A method for correcting the test result of a grounding resistance of a pole tower by using a clamp-on method

Abstract

The application discloses a method for correcting test results of tower grounding resistance by using a clamp-on method, and comprises the following steps: judging whether the grounding resistance of a tower meets the use condition of the clamp-on method; if yes, the clamp-on method is used; if not, a three-pole method is used to test all towers one by one to obtain the real grounding resistance of all towers; the clamp-on method is used to test the grounding resistance of all towers meeting the condition to obtain the grounding resistance of all towers tested by using the clamp-on method; the three-pole method is used to test any tower to obtain the grounding resistance of the tower tested by using the three-pole method; a new set of simultaneous equations is obtained according to the relationship between the grounding resistance of all towers tested by using the clamp-on method and the grounding resistance of any tower tested by using the three-pole method; and the grounding resistance of all towers is obtained by solving the new set of simultaneous equations. The grounding resistance of all towers is obtained by solving the set of simultaneous equations, and the test efficiency of the grounding resistance of the tower is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission and transformation equipment operation and maintenance, and specifically to a method for correcting tower grounding resistance test results using a clamp meter method. Background Art

[0002] Grounding a tower is the most fundamental lightning protection measure for transmission lines. Proper grounding ensures smooth discharge of lightning current after a lightning strike on a transmission line. It also limits the overvoltage generated on the tower, preventing insulator (string) flashover and tripping. Grounding resistance directly affects the tower's lightning strike resistance. Reducing grounding resistance is key to improving the tower's lightning strike resistance and reducing the line's lightning strike tripping rate.

[0003] Due to the large number of base towers and the significant workload associated with ground resistance testing, a "wheel test" method is currently commonly used to test the ground resistance of base towers. The main methods for testing base tower ground resistance are the "three-pole method" and the "clamp meter method." The "three-pole method" treats the base tower grounding device as a hemisphere. By properly setting the voltage and current electrodes, the grounding device's grounding resistance can be accurately measured. However, the "three-pole method" requires significant wiring effort. The voltage electrode is generally required to measure 1.8 to 2.5 times the grounding ray, and the current electrode is generally required to measure 3 to 4 times the grounding ray. Furthermore, the method is significantly affected by the testing personnel's level of expertise. The "clamp meter method," also known as the "loop resistance method," measures the ground resistance of the base tower by measuring the loop formed by the base tower and other base towers. This method is suitable for base-to-base grounding. The test is simple and convenient, requiring no wiring, but inherent deviation exists, primarily due to the resistance increment caused by the parallel connection of other base towers. If this inherent deviation can be quantitatively eliminated, the "clamp meter method" can be used to easily and conveniently determine the ground resistance of the base tower. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a method for correcting the grounding resistance test results of a tower using a clamp meter method, which aims to eliminate the inherent deviation of the clamp meter method, accurately obtain the grounding resistance of the tower, and improve the efficiency of the tower grounding resistance test.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for correcting the grounding resistance test results of a tower using a clamp meter method, comprising the following steps:

[0006] Step S1: Determine whether the grounding resistance of the base tower meets the conditions for using the clamp meter method. If the conditions are met, proceed to step S2. If the conditions are not met, use the three-pole method to test all base towers one by one to obtain the true grounding resistance of all base towers.

[0007] Step S2: using a clamp meter method to test the grounding resistance of all base towers that meet the conditions, and obtaining the grounding resistance of all base towers tested by the clamp meter method;

[0008] Step S3: Test the ground resistance of any one base tower by the three-pole method to obtain the ground resistance of any one base tower by the three-pole method;

[0009] Step S4: Substitute the ground resistance of any one base tower by the three-pole method into the simultaneous equations to obtain new simultaneous equations. i Step S5: Solve the new simultaneous equations to obtain the real ground resistance of all base towers. i The expression of the relationship between the two is:

[0010] r i = R i + (R1 / / R2 / / … / / R (i-1) / / R (i+1) / / … / / R n ) (1).

[0011] In the formula (1), R (i-1) represents the ground resistance of the i-1th base tower by the three-pole method; R (i+1) represents the ground resistance of the i+1th base tower by the three-pole method; and R n represents the ground resistance of the nth base tower by the three-pole method.

[0012] According to the formula (1), the expression of the relationship between the ground resistance of all base towers by the clamp-on method and the ground resistance of any one base tower by the three-pole method is established, and the simultaneous equations are solved to obtain a simultaneous equation group:

[0013] (2).

