System and method for detecting insulation resistance of line arrester

Abstract

The invention discloses a line lightning arrester insulation resistance detection system, which comprises a measurement module, multiple lightning arrester series-parallel models are obtained by changing the wiring mode among an A-section lightning arrester, a B-section lightning arrester and a C-section lightning arrester, and the resistance values of the various lightning arrester series-parallel models are measured; the humidity correction module uses the humidity correction coefficient to correct the resistance values of the various lightning arrester series-parallel models to obtain the corrected resistance values of the various lightning arrester series-parallel models; and the series-parallel resolving module is used for respectively calculating insulation resistance values of the A-section lightning arrester, the B-section lightning arrester and the C-section lightning arrester by utilizing the various lightning arrester series-parallel models and combining the corrected resistance values of the various lightning arrester series-parallel models. According to the invention, the insulation resistance of the line arrester can be detected on site, and the working efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of power system detection and maintenance, and in particular to a line arrester insulation resistance detection system and method. Background Art

[0002] With the gradual advancement of the transmission line lightning protection renovation project, the number of line arresters installed and the coverage rate of poles and towers are steadily increasing. Timely testing and troubleshooting of line arrester failures can effectively improve the safety and stability of line operation.

[0003] Traditional power outage sampling detection is to dismantle the arrester and transport it to the laboratory for testing. The disadvantages of traditional measurement methods are heavy workload, tight time cycle, low coverage of test samples, lack of on-site detection means, and disassembly may cause damage to the arrester. Summary of the invention

[0004] The purpose of the present invention is to provide a line arrester insulation resistance detection system and method, the present invention can perform on-site detection of the line arrester insulation resistance and improve work efficiency.

[0005] To achieve this purpose, the line lightning arrester insulation resistance detection system designed by the present invention comprises a lightning arrester of section A, a lightning arrester of section B and a lightning arrester of section C, wherein the lightning arrester of section A, the lightning arrester of section B and the lightning arrester of section C are sequentially connected in series between the ground terminal and the high voltage terminal; it is characterized in that it comprises:

[0006] The measurement module is used to obtain various arrester series-parallel models by changing the wiring mode between the arrester of section A, the arrester of section B, and the arrester of section C, and to measure the resistance values ​​of various arrester series-parallel models;

[0007] The humidity correction module is used to correct the resistance values ​​of various arrester series-parallel models using the humidity correction coefficient to obtain the corrected resistance values ​​of various arrester series-parallel models;

[0008] The series-parallel solution module is used to calculate the insulation resistance values ​​of the A-section arrester, the B-section arrester, and the C-section arrester respectively by using the multiple arrester series-parallel models and combining the resistance values ​​of the various corrected arrester series-parallel models.

[0009] Preferably, it also includes a status diagnosis module, which is used to convert the insulation resistance values ​​of section A lightning arrester, section B lightning arrester and section C lightning arrester into leakage current of each section lightning arrester under a set voltage according to the voltage and current correction curve equation, and to determine the status of each section lightning arrester according to the set leakage current threshold.

[0010] Preferably, the first series-parallel connection mode among the multiple series-parallel connection models of lightning arresters is:

[0011] The B section lightning arrester and the C section lightning arrester are connected in series and then connected in parallel with the A section lightning arrester. The resistance value of the first series-parallel connection is R11=R1 / / (R2+R3), where / / represents parallel connection, R1 represents the insulation resistance value of the A section lightning arrester; R2 represents the insulation resistance value of the B section lightning arrester; and R3 represents the insulation resistance value of the C section lightning arrester.

[0012] Preferably, the second series-parallel connection mode in the plurality of arrester series-parallel connection models is:

[0013] The A section lightning arrester and the B section lightning arrester are connected in series and then connected in parallel with the C section lightning arrester. The resistance value of the second series-parallel connection is R21=R3 / / (R1+R2).

[0014] Preferably, the third series-parallel connection mode in the plurality of arrester series-parallel connection models is:

[0015] Only the B section lightning arrester and the C section lightning arrester are connected in parallel, and the resistance value of the third series-parallel connection method is R31=R2 / / (R3).

