A cable fault analysis method and terminal integrating electric power measurement information

Abstract

The present invention discloses a cable fault analysis method and terminal integrating electric power measurement information, which obtain physical parameters of cables corresponding to each node of the cable to be monitored, and determine the reference impedance value of the cables corresponding to each node according to the physical parameters; collect electric power measurement information measured by electric meters distributed at each node of the cable to be monitored, and the electric power measurement information includes the current and voltage of the cables corresponding to each node; determine the measured impedance value of the cables corresponding to each node according to the current and voltage, and analyze the fault of the cables corresponding to each node according to the reference impedance value and the measured impedance value; make full use of the existing electric meter system, and only need to obtain the current value and voltage value from the existing electric meter system to realize the analysis of the cable fault, which is convenient and easy, and can greatly improve the efficiency and reliability of cable fault analysis, thereby realizing reliable and convenient monitoring of cable faults.

Description

Technical Field

[0001] The present invention relates to the field of cable fault analysis and judgment, and in particular to a cable fault analysis and judgment method and a terminal integrating electric power measurement information. Background Art

[0002] With the increasing complexity of power cable networks, cable fault inspection and troubleshooting have caused serious work pressure on cable operation and maintenance management departments. Power cables are laid over a wide range of areas, and a considerable number of them are buried deep underground. The location and type of faults are highly random, so the use of manual on-site inspections will face problems such as complex geographical environments, difficult conditions, and difficult maintenance. In addition, the manual inspection management model cannot achieve real-time monitoring and location handling of power cable faults, which has caused great trouble to the overall stability and reliability of the power system operation.

[0003] In general, the degree of insulation degradation of cables increases with the increase of service time. However, in practice, the speed of cable insulation degradation is largely affected by comprehensive factors such as operating conditions and laying environment, and it is difficult to quantify it simply by service time. Therefore, quantitative detection of cable insulation status and providing reliable evaluation indicators are necessary means to guide the arrangement of cable replacement and maintenance plans. At present, preventive tests (offline measurements) for evaluating cable insulation status have formed standard procedures in the power sector, such as insulation resistance measurement, variable frequency resonance withstand voltage test, dielectric loss detection, ultra-low frequency (0.01~0.1Hz) dielectric loss detection, AC / DC withstand voltage test, leakage current test, partial discharge test, etc. Offline conventional measurement plays an important role in ensuring the safe operation of power equipment. However, offline measurement not only requires the regular shutdown and withdrawal of working cables, but also affects the normal operation of the power system; at the same time, since power cables are often laid in cable trenches or buried directly underground, each test measurement and recovery installation will cause a lot of waste of manpower and material resources, and the impulse test voltage applied during the test may also cause secondary damage to the cable insulation.

[0004] In view of the various defects of offline measurement, in the early years, there appeared such as infrared detection method, leakage current method and other periodic live detection methods using portable equipment, and distributed optical fiber temperature measurement method, but due to the inconvenience of operation and the limitation of laying conditions and investment and maintenance cost, they have not been promoted. With the further improvement of the requirements for power supply reliability and intelligent operation of power systems, a wealth of cable online monitoring methods have been developed and emerged in recent years, such as DC component method, ground current method, online dielectric loss angle method, AC superposition method, DC superposition method, partial discharge method, time domain reflection method, frequency domain reflection method, etc., but these methods have not been widely used in practice. The main limiting reasons are: the insulation-related monitoring signal measured under the steady state of power frequency is weak, the insulation monitoring effect is not good, and the artificial disturbance signal will cause additional interference to the power system, and the existing cable online monitoring methods need to be connected to a specific fault analyzer, the connection is cumbersome, which also brings inconvenience to cable fault monitoring. Therefore, further developing reliable and convenient online monitoring methods for cable status is still an urgent need for power grid operation. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a cable fault analysis method and terminal integrating electric power measurement information, which can reliably and conveniently monitor cable faults.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0007] A cable fault analysis method integrating electric power measurement information comprises the following steps:

[0008] S1. Obtaining the physical parameters of the cable corresponding to each node of the cable to be monitored, and determining the reference impedance value of the cable corresponding to each node according to the physical parameters;

[0009] S2. Collecting power measurement information obtained by electric meters distributed at each node of the cable to be monitored, wherein the power measurement information includes the current and voltage of the cable corresponding to each node;

[0010] S3. Determine the measured impedance value of the cable corresponding to each node according to the current and voltage, and analyze and judge the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value.

