A low-voltage distribution line fault automatic positioning method and system

Abstract

The application discloses a kind of low-voltage distribution line fault automatic positioning method, comprising: real-time telemeter sampling is carried out to distribution line, and real-time current data is obtained;When the amplitude of zero sequence current upstream of the fault point is greater than the amplitude of zero sequence current downstream of the fault point, and current polarity is opposite, steady-state characteristic criterion is selected to judge the fault point, and the steady-state characteristic fault positioning result is obtained;The steady-state characteristic fault positioning result is verified, and the final fault positioning result is obtained;When the amplitude of zero sequence current upstream of the fault point is less than the amplitude of zero sequence current downstream of the fault point, and current polarity is same, transient characteristic criterion is selected to judge the fault point, and the transient characteristic fault positioning result is obtained;The transient characteristic fault positioning result is verified, and the final fault positioning result is obtained.The application realizes the high efficiency and higher stability of distribution line fault positioning.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power distribution network fault location, in particular, to a low-voltage distribution line fault automatic positioning method and system. BACKGROUND

[0002] Low-voltage line fault identification and positioning is a key and complex task in the power system, and is a key link to ensure the stable operation of the power system. With the continuous expansion of the power system, the number and length of the lines are increasing, thereby bringing greater challenges to the diagnosis of line faults.

[0003] Currently, low-voltage line fault identification and positioning mainly relies on various fault diagnosis techniques. These techniques usually only perform fault identification individually, and have single function and traditional method, which are obviously not suitable for the current power grid environment requirements. For example, traditional identification and positioning methods such as partial discharge detection, cable resistance measurement, and fault indicator method for fault identification all require a large amount of manpower, material resources and time, and have extremely low efficiency. In particular, for complex and hidden faults, experienced operation and maintenance personnel are still needed to judge and handle. In addition, due to the lack of automatic fault positioning function, after identifying the line fault, the experience of the operation and maintenance personnel is still needed to judge and handle the fault, which has extremely low timeliness and may cause the damage to expand. Therefore, the reliability and accuracy of the traditional line fault identification and positioning method are difficult to guarantee, and cannot meet the requirements of the times.

[0004] The technical problems existing in the above-mentioned prior art include:

[0005] 1) The method of fault identification and positioning is single and traditional, and has low efficiency. The traditional low-voltage line fault identification method basically invests manpower to find after the fault occurs, which cannot meet the needs of today's society in terms of cost, timeliness and power quality.

[0006] 2) Real-time data on the line at the time of line fault cannot be recorded. Due to the lack of fault recording function, real-time data at the time of fault cannot be saved and recorded, which is not conducive to analyzing the causes and solving the root causes afterwards.

[0007] 3) Due to the lack of intelligent and feasible criteria and mechanism, the method or experience of fault identification cannot be applied on a large scale, thereby greatly limiting the traditional fault identification method.

[0008] In view of the above situation, the present application uses a more flexible and feasible distribution line grounding fault identification and positioning method, which can realize line grounding fault identification and positioning at the same time, and provides a more efficient and reliable method for fault management of the distribution network. SUMMARY

[0009] To solve the technical problems of low efficiency, poor stability and insufficient positioning accuracy in fault identification and positioning of the prior art, the present application provides a low-voltage distribution line fault automatic positioning method and system, and the technical scheme adopted by the present application comprises:

[0010] The present application provides a low-voltage distribution line fault automatic positioning method in the first aspect, comprising:

[0011] Real-time telemetering sampling is performed on the distribution line to obtain real-time current data; the real-time current data includes the amplitude of the zero sequence current upstream of the fault point, the polarity of the zero sequence current upstream of the fault point, the amplitude of the zero sequence current downstream of the fault point, and the polarity of the zero sequence current downstream of the fault point;

[0012] When the amplitude of the zero sequence current upstream of the fault point is greater than the amplitude of the zero sequence current downstream of the fault point, and the polarity of the zero sequence current upstream of the fault point is opposite to the polarity of the zero sequence current downstream of the fault point, a steady-state characteristic criterion is selected to judge the fault point to obtain a steady-state characteristic fault positioning result, and the steady-state characteristic fault positioning result is verified to obtain a final fault positioning result;

[0013] When the amplitude of the zero sequence current upstream of the fault point is less than the amplitude of the zero sequence current downstream of the fault point, and the polarity of the zero sequence current upstream of the fault point is the same as the polarity of the zero sequence current downstream of the fault point, a transient-state characteristic criterion is selected to judge the fault point to obtain a transient-state characteristic fault positioning result, and the transient-state characteristic fault positioning result is verified to obtain a final fault positioning result.