[0014] In the formula (2), R represents the ground resistance of the n-1th base tower by the three-pole method.

[0015] Step S4: Substitute the ground resistance of any one base tower by the three-pole method into the simultaneous equations to obtain new simultaneous equations.

[0016] Step S5: Solve the new simultaneous equations to obtain the real ground resistance of all base towers.

[0017] Further, in step S1, it is determined whether the ground resistance of the base tower meets the clamp-on method use condition, and the specific process is as follows:

[0018] First, whether the line of the base tower has a lightning rod, and whether the lightning rod of the base tower is directly grounded; second, whether the number of base towers with directly grounded lightning rods exceeds the specified number; if the conditions are met, the clamp-on method is used to test the ground resistance of all base towers that meet the conditions; if the conditions are not met, the three-pole method is used to test all base towers to obtain the real ground resistance of all base towers.

[0019] Further, in step S2, the ground resistance of all base towers by the clamp-on method is obtained, and the specific process is as follows:

[0020] When using the clamp meter method for testing, only one grounding down conductor is left connected to the tower body of the base tower. The remaining grounding down conductors should be disconnected from the tower body of the base tower, and the disconnected grounding conductor should be connected in parallel with the retained grounding conductor using a metal conductor. Use a clamp-type ground resistance tester to clamp the retained grounding down conductor. The internal power supply E of the clamp-type ground resistance tester excites a current I in the loop. According to Ohm's law, the loop resistance is obtained. In the test, the current test resistance is regarded as the base tower test ground resistance r i According to this method, the clamp meter method is used to test the grounding resistance of all base towers that meet the conditions, and the grounding resistances r1, r2, r3, ..., r n ;

[0021] Where E is the power supply voltage and I is the loop current.

[0022] Furthermore, in step S3, the grounding resistance of any base tower is obtained by three-pole method test, and the specific process is as follows:

[0023] The ground resistance tester has four connection ports, namely C1, P1, C2, and P2. Connect C1 and P1 to the grounding down conductor, connect the voltage electrode P and the current electrode C to P2 and C2 in the ground resistance tester, and place the voltage electrode P and the current electrode C at the edge of the tower foundation d. GC =4l and d GP At 2.5l, the three-pole method is used to test the ground resistance of any base tower;

[0024] Among them, d GP Indicates the straight-line distance between the grounding device G and the voltage electrode P; d GC It represents the straight-line distance between the grounding device G and the current electrode C; l represents the maximum length of the radial grounding electrode for the base tower grounding.

[0025] Furthermore, in step S4, a new set of simultaneous equations is obtained, and the specific process is as follows:

[0026] Let R i =A, the obtained R i =A is substituted into formula (2) to obtain the new simultaneous equations:

[0027] (3);

[0028] Where, It represents the ground resistance of the ith base tower tested by the three-pole method, which is a certain value.

[0029] Compared with the existing technology, the present invention has the following beneficial effects: (1) The present invention uses the clamp meter method to test the grounding resistance of all base towers that meet the conditions, and obtains the grounding resistance of all base towers tested by the clamp meter method. By using the three-pole method to test any base tower, the grounding resistance of any base tower tested by the three-pole method is obtained. Based on the relationship between the grounding resistance of all base towers tested by the clamp meter method and the grounding resistance of any base tower tested by the three-pole method, an n-order simultaneous equation system is formed, which can reduce the n-order simultaneous equation system to an n-1-order simultaneous equation system. By solving the simultaneous equation system, the grounding resistance of all base towers can be obtained, which significantly improves the efficiency of the base tower grounding resistance test. (2) The method of the present invention can eliminate the inherent deviation of the base tower clamp meter method grounding resistance test, obtain the base tower grounding resistance conveniently and accurately, improve the quality and efficiency of line operation and maintenance, and ensure the lightning resistance level of the transmission line. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the flow diagram of the present invention.

[0031] Figure 2 This is a schematic diagram of the test results of the clamp meter method of the present invention.

[0032] Figure 3 Schematic diagram of the test results of the three-pole method of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to implementation cases and accompanying drawings.

[0034] like Figure 1 As shown, a method for correcting the results of a tower grounding resistance test using a clamp meter method includes the following steps:

[0035] Step S1: Determine whether the grounding resistance of the base tower meets the conditions for using the clamp meter method. If the conditions are met, proceed to step S2. If the conditions are not met, use the three-pole method to test all base towers one by one to obtain the true grounding resistance of all base towers.