[0011] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0012] A cable fault analysis terminal integrating power measurement information includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the following steps are implemented:

[0013] S1. Obtaining the physical parameters of the cable corresponding to each node of the cable to be monitored, and determining the reference impedance value of the cable corresponding to each node according to the physical parameters;

[0014] S2. Collecting power measurement information obtained by electric meters distributed at each node of the cable to be monitored, wherein the power measurement information includes the current and voltage of the cable corresponding to each node;

[0015] S3. Determine the measured impedance value of the cable corresponding to each node according to the current and voltage, and analyze and judge the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value.

[0016] The beneficial effects of the present invention are as follows: with the help of the existing electric meters laid at various nodes of the cable, the current and voltage of the electric meters at each node are obtained, and the measured impedance value of the cable corresponding to each node is determined by using the obtained current and voltage. The fault of the cable corresponding to each node is judged by comparing the measured impedance value with the reference impedance value, and the low-voltage power measurement information that would have been measured in the cable line is integrated into the cable fault judgment, and the judgment is performed based on the impedance comparison. On the one hand, the existing electric meter system is fully utilized, and there is no need to additionally lay out monitoring circuits like the existing real-time monitoring, which leads to inaccurate judgment, low efficiency, cumbersome operation and other problems. On the other hand, it only needs to obtain the current value and voltage value from the existing electric meter system to realize the judgment of the cable fault, which is convenient and easy, and can greatly improve the efficiency and reliability of cable fault judgment, thereby realizing reliable and convenient monitoring of cable faults, shortening the fault time, improving the power supply reliability, and providing data basis for power emergency repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flowchart of the steps of a cable fault analysis method integrating power measurement information according to an embodiment of the present invention;

[0018] Figure 2 This is a structural schematic diagram of a cable fault analysis terminal integrating power measurement information according to an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of a cable branching structure according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of another cable branching structure according to an embodiment of the present invention;

[0021] Figure 5 A specific flow chart of cable fault analysis in a cable fault analysis method integrating power measurement information according to an embodiment of the present invention;

[0022] Figure 6The present invention is a schematic diagram of the structure of a cable fault analysis system integrating distributed power measurement information according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0024] Please refer to Figure 1 , a cable fault analysis method integrating power measurement information, comprising the steps of:

[0025] S1. Obtaining the physical parameters of the cable corresponding to each node of the cable to be monitored, and determining the reference impedance value of the cable corresponding to each node according to the physical parameters;

[0026] S2. Collecting power measurement information obtained by electric meters distributed at each node of the cable to be monitored, wherein the power measurement information includes the current and voltage of the cable corresponding to each node;

[0027] S3. Determine the measured impedance value of the cable corresponding to each node according to the current and voltage, and analyze and judge the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value.

[0028] From the above description, it can be seen that the beneficial effects of the present invention are: with the help of the existing electric meters laid at each node of the cable, the current and voltage of the electric meters at each node are obtained, and the measured impedance value of the cable corresponding to each node is determined by using the obtained current and voltage. The fault of the cable corresponding to each node is judged by comparing the measured impedance value with the reference impedance value, and the low-voltage power measurement information that would be measured in the cable line is integrated into the cable fault judgment, and the judgment is performed based on the impedance comparison. On the one hand, the existing electric meter system is fully utilized, and there is no need to additionally lay out monitoring circuits like the existing real-time monitoring, which leads to inaccurate judgment, low efficiency, cumbersome operation and other problems. On the other hand, it only needs to obtain current and voltage values ​​from the existing electric meter system to realize the judgment of cable faults, which is convenient and easy, and can greatly improve the efficiency and reliability of cable fault judgment, thereby realizing reliable and convenient monitoring of cable faults, shortening fault time, improving power supply reliability, and providing data basis for power repair.