[0016] Preferably, the fourth series-parallel connection mode in the plurality of arrester series-parallel connection models is:

[0017] Only the A section lightning arrester and the B section lightning arrester are connected in parallel, and the resistance value of the fourth series-parallel connection method is R41=R1 / / (R2).

[0018] Preferably, the specific process of obtaining the humidity correction coefficient is:

[0019] The insulation resistance change of the lightning arrester under typical environmental humidity is simulated and calculated, and the humidity ranges from 30% to 90%, and multiple characteristic points are taken for analysis; the corresponding relationship between humidity and the insulation resistance of the lightning arrester is obtained through simulation; the corresponding relationship diagram of the insulation resistance of the lightning arrester and humidity is obtained, and the corresponding relationship diagram of the insulation resistance of the lightning arrester and humidity is obtained by curve fitting to obtain the curve equation k=a*(1-exp(-b*x)), wherein k is the humidity correction coefficient, a is the first fitting coefficient, b is the second fitting coefficient, and x is the current measured ambient humidity of the lightning arrester; the current measured ambient humidity value of the lightning arrester is substituted into the curve equation for calculation to obtain the humidity correction coefficient k; and then according to the resistance correction formulas R11'=k*R11, R21'=k*R21, R31'=k*R31 and R41'=k*R41, the corrected resistance values ​​R11', R21', R31' and R41' of various series-parallel models of lightning arresters are obtained.

[0020] Preferably, the specific method of using the multiple arrester series-parallel models and combining the resistance values ​​of the various arrester series-parallel models after correction to calculate the insulation resistance values ​​of the A-section arrester, the B-section arrester (4), and the C-section arrester is as follows:

[0021] R11'=R1 / / (R2+R3)

[0022] R21'=R3 / / (R1+R2)

[0023] R31'=R2 / / (R3)

[0024] R41'=R1 / / (R2)

[0025] By solving the above equations, we can obtain the insulation resistance value R1 of the arrester in section A, the insulation resistance value R2 of the arrester in section B, and the insulation resistance value R3 of the arrester in section C.

[0026] Preferably, according to the voltage and current correction curve equation, the insulation resistance values ​​of the A-section arrester, the B-section arrester and the C-section arrester are respectively converted into the insulation resistance values ​​of each section arrester at 0.75U 1mA The specific process of measuring the leakage current under voltage and judging the arrester status according to the leakage current threshold of 50uA is as follows:

[0027] According to the formula In 20kV =20kV / Rn, n=1,2,3 Convert the insulation resistance value R1 of the A section arrester, the insulation resistance value R2 of the B section arrester and the insulation resistance value R3 of the C section arrester measured by 20kV DC current into the current I1 of the A section arrester under 20kV DC voltage respectively 20kV , the current I2 of the arrester in section B 20kV , the current I3 of the C section arrester 20kV ;

[0028] Set U = 20kV and current I1 20kV 、Current I2 20kV 、Current I3 20kV Substitute the voltage and current correction curve equation U = An * I 2 +B,n=1,2,3, obtain the parameters A1 corresponding to the arrester in section A, A2 corresponding to the arrester in section B, and A3 corresponding to the arrester in section C, and then substitute U=150kV and the parameters A1 corresponding to the arrester in section A, A2 corresponding to the arrester in section B, and A3 corresponding to the arrester in section C into the voltage and current correction curve equation U=An*I 2 +B each gets 0.75U 1mA The leakage current of the arrester in section A, the leakage current of the arrester in section B and the leakage current of the arrester in section C under the voltage; parameter B is the empirical value of the critical voltage value of the arrester to generate current;

[0029] When 0.75U 1mA When the leakage current of the A-section lightning arrester under voltage, the leakage current of the B-section lightning arrester, or the leakage current of the C-section lightning arrester exceeds 50uA, the alarm program starts the alarm.

[0030] A method for detecting insulation resistance of a line lightning arrester, characterized in that it comprises the following steps:

[0031] By changing the wiring mode between the A-section arrester, the B-section arrester, and the C-section arrester, a variety of arrester series-parallel models are obtained, and the resistance values ​​of various arrester series-parallel models are measured;

[0032] The resistance values ​​of various arrester series-parallel models are corrected by using the humidity correction coefficient to obtain the corrected resistance values ​​of various arrester series-parallel models;

[0033] The insulation resistance values ​​of the A-section arrester, the B-section arrester and the C-section arrester are calculated respectively by using the multiple arrester series-parallel models and combining the resistance values ​​of the various corrected arrester series-parallel models.

