1And solving to obtain the voltage of the current reference T-shaped node N-1 according to the following formula:
Figure BDA0003159657960000092
preferably, in step S5, the determining the fault region according to the magnitude relationship between the three calculated voltages further includes:
when | VN-1(S1)-VN-1(S2)|>|VN-1(S2)-VN-1(S3)I, and I VN-1(S1)-VN-1(S3)|>|VN-1(S2)-VN-1(S3)If l, it is determined that the failure has occurred in the first area S1.
When | VN-1(S2)-VN-1(S1)|>|VN-1(S1)-VN-1(S3)I, and I VN-1(S2)-VN-1(S3)|>|VN-1(S1)-VN-1(S3)If l, it is determined that the failure has occurred in the second area S2.
When | VN-1(S3)-VN-1(S1)|>|VN-1(S2)-VN-1(S1)I, and I VN-1(S3)-VN-1(S2)|>|VN-1(S2)-VN-1(S1)When | the failure is determined to occur in the third area S3.
Step S6, when the fault occurs in the single branch area, calculating to obtain the fault position; when the fault occurs in the multi-branch area, combining the non-fault areas, establishing a new power distribution system, updating the voltage and current sampling values measured by the power management unit PMU, and repeating the steps until an accurate fault position is obtained.
It will be appreciated that calculating the fault location is achieved by the following principles:
because the distribution network sequence component system is decoupled, the invention uses a positive sequence network for fault analysis.
And (4) converting the three-phase distribution network system into a sequence component system by adopting a phase sequence transformation formula.
Figure BDA0003159657960000101
In the formula Ia、IbAnd IcRepresenting three-phase currents, I0、I1And I2Representing zero sequence current, positive sequence current and negative sequence current, respectively.
A typical two-port transmission line distribution network system is adopted for fault location research, and a positive sequence network schematic diagram of the system is shown in fig. 6:
in fig. 6, F represents a failure position. Vm1And Vn1Is the positive sequence voltage during the bus M and bus N faults; i isn1Represents a positive sequence current; zmn、Cm1And Cn1Representing the positive sequence impedance and the ground capacitance per unit length of the transmission line.
Neglecting the grounding capacitance, the positive sequence voltage and current of the bus m and the bus n satisfy the formula (5) and the formula (6):
Vm1＝xZmn·Im1+VF1 (5)
Vn1＝(L-x)Zmn·In1+VF1 (6)
VF1is the voltage of the fault point; vm1,Vn1,Im1And In1The measurements may be made by PMU means.
The failure distance can be calculated by equations (5) and (6):
Figure BDA0003159657960000111
when considering the ground capacitance, the positive sequence current at bus m and bus n should be subtracted by the ground current, as shown in equations (8) and (9):
I'm1＝Im1-jwCm1Vm1 (8)
I'n1＝In1-jwCn1Vn1 (9)
from the equations (5) to (9), the fault distance is calculated from equation (10) in consideration of the influence on the earth capacitance.
Figure BDA0003159657960000112
Since the size of the ground capacitance is related to the fault distance, a finite number of iterations of equation (10) are required, and the size of the ground capacitance is not calculated to be updated in the iteration process.
Preferably, in the step S6, if the fault occurs in the first area or the second area, the fault location x is obtained by calculating according to the following formula:
Figure BDA0003159657960000113
wherein, Vm1And Vn1Is the positive sequence voltage of the two end nodes during the fault in the fault area; i ism1、In1Respectively representing positive sequence currents at the end nodes; zmnRepresenting the positive sequence impedance per unit length of the transmission line.
Therefore, in the present invention, in the step S6, if a failure occurs in the first area or the second area, the failure position x is obtained by calculation with the following formula:
Figure BDA0003159657960000114
I'm1＝Im1-jwCm1Vm1 (8)
I'n1＝In1-jwCn1Vn1 (9)
wherein, Vm1And Vn1In the fault area, twoPositive sequence voltage of the individual end node during the fault; i ism1、In1Respectively, represent positive sequence currents at the end nodes (e.g., nodes N and N-1, or N-1 and N-2 in fig. 5); zmnPositive sequence impedance, C, representing a unit length of the transmission linem1And Cn1Respectively representing the grounded capacitances of the two end node sides.
When a fault occurs in multi-branch region S3, single branch regions S1 and S2 are merged and the measured voltages and currents in the PMUs are updated to build a new distribution system. In this system, the combined structure model is shown in fig. 7.
The updated measured voltage and current of the PMU are shown as follows:
Vp＝[V1 V2 Vk+1 Vk+3 Vk+5...VN-4 VN-1]T (17)
Ip＝[IB1 IB2 IB(k)IB(k+2)IB(k+4)...IB(N-4)IB(N-3)]T (18)