[0029] Further, the physical parameters include cable model and length;

[0030] Determining the reference impedance value of the cable corresponding to each node according to the physical parameter includes:

[0031] Determine the resistivity, reactance and cross-sectional area of ​​the cable corresponding to each node according to the cable model of the cable corresponding to each node;

[0032] Determine the resistance and reactance of the cables corresponding to each node according to the resistivity, reactance, cross-sectional area and length of the cables corresponding to each node;

[0033] The reference impedance value of the cable corresponding to each node is determined according to the resistance and reactance of the cable corresponding to each node.

[0034] From the above description, it can be seen that with the help of the model and length of the cable corresponding to each node, the cable ground reference impedance value corresponding to each node can be accurately determined, thereby ensuring the accuracy of cable fault analysis.

[0035] Further, determining the measured impedance value of the cable corresponding to each node according to the current and voltage includes:

[0036] The measured impedance value of the cable corresponding to each node is determined according to the current and voltage using a multivariate linear regression analysis method.

[0037] From the above description, it can be seen that the multivariate linear regression analysis method can quickly and accurately determine the measured impedance value of the cable corresponding to each node, further ensuring the accuracy and reliability of cable analysis.

[0038] Further, judging the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value includes:

[0039] If the measured impedance value is infinite, determining that the cable corresponding to the measured impedance value is broken or broken;

[0040] If the measured impedance value is greater than or equal to n times the reference impedance value, it is determined that a high-resistance fault exists in the cable corresponding to the measured impedance value, where n represents a discrimination coefficient;

[0041] If the measured impedance value is greater than or equal to the reference impedance value and less than n times the reference impedance value, it is determined that the cable corresponding to the measured impedance value is normal;

[0042] If the measured impedance value is less than the reference impedance value, it is determined that a low-resistance fault exists in the cable corresponding to the measured impedance value.

[0043] From the above description, it can be seen that by judging the size of the measured impedance value and comparing the measured impedance value with the reference impedance value, various fault conditions of the cable corresponding to the measured impedance value can be accurately and quickly judged, thereby realizing the refinement of cable fault analysis.

[0044] Furthermore, the method further comprises the steps of:

[0045] Obtaining the real-time temperature value of the cable corresponding to each node of the cable to be monitored;

[0046] It is determined whether the real-time temperature value is greater than or equal to a preset temperature threshold value. If so, it is determined that a high temperature fault exists in the cable corresponding to the real-time temperature value.

[0047] From the above description, it can be seen that by monitoring the real-time temperature values ​​of the cables corresponding to each node, it is also possible to determine whether the cable has a high-temperature fault, which increases the latitude of cable fault determination and further ensures the reliability of the determination.

[0048] Please refer to Figure 2 , a cable fault analysis terminal integrating power measurement information, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program:

[0049] S1. Obtaining the physical parameters of the cable corresponding to each node of the cable to be monitored, and determining the reference impedance value of the cable corresponding to each node according to the physical parameters;

[0050] S2. Collecting power measurement information obtained by electric meters distributed at each node of the cable to be monitored, wherein the power measurement information includes the current and voltage of the cable corresponding to each node;

[0051] S3. Determine the measured impedance value of the cable corresponding to each node according to the current and voltage, and analyze and judge the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value.

