A method for assessing the condition of line-connected series gap surge arresters based on phase difference comparison

Abstract

This invention discloses a method for assessing the condition of surge arresters with series gaps on power lines based on phase difference comparison. The steps are as follows: Calculate the voltage phase difference between the beginning and end of the line; collect the sum of the horizontal spans of all towers along the line, and establish a system of equations to solve for the phase angle difference of each span; after obtaining the phase angle difference of each span, use the voltage phase of the busbar at the beginning substation as a reference, and subtract the sum of the phase angle differences from the beginning to the target tower to obtain the voltage phase of the target tower. Obtain the total leakage current of the surge arrester on the target tower, measure the surface current using a current-taking ring, and subtract this value from the total current to obtain the body current and phase; subtract the voltage phase of the target tower from the phase phase of the body current to obtain the current-voltage phase difference, and extend this to calculate the phase difference of all surge arresters of the same phase along the entire line. Calculate the average phase difference, and calculate the deviation value of each surge arrester; a negative deviation indicates an anomaly, while a non-negative deviation indicates normal operation. This invention solves the problem of obtaining the phase of the surge arrester, and provides a new approach and implementation method for assessing the condition through lateral comparison of phase differences.

Description

Technical Field

[0001] This invention relates to the field of operation and maintenance technology for power transmission and transformation equipment, specifically to a method for assessing the condition of line-connected series gap surge arresters based on phase difference comparison. Background Technology

[0002] Line surge arresters are currently the most commonly used lightning protection measure for transmission lines. Their main functions are clamping and current discharge. When the line is operating normally, the line surge arrester is in a high-resistance state. When the line is struck by lightning, and the lightning overvoltage exceeds the lightning impulse discharge voltage threshold of the surge arrester, the arrester's varistor changes from a high-resistance state to a low-resistance state, discharging before the line insulator string, releasing the lightning energy and instantaneously cutting off the power frequency follow current, preventing line tripping and insulator string flashover. To slow down the deterioration (aging) of the arrester's varistor and ensure that a fault in the arrester does not directly cause line tripping, current line surge arresters all use surge arresters with series gaps. The gaps are of two types: pure air gaps and insulated support gaps.

[0003] Due to their unique installation and operating conditions, line surge arresters are currently in a "maintenance-free" state, with only visual inspections and counter operation counts being recorded, making it impossible to effectively grasp their true operating status. However, incidents such as arrester failure, breakdown, and explosion due to deterioration or aging still occur frequently, seriously affecting the safe and stable operation of line surge arresters and the reliability of lightning protection.

[0004] The condition detection and assessment of line surge arresters with series gaps is quite difficult. For gapless surge arresters in substations, their operating status is generally assessed by detecting the resistive current of the surge arrester. The key is to obtain the leakage current of the surge arrester and the phase angle between the current and voltage. However, line surge arresters are installed on outdoor poles and towers, and it is impossible to obtain the voltage and current phase information at the installation point. Therefore, it is not possible to effectively carry out the operation status detection and assessment. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for assessing the condition of line-connected series gap surge arresters based on phase difference comparison, aiming to solve the problems in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for assessing the condition of a line arrester with a series gap based on phase difference comparison, comprising the following steps:

[0007] Step S1: Obtain the bus voltage vector of the substation at the beginning of the line and the bus voltage vector of the substation at the end of the line through the substation PMU device, and combine them with the WAMS system to obtain the voltage phase difference between the beginning and end of the line.

[0008] Step S2: Collect the horizontal spans of all towers along the entire line and sum them to obtain the total span. Based on the principles that "span is proportional to phase angle difference" and "voltage phase difference between the beginning and end = sum of phase angle differences of each span", establish a set of equations to solve for the phase angle difference of each span.

[0009] Step S3: Solve the system of equations from step S2 simultaneously to calculate the phase angle difference for each span of the entire tower line;

[0010] Step S4: Using the bus voltage phase angle of the substation at the beginning of the line as a reference, subtract the sum of the phase angle differences of each span from the substation at the beginning of the line to the target tower to obtain the voltage phase angle of the target tower.

[0011] Step S5: Use a surge arrester leakage current detection device with Beidou time stamp to obtain the total leakage current of the surge arrester on the target tower;

[0012] Step S6: Measure the leakage current on the outer surface of the surge arrester using a current-taking ring, and subtract the leakage current on the outer surface from the total leakage current to obtain the actual current value and current phase angle flowing through the surge arrester body;

[0013] Step S7: Subtract the voltage phase angle of the target tower from the current phase angle to obtain the current-voltage phase difference of the surge arrester of the target tower; then calculate the current-voltage phase difference of each surge arrester of the same phase on the entire line using the same method.