and judging the fault area of the combined new system by using the voltage of the T-shaped node calculated in different areas again until the fault branch is determined.
In order to verify the practical effect of the method provided by the present invention, in a specific example, the following test is performed on a practical power distribution network by using the method provided by the present invention, and the topology of the system is shown in fig. 8.
In fig. 8, the actual distribution network system consists of 5 voltage sources, 7 transmission lines. The voltage and current of the bus M, R, N, S, J are measured by PMU devices. The sampling frequency fs is 2400Hz, and the power supply voltage is 110 kV. The parameters of the transmission line are shown in table 1.
TABLE 1 Transmission line parameters
Branch circuit Length (Km) Z1(p.u./km) Z0(p.u./km)
L 1 1 0.015+j0.025 0.01+j0.02
L 2 1 0.015+j0.02 0.025+j0.015
L 3 1 0.022+j0.025 0.018+j0.017
L 4 1 0.018+j0.016 0.017+j0.015
L 5 1 0.03+j0.03 0.02+j0.02
L 6 1 0.015+j0.025 0.02+j0.015
L 7 1 0.021+j0.022 0.025+j0.023
The directed graph of the power distribution system is shown in fig. 9, and the topology has three T-shaped nodes, namely a bus 3, a bus 5 and a bus 7.
The ground fault is 50 Ω, and when a phase a ground fault occurs in a branch circuit of the system, the fault location result is shown in the following table:
TABLE 2 Fault location results when different branches are faulty
Figure BDA0003159657960000131
From table 2, it can be concluded that when a fault occurs at different positions of the multi-branch distribution network, the branch with the fault can be correctly judged.
In addition, the accuracy of the fault positioning method is not influenced by the fault distance, and the effectiveness and the robustness of the algorithm adopted by the method are proved.
When different types of faults occur in the multi-branch distribution network system, the fault branch and the fault distance are calculated by using the method provided by the invention, wherein the grounding resistance and the interphase transition resistance are 10 omega.
From table 3, it can be concluded that the method provided by the present invention can accurately calculate the fault distance when the fault occurs in different branches of the system. The algorithm has high precision, and the maximum error of the fault distance is less than 0.0007km under different fault conditions listed in the table.
TABLE 3 Fault location results when different branches are faulty
Figure BDA0003159657960000132
Figure BDA0003159657960000141
The calculated fault distances for different transition resistance conditions, as provided by the present invention, are shown in table 4, where the fault occurred on branch L7.
From table 4 it can be concluded that the method provided by the present invention is not affected by the transition resistance. The high precision is achieved under different transition resistances, and the maximum error of the fault distance is less than 0.0007 km.
TABLE 4 Fault location results under different transition resistance conditions
Figure BDA0003159657960000142
From the above, the method for realizing fault location in a power distribution system with a plurality of branch transmission lines provided by the invention is based on a loop analysis method, and can effectively and accurately judge fault branches to further calculate fault distance. The defects of high economic cost and high investment cost of a measuring device in a traveling wave method are overcome. The method overcomes the defects that the derivation process is complex, the implementation process is complicated and the fault branch cannot be correctly determined when the system scale is large when the fault branch is judged by the existing impedance method.
The embodiment of the invention has the following beneficial effects:
the invention provides a method for realizing fault positioning in a power distribution system with a plurality of branch transmission lines, which divides system nodes into T-shaped nodes and non-T-shaped nodes by establishing a directed graph after a power distribution network fault. Dividing the system into a plurality of areas according to the T-shaped nodes, calculating the voltage of the T-shaped nodes in each area by using a loop voltage equation so as to determine a fault area, and combining non-fault areas so as to reduce the fault area and further perform fault positioning. The method can be used for the online fault location of the actual power distribution network, when the system has a fault, the fault is located and removed in time, further development of the fault is prevented, power supply recovery is guaranteed, and the safety and stability of the system are improved.
The method provided by the invention has the advantages of simple principle, easy realization and no influence of system scale.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims (9)