[0052] Further, the physical parameters include cable model and length;

[0053] Determining the reference impedance value of the cable corresponding to each node according to the physical parameter includes:

[0054] Determine the resistivity, reactance and cross-sectional area of ​​the cable corresponding to each node according to the cable model of the cable corresponding to each node;

[0055] Determine the resistance and reactance of the cables corresponding to each node according to the resistivity, reactance, cross-sectional area and length of the cables corresponding to each node;

[0056] The reference impedance value of the cable corresponding to each node is determined according to the resistance and reactance of the cable corresponding to each node.

[0057] Further, determining the measured impedance value of the cable corresponding to each node according to the current and voltage includes:

[0058] The measured impedance value of the cable corresponding to each node is determined according to the current and voltage using a recursive least square method.

[0059] Further, judging the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value includes:

[0060] If the measured impedance value is infinite, determining that the cable corresponding to the measured impedance value is broken or broken;

[0061] If the measured impedance value is greater than or equal to n times the reference impedance value, it is determined that a high-resistance fault exists in the cable corresponding to the measured impedance value, where n represents a discrimination coefficient;

[0062] If the measured impedance value is greater than or equal to the reference impedance value and less than n times the reference impedance value, it is determined that the cable corresponding to the measured impedance value is normal;

[0063] If the measured impedance value is less than the reference impedance value, it is determined that a low-resistance fault exists in the cable corresponding to the measured impedance value.

[0064] Furthermore, when the processor executes the computer program, the processor also implements the following steps:

[0065] Obtaining the real-time temperature value of the cable corresponding to each node of the cable to be monitored;

[0066] It is determined whether the real-time temperature value is greater than or equal to a preset temperature threshold value. If so, it is determined that a high temperature fault exists in the cable corresponding to the real-time temperature value.

[0067] Embodiment 1

[0068] Please refer to Figure 1 , a cable fault analysis method integrating power measurement information, comprising the steps of:

[0069] S1. Obtaining the physical parameters of the cable corresponding to each node of the cable to be monitored, and determining the reference impedance value of the cable corresponding to each node according to the physical parameters;

[0070] Wherein, the physical parameters include cable model and length;

[0071] Determining the reference impedance value of the cable corresponding to each node according to the physical parameter includes:

[0072] Determine the resistivity, reactance and cross-sectional area of ​​the cable corresponding to each node according to the cable model of the cable corresponding to each node;

[0073] Determine the resistance and reactance of the cables corresponding to each node according to the resistivity, reactance, cross-sectional area and length of the cables corresponding to each node;

[0074] Determine a reference impedance value of the cable corresponding to each node according to the resistance and reactance of the cable corresponding to each node;

[0075] Specifically, assume that the length of the cable corresponding to a node is l, the cross-sectional area is S, and the resistivity of the cable is ρ Y , the reactance is ρ X ,but

[0076] The resistance of this cable is:

[0077] R=ρ y l / S;

[0078] The reactance of the cable:

[0079] X=p X l / S;

[0080] Then the reference impedance value of the cable can be approximately equivalent to:

[0081] Z = R + jX;

[0082] S2. Collecting power measurement information obtained by electric meters distributed at each node of the cable to be monitored, wherein the power measurement information includes the current and voltage of the cable corresponding to each node;

[0083] Among them, each node of the cable is equipped with an electric meter required for normal measurement in the actual low-voltage power grid, which can be an electromagnetic meter or a photoelectric meter. The electric meter can read the current and voltage corresponding to each node;

[0084] When collecting data, the current and voltage data collected by the electric meter at each node can be obtained through wireless communication, carrier communication or optical cable communication;

[0085] S3. Determine the measured impedance value of the cable corresponding to each node according to the current and voltage, and analyze and judge the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value.

