A method and device for diagnosing insulation of a transmission line

Abstract

The present invention belongs to the technical field of transmission line insulation detection and provides a transmission line insulation diagnosis method and device. By constructing different neutral point resistors, the parameters at the two ends of the transmission line are synchronously compared under different conditions. The present invention is used to calculate the conductivity parameter reflecting the insulation condition of the transmission line, providing a new means and diagnostic method for predicting transmission line insulation damage. This solves the current technical problem that when insulation damage occurs in a transmission line, the transmission line trips, the user stops power supply, and the operation and maintenance personnel conduct inspections and troubleshooting until power is restored, making it impossible to predict the trend of transmission line insulation damage in advance.

Description

Technical Field

[0001] The present invention belongs to the technical field of transmission line insulation detection, and in particular relates to a transmission line insulation diagnosis method and device. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Currently, when insulation damage occurs on a transmission line, the line trips, and power is cut off. Operations and maintenance personnel conduct inspections and troubleshoot until power is restored. However, without a method for diagnosing transmission line insulation damage to predict its potential, grid operations and maintenance personnel lack a clear understanding of the operating status of the electrical equipment connected to the power system. Consequently, blindly implementing repair measures can lead to inaccurate repairs and potentially even greater failures. Summary of the Invention

[0004] In order to solve at least one technical problem existing in the above-mentioned background technology, the present invention provides a transmission line insulation diagnosis method and device. By constructing different neutral point resistors, the parameters of the two ends of the transmission line are synchronously compared under different conditions. The present invention is used to calculate the conductivity parameter reflecting the insulation condition of the transmission line, providing a new means and diagnostic method for predicting transmission line insulation damage.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A first aspect of the present invention provides a method for diagnosing insulation of a transmission line, comprising the following steps:

[0007] Determine the time synchronization point and obtain the electrical quantities at the power supply and load ends of the transmission line at the same time under various states by controlling the switching process of different neutral point switches;

[0008] Based on the electrical quantities at the power supply and load ends of the transmission line at the same time under various states, a power balance equation group is constructed to obtain the admittance of the transmission line and the electrical quantities of the insulator;

[0009] Based on the admittance of the transmission line and the electrical quantity of the insulator, different three-phase power supply operation modes are constructed to obtain the power consumed by the three-phase insulation resistance respectively;

[0010] The insulation condition of the transmission line is comprehensively judged based on the admittance of the transmission line, the electrical quantity of the insulator, and the power consumed by the three-phase insulation resistance.

[0011] A second aspect of the present invention provides a transmission line insulation diagnostic device, comprising:

[0012] The switch switching control module is configured to: determine a time synchronization point and obtain electrical quantities at the power supply end and the load end of the transmission line at the same time under various states by controlling different neutral point switch switching processes;

[0013] The transmission line insulation parameter determination module is configured to: construct a power balance equation system based on the electrical quantities at the power supply end and the load end of the transmission line at the same time under various states to obtain the admittance of the transmission line and the electrical quantities of the insulator;

[0014] Based on the admittance of the transmission line and the electrical quantity of the insulator, different three-phase power supply operation modes are constructed to obtain the power consumed by the three-phase insulation resistance respectively;

[0015] The comprehensive diagnosis module is configured to comprehensively judge the insulation condition of the transmission line according to the admittance of the transmission line, the electrical quantity of the insulator and the power consumed by the three-phase insulation resistance.

[0016] A third aspect of the present invention provides a computer-readable storage medium.

[0017] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for diagnosing insulation of a power transmission line.

[0018] A fourth aspect of the present invention provides a computer device.

[0019] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in the above-mentioned method for diagnosing insulation of a power transmission line are implemented.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention constructs different neutral point resistors and synchronously compares the parameters at both ends of a transmission line under different conditions. The present invention calculates the conductivity parameter reflecting the insulation condition of the transmission line, providing a new means and diagnostic method for predicting insulation damage in transmission lines. This allows grid operation and maintenance managers to have a clear understanding of the operating conditions of electrical equipment connected to the power system, pay special attention to electrical equipment on the verge of normal operation, and take corresponding measures.

[0022] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 This is a schematic diagram of a neutral point resistance circuit according to a first embodiment of the present invention;

[0025] Figure 2 This is a flow chart of a method for diagnosing insulation of a transmission line according to a first embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] Example 1

[0030] like Figure 2 As shown, this embodiment provides a transmission line insulation diagnosis method, comprising the following steps:

[0031] Step 101: Determine a time synchronization point, and obtain electrical quantities at the power supply end and the load end of the transmission line at the same time under various states by controlling different neutral point switch switching processes;

[0032] Step 102: Based on the electrical quantities at the power source end and the load end of the transmission line at the same time under various states, a power balance equation group is constructed to obtain the admittance of the transmission line and the electrical quantities of the insulator;

[0033] Step 103: Based on the admittance of the transmission line and the electrical quantity of the insulator, construct different three-phase power supply operation modes to obtain the power consumed by the three-phase insulation resistance respectively;

[0034] Step 104: Comprehensively judge the insulation condition of the transmission line based on the admittance of the transmission line, the electrical quantity of the insulator, and the power consumed by the three-phase insulation resistance.