[0034] Beneficial effects of the present invention:

[0035] The present invention can solve the cumbersome traditional method of transporting large-scale detection equipment to the site or dismantling the lightning arrester from high altitude for ground detection, which can reduce labor intensity, reduce safety risks and improve work efficiency.

[0036] The present invention realizes wiring through a remotely retractable insulating rod and a wire clamp, thereby realizing multi-point insulation resistance measurement of multiple series-connected lightning arresters, and simultaneously measuring the ambient humidity to correct the error of the single-point measurement value. After the insulation resistance of multiple points is measured in sequence, the internal software of the measuring device calculates the insulation resistance value through a series-parallel circuit model to obtain the insulation resistance value of a single lightning arrester. The invention can provide a simple and feasible measurement method for on-site maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of the present invention;

[0038] Figure 2 It is a schematic diagram of the testing principle of the present invention;

[0039] Figure 3 It is the correction coefficient curve equation diagram;

[0040] Figure 4 It is the voltage and current correction curve equation diagram;

[0041] Figure 5 It is a flow chart of the present invention.

[0042] Among them, 1-grounding terminal, 2-A section lightning arrester, 3-AB point, 4-B section lightning arrester, 5-BC point, 6-C section lightning arrester, 7-high voltage terminal. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0044] Example 1

[0045] A line arrester insulation resistance detection system, such as Figure 1 , 2 As shown in , 3, and 4, the arrester comprises an A-section arrester 2, a B-section arrester 4, and a C-section arrester 6, wherein the A-section arrester 2, the B-section arrester 4, and the C-section arrester 6 are sequentially connected in series between the ground terminal 1 and the high-voltage terminal 7; it is characterized in that it comprises:

[0046] The measurement module is used to obtain a variety of arrester series-parallel models by changing the wiring mode between the A section arrester 2, the B section arrester 4, and the C section arrester 6, and to measure the resistance values ​​of various arrester series-parallel models. This design can improve the accuracy of arrester insulation resistance measurement;

[0047] The humidity correction module is used to correct the resistance values ​​of various arrester series-parallel models using the humidity correction coefficient to obtain the corrected resistance values ​​of various arrester series-parallel models. This design can reduce the influence of humidity on the surface of the arrester on the accuracy of insulation resistance, and is used to improve the accuracy of resistance value measurement and the reliability and consistency of arrester testing.

[0048] The series-parallel solution module is used to calculate the insulation resistance values ​​of section A arrester 2, section B arrester 4, and section C arrester 6 respectively by using the multiple arrester series-parallel models and combining the resistance values ​​of the various arrester series-parallel models after correction. This design can accurately evaluate the insulation performance of each section of the arrester, improve the reliability of the arrester system, and improve the test efficiency and accuracy.

[0049] The above technical solution also includes a state diagnosis module, which is used to convert the insulation resistance values ​​of the A-section lightning arrester 2, the B-section lightning arrester 4 and the C-section lightning arrester 6 into the insulation resistance values ​​of each section of the lightning arrester under the set voltage (the set voltage is 0.75U 1mA ) and determine the status of each section of the arrester according to the set leakage current threshold (the leakage current threshold is set to 50uA); if the insulation resistance is unqualified, it can be determined that the arrester is faulty; if the insulation resistance is qualified, the arrester may be faulty; the above design improves the accuracy of arrester status diagnosis and optimizes the maintenance and management of the arrester.

[0050] In the above technical solution, the first series-parallel mode of the plurality of arrester series-parallel models is:

[0051] The B section lightning arrester 4 and the C section lightning arrester 6 are connected in series and then connected in parallel with the A section lightning arrester 2 (the resistance value R11 can be measured by connecting the high-voltage test line to the AB point 3 between the A section lightning arrester 2 and the B section lightning arrester 4). The resistance value of the first series-parallel mode is R11=R1 / / (R2+R3), where / / represents parallel connection, R1 represents the insulation resistance value of the A section lightning arrester 2; R2 represents the insulation resistance value of the B section lightning arrester 4; R3 represents the insulation resistance value of the C section lightning arrester 6. The above design uses the series-parallel model of the lightning arrester to perform measurements without removing the wires, which can simplify the resistance value calculation and analysis.