[0086] Embodiment 2

[0087] This embodiment further defines:

[0088] Determining the measured impedance value of the cable corresponding to each node according to the current and voltage includes:

[0089] Determine the measured impedance value of the cable corresponding to each node according to the current and voltage using a multivariate linear regression analysis method;

[0090] Specifically, the steps include:

[0091] (1) Add all nodes in the cable to set A and obtain the current and voltage values ​​of each node;

[0092] (2) taking each two nodes in set A as a pair, constructing a multiple linear regression equation based on their current and voltage values, performing multiple linear regression analysis, and determining the measured impedance value of the cable corresponding to each pair of two nodes according to the multiple linear regression analysis results;

[0093] (3) Compare the coefficients of determination of all the multiple linear regression equations constructed in step (2), set the measured impedance value corresponding to the node determined by the multiple linear regression equation with the largest coefficient of determination as the effective value, delete the two nodes corresponding to the multiple linear regression equation with the largest coefficient of determination from set A, merge the two nodes into a new node according to the voltage and current values, add the new node to set A, and return to step (2) to perform topological recursion until only one node is left in set A, then the measured impedance values ​​of all the determined effective values ​​are the measured impedance values ​​of the cables corresponding to each node;

[0094] The judgment in step (3) can realize the reverse deduction of the circuit topology, and determine the corresponding circuit parameters based on the topology, so as to better adapt to the topology changes caused by many circuit modifications in the actual field, and ensure the accuracy of the measured impedance value of the determined cable;

[0095] In specific implementation, for example, Figure 3 The wiring shown has cable branches 1 and 2. Combined with Kirchhoff's law, the data of cable branches 1 and 2 satisfy the following formula:

[0096] U0=U1+R1I 1,R +X1I 1,X =U2+R2I 2,R +X2I 2,X (1)

[0097] Where: U1, U2, U0 are the active voltage components of node 1, node 2, and node 0 respectively; R1, R2, X1, and X2 are the resistance and reactance of line 1 and line 2 respectively; I 1,R ,I 2,R ,I 1,X ,I 2,X are the active and reactive components of the current. Since the imaginary part of the voltage drop has a small effect on the active component of the voltage, it is ignored to simplify the calculation. Here, only the real part of the voltage drop is considered.

[0098] Formula (1) can be used to obtain the linear regression equation as shown in formula (2):

[0099] U2=β0+β1U1+R1I 1,R +X1I 1,X+R2(-I 2,R )+X2(-I 2,X ) (2)

[0100] Multiple linear regression analysis was used, with U2 as the dependent variable, U1, I 1,R ,I 1,X 、(-I 2,R )、(-I 2,X ) as the independent variable, β0, β1, R1, X1, R2, X2 as the regression coefficients to be solved, then the regression coefficients to be solved in formula (2) can be obtained through multiple sets of measured voltage and current values ​​of each node. Among them, β0 and β1 are mainly used to improve the fitting degree of the regression equation.

[0101] The goodness of fit is determined by the coefficient of determination R2 of the regression equation. Based on the goodness of fit result, it can be inferred whether node 1 and node 2 do have a common upper node. If there is a common upper node, the voltage and current of node 0 can be obtained by equation (3), and nodes 1 and 2 are merged into node 0 to continue to participate in topology recursion.

[0102]

[0103] I0=I1+I2 (3)

[0104] The specific steps of line impedance analysis method are as follows:

[0105] 1) Let the set of all underlying nodes be A, and obtain the U and I of each node R ,I X curve;

[0106] 2) Take every two nodes in set A as a pair and perform regression analysis of formula (2);

[0107] 3) The pair with the largest R2 is considered to have a common upper node. The two nodes in this pair are deleted from the set A, and their common upper node k is added. At the same time, the U of node k is calculated. k ,I k,R ,I k,X .

[0108] 4) Repeat step 2) until there is only one node left in set A.