[0035] In step 101, the electrical quantities at the power supply end and the load end of the transmission line include: the voltage applied to the power supply end and the load end of the transmission line, and the current at the power supply end and the load end generated by the voltage, the active power at the power supply end and the load end, and the reactive power at the power supply end and the load end.

[0036] like Figure 1 As shown, the different neutral point switch switching processes specifically include:

[0037] Close the second main switch K N2 , when closing the first main switch K N1 When the active power at the power supply end of the transmission line and the active power at the load end of the transmission line at the same moment are measured, the two values ​​are subtracted to obtain the active power difference △P between the power supply end and the load end of the transmission line at the same moment; and so on, the reactive power difference △Q between the power supply end and the load end of the transmission line at the same moment is obtained.

[0038] The methods for obtaining ΔP1, ΔP2, ΔP3 and ΔQ1, ΔQ2, ΔQ3 involved in the following embodiments are similar to the methods for obtaining ΔP and ΔQ herein, and are specifically discussed as follows:

[0039] When the first main switch K is closed N1 When the active power difference △P and reactive power difference △Q at the power supply end and the load end of the transmission line are measured at the same time;

[0040] Turn off the first main switch K N1 When the first switch K1 is closed, the active power difference △P1 and the reactive power difference △Q1 between the power supply end and the load end of the transmission line are measured at the same time;

[0041] When the first switch K1 is opened and the second switch K2 is closed, the active power difference ΔP2 and the reactive power difference ΔQ2 between the power supply end and the load end of the transmission line are measured at the same time;

[0042] When the second switch K2 is opened and the third switch K3 is closed, the active power difference ΔP3 and the reactive power difference ΔQ3 between the power supply end and the load end of the transmission line are measured at the same time, and the third switch K3 is opened.

[0043] Analysis of the reactive power difference △Q3 change during the switching process at different center points is as follows: When the first main switch K is closed, N1 And the second main switch K N2 During the switching process of the first switch K1, the second switch K2 and the third switch K3, the reactive power difference ΔQ3 between the power supply end and the load end of the transmission line does not change significantly.

[0044] Parameter synchronization measurement, that is, determining the time synchronization point, the electrical quantity (including current, voltage, active power, reactive power, etc.) measuring devices at the power supply end and load end of the transmission line that needs insulation diagnosis are unified with satellite timing to ensure that the measured electrical quantities belong to the same moment.

[0045] In step 102, the power balance equations are expressed as:

[0046] I N1 2 R D2 +I N1 2 R D1 +I N3 2 R D1 +∑P=△P

[0047] I1 2 R D2 +I1 2 R D1 +I N3 2 R D1 +∑P=△P1

[0048] I2 2 R D2 +I2 2 R D1 +I N3 2 R D1 +∑P=△P2

[0049] I3 2 R D2 +I3 2 R D1 +I N3 2 R D1 +∑P=△P3

[0050] Where, I N1 represents the current flowing through the first main switch KN1, I1 represents the current flowing through the resistor R1, I2 represents the current flowing through the resistor R2, I3 represents the current flowing through the resistor R3, and R D1 Represents the admittance grounding resistance of the transmission line, R D2 Indicates the load-side grounding resistance.

[0051] In step 103, the process of constructing the different three-phase power supply operation modes is as follows:

[0052] (1) Disconnect the load end, and the power supply side A phase sends power to the transmission line. According to the measured active power P of the power supply side A phase A and phase A current I N2 , we get: IN2 2 R D1 +∑P A =P A The active power loss of phase A of the transmission line is obtained by sorting out, that is, the power consumed by the insulation resistance of phase A: ∑P A =P A -I N2 2 R D1 The insulation condition of phase A can be determined based on the power consumed by the insulation resistance of phase A.

[0053] (2) Disconnect the load end, and send power to the power supply side B phase to the transmission line, and measure the active power P of the power supply side B phase B and B phase current I N2 ', get: I N2 ' 2 R D1 +∑P B =P B The active power loss of phase B of the transmission line is obtained by sorting out, that is, the power consumed by the insulation resistance of phase B: ∑P B =P B -I N2 ' 2 R D1 The insulation condition of phase B can be determined based on the power consumed by the insulation resistance of phase B.