[0014] As a preferred scheme, the method for verifying the steady-state characteristic fault positioning result to obtain a final fault positioning result comprises:

[0015] The steady-state characteristic and the transient-state characteristic are simultaneously operated to judge and position the fault, if the steady-state characteristic fault positioning result and the transient-state characteristic fault positioning result are consistent, the steady-state characteristic fault positioning result is adopted; if the steady-state characteristic fault positioning result and the transient-state characteristic fault positioning result are inconsistent, the transient-state characteristic fault positioning result is adopted.

[0016] As a preferred scheme, the method for verifying the transient-state characteristic fault positioning result to obtain a final fault positioning result comprises:

[0017] The steady-state characteristic and the transient-state characteristic are simultaneously operated to judge and position the fault, if the steady-state characteristic fault positioning result and the transient-state characteristic fault positioning result are consistent, the transient-state characteristic fault positioning result is adopted; if the steady-state characteristic fault positioning result and the transient-state characteristic fault positioning result are inconsistent, the steady-state characteristic fault positioning result is adopted.

[0018] As a preferred solution, the method further comprises a power distribution line fault automatic positioning algorithm for generating a topological network matrix D according to a low-voltage power distribution line topology structure, and finally obtaining a fault information matrix E from the topological network matrix D.

[0019] As a preferred solution, in the topological network matrix D, the definition element d ij ;;

[0020] When the node i is directly connected with the node j, and the node j is in the positive direction of the node, the value of d ij is 1, when the node i is directly connected with the node j, and the node j is in the reverse direction of the node, the value of d ij is -1, and when the node i is not connected with the node j, the value of d ij is 0.

[0021] If the positive direction is defined as the direction of the load current before the fault occurs, the topological network matrix D can be expressed as:

[0022]

[0023] As a preferred solution, the method comprises:

[0024] When the fault occurs, due to the different outputs of the fault switch at the sectionalizing switch, a three-state representation method is used for description, and the detected injection signal is represented as 1, the undetected injection signal is represented as 0, and the unobtainable fault information is represented as -1, when the fault occurs on the branch E5, the fault information matrix E can be expressed as:

[0025] E = [1 1 1 0 0 1 0 0].

[0026] As a preferred solution, the fault information matrix E is corrected by probability theory; specifically:

[0027] The elements on the main diagonal of the topological network matrix are replaced by the fault information matrix in the corresponding order to form a fault discrimination matrix, and then the fault information matrix L is automatically corrected according to the occurrence of the fault positioning switch reading as shown below:

[0028]

[0029] According to the fault area judgment principle, the initial fault set θ0 = {1} can be obtained, and the final fault set θ = {5} can be obtained after traversal, so it can be judged that the fault occurs on the line E5.

[0030] The second aspect of the present application provides a low-voltage power distribution line fault automatic positioning system, comprising a telemetry sampling module, a steady-state characteristic judgment module and a transient-state characteristic judgment module.

[0031] The telemetry sampling module is used for real-time telemetry sampling of the power distribution line to obtain real-time current data; the real-time current data includes the amplitude of the zero sequence current upstream of the fault point, the polarity of the zero sequence current upstream of the fault point, the amplitude of the zero sequence current downstream of the fault point, and the polarity of the zero sequence current downstream of the fault point;

[0032] The steady-state characteristic judgment module is used for judging the fault point to obtain a fault positioning result of the steady-state characteristic, verifying the fault positioning result of the steady-state characteristic, and obtaining a final fault positioning result.

[0033] The transient-state characteristic judgment module is used for judging the fault point to obtain a fault positioning result of the transient-state characteristic, verifying the fault positioning result of the transient-state characteristic, and obtaining a final fault positioning result.

[0034] The third aspect of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to realize the steps of the low-voltage power distribution line fault automatic positioning method.

[0035] The fourth aspect of the present application provides a computer device, which includes a storage medium, a processor, and a computer program stored in the storage medium and executable by the processor, and the computer program is executed by the processor to realize the steps of the low-voltage power distribution line fault automatic positioning method.