[0109] By repeating this process recursively, we can obtain the measured impedance value Rt of the cable corresponding to each node in the cable line. Figure 4As shown in the line topology, through regression analysis of each pair of nodes, it can be known that the R2 of node 1 and node 2 is larger than the R2 of other nodes (such as node 1 and node 4; node 2 and node 3, etc.), so node 1 and node 2 have a common upper node. Therefore, nodes 1 and 2 can be deleted and merged into their common node 0. At this time, the line only has nodes 0, node 3, and node 4 left, and finally merged into only node 0. At this time, the measured impedance values ​​of the cables corresponding to each node are also calculated.

[0110] Embodiment 3

[0111] This embodiment further defines how to analyze and judge the cable fault, specifically:

[0112] The determining of the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value includes:

[0113] If the measured impedance value is infinite, determining that the cable corresponding to the measured impedance value is broken or broken;

[0114] If the measured impedance value is greater than or equal to n times the reference impedance value, it is determined that a high-resistance fault exists in the cable corresponding to the measured impedance value, where n represents a discrimination coefficient;

[0115] If the measured impedance value is greater than or equal to the reference impedance value and less than n times the reference impedance value, it is determined that the cable corresponding to the measured impedance value is normal;

[0116] If the measured impedance value is less than the reference impedance value, it is determined that a low-resistance fault exists in the cable corresponding to the measured impedance value;

[0117] Specifically, Figure 5 As shown:

[0118] If Rt is infinite, the cable is judged to be broken or punctured, and an alarm is displayed;

[0119] If Rt≥R×n (n>1, which is the discrimination coefficient, varies according to different cables and interfaces, and the typical value is 10), the cable is judged to have a high-resistance fault, which may be a disconnection or external damage fault, and an alarm is displayed;

[0120] If Rt∈[R, R×n], the cable is considered normal;

[0121] If Rt<R, the cable is judged to have a low resistance fault, which may be a grounding or breakdown fault, and an alarm is displayed.

[0122] Embodiment 4

[0123] This embodiment further defines the step of:

[0124] Obtaining the real-time temperature value of the cable corresponding to each node of the cable to be monitored;

[0125] Wherein, a temperature sensor may be arranged at each node of the cable to collect the real-time temperature value of the cable corresponding to each node. The temperature sensor may be a light temperature measuring device or an electronic contact temperature measuring device;

[0126] Determine whether the real-time temperature value is greater than or equal to a preset temperature threshold, and if so, determine that a high temperature fault exists in the cable corresponding to the real-time temperature value;

[0127] like Figure 5 As shown, if the cable temperature t≥T0, the cable is judged to be a high temperature fault, and the temperature measurement node address is transmitted to the cable temperature monitoring module to display an alarm, where T0 is the cable fault temperature, and the typical value is 80℃-120℃.

[0128] Embodiment 5

[0129] Please refer to Figure 2 , a cable fault analysis terminal integrating electric power measurement information, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, each step of the cable fault analysis method integrating electric power measurement information described in any one of the first to fourth embodiments above is implemented;

[0130] In another optional embodiment, Figure 6 As shown, a power fault analysis system integrating distributed power measurement information can be designed, which includes a data acquisition module, a data analysis module and a visualization display module. The data acquisition module includes a temperature acquisition module, a current acquisition module and a voltage acquisition module. The collected information is connected to the data analysis module through a data acquisition coordinator.

[0131] The data analysis module includes a cable temperature monitoring module, a line impedance analysis module, and a cable status analysis module, which can analyze the data in the data acquisition module and present the analysis results for use by the visualization display module. The visualization display module includes cable management, cable topology, cable fault alarm, cable fault analysis, and system management, and displays cable fault temperature monitoring, fault analysis results, and cable topology structure on a large screen.

[0132] Among them, the temperature acquisition module is a light temperature measurement or an electronic contact temperature measurement module, the voltage acquisition module and the current acquisition module are distributed at each node of the cable, and can be an electric meter or a single electromagnetic or photoelectric voltage and current acquisition module, and the communication mode of the communication module of the data acquisition coordinator can be wireless communication, carrier communication or optical cable wired communication.