[0052] In the above technical solution, the second series-parallel connection mode in the multiple series-parallel connection models of lightning arresters is:

[0053] The A section lightning arrester 2 and the B section lightning arrester 4 are connected in series and then connected in parallel with the C section lightning arrester 6 (the resistance value R21 can be measured by connecting the high-voltage test line to the BC point 5 between the B section lightning arrester 4 and the C section lightning arrester 6). The resistance value of the second series-parallel connection is R21=R3 / / (R1+R2). The above design uses the series-parallel model of the lightning arrester to perform measurements without removing the wires, which can simplify the calculation and analysis of the resistance value.

[0054] In the above technical solution, the third series-parallel connection mode among the multiple series-parallel connection models of lightning arresters is:

[0055] Only the B-section lightning arrester 4 and the C-section lightning arrester 6 are connected in parallel (the resistance value R31 can be measured by connecting the AB point 3 to the ground terminal 1 and the high-voltage test line to the BC point 5). The resistance value of the third series-parallel connection is R31=R2 / / (R3). The above design uses the series-parallel model of the lightning arrester to perform measurements without removing the wires, which can simplify the calculation and analysis of the resistance value.

[0056] In the above technical solution, the fourth series-parallel connection mode among the multiple series-parallel connection models of lightning arresters is:

[0057] Only the A section lightning arrester 2 and the B section lightning arrester 4 are connected in parallel (the resistance value R41 can be measured by connecting the BC point 5 to the ground terminal 1 and the high-voltage test line to the AB point 3). The resistance value of the fourth series-parallel connection method is R41=R1 / / (R2). The above design uses the lightning arrester series-parallel model to perform measurements without removing the wires, which can simplify the resistance value calculation and analysis.

[0058] In the above technical solution, the specific process of obtaining the humidity correction coefficient is:

[0059] The change of the arrester insulation resistance under typical environmental humidity is simulated and calculated, and the humidity is in the range of 30%-90%, and multiple characteristic points are taken for analysis; the corresponding relationship between humidity and the arrester insulation resistance is obtained through simulation; the arrester insulation resistance is measured in the laboratory simulating typical humidity, the simulation results are verified, and actual corrections are made to obtain the corresponding relationship diagram between the arrester insulation resistance and humidity, and the corresponding relationship diagram between the arrester insulation resistance and humidity is obtained by curve fitting to obtain the curve equation k=a*(1-exp(-b*x)), such as Figure 3 As shown, k is the humidity correction coefficient, a is the first fitting coefficient, b is the second fitting coefficient (take a=1.3; b=0.04), and x is the current measured arrester ambient humidity; the current measured arrester ambient humidity value is substituted into the curve equation for calculation to obtain the humidity correction coefficient k; then according to the resistance correction formulas R11'=k*R11, R21'=k*R21, R31'=k*R31 and R41'=k*R41, the corrected resistance values ​​R11', R21', R31' and R41' of various arrester series-parallel models are obtained. The above design eliminates the influence of humidity on the accuracy of the arrester insulation resistance, optimizes the arrester performance evaluation, and enhances the reliability of the arrester detection system.

[0060] In the above technical solution, the specific method of using the multiple arrester series-parallel models and combining the resistance values ​​of the various arrester series-parallel models after correction to calculate the insulation resistance values ​​of the A-section arrester 2, the B-section arrester 4, and the C-section arrester 6 is as follows:

[0061] R11'=R1 / / (R2+R3)

[0062] R21'=R3 / / (R1+R2)

[0063] R31'=R2 / / (R3)

[0064] R41'=R1 / / (R2)

[0065] By solving the above equations, the insulation resistance value R1 of the A section arrester 2, the insulation resistance value R2 of the B section arrester 4, and the insulation resistance value R3 of the C section arrester 6 are obtained. The above design can improve the accuracy of the insulation resistance value calculation and solve the insulation resistance of a single arrester.