[0014] Step S8: Calculate the average value of the current-voltage phase difference of all surge arresters in the same phase along the entire line, and then subtract the average value from the current-voltage phase difference of each surge arrester to obtain the deviation value of each surge arrester;

[0015] Step S9: Determine the status of each surge arrester based on its deviation value. If the deviation value is negative, the surge arrester is determined to be in an abnormal state; if it is non-negative, the surge arrester is determined to be in a normal state.

[0016] Furthermore, the specific process of step S1 is as follows: The bus voltage vector of substation A at the beginning of the line is collected through the substation PMU device, i.e., the phasor measurement unit. The bus voltage vector of substation B at the end of the line , This indicates the bus voltage amplitude at substation A at the beginning of the line. This indicates the bus voltage phase angle at substation A at the beginning of the line. This indicates the bus voltage amplitude at substation B at the end of the line. This represents the bus voltage phase angle at substation B at the end of the line; then, based on the WAMS system (Wide Area Measurement System), the bus voltage phase angle at substation A at the beginning of the line is used. Subtract the bus voltage phase angle of substation B at the end of the line. The voltage phase difference between the beginning and end of the line was calculated. .

[0017] Furthermore, the specific process of step S2 is as follows: First, collect the horizontal span of all towers along the entire line; then, add up the horizontal spans of all towers to obtain the total span of the entire line. Based on the rule that "the phase angle difference of each span is proportional to the corresponding span distance", a correlation is established between the phase angle difference of each span and the corresponding span distance, while also considering the voltage phase difference at the beginning and end of the line. A system of equations was constructed to solve for the phase angle difference of each gear.

[0018] Furthermore, the tower numbering is done using... express, , This indicates the total number of towers along the entire line; the span number corresponds to the tower number, and is selected sequentially. The first phase angle difference refers to the phase angle difference between the span from the substation at the beginning of the line to tower No. 1. Phase angle difference index Phase angle difference between the span from the tower to the substation at the end of the line; voltage phase difference It equals the sum of the phase angle differences of all gears.

[0019] Furthermore, the system of equations can be expressed as:

[0020] ;

[0021] ;

[0022] ;

[0023] In the formula, Indicates the first The horizontal distance between gears; Indicates the first The phase angle difference of the gears; Indicates the first The horizontal distance between gears; Indicates the first Phase angle difference.

[0024] Furthermore, the specific process of step S4 is as follows: targeting the tower... The phase angle of the bus voltage at the substation at the beginning of the line As a reference phase The voltage phase angle of the target tower is calculated by subtracting the sum of the phase angle differences of all spans from the first substation to the target tower from the reference phase. .

[0025] Furthermore, the specific process of step S6 is as follows: using a voltage collection ring to collect and measure the target tower. Leakage current on the external surface of the surge arrester The total leakage current obtained in step S5 Subtract the leakage current from the outer surface The actual current value flowing through the surge arrester body is obtained. Simultaneously, the phase angle of the current flowing through the surge arrester body is obtained. .

[0026] Furthermore, the specific process of step S7 is as follows: using the phase angle of the surge arrester's body current. Subtract the voltage phase angle of the target tower The current-voltage phase difference of the target tower surge arrester is obtained. Following this method, the current-voltage phase difference of each surge arrester on each tower in the same direction along the entire line is calculated one by one. .

[0027] An electronic device includes a processor, a memory, and a bus, wherein the processor and the memory are connected via the bus, wherein the memory is used to store a set of program code, and the processor is used to call the program code stored in the memory to execute a line-band series gap surge arrester condition assessment method based on phase difference comparison.

[0028] A non-volatile computer storage medium stores computer-executable instructions that execute a line-with-series-gap surge arrester condition assessment method based on phase difference comparison.

[0029] Compared with existing technologies, the present invention has the following advantages: The present invention solves the problem that the current, voltage phase and phase difference of surge arresters with series gaps in transmission lines cannot be obtained, and evaluates the operating status of surge arresters by directly comparing the current and voltage phase angle differences of all surge arresters in a certain phase of the entire line, providing a new idea and specific implementation method for evaluating the operating status of line surge arresters; it is applicable to the evaluation of the operating status of surge arresters in transmission lines, with a clear approach and convenient operation, and has significant advantages, especially for the rapid screening of the operating status of a large number of line surge arresters across the entire line. Attached Figure Description

[0030] Figure 1 This is a flowchart of the method of the present invention.