[0036] Step S2: using a clamp meter method to test the grounding resistance of all base towers that meet the conditions, and obtaining the grounding resistance of all base towers tested by the clamp meter method;

[0037] Step S3: testing any base tower using a three-pole method to obtain the three-pole test grounding resistance of any base tower;

[0038] The grounding resistance of the clamp meter method is equivalent to the resistance of the entire test loop. The grounding resistance of the i-th base tower tested by the clamp meter method is the grounding resistance R i The result after connecting in series with the parallel value of the three-pole method test grounding resistance of any base tower, so the grounding resistance r of the i-th base tower clamp meter test is i The ground resistance R of the i-th tower is tested by three-pole method.i The expression of the relationship between the two is:

[0039] r i =R i +(R1 / / R2 / / … / / R (i-1) / / R (i+1) / / … / / R n )(1);

[0040] Where R (i-1) Represents the ground resistance of the i-1th base tower tested by three-pole method; R (i+1) Indicates the ground resistance of the i+1th tower tested by three-pole method; R n Indicates the three-pole method ground resistance test of the n-th base tower;

[0041] According to formula (1), the relationship between the ground resistance of all base towers tested by the clamp meter method and the ground resistance of any base tower tested by the three-pole method is established, and the simultaneous equations are obtained:

[0042] (2);

[0043] Where, Indicates the ground resistance of the n-1th base tower tested by the three-pole method;

[0044] Among them, the grounding resistance of the clamp meter method is r1, r2, r3, ..., r n All of them are known values. The three-pole grounding resistances R1, R2, R3, ..., R n All are unknown values ​​to be determined;

[0045] Among them, R n-1 There are n-1 independent equations, but there are n variables to be solved, so it cannot be solved directly;

[0046] Step S4: Substitute the grounding resistance of any tower tested by the three-pole method into the simultaneous equations to obtain a new simultaneous equations;

[0047] Step S5: Solve the new simultaneous equations to obtain the true grounding resistance of all base towers.

[0048] In step S1, it is determined whether the grounding resistance of the base tower meets the conditions for using the clamp meter method. The specific process is as follows:

[0049] To determine whether the grounding resistance of the base tower meets the conditions for using the clamp meter method, first, the base tower line has a lightning conductor, and the lightning conductor of the base tower is directly grounded; second, the number of base towers with lightning conductors directly grounded exceeds 13; if the above conditions are met, use the clamp meter method to test the grounding resistance of all base towers that meet the conditions; if the conditions are not met, use the three-pole method to test all base towers one by one to obtain the true grounding resistance of all base towers.

[0050] like Figure 2 As shown, in step S2, the grounding resistance of all base towers is measured by clamp meter method, and the specific process is as follows:

[0051] When using the clamp meter method for testing, only one grounding down conductor is left connected to the tower body of the base tower. The remaining grounding down conductors should be disconnected from the tower body of the base tower, and the disconnected grounding conductor should be connected in parallel with the retained grounding conductor using a metal conductor. Use a clamp-type ground resistance tester to clamp the retained grounding down conductor. The internal power supply E of the clamp-type ground resistance tester excites a current I in the loop. According to Ohm's law, the loop resistance is obtained. In the test, the current test resistance is regarded as the base tower test ground resistance r i According to this method, the clamp meter method is used to test the grounding resistance of all base towers that meet the conditions, and the grounding resistances r1, r2, r3, ..., r n , take and record the readings;

[0052] Where E is the power supply voltage and I is the loop current.

[0053] like Figure 3 In the above, in step S3, the three-pole method grounding resistance test of any base tower is obtained, and the specific process is as follows:

[0054] The ground resistance tester has four connection ports, namely C1, P1, C2, and P2. Connect C1 and P1 to the grounding down conductor, connect the voltage electrode P and the current electrode C to P2 and C2 in the ground resistance tester, and place the voltage electrode P and the current electrode C at the edge of the tower foundation d. GC =4l and d GP At 2.5l, the three-pole method is used to test the ground resistance R of any base tower. i ;

[0055] Among them, d GP Indicates the straight-line distance between the grounding device G and the voltage electrode P; d GC It represents the straight-line distance between the grounding device G and the current electrode C; l represents the maximum length of the radial grounding electrode for the base tower grounding.

[0056] In step S4, a new set of simultaneous equations is obtained, and the specific process is as follows:

[0057] Let R i =A, the obtained R i =A is substituted into formula (2) to obtain the new simultaneous equations:

[0058] (3);

[0059] Where, It represents the ground resistance of the ith base tower tested by the three-pole method, which is a certain value.