[0066] In the above technical solution, according to the voltage and current correction curve equation, the insulation resistance values ​​of the A section lightning arrester 2, the B section lightning arrester 4 and the C section lightning arrester 6 are respectively converted into the insulation resistance values ​​of each section lightning arrester at 0.75U 1mA The specific process of measuring the leakage current under voltage and judging the arrester status according to the leakage current threshold of 50uA is as follows:

[0067] (The insulation resistance value is within the qualified range, which does not mean that the insulation state of the arrester is normal. An important indicator for judging the normal insulation state of a 500kV arrester is 0.75U 1mA The leakage current under voltage does not exceed 50uA; single 500kV lightning arrester 0.75U 1mA =150kV, so it is necessary to convert the insulation resistance value R1 of the A section arrester 2, the insulation resistance value R2 of the B section arrester 4, and the insulation resistance value R3 of the C section arrester 6 measured at 20kV DC current into the current under 20kV DC voltage) according to the formula In 20kV =20kV / Rn, n=1,2,3. The insulation resistance value R1 of the A-section arrester 2, the insulation resistance value R2 of the B-section arrester 4 and the insulation resistance value R3 of the C-section arrester 6 measured at 20kV DC current are converted into the current I1 of the A-section arrester 2 under 20kV DC voltage. 20kV , the current I2 of arrester 4 in section B 20kV , the current I3 of the arrester 6 in section C 20kV ;

[0068] Set U = 20kV and current I1 20kV 、Current I2 20kV 、Current I3 20kV Substitute the voltage and current correction curve equation U = An * I 2 +B,n=1,2,3, such as Figure 4 As shown, the parameter A1 corresponding to the arrester 2 in section A, the parameter A2 corresponding to the arrester 4 in section B, and the parameter A3 corresponding to the arrester 6 in section C are obtained, and then U=150kV and the parameter A1 corresponding to the arrester 2 in section A, the parameter A2 corresponding to the arrester 4 in section B, and the parameter A3 corresponding to the arrester 6 in section C are substituted into the voltage and current correction curve equation U=An*I 2 +B each gets 0.75U 1mA The leakage current of the arrester 2 in section A, the leakage current of the arrester 4 in section B and the leakage current of the arrester 6 in section C under voltage; wherein parameter B is the empirical value of the critical voltage value of the arrester to generate current (the value range of parameter B is 15kV-18kV);

[0069] When 0.75U 1mA When the leakage current of arrester 2 in section A, arrester 4 in section B, or arrester 6 in section C exceeds 50uA under voltage, the alarm program starts to alarm; when 0.75U 1mA When the leakage current of the arrester 2 of section A or the leakage current of the arrester 4 of section B or the leakage current of the arrester 6 of section C does not exceed 50uA under the voltage, the alarm program will not start the alarm; in the above design, when the leakage current of the arrester is 0.75U 1mAWhen the voltage does not exceed 50uA, the arrester is in normal condition; when the leakage current of the arrester is 0.75U 1mA When the voltage exceeds 50uA, the arrester is in an abnormal state. Through precise leakage current measurement and state determination, the accuracy of arrester state assessment is improved, the maintenance and management of the arrester is optimized, and the test efficiency and reliability are improved.

[0070] Example 2

[0071] A method for detecting insulation resistance of a line lightning arrester, such as Figure 5 As shown, by changing the wiring mode between section A arrester 2, section B arrester 4, and section C arrester, a plurality of arrester series-parallel models are obtained, and the resistance values ​​of the various arrester series-parallel models are measured; the resistance values ​​of the various arrester series-parallel models are corrected by using the humidity correction coefficient to obtain the corrected resistance values ​​of the various arrester series-parallel models; the insulation resistance values ​​of section A arrester 2, section B arrester 4, and section C arrester 6 are calculated respectively by using the plurality of arrester series-parallel models and combining the corrected resistance values ​​of the various arrester series-parallel models.