[0031] Figure 2 This is a schematic diagram of the voltage phase of each base tower along the entire line of this invention.

[0032] Figure 3 This is a schematic diagram of the surge arrester anomaly determination method of the present invention. Detailed Implementation

[0033] like Figure 1 As shown, the present invention provides a technical solution: a method for assessing the condition of a line arrester with a series gap based on phase difference comparison, comprising the following steps:

[0034] Step S1: Obtain the bus voltage vector of the substation at the beginning of the line and the bus voltage vector of the substation at the end of the line through the PMU device (phasor measurement unit) of the substation, and combine it with the WAMS system (wide area measurement system) to obtain the voltage phase difference between the beginning and end of the line.

[0035] The specific process of step S1 is as follows: The bus voltage vector of substation A at the beginning of the line is collected using the substation PMU (phasor measurement unit). The bus voltage vector of substation B at the end of the line , This indicates the bus voltage amplitude at substation A at the beginning of the line. This indicates the bus voltage phase angle at substation A at the beginning of the line. This indicates the bus voltage amplitude at substation B at the end of the line. This represents the bus voltage phase angle at substation B at the end of the line; then, based on the WAMS system (Wide Area Measurement System), the bus voltage phase angle at substation A at the beginning of the line is used. Subtract the bus voltage phase angle of substation B at the end of the line. The voltage phase difference between the beginning and end of the line was calculated. , represented as:

[0036] .

[0037] Step S2: Collect the horizontal spans of all towers along the entire line and sum them to obtain the total span. Based on the principles that "span is proportional to phase angle difference" and "voltage phase difference between the beginning and end = sum of phase angle differences of each span", establish a set of equations to solve for the phase angle difference of each span.

[0038] The specific process of step S2 is as follows: First, collect the horizontal span of all towers along the entire line (based on the smaller side, where the tower numbers are represented by...). express, , (This represents the total number of towers along the entire line); the total span of all towers is obtained by adding up the horizontal spans of all towers. Based on the rule that "the phase angle difference of each span is proportional to the corresponding span distance", a phase angle difference for each span is established (the span number corresponds to the tower number, and is taken sequentially). The first phase angle difference refers to the phase angle difference between the span from the substation at the beginning of the line to tower No. 1. Phase angle difference index The relationship between the phase angle difference of the span from tower number 1 to the substation at the end of the line and the corresponding span, combined with the voltage phase difference between the beginning and end of the line. (This voltage phase difference) This is equal to the sum of the phase angle differences of all spans), constructing a system of equations to solve for the phase angle differences of each span. The voltage phase of each tower along the entire line is as follows: Figure 2 As shown.

[0039] The system of equations is represented as follows:

[0040] ;

[0041] ;

[0042] ;

[0043] In the formula, Indicates the first The horizontal distance between gears; Indicates the first The phase angle difference of the gears; Indicates the first Horizontal distance of gear ( (Horizontal distance between tower number 1 and the substation at the end of the line). Indicates the first Phase angle difference.

[0044] Step S3: Solve the system of equations from Step S2 simultaneously to calculate the phase angle difference for each span of the entire tower line. .

[0045] Step S4: Using the bus voltage phase angle of the substation at the beginning of the line as a reference, subtract the sum of the phase angle differences of each span from the substation at the beginning of the line to the target tower to obtain the voltage phase angle of the target tower.

[0046] The specific process of step S4 is as follows: For the target tower that needs to be evaluated... The phase angle of the bus voltage at the substation at the beginning of the line As a reference phase The voltage phase angle of the target tower is calculated by subtracting the sum of the phase angle differences of all spans from the first substation to the target tower from the reference phase. .

[0047] Step S5: Use a surge arrester leakage current detection device with BeiDou time stamp to obtain the total leakage current of the surge arrester on the target tower. (Including amplitude and phase information).

[0048] Step S6: Measure the leakage current on the outer surface of the surge arrester using a current-taking ring, and subtract the leakage current on the outer surface from the total leakage current to obtain the actual current value and current phase angle flowing through the surge arrester body.

[0049] The specific process of step S6 is as follows: Use a voltage collection ring to collect and measure the target tower. Leakage current on the external surface of the surge arrester The total leakage current obtained in step S5 Subtract the leakage current from the outer surface The actual current value flowing through the surge arrester body is obtained. Simultaneously, the phase angle of the current flowing through the surge arrester body is obtained. .