[0133] In summary, the present invention provides a cable fault analysis method and terminal integrating power measurement information, which obtains the current and voltage of the meter at each node by means of the existing electric meters laid at each node of the cable, and determines the measured impedance value of the cable corresponding to each node by using the obtained current and voltage and through the recursive least squares method, and analyzes the fault of the cable corresponding to each node by comparing the measured impedance value with the reference impedance value, and integrates the low-voltage power measurement information that would be measured in the cable line into the cable fault analysis, and conducts analysis based on the comparison of impedances and visualizes the analysis results. On the one hand, it makes full use of The existing electric meter system does not require additional monitoring circuits like the existing real-time monitoring, which leads to inaccurate analysis, low efficiency, and cumbersome operation. On the other hand, it only needs to obtain current and voltage values ​​from the existing electric meter system to realize the analysis of cable faults. It is convenient and easy, and can greatly improve the efficiency and reliability of cable fault analysis, thereby realizing reliable and convenient monitoring of cable faults, shortening fault time, improving power supply reliability, and providing data basis for power repair. It can also realize digital cable management, cable topology, cable fault alarm, cable fault analysis, system management and other functions, which is conducive to lean cable operation and maintenance.

[0134] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A cable fault analysis method integrating power measurement information, characterized in that: Includes steps: S1. Obtaining the physical parameters of the cable corresponding to each node of the cable to be monitored, and determining the reference impedance value of the cable corresponding to each node according to the physical parameters; S2. Collecting power measurement information obtained by electric meters distributed at each node of the cable to be monitored, wherein the power measurement information includes the current and voltage of the cable corresponding to each node; S3, determining the measured impedance value of the cable corresponding to each node according to the current and voltage, and analyzing the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value; Determining the measured impedance value of the cable corresponding to each node according to the current and voltage includes: The measured impedance value of the cable corresponding to each node is determined according to the current and voltage using a multivariate linear regression analysis method: (1) Add all nodes in the cable to set A and obtain the current and voltage values ​​of each node; (2) taking each two nodes in set A as a pair, constructing a multiple linear regression equation based on their current and voltage values, performing multiple linear regression analysis, and determining the measured impedance value of the cable corresponding to each pair of two nodes according to the multiple linear regression analysis results; (3) Compare the coefficients of determination of all the multivariate linear regression equations constructed in step (2), set the measured impedance value corresponding to the node determined by the multivariate linear regression equation with the largest coefficient of determination as the effective value, delete the two nodes corresponding to the multivariate linear regression equation with the largest coefficient of determination from set A, merge the two nodes into a new node according to the voltage and current values, add the new node to set A, and return to step (2) to perform topological recursion until only one node is left in set A. Then, the measured impedance values ​​of all the determined effective values ​​are the measured impedance values ​​of the cables corresponding to each node.

2. A cable fault analysis method integrating power measurement information according to claim 1, characterized in that: The physical parameters include cable model and length; Determining the reference impedance value of the cable corresponding to each node according to the physical parameter includes: Determine the resistivity, reactance and cross-sectional area of ​​the cable corresponding to each node according to the cable model of the cable corresponding to each node; Determine the resistance and reactance of the cables corresponding to each node according to the resistivity, reactance, cross-sectional area and length of the cables corresponding to each node; The reference impedance value of the cable corresponding to each node is determined according to the resistance and reactance of the cable corresponding to each node.

3. A cable fault analysis method integrating power measurement information according to claim 1 or 2, characterized in that: The determining of the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value includes: If the measured impedance value is infinite, determining that the cable corresponding to the measured impedance value is broken or broken; If the measured impedance value is greater than or equal to n times the reference impedance value, it is determined that a high-resistance fault exists in the cable corresponding to the measured impedance value, where n represents a discrimination coefficient; If the measured impedance value is greater than or equal to the reference impedance value and less than n times the reference impedance value, it is determined that the cable corresponding to the measured impedance value is normal; If the measured impedance value is less than the reference impedance value, it is determined that a low-resistance fault exists in the cable corresponding to the measured impedance value.