[0054] (3) Disconnect the load end, and the power supply side C phase sends power to the transmission line, and measure the power supply side C phase active power P C and C phase current I N2 ", we get: I N2 ” 2 R D1 +∑P C =P C The active power loss of phase C of the transmission line is obtained by sorting out, that is, the power consumed by the insulation resistance of phase C: ∑P C =P C -I N2 ” 2 R D1 The insulation condition of phase C can be determined based on the power consumed by the insulation resistance of phase C.

[0055] In step 104, the process of determining the insulation condition of the transmission line is as follows:

[0056] (1) The normal insulation condition of the transmission line is: ∑PA=∑PB=∑PC, and the three values ​​are basically the same;

[0057] (2) Abnormal transmission line insulation conditions are: ∑PA, ∑PB, ∑PC. If these three values ​​are inconsistent, a smaller value indicates that the insulation condition of the corresponding phase of the transmission line is not good. For example, a smaller ∑PA value indicates that the insulation condition of phase A of the transmission line is not good.

[0058] (3) By comparing the measured values ​​of ∑PA, ∑PB, and ∑PC, as well as their changing trends, the insulation condition of the transmission line can be determined. To a certain extent, the insulation condition of the transmission line can be prejudged. For example, if the ∑PA value gradually decreases, it means that the insulation condition of phase A of the transmission line is gradually deteriorating.

[0059] Example 2

[0060] This embodiment provides a transmission line insulation diagnostic device, comprising:

[0061] The switch switching control module is configured to: determine a time synchronization point and obtain electrical quantities at the power supply end and the load end of the transmission line at the same time under various states by controlling different neutral point switch switching processes;

[0062] The transmission line insulation parameter determination module is configured to: construct a power balance equation system based on the electrical quantities at the power supply end and the load end of the transmission line at the same time under various states to obtain the admittance of the transmission line and the electrical quantities of the insulator;

[0063] Based on the admittance of the transmission line and the electrical quantity of the insulator, different three-phase power supply operation modes are constructed to obtain the power consumed by the three-phase insulation resistance respectively;

[0064] The comprehensive diagnosis module is configured to comprehensively judge the insulation condition of the transmission line according to the admittance of the transmission line, the electrical quantity of the insulator and the power consumed by the three-phase insulation resistance.

[0065] Example 3

[0066] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the steps in the above-mentioned method for diagnosing insulation of a power transmission line are implemented.

[0067] Example 4

[0068] This embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps in the above-described method for diagnosing insulation of a power transmission line are implemented.

[0069] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage and optical storage, etc.) containing computer-usable program code.

[0070] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0071] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0072] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0073] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing related hardware through a computer program. The program can be stored in a computer-readable storage medium, and when executed, the program can include the processes in the above-described method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0074] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for diagnosing insulation of a transmission line, characterized in that: The steps include: Determine the time synchronization point and obtain the electrical quantities at the power supply and load ends of the transmission line at the same time under various states by controlling the switching process of different neutral point switches; Based on the electrical quantities at the power supply and load ends of the transmission line at the same time under various states, a power balance equation group is constructed to obtain the admittance of the transmission line and the electrical quantities of the insulator; Based on the admittance of the transmission line and the electrical quantity of the insulator, different three-phase power supply operation modes are constructed to obtain the power consumed by the three-phase insulation resistance respectively; Comprehensively judge the insulation condition of the transmission line based on the admittance of the transmission line, the electrical quantity of the insulator, and the power consumed by the three-phase insulation resistance; The neutral point switch switching circuit includes a three-phase power supply, a load, a first main switch K N1 and the second main switch K N2 , The first end of the three-phase power supply is connected to the second main switch K N2 One end of the second main switch K N2 The other end is connected to the ground resistor R D1 , the second end of the three-phase power supply is connected to one end of the load, and the other end of the load is connected to the grounding resistor R D2 , grounding resistance R D1 and grounding resistance R D2 The load includes resistors R1, R2 and R3 connected in parallel. The branches where resistors R1, R2 and R3 are located correspond to the first switch K1, the second switch K2 and the third switch K3 connected in series. The first main switch K N1 Connect in parallel to both ends of the load; Among them, controlling different neutral point switch switching processes to obtain the electrical quantities at the power supply end and load end of the transmission line at the same time in various states specifically includes: Close the second main switch K N2 , when closing the first main switch K N1 When the active power difference △P and reactive power difference △Q at the power supply end and the load end of the transmission line are measured at the same time; Turn off the first main switch K N1 , when the first switch K1 is closed, the active power difference △P1 and the reactive power difference △Q1 between the power supply end and the load end of the transmission line in the first state at the same moment are measured; When the first switch K1 is opened and the second switch K2 is closed, the active power difference ΔP2 and the reactive power difference ΔQ2 between the power supply end and the load end of the power transmission line in the second state at the same moment are measured; When the second switch K2 is opened and the third switch K3 is closed, the active power difference ΔP3 and the reactive power difference ΔQ3 between the power supply end and the load end of the transmission line in the third state at the same moment are measured, and the third switch K3 is opened.