1. A method for fault location in an electrical distribution system having a plurality of branch transmission lines, comprising the steps of:
step S1, determining a detailed topological structure of the current power distribution system with a plurality of branch transmission lines, equivalently, a directed graph containing nodes and branches, numbering the nodes and the branches, and obtaining a node branch incidence matrix of the power distribution system;
step S2, obtaining sampling values of voltage and current of each node measured by a Power Management Unit (PMU) arranged in the power distribution system;
step S3, calculating and obtaining the current value of each branch by combining the node branch incidence matrix according to the current sampling value of each node;
step S4, dividing the node into T-type and non-T-type nodes according to the number of branches connected with the node, and determining the T-type node nearest to the root node as the current reference T-type node,
step S5, dividing the system into three areas including two single-branch areas and one multi-branch area according to the current reference T-shaped node; calculating the voltage of the current reference T-shaped node in the three regions respectively through a loop voltage equation, and judging a fault region according to the magnitude relation among the three calculated voltages;
step S6, when the fault occurs in the single branch area, calculating to obtain the fault position; when the fault occurs in the multi-branch area, combining the non-fault areas, establishing a new power distribution system, updating the voltage and current sampling values measured by the power management unit PMU, and repeating the steps until an accurate fault position is obtained.
2. The method of claim 1, wherein the step S1 further comprises:
the method comprises the steps of (1) enabling a distribution network system to be equivalent to a directed graph containing nodes and branches, wherein the nodes correspond to a bus, and the branches correspond to a transmission line, a transformer, series compensation, a voltage regulator, a circuit breaker and other equipment;
and obtaining a node branch incidence matrix T of the distribution network systemN×b(I, J), wherein for a distribution network system with N nodes and B branches, the number of a root node is the largest, the farther the root node is, the smaller the number of the node is, and the branch number points to the node with the larger number from the node with the smaller number; if the branch J is on the road I, T (I, J) is 1, otherwise T (I, J) is 0;
wherein, the node number is 1,2, K … N-2, N, the branch number is B1,B2…BN-2,BN-1。
3. The method of claim 2, wherein the step S3 further comprises:
will branch into the incidence matrix TN×bDivision into sub-matrices T1And T2Respectively representing the relationship between branches, branches and roads, wherein T1Is an upper triangular matrix, T2Is an empty matrix;
calculating the current I of each branch according to the following formulab：
Ib＝T1 TIN (2)
Wherein, INThe current at each node is sampled.
4. The method of claim 3, wherein the step S4 further comprises:
the nodes of the distribution network system with the multi-branch transmission lines are divided into T-shaped nodes and non-T-shaped nodes, wherein the T-shaped nodes are numbered as 3, K +1, K +3, …, N-1 and N.
5. The method of claim 4, wherein the step S5 further comprises:
according to the current reference T-type node N-1, the system is divided into three regions including two single-branch regions and one multi-branch region, the region between the root node N and the current reference T-type node N-1 is determined as a first region S1, the region between the current reference T-type node N-1 and the branch node N-2 is determined as a second region S2, and the region between the current reference T-type node and the next T-type node until the end node is taken as a third region S3.
6. The method of claim 5, wherein the step S5 further comprises:
in the first region S1, the voltage of the current reference T-type node N-1 is calculated by the following equation:
VN-1(S1)＝VN-ZB(N-1)·IN·LB(N-1) (14)
in the formula, VNAnd INMeasured by a PMU device; zB(N-1)Is the system positive sequence impedance;
in the second region S1, the voltage of the current reference T-type node N-1 is calculated by the following equation:
VN-1(S2)＝VN-2-ZB(N-2)·IB(N-2)·LB(N-2) (15)
in a second region S1, a road having a T-node and an end node with PMU measurement is selected to establish a loop voltage equation, and in this system, B is selected1,B3,BK+1,BK+3,BK+5,BN-3And BN-1And solving to obtain the voltage of the current reference T-shaped node N-1 according to the following formula:
Figure FDA0003159657950000031
7. the method according to claim 6, wherein the step S5, the determining the fault region according to the magnitude relationship between the three calculated voltages further comprises:
when | VN-1(S1)-VN-1(S2)|>|VN-1(S2)-VN-1(S3)I, and I VN-1(S1)-VN-1(S3)|>|VN-1(S2)-VN-1(S3)If l, it is determined that the failure has occurred in the first area S1.
When | VN-1(S2)-VN-1(S1)|>|VN-1(S1)-VN-1(S3)I, and I VN-1(S2)-VN-1(S3)|>|VN-1(S1)-VN-1(S3)If l, it is determined that the failure has occurred in the second area S2.
When | VN-1(S3)-VN-1(S1)|>|VN-1(S2)-VN-1(S1)I, and I VN-1(S3)-VN-1(S2)|>|VN-1(S2)-VN-1(S1)When | the failure is determined to occur in the third area S3.
8. The method according to any one of claims 1 to 7, wherein in the step S6, if the fault occurs in the first area or the second area, the fault location x is obtained by calculating according to the following formula:
Figure FDA0003159657950000032
wherein, Vm1And Vn1Is the positive sequence voltage of the two end nodes during the fault in the fault area; i ism1、In1Respectively representing positive sequence currents at the end nodes; zmnRepresenting the positive sequence impedance per unit length of the transmission line.
9. The method according to any one of claims 1 to 7, wherein in the step S6, if the fault occurs in the first area or the second area, the fault location x is obtained by calculating according to the following formula:
Figure FDA0003159657950000041
I'm1＝Im1-jωCm1Vm1 (8)
I'n1＝In1-jωCn1Vn1 (9)
wherein, Vm1And Vn1Is the positive sequence voltage of the two end nodes during the fault in the fault area; i ism1、In1Respectively representing positive sequence currents at the end nodes; zmnPositive sequence impedance, C, representing a unit length of the transmission linem1And Cn1Respectively representing the grounded capacitances of the two end node sides.
CN202110787805.5A 2021-07-13 2021-07-13 Method for realizing fault location in power distribution system with multi-branch transmission line Active CN113589099B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110787805.5A CN113589099B (en) 2021-07-13 2021-07-13 Method for realizing fault location in power distribution system with multi-branch transmission line