[0036] Compared with the prior art, the present application has the beneficial effects that:

[0037] The present application can more efficiently and accurately identify and locate the grounding fault of the power distribution line by automatically selecting appropriate fault judgment basis, so that the low-voltage power distribution line can operate more stably, reliably and efficiently. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A low-voltage power distribution line fault automatic positioning method flowchart is provided for the present embodiment.

[0039] Figure 2 A network topology structure diagram is provided for the present embodiment. DETAILED DESCRIPTION

[0040] The accompanying drawings are only used for illustrative purposes and cannot be understood as limiting the present application;

[0041] It should be clear that the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0042] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0043] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. The invention will be further described below with reference to the accompanying drawings and embodiments.

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] Example 1

[0047] Please refer to Figure 1 as well as Figure 2 This embodiment provides an automatic fault location method for low-voltage power distribution lines, including:

[0048] Real-time telemetry sampling is performed on the power distribution line to obtain real-time current data; the real-time current data includes the amplitude of the zero-sequence current upstream of the fault point, the polarity of the zero-sequence current upstream of the fault point, the amplitude of the zero-sequence current downstream of the fault point, and the polarity of the zero-sequence current downstream of the fault point.

[0049] When the amplitude of the zero sequence current upstream of the fault point is greater than the amplitude of the zero sequence current downstream of the fault point, and the polarity of the zero sequence current upstream of the fault point is opposite to the polarity of the zero sequence current downstream of the fault point, a steady-state characteristic criterion is selected to judge the fault point to obtain a steady-state characteristic fault locating result, and the steady-state characteristic fault locating result is verified to obtain a final fault locating result.

[0050] When the amplitude of the zero sequence current upstream of the fault point is less than the amplitude of the zero sequence current downstream of the fault point, and the polarity of the zero sequence current upstream of the fault point is the same as the polarity of the zero sequence current downstream of the fault point, a transient-state characteristic criterion is selected to judge the fault point to obtain a transient-state characteristic fault locating result, and the transient-state characteristic fault locating result is verified to obtain a final fault locating result.

[0051] In one specific embodiment, the method of verifying the steady-state characteristic fault locating result to obtain a final fault locating result comprises:

[0052] The steady-state characteristic and the transient-state characteristic are simultaneously used to judge and locate the fault, if the steady-state characteristic fault locating result is consistent with the transient-state characteristic fault locating result, the steady-state characteristic fault locating result is adopted, and if the steady-state characteristic fault locating result is not consistent with the transient-state characteristic fault locating result, the transient-state characteristic fault locating result is adopted.

[0053] In one specific embodiment, the method of verifying the transient-state characteristic fault locating result to obtain a final fault locating result comprises:

[0054] The steady-state characteristic and the transient-state characteristic are simultaneously used to judge and locate the fault, if the steady-state characteristic fault locating result is consistent with the transient-state characteristic fault locating result, the transient-state characteristic fault locating result is adopted, and if the steady-state characteristic fault locating result is not consistent with the transient-state characteristic fault locating result, the steady-state characteristic fault locating result is adopted.

[0055] In one specific embodiment, the method further comprises a power distribution line fault automatic locating algorithm, the power distribution line fault automatic locating algorithm is used to generate a topological network matrix D according to a low-voltage power distribution line topological structure, and finally a fault information matrix E is obtained from the topological network matrix D.

[0056] In one specific embodiment, in the topological network matrix D, an element d ij ;

[0057] When the node i is directly connected with the node j, and the node j is in the positive direction of the node, the value of d ij is 1, when the node i is directly connected with the node j, and the node j is in the negative direction of the node, the value of d ijthe value of d is -1 when the node i is not connected with the node j ij the value of d is 0;

[0058] If the positive direction is defined as the direction of the load current before the fault occurs, the topological grid matrix D can be expressed as:

[0059]

[0060] In one specific embodiment, the method comprises:

[0061] When the fault occurs, due to the different outputs of the fault switch at the sectionalizing switch, a three-state representation method is used for description, and the detected injection signal is expressed as 1, the undetected injection signal is expressed as 0, and the fault information cannot be obtained and is expressed as -1, when the fault occurs on the branch E5, the fault information matrix E can be expressed as:

[0062] E = [1 1 1 0 0 1 0 0].