2. A transmission line insulation diagnosis method according to claim 1, characterized in that: The electrical quantities at the power supply end and the load end of the transmission line include: the voltage applied to the power supply end and the load end of the transmission line, and the current at the power supply end and the load end generated by the voltage, the active power at the power supply end and the load end, and the reactive power at the power supply end and the load end.

3. A method for diagnosing insulation of a transmission line according to claim 1, characterized in that: The expression of the power balance equation group is: I N1 2 R D2 + I N1 2 R D1 + I N3 2 R D1 +∑P=△P I1 2 R D2 + I1 2 R D1 + I N3 2 R D1 +∑P=△P1 I2 2 R D2 + I2 2 R D1 + I N3 2 R D1 +∑P=△P2 I3 2 R D2 + I3 2 R D1 + I N3 2 R D1 +∑P=△P3 Where, I N1 represents the current flowing through the first main switch KN1, I1 represents the current flowing through the resistor R1, I2 represents the current flowing through the resistor R2, I3 represents the current flowing through the resistor R3, and R D1 Represents the admittance grounding resistance of the transmission line, R D2 Represents the grounding resistance on the load side, ∑P refers to the active power loss of the three phases A, B, and C of the transmission line itself and the active power consumed in the insulation to the ground, I N3 It is the vector sum of the six currents generated by the ground voltages of phases A, B and C of the three-phase transmission line acting on the ground resistance and ground capacitance of phases A, B and C respectively.

4. A method for diagnosing insulation of a transmission line according to claim 1, characterized in that: The construction process of the different three-phase power supply operation modes is as follows: Disconnect the load end, and sequentially send power from phase A on the power supply side, phase B on the power supply side, and phase C on the power supply side to the transmission line to obtain the active power and current of the three-phase power supply; The active power loss of each phase transmission line is obtained according to the active power and current of the three-phase power supply.

5. A transmission line insulation diagnosis method according to claim 1, characterized in that: After obtaining the electrical quantities at the power supply end and the load end of the transmission line at the same time in various states through different neutral point switch switching processes, the changing rules of the electrical quantities are analyzed and it is obtained that: when the first main switch K is closed, N1 And the second main switch K N2 During the switching process of the first switch K1, the second switch K2 and the third switch K3, the reactive power difference between the power supply end and the load end of the transmission line in the third state does not change significantly.

6. A method for diagnosing insulation of a power transmission line according to claim 1, characterized in that: The process of judging the insulation condition of the transmission line is as follows: If the power consumed by the insulation resistance of phase A, the power consumed by the insulation resistance of phase B, and the power consumed by the insulation resistance of phase C are consistent, the transmission line is normal; If the power consumed by the insulation resistance of phase A, the power consumed by the insulation resistance of phase B, and the power consumed by the insulation resistance of phase C are inconsistent, the smaller the value, the worse the insulation condition of the corresponding phase of the transmission line; If the power consumed by the insulation resistance of phase A, the power consumed by the insulation resistance of phase B, and the power consumed by the insulation resistance of phase C gradually decrease, it means that the insulation conditions of the corresponding phases of the corresponding transmission lines are gradually deteriorating.

7. A transmission line insulation diagnostic device, characterized in that: A transmission line insulation diagnosis method according to any one of claims 1 to 6, comprising: The switch switching control module is configured to: determine a time synchronization point and obtain electrical quantities at the power supply end and the load end of the transmission line at the same time under various states by controlling different neutral point switch switching processes; The transmission line insulation parameter determination module is configured to: construct a power balance equation system based on the electrical quantities at the power supply end and the load end of the transmission line at the same time under various states to obtain the admittance of the transmission line and the electrical quantities of the insulator; Based on the admittance of the transmission line and the electrical quantity of the insulator, different three-phase power supply operation modes are constructed to obtain the power consumed by the three-phase insulation resistance respectively; The comprehensive diagnosis module is configured to comprehensively judge the insulation condition of the transmission line according to the admittance of the transmission line, the electrical quantity of the insulator and the power consumed by the three-phase insulation resistance.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the transmission line insulation diagnosis method according to any one of claims 1 to 6 are implemented.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the transmission line insulation diagnosis method according to any one of claims 1 to 6 are implemented.

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