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110787805.5A CN113589099B (en) 2021-07-13 2021-07-13 Method for realizing fault location in power distribution system with multi-branch transmission line

Publications (2)

Publication Number Publication Date
CN113589099A true CN113589099A (en) 2021-11-02
CN113589099B CN113589099B (en) 2023-07-25

Family

ID=78247046

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110787805.5A Active CN113589099B (en) 2021-07-13 2021-07-13 Method for realizing fault location in power distribution system with multi-branch transmission line

Country Status (1)

Country Link
CN (1) CN113589099B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023160020A1 (en) * 2022-02-23 2023-08-31 国电南瑞科技股份有限公司 Two-terminal fault location method and system for four-terminal line

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020053912A1 (en) * 2000-07-11 2002-05-09 Murari Saha Method and device of fault location for distribution networks
EP2840406A1 (en) * 2013-08-15 2015-02-25 General Electric Company Fault location system and method for distribution network
US9274161B1 (en) * 2013-01-28 2016-03-01 The Florida State University Research Foundation, Inc. Voltage profile based fault location identification system and method of use
CN108387818A (en) * 2018-01-23 2018-08-10 中国石油大学(华东) A kind of fault distance-finding method suitable for the tree-shaped catalogue containing distributed generation resource
CN108802564A (en) * 2018-04-12 2018-11-13 山东大学 The unrelated Fault Location Algorithm of power distribution network T-type line parameter and system
CN109283430A (en) * 2018-09-25 2019-01-29 南方电网科学研究院有限责任公司 A kind of Fault Location for Distribution Network method based on voltage's distribiuting principle
CN109470988A (en) * 2018-10-10 2019-03-15 国网浙江省电力有限公司杭州供电公司 A kind of fault localization system and method suitable for T-type transmission line of electricity
CN109655718A (en) * 2019-02-25 2019-04-19 广东工业大学 A kind of electrical power distribution network fault location method
CN110389282A (en) * 2019-07-17 2019-10-29 华北电力大学 Accurate fault distance-finding method suitable for more power distribution circuits
CN110850236A (en) * 2019-11-28 2020-02-28 国网福建省电力有限公司厦门供电公司 Power distribution network fault positioning method based on parameter estimation
CN110927519A (en) * 2019-11-20 2020-03-27 东南大学 Active power distribution network fault positioning method based on mu PMU measurement value