[0063] In one specific embodiment, the fault information matrix E is corrected through probability theory; specifically:

[0064] The elements on the main diagonal of the topological network matrix are replaced by the fault information matrix in the corresponding order to form a fault discrimination matrix, and then the fault information matrix L is automatically corrected according to the occurrence of the fault positioning switch reading as shown below:

[0065]

[0066] According to the fault area judgment principle, the initial fault set θ0 = {1} can be obtained, and after traversal, the final fault set θ = {5} is obtained, so it can be judged that the fault occurs on the line E5.

[0067] The present application can more efficiently and accurately identify and locate the grounding fault of the distribution line by automatically selecting appropriate fault judgment basis, so that the low-voltage distribution line can operate more stably, reliably and efficiently.

[0068] Embodiment 2

[0069] The embodiment provides a low-voltage distribution line fault automatic positioning system, which comprises a telemetry sampling module 1, a steady-state characteristic judgment module 2 and a transient-state characteristic judgment module 3.

[0070] The telemetry sampling module 1 is used for real-time telemetry sampling of the distribution line to obtain real-time current data; the real-time current data comprises the amplitude of the zero sequence current upstream of the fault point, the polarity of the zero sequence current upstream of the fault point, the amplitude of the zero sequence current downstream of the fault point and the polarity of the zero sequence current downstream of the fault point.

[0071] The steady-state feature judgment module 2 is configured to judge the fault point to obtain a steady-state feature fault positioning result, verify the steady-state feature fault positioning result, and obtain a final fault positioning result.

[0072] The transient-state feature judgment module 3 is configured to judge the fault point to obtain a transient-state feature fault positioning result, verify the transient-state feature fault positioning result, and obtain a final fault positioning result.

[0073] In one specific embodiment, the steady-state feature judgment module further comprises a steady-state feature positioning result verification unit.

[0074] The steady-state feature positioning result verification unit is configured to simultaneously judge and locate the fault by using the steady-state feature and the transient-state feature, and if the steady-state feature fault positioning result and the transient-state feature fault positioning result are consistent, the steady-state feature fault positioning result is adopted; if the steady-state feature fault positioning result and the transient-state feature fault positioning result are inconsistent, the transient-state feature fault positioning result is adopted.

[0075] In one specific embodiment, the transient-state feature judgment module further comprises a transient-state feature positioning result verification unit.

[0076] The transient-state feature positioning result verification unit is configured to simultaneously judge and locate the fault by using the steady-state feature and the transient-state feature, and if the steady-state feature fault positioning result and the transient-state feature fault positioning result are consistent, the transient-state feature fault positioning result is adopted; if the steady-state feature fault positioning result and the transient-state feature fault positioning result are inconsistent, the steady-state feature fault positioning result is adopted.

[0077] Embodiment 3

[0078] A computer readable storage medium, having a computer program stored thereon, the computer program being executed by a processor to implement the steps of the low-voltage distribution line fault automatic positioning method in embodiment 1.

[0079] Embodiment 4

[0080] A computer device, comprising a storage medium, a processor, and a computer program stored in the storage medium and executable by the processor, the computer program being executed by the processor to implement the steps of the low-voltage distribution line fault automatic positioning method in embodiment 1.

[0081] Obviously, the above embodiments of the present application are merely exemplary but not intended to limit the embodiments of the present application. Based on the above description, any other variations or changes can be made by those skilled in the art without departing from the spirit and principles of the present application. It is not necessary to list all the embodiments here. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall fall within the scope of the claims of the present application.