[0072] The specific method for detecting the insulation resistance of the lightning arrester includes the following steps:

[0073] By changing the connection mode between the A section lightning arrester 2, the B section lightning arrester 4, and the C section lightning arrester 6, a variety of lightning arrester series-parallel models are obtained, and the resistance values ​​of various lightning arrester series-parallel models are measured;

[0074] The resistance values ​​of various arrester series-parallel models are corrected by using the humidity correction coefficient to obtain the corrected resistance values ​​of various arrester series-parallel models;

[0075] The insulation resistance values ​​of the A-section arrester 2, the B-section arrester 4 and the C-section arrester 6 are calculated respectively by using the multiple arrester series-parallel models and combining the resistance values ​​of the various arrester series-parallel models after correction.

[0076] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A line arrester insulation resistance detection system, wherein the arrester comprises an A-section arrester (2), a B-section arrester (4), and a C-section arrester (6), wherein the A-section arrester (2), the B-section arrester (4), and the C-section arrester (6) are sequentially connected in series between a ground terminal (1) and a high-voltage terminal (7); characterized in that: It includes: The measuring module is used to obtain a variety of arrester series-parallel models by changing the wiring mode between the A-section arrester (2), the B-section arrester (4) and the C-section arrester (6), and to measure the resistance values ​​of the various arrester series-parallel models; The humidity correction module is used to correct the resistance values ​​of various arrester series-parallel models using the humidity correction coefficient to obtain the corrected resistance values ​​of various arrester series-parallel models; The series-parallel calculation module is used to respectively calculate the insulation resistance values ​​of the A-section arrester (2), the B-section arrester (4), and the C-section arrester (6) by using the multiple arrester series-parallel models and combining the resistance values ​​of the various corrected arrester series-parallel models.

2. The line lightning arrester insulation resistance detection system according to claim 1 further includes a status diagnosis module, which is used to convert the insulation resistance values ​​of section A lightning arrester (2), section B lightning arrester (4) and section C lightning arrester (6) into leakage currents of each section of lightning arrester under a set voltage according to a voltage-current correction curve equation, and perform status judgment on each section of lightning arrester according to a set leakage current threshold.

3. The line arrester insulation resistance detection system according to claim 1, characterized in that: The first series-parallel connection mode in the multiple series-parallel connection models of lightning arresters is: The B section lightning arrester (4) and the C section lightning arrester (6) are connected in series and then connected in parallel with the A section lightning arrester (2). The resistance value of the first series-parallel connection mode is R11=R1 / / (R2+R3), wherein / / represents parallel connection, R1 represents the insulation resistance value of the A section lightning arrester (2); R2 represents the insulation resistance value of the B section lightning arrester (4); and R3 represents the insulation resistance value of the C section lightning arrester (6).

4. The line arrester insulation resistance detection system according to claim 3, characterized in that: The second series-parallel connection mode in the multiple series-parallel connection models of lightning arresters is: The A section lightning arrester (2) and the B section lightning arrester (4) are connected in series and then connected in parallel with the C section lightning arrester (6). The resistance value of the second series-parallel connection is R21=R3 / / (R1+R2).

5. The line arrester insulation resistance detection system according to claim 4, characterized in that: The third series-parallel connection mode in the multiple series-parallel connection models of lightning arresters is: Only the B-section lightning arrester (4) and the C-section lightning arrester (6) are connected in parallel, and the resistance value of the third series-parallel connection mode is R31=R2 / / (R3).

6. The line arrester insulation resistance detection system according to claim 5, characterized in that: The fourth series-parallel connection mode in the multiple series-parallel connection models of lightning arresters is: Only the A-section lightning arrester (2) and the B-section lightning arrester (4) are connected in parallel, and the resistance value of the fourth series-parallel connection mode is R41=R1 / / (R2).

7. The line arrester insulation resistance detection system according to claim 6, characterized in that: The specific process of obtaining the humidity correction coefficient is: The insulation resistance change of the lightning arrester under typical environmental humidity is simulated and calculated, and the humidity ranges from 30% to 90%, and multiple characteristic points are taken for analysis; the corresponding relationship between humidity and the insulation resistance of the lightning arrester is obtained through simulation; the corresponding relationship diagram of the insulation resistance of the lightning arrester and humidity is obtained, and the corresponding relationship diagram of the insulation resistance of the lightning arrester and humidity is obtained by curve fitting to obtain the curve equation k=a*(1-exp(-b*x)), wherein k is the humidity correction coefficient, a is the first fitting coefficient, b is the second fitting coefficient, and x is the current measured ambient humidity of the lightning arrester; the current measured ambient humidity value of the lightning arrester is substituted into the curve equation for calculation to obtain the humidity correction coefficient k; and then according to the resistance correction formulas R11'=k*R11, R21'=k*R21, R31'=k*R31 and R41'=k*R41, the corrected resistance values ​​R11', R21', R31' and R41' of various series-parallel models of lightning arresters are obtained.