[0050] Among them, the actual current value flowing through the surge arrester body is obtained. , represented as:

[0051] .

[0052] Step S7: Subtract the voltage phase angle of the target tower from the current phase angle to obtain the current-voltage phase difference of the surge arrester of the target tower; then calculate the current-voltage phase difference of each surge arrester of the same phase on the entire line using the same method.

[0053] The specific process of step S7 is as follows: using the phase angle of the surge arrester's body current. Subtract the voltage phase angle of the target tower The current-voltage phase difference of the target tower surge arrester is obtained. Following this method, the current-voltage phase difference of each surge arrester on each tower in the same direction along the entire line is calculated one by one. If the line surge arrester is in good condition, the current-voltage phase difference of the tower surge arrester will be... It should remain basically constant.

[0054] Step S8: Calculate the average value of the current-voltage phase difference for all surge arresters in phase across the entire line. Then use the current-voltage phase difference of each surge arrester Subtract average The deviation value of each surge arrester is obtained. .

[0055] Step S9: Determine the status of each surge arrester based on its deviation value. If the deviation value is negative, the surge arrester is determined to be in an abnormal state; if it is non-negative, the surge arrester is determined to be in a normal state.

[0056] If the surge arrester is in normal condition, its resistive current accounts for a small proportion, while its capacitive current accounts for a large proportion. Therefore, the current phase leads the voltage phase by a significant amount, resulting in a large deviation value for the surge arrester. The deviation is relatively large; conversely, when the internal varistors of the surge arrester deteriorate or age, the resistive current increases significantly while the capacitive current remains basically unchanged. Therefore, the deviation value of the surge arrester is relatively large. Reduce. Based on this principle, when the deviation value of a surge arrester on a certain branch line decreases... Greater than or equal to the average When the deviation is positive, the surge arrester is in normal condition; conversely, when the deviation value of a surge arrester on a certain branch line is negative... Less than the average When the deviation is negative, the surge arrester is in an abnormal state; for example... Figure 3 As shown, the target tower If the current-voltage phase difference of the surge arrester N-1 on the tower is lower than the average phase difference of all surge arresters on the line, which is a negative deviation, these surge arresters are judged to be in abnormal condition (marked in red).

[0057] This invention has two main aspects: First, it obtains the voltage phase at the beginning and end of the line through a substation PMU (Phasor Measurement Unit), obtains the voltage phase difference between the beginning and end of the line through a WAMS (Wide Area Measurement System), and obtains the surge arrester leakage current through a surge arrester leakage current detection device equipped with a Beidou timing module. After certain data processing methods, it obtains the line surge arrester leakage current phase and the tower (surge arrester) voltage phase. Second, it directly compares the surge arrester leakage current and voltage phase difference to evaluate the surge arrester's operating status. The principle is clear and the operation is convenient. It not only solves the problem of no state evaluation method for surge arresters with series gaps on the line, but also has a significant advantage for batch screening of the operating status of surge arresters across the entire line, effectively ensuring the safe and reliable operation of line surge arresters.

[0058] An electronic device includes a processor, a memory, and a bus, wherein the processor and the memory are connected via the bus, wherein the memory is used to store a set of program code, and the processor is used to call the program code stored in the memory to execute a line-band series gap surge arrester condition assessment method based on phase difference comparison.

[0059] A non-volatile computer storage medium stores computer-executable instructions that execute a line-with-series-gap surge arrester condition assessment method based on phase difference comparison.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the state of a line band series gap surge arrester based on phase difference comparison, characterized by, Comprising the following steps: Step S1: Obtain the line head substation bus voltage vector and the line end substation bus voltage vector through the substation PMU device, i.e. the phasor measurement unit, and obtain the line head-end voltage phase difference in combination with the WAMS system, i.e. the wide area measurement system; Step S2: Collect the total line tower horizontal span and sum to obtain the total line span, and establish an equation set for solving the phase angle difference of each span according to the "span proportional to phase angle difference" and "head-end voltage phase difference = sum of each span phase angle difference"; Step S3: Solve the equation set of step S2 to calculate the phase angle difference of each span of the total line tower; Step S4: Take the bus voltage phase angle of the line head substation as the reference, and subtract the sum of the phase angle difference of each span from the line head substation to the target tower to obtain the voltage phase angle of the target tower; Step S5: Use the lightning arrester leakage current detection device with Beidou time scale to obtain the total leakage current of the target tower lightning arrester; Step S6: Measure the leakage current on the outer surface of the lightning arrester with the power taking ring, and subtract the outer surface leakage current from the total leakage current to obtain the actual current value and current phase angle flowing through the lightning arrester body; Step S7: Use the current phase angle to subtract the voltage phase angle of the target tower to obtain the current-voltage phase difference of the lightning arrester of the target tower; and according to this method, the current-voltage phase difference of the lightning arrester of each tower on the same phase of the total line is calculated; Step S8: Calculate the average value of the current-voltage phase difference of all lightning arresters on the same phase of the total line, and subtract the average value from the current-voltage phase difference of each lightning arrester to obtain the deviation value of each lightning arrester; Step S9: Determine based on the deviation value of each lightning arrester, and if the deviation value is negative, it is determined that the corresponding lightning arrester is abnormal, and if the deviation value is not negative, it is determined that the corresponding lightning arrester is normal.