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

Claims

1. A method for correcting the results of a tower grounding resistance test using a clamp meter method, characterized in that: The following steps are involved: Step S1: Determine whether the grounding resistance of the base tower meets the conditions for using the clamp meter method. If the conditions are met, proceed to step S2. If the conditions are not met, use the three-pole method to test all base towers one by one to obtain the true grounding resistance of all base towers. Step S2: using a clamp meter method to test the grounding resistance of all base towers that meet the conditions, and obtaining the grounding resistance of all base towers tested by the clamp meter method; Step S3: testing any base tower using a three-pole method to obtain the three-pole test grounding resistance of any base tower; Establish the i-th base tower clamp meter method to test the ground resistance r i The ground resistance R of the i-th tower is tested by three-pole method. i The expression of the relationship between the two is: r i =R i +(R1 / / R2 / / … / / R (i-1) / / R (i+1) / / … / / R n )(1); Where R (i-1) Represents the ground resistance of the i-1th base tower tested by three-pole method; R (i+1) Indicates the ground resistance of the i+1th tower tested by three-pole method; R n Indicates the three-pole test ground resistance of the n-th base tower; According to formula (1), the relationship between the ground resistance of all base towers tested by the clamp meter method and the ground resistance of any base tower tested by the three-pole method is established, and the simultaneous equations are obtained: （2）； Where, Indicates the ground resistance of the n-1th base tower tested by the three-pole method; Step S4: Substitute the grounding resistance of any tower tested by the three-pole method into the simultaneous equations to obtain a new simultaneous equations; Step S5: Solve the new simultaneous equations to obtain the true grounding resistance of all base towers.

2. The method for correcting the results of a clamp meter tower ground resistance test according to claim 1, wherein: In step S1, it is determined whether the grounding resistance of the base tower meets the conditions for using the clamp meter method. The specific process is as follows: To determine whether the grounding resistance of the base tower meets the conditions for using the clamp meter method, first, the base tower line has a lightning conductor, and the lightning conductor of the base tower is directly grounded; second, the number of base towers with lightning conductors directly grounded exceeds the specified number; if the conditions are met, use the clamp meter method to test the grounding resistance of all base towers that meet the conditions; if the conditions are not met, use the three-pole method to test all base towers one by one to obtain the true grounding resistance of all base towers.

3. The method for correcting the results of a clamp meter tower ground resistance test according to claim 2, wherein: In step S2, the ground resistance of all base towers is obtained by clamp meter test. The specific process is as follows: When using the clamp meter method for testing, only one grounding down conductor is left connected to the tower body of the base tower. The remaining grounding down conductors should be disconnected from the tower body of the base tower, and the disconnected grounding conductor should be connected in parallel with the retained grounding conductor using a metal conductor. Use a clamp-type ground resistance tester to clamp the retained grounding down conductor. The internal power supply E of the clamp-type ground resistance tester excites a current I in the loop. According to Ohm's law, the loop resistance is obtained. In the test, the current test resistance is regarded as the base tower test ground resistance r i According to this method, the clamp meter method is used to test the grounding resistance of all base towers that meet the conditions, and the grounding resistances r1, r2, r3, ..., r n ; Where E is the power supply voltage and I is the loop current.

4. The method for correcting the results of a clamp meter tower ground resistance test according to claim 3, wherein: In step S3, the three-pole method grounding resistance of any base tower is obtained, and the specific process is as follows: The ground resistance tester has four connection ports, namely C1, P1, C2, and P2. Connect C1 and P1 to the grounding down conductor, connect the voltage electrode P and the current electrode C to P2 and C2 in the ground resistance tester, and place the voltage electrode P and the current electrode C at the edge of the tower foundation d. GC =4l and d GP At 2.5l, the three-pole method is used to test the ground resistance of any base tower; Among them, d GP Indicates the straight-line distance between the grounding device G and the voltage electrode P; d GC It represents the straight-line distance between the grounding device G and the current electrode C; l represents the maximum length of the radial grounding electrode for the base tower grounding.

5. The method for correcting the results of a clamp meter tower ground resistance test according to claim 4, characterized in that: In step S4, a new set of simultaneous equations is obtained. The specific process is as follows: Let R i =A, the obtained R i =A is substituted into formula (2) to obtain the new simultaneous equations: （3）； Where, It represents the ground resistance of the ith base tower tested by the three-pole method, which is a certain value.

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