Claims

1. A method for automatic fault location in low voltage distribution lines, characterized in that, The method comprises the following steps: Real-time remote sampling of a power distribution line to obtain real-time current data; The real-time current data comprises an amplitude of zero sequence current upstream of a fault point, a polarity of the zero sequence current upstream of the fault point, an amplitude of zero sequence current downstream of the fault point, and a polarity of the zero sequence current downstream of the fault point; When the amplitude of the zero sequence current upstream of the fault point is greater than the amplitude of the zero sequence current downstream of the fault point, and the polarity of the zero sequence current upstream of the fault point is opposite to the polarity of the zero sequence current downstream of the fault point, a steady-state characteristic criterion is selected to judge the fault point to obtain a steady-state characteristic fault locating result, and the steady-state characteristic fault locating result is verified to obtain a final fault locating result; When the amplitude of the zero sequence current upstream of the fault point is less than the amplitude of the zero sequence current downstream of the fault point, and the polarity of the zero sequence current upstream of the fault point is the same as the polarity of the zero sequence current downstream of the fault point, a transient-state characteristic criterion is selected to judge the fault point to obtain a transient-state characteristic fault locating result, and the transient-state characteristic fault locating result is verified to obtain a final fault locating result; The method for verifying the steady-state characteristic fault locating result to obtain a final fault locating result comprises the following steps: The steady-state characteristic and the transient-state characteristic are simultaneously used to judge and locate the fault, if the steady-state characteristic fault locating result is consistent with the transient-state characteristic fault locating result, the steady-state characteristic fault locating result is adopted, and if the steady-state characteristic fault locating result is inconsistent with the transient-state characteristic fault locating result, the transient-state characteristic fault locating result is adopted; The method for verifying the transient-state characteristic fault locating result to obtain a final fault locating result comprises the following steps: The steady-state characteristic and the transient-state characteristic are simultaneously used to judge and locate the fault, if the steady-state characteristic fault locating result is consistent with the transient-state characteristic fault locating result, the transient-state characteristic fault locating result is adopted, and if the steady-state characteristic fault locating result is inconsistent with the transient-state characteristic fault locating result, the steady-state characteristic fault locating result is adopted.

2. The method for automatic fault location of low voltage distribution line according to claim 1, characterized in that, The method further comprises a power distribution line fault automatic locating algorithm, and the power distribution line fault automatic locating algorithm is used to generate a topological network matrix D according to a low-voltage power distribution line topological structure, and finally obtain a fault information matrix E from the topological network matrix D.

3. A method for automatic fault location of a low voltage distribution line according to claim 2, characterized in that, In the topological network matrix D, the elements d ij are defined by d(i, j) = 1 when node i is directly connected to node j and node j is in the positive direction of node i ij d(i, j) = -1 when node i is directly connected to node j and node j is in the negative direction of node i ij d(i, j) = 0 when node i is not directly connected to node j ij d(i, j) = 0 when node i is not directly connected to node j If a positive direction is defined as a direction of a load current before the fault occurs, the topological network matrix D can be expressed as: 。 4. The method of claim 3, wherein, The method comprises the following steps: After the fault occurs, different outputs of fault switches at sectionalizing switches are described by using a three-state representation method, and detection of an injected signal is represented as 1, no detection of the injected signal is represented as 0, and failure to obtain fault information is represented as -1, and when a fault occurs on a branch E5, the fault information matrix E can be expressed as: E ＝ [11100100]。 5. A method for automatic fault location of a low voltage distribution line according to claim 4, characterized in that, The fault information matrix E is corrected by using a probability theory, and specifically, Elements on a main diagonal line of the topological network matrix are replaced by the fault information matrix according to a corresponding order to form a fault discrimination matrix, and then the fault information matrix L is automatically corrected according to a fault locating switch reading as follows: According to the fault area judgment principle, an initial fault set θ0 = {1} is obtained, and a final fault set θ = {5} is obtained after traversal, so it is determined that the fault occurs in line E5.

6. A low voltage distribution line fault automatic locating system for use in a low voltage distribution line fault automatic locating method as claimed in claim 1, characterized in that, The method comprises a telemetry sampling module (1), a steady-state characteristic judgment module (2), and a transient-state characteristic judgment module (3). The telemetry sampling module (1) is configured to perform real-time telemetry sampling on the distribution line to obtain real-time current data. The real-time current data comprises an amplitude of zero sequence current upstream of the fault point, a polarity of the zero sequence current upstream of the fault point, an amplitude of zero sequence current downstream of the fault point, and a polarity of the zero sequence current downstream of the fault point. The steady-state characteristic judgment module (2) is configured to judge the fault point to obtain a steady-state characteristic fault positioning result, and verify the steady-state characteristic fault positioning result to obtain a final fault positioning result. The transient-state characteristic judgment module (3) is configured to judge the fault point to obtain a transient-state characteristic fault positioning result, and verify the transient-state characteristic fault positioning result to obtain a final fault positioning result.

7. A computer readable storage medium having stored thereon a computer program, characterized in that: The computer program, when executed by a processor, implements the steps of the low-voltage distribution line fault automatic positioning method according to any one of claims 1 to 5.

8. A computer device, comprising: The computer program, when executed by a processor, implements the steps of the low-voltage distribution line fault automatic positioning method according to any one of claims 1 to 5.

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