8. The line arrester insulation resistance detection system according to claim 1, characterized in that: The specific method of calculating the insulation resistance values ​​of the A-section lightning arrester (2), the B-section lightning arrester (4), and the C-section lightning arrester (6) respectively by using the plurality of lightning arrester series-parallel models and combining the resistance values ​​of the various lightning arrester series-parallel models after correction is as follows: R11'=R1 / / (R2+R3) R21'=R3 / / (R1+R2) R31'=R2 / / (R3) R41'=R1 / / (R2) By solving the above equations, the insulation resistance value R1 of the A-section lightning arrester (2), the insulation resistance value R2 of the B-section lightning arrester (4), and the insulation resistance value R3 of the C-section lightning arrester (6) are obtained.

9. The line arrester insulation resistance detection system according to claim 1 or 2, characterized in that: According to the voltage and current correction curve equation, the insulation resistance values ​​of the A-section lightning arrester (2), the B-section lightning arrester (4) and the C-section lightning arrester (6) are respectively converted into the insulation resistance values ​​of each section of the lightning arrester at 0.75U 1mA The specific process of measuring the leakage current under voltage and judging the arrester status according to the leakage current threshold of 50uA is as follows: According to the formula In 20kV = 20kV / Rn, n = 1, 2, 3. The insulation resistance value R1 of the A-section arrester (2), the insulation resistance value R2 of the B-section arrester (4) and the insulation resistance value R3 of the C-section arrester (6) measured at 20kV DC current are converted into the current I1 of the A-section arrester (2) at 20kV DC voltage. 20kV , the current I2 of the arrester (4) in section B 20kV , the current I3 of the arrester (6) in section C 20kV ; Set U = 20kV and current I1 20kV 、Current I2 20kV 、Current I3 20kV Substitute the voltage and current correction curve equation U = An * I 2 +B, n = 1, 2, 3, obtain the parameter A1 corresponding to the lightning arrester (2) of section A, the parameter A2 corresponding to the lightning arrester (4) of section B and the parameter A3 corresponding to the lightning arrester (6) of section C, and then substitute U = 150 kV and the parameter A1 corresponding to the lightning arrester (2) of section A, the parameter A2 corresponding to the lightning arrester (4) of section B and the parameter A3 corresponding to the lightning arrester (6) of section C into the voltage and current correction curve equation U = An * I 2 +B each gets 0.75U 1mA The leakage current of the lightning arrester (2) of section A, the leakage current of the lightning arrester (4) of section B and the leakage current of the lightning arrester (6) of section C under the voltage; wherein parameter B is an empirical value of the critical voltage value of the current generated by the lightning arrester; When 0.75U 1mA When the leakage current of the A-section lightning arrester (2) or the B-section lightning arrester (4) or the C-section lightning arrester (6) under the voltage exceeds 50uA, the alarm program starts to alarm.

10. A method for detecting insulation resistance of a line lightning arrester based on the system of claim 1, characterized in that: It includes the following steps: By changing the connection mode between the A-section lightning arrester (2), the B-section lightning arrester (4), and the C-section lightning arrester (6), a variety of lightning arrester series-parallel models are obtained, and the resistance values ​​of the various lightning arrester series-parallel models are measured; The resistance values ​​of various arrester series-parallel models are corrected by using the humidity correction coefficient to obtain the corrected resistance values ​​of various arrester series-parallel models; The insulation resistance values ​​of the A-section arrester (2), the B-section arrester (4), and the C-section arrester (6) are calculated respectively by using the multiple arrester series-parallel models and combining the resistance values ​​of the various corrected arrester series-parallel models.

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