4. A cable fault analysis method integrating power measurement information according to claim 1 or 2, characterized in that: Also includes the steps: Obtaining the real-time temperature value of the cable corresponding to each node of the cable to be monitored; It is determined whether the real-time temperature value is greater than or equal to a preset temperature threshold value. If so, it is determined that a high temperature fault exists in the cable corresponding to the real-time temperature value.

5. A cable fault analysis terminal integrating power measurement information, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the following steps are implemented: S1. Obtaining the physical parameters of the cable corresponding to each node of the cable to be monitored, and determining the reference impedance value of the cable corresponding to each node according to the physical parameters; S2. Collecting power measurement information obtained by electric meters distributed at each node of the cable to be monitored, wherein the power measurement information includes the current and voltage of the cable corresponding to each node; S3, determining the measured impedance value of the cable corresponding to each node according to the current and voltage, and analyzing the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value; Determining the measured impedance value of the cable corresponding to each node according to the current and voltage includes: The measured impedance value of the cable corresponding to each node is determined according to the current and voltage using a multivariate linear regression analysis method: (1) Add all nodes in the cable to set A and obtain the current and voltage values ​​of each node; (2) taking each two nodes in set A as a pair, constructing a multiple linear regression equation based on their current and voltage values, performing multiple linear regression analysis, and determining the measured impedance value of the cable corresponding to each pair of two nodes according to the multiple linear regression analysis results; (3) Compare the coefficients of determination of all the multivariate linear regression equations constructed in step (2), set the measured impedance value corresponding to the node determined by the multivariate linear regression equation with the largest coefficient of determination as the effective value, delete the two nodes corresponding to the multivariate linear regression equation with the largest coefficient of determination from set A, merge the two nodes into a new node according to the voltage and current values, add the new node to set A, and return to step (2) to perform topological recursion until only one node is left in set A. Then, the measured impedance values ​​of all the determined effective values ​​are the measured impedance values ​​of the cables corresponding to each node.

6. A cable fault analysis terminal integrating electric power measurement information according to claim 5, characterized in that: The physical parameters include cable model and length; Determining the reference impedance value of the cable corresponding to each node according to the physical parameter includes: Determine the resistivity, reactance and cross-sectional area of ​​the cable corresponding to each node according to the cable model of the cable corresponding to each node; Determine the resistance and reactance of the cables corresponding to each node according to the resistivity, reactance, cross-sectional area and length of the cables corresponding to each node; The reference impedance value of the cable corresponding to each node is determined according to the resistance and reactance of the cable corresponding to each node.

7. A cable fault analysis terminal integrating electric power measurement information according to claim 5 or 6, characterized in that: The determining of the fault of the cable corresponding to each node according to the reference impedance value and the measured impedance value includes: If the measured impedance value is infinite, determining that the cable corresponding to the measured impedance value is broken or broken; If the measured impedance value is greater than or equal to n times the reference impedance value, it is determined that a high-resistance fault exists in the cable corresponding to the measured impedance value, where n represents a discrimination coefficient; If the measured impedance value is greater than or equal to the reference impedance value and less than n times the reference impedance value, it is determined that the cable corresponding to the measured impedance value is normal; If the measured impedance value is less than the reference impedance value, it is determined that a low-resistance fault exists in the cable corresponding to the measured impedance value.

8. A cable fault analysis terminal integrating electric power measurement information according to claim 5 or 6, characterized in that: When the processor executes the computer program, the following steps are also implemented: Obtaining the real-time temperature value of the cable corresponding to each node of the cable to be monitored; It is determined whether the real-time temperature value is greater than or equal to a preset temperature threshold value. If so, it is determined that a high temperature fault exists in the cable corresponding to the real-time temperature value.

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