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020053912A1 (en) * 2000-07-11 2002-05-09 Murari Saha Method and device of fault location for distribution networks
US9274161B1 (en) * 2013-01-28 2016-03-01 The Florida State University Research Foundation, Inc. Voltage profile based fault location identification system and method of use
EP2840406A1 (en) * 2013-08-15 2015-02-25 General Electric Company Fault location system and method for distribution network
CN108387818A (en) * 2018-01-23 2018-08-10 中国石油大学(华东) A kind of fault distance-finding method suitable for the tree-shaped catalogue containing distributed generation resource
CN108802564A (en) * 2018-04-12 2018-11-13 山东大学 The unrelated Fault Location Algorithm of power distribution network T-type line parameter and system
CN109283430A (en) * 2018-09-25 2019-01-29 南方电网科学研究院有限责任公司 A kind of Fault Location for Distribution Network method based on voltage's distribiuting principle
CN109470988A (en) * 2018-10-10 2019-03-15 国网浙江省电力有限公司杭州供电公司 A kind of fault localization system and method suitable for T-type transmission line of electricity
CN109655718A (en) * 2019-02-25 2019-04-19 广东工业大学 A kind of electrical power distribution network fault location method
CN110389282A (en) * 2019-07-17 2019-10-29 华北电力大学 Accurate fault distance-finding method suitable for more power distribution circuits
CN110927519A (en) * 2019-11-20 2020-03-27 东南大学 Active power distribution network fault positioning method based on mu PMU measurement value
CN110850236A (en) * 2019-11-28 2020-02-28 国网福建省电力有限公司厦门供电公司 Power distribution network fault positioning method based on parameter estimation

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
LIU GUILIN 等: "Research on positioning the fault locations automatically in a multi branch transmission line network", 《2018 INTERNATIONAL CONFERENCE ON POWER SYSTEM TECHNOLOGY》 *
李胜芳等: "T型支接线路的自适应故障测距算法", 《电工技术学报》 *
王波等: "一种适于多分支输电线路的故障定位新方法", 《电网技术》 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023160020A1 (en) * 2022-02-23 2023-08-31 国电南瑞科技股份有限公司 Two-terminal fault location method and system for four-terminal line

Also Published As

Publication number Publication date
CN113589099B (en) 2023-07-25

Similar Documents

Publication Publication Date Title
Salim et al. Further improvements on impedance-based fault location for power distribution systems
Suonan et al. A novel fault-location method for HVDC transmission lines
Liao et al. Online optimal transmission line parameter estimation for relaying applications
CN109283430B (en) Power distribution network fault location method based on voltage distribution principle
CN103927459A (en) Method for locating faults of power distribution network with distributed power supplies
CN109283429B (en) Power distribution network fault location method based on positive and negative sequence impedance equality principle
CN106054023B (en) The method of two sides system impedance is estimated in a kind of transmission line of electricity single end distance measurement
CN108802564B (en) distribution network T-shaped line parameter-independent fault location algorithm and system
CN109523165B (en) Voltage sag state estimation method based on limited information
CN111141995B (en) Line double-end steady-state distance measuring method and system based on amplitude comparison principle
CN110333394B (en) Low-voltage distribution network line impedance estimation method
Ramar et al. A new impedance-based fault location method for radial distribution systems
CN104062547A (en) Fault distance measurement method of T-type power transmission network and application of fault location method
CN114236288B (en) Fault positioning method based on power transmission line
CN112415273B (en) Method for accurately measuring zero sequence parameters of double-circuit non-full-line parallel transmission line
Lu et al. Unsynchronized fault location on untransposed transmission lines with fully distributed parameter model considering line parameter uncertainties
CN113589099B (en) Method for realizing fault location in power distribution system with multi-branch transmission line
CN110879332A (en) Single-phase earth fault phase selection method suitable for small current grounding system
Li et al. Augmented state estimation method for fault location based on on-line parameter identification of PMU measurement data
CN106526424A (en) Power transmission line single-phase ground fault parameter recognition method
Goklani et al. Quantification of minimum unbalance required for accurate estimation of sequence parameters of transmission line using PMU data
CN109470988A (en) A kind of fault localization system and method suitable for T-type transmission line of electricity
CN113805012A (en) Method for identifying fault section of power distribution network with neutral point grounded through small resistor
Wang et al. State Estimation Based Fault Location Method for Active Distribution Networks
Peng et al. Fault Location Algorithm for Multi-Terminal Transmission Lines of Distribution System Based on Loop-Analysis

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
GR01 Patent grant
GR01 Patent grant