2. The method of claim 1, wherein the method further comprises: The specific process of step S1 is: collecting bus voltage vector of line head substation A and bus voltage vector of line tail substation B respectively by substation PMU device represents bus voltage amplitude of line head substation A, represents bus voltage phase angle of line head substation A, represents bus voltage amplitude of line tail substation B, represents bus voltage phase angle of line tail substation B; and then based on WAMS system, bus voltage phase angle of line head substation A is subtracted from bus voltage phase angle of line tail substation B , and voltage phase difference between line head and tail is calculated .​​ 3. The method of claim 2, wherein the method further comprises: determining a phase difference between the first and second voltage signals; and determining a phase difference between the third and fourth voltage signals. The specific process of step S2 is as follows: First, collect the horizontal span of all towers along the entire line; then, add up the horizontal spans of all towers to obtain the total span of the entire line. Based on the rule that "the phase angle difference of each span is proportional to the corresponding span distance", a correlation is established between the phase angle difference of each span and the corresponding span distance, while also considering the voltage phase difference at the beginning and end of the line. A system of equations was constructed to solve for the phase angle difference of each gear.

4. The method of claim 3, wherein the method further comprises: Tower number is indicated by , , Total number of towers along the whole line is indicated by , the phase angle difference of the first tower indicates the phase angle difference between the first end substation and the first tower, the phase angle difference of the second tower indicates the phase angle difference between the first tower and the second tower, and the phase angle difference of the last tower indicates the phase angle difference between the last tower and the last end substation. , ​ Voltage phase difference between the beginning and end of a line is equal to the sum of all the phase angle differences.

5. The method of claim 4, wherein the method further comprises: The equation set is represented as: ； ； ； wherein denotes the horizontal range of the th gear; denotes the phase angle difference of the th gear; denotes the horizontal range of the th gear; denotes the phase angle difference of the th gear.

6. The phase-difference comparison based line series-gap surge arrestor status evaluation method according to claim 5, characterized in that: The specific process of step S4 is: for the target tower , the bus voltage phase angle of the line head substation , as the reference phase ; subtract the sum of the phase angle differences of all span from the head substation to the target tower from the reference phase to calculate the voltage phase angle of the target tower .

7. The phase-difference comparison based line series-gap surge arrestor status evaluation method according to claim 6, characterized in that: The specific process of step S6 is: collecting and measuring the target tower with the power collecting ring The external surface leakage current of the lightning arrester , the total leakage current obtained by using step S5 Subtract the external surface leakage current , get the current value flowing through the lightning arrester body , and synchronously obtain the phase angle of the current flowing through the lightning arrester body .

8. The phase-difference comparison based line series-gap surge arrestor status evaluation method according to claim 7, characterized in that: The specific process of step S7 is: using the phase angle of the lightning arrester body current Subtract the voltage phase angle of the target tower , to get the current-voltage phase difference of the target tower lightning arrester According to this method, the current-voltage phase difference of each tower lightning arrester in the same direction of the whole line is calculated one by one .

9. An electronic device, comprising: A computer including a processor, a memory and a bus, wherein the processor and the memory are connected through the bus, wherein the memory is used to store a set of program codes, and the processor is used to call the program codes stored in the memory to execute the line state evaluation method based on phase difference comparison of the line with series gap lightning arrester according to any one of claims 1-8.

10. A non-transitory computer storage medium having stored computer- executable instructions, the computer-executable instructions comprising instructions for: The computer executable instructions execute the line state evaluation method based on phase difference comparison of the line with series gap lightning arrester according to any one of claims 1-8.

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