Clamp meter method tower grounding resistance test result correction method

Abstract

The invention discloses a clamp meter method tower grounding resistance test result correction method, which comprises the following steps of judging whether base tower grounding resistance meets clamp meter method use conditions, meeting the conditions, using a clamp meter method and not meeting the conditions, testing all base towers one by one by using a three-pole method, and obtaining real grounding resistance of all the base towers. All base tower grounding resistances meeting the conditions are tested through a clamp meter method, all base tower clamp meter method test grounding resistances are obtained, any base tower is tested through a three-pole method, and any base tower three-pole method test grounding resistance is obtained; and obtaining a new simultaneous equation set according to the obtained relation between the grounding resistance tested by the clamp meter method of all the base towers and the grounding resistance tested by any one of the base towers by the three-pole method, and solving the new simultaneous equation set to obtain the grounding resistance of all the base towers. According to the method, all the base tower grounding resistances are obtained by solving the simultaneous equation set, and the base tower grounding resistance testing efficiency 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 a result of a clamp meter method pole tower grounding resistance test. Background Art

[0002] The grounding of the base tower is the most basic lightning protection measure for the transmission line. Good grounding can ensure the smooth discharge of lightning current after the lightning strikes the transmission line; on the other hand, it can limit the overvoltage value generated on the base tower to avoid the flashover tripping of the insulator (string). The grounding resistance will directly affect the lightning resistance level of the base tower. Reducing the grounding resistance is the key to improving the lightning resistance level of the base tower and reducing the lightning tripping rate of the line.

[0003] Due to the large number of base towers and the large workload of grounding resistance testing, the "wheel test" method is currently widely used to test the grounding resistance of base towers. The grounding resistance test of base towers currently mainly includes the "three-pole method" and the "clamp meter method". The "three-pole method" treats the base tower grounding device as equivalent to a hemisphere. By reasonably setting the voltage electrode and the current electrode, the grounding resistance of the grounding device can be accurately measured. However, the disadvantage is that the workload of laying out the wire is large. The voltage electrode is generally required to reach 1.8~2.5 times the grounding ray, and the current electrode is generally required to reach 3~4 times the grounding ray. It is also greatly affected by the detection level of the tester; the "clamp meter method" is also called the "loop resistance method". It tests the grounding resistance of the loop composed of the base tower and other base towers. It is suitable for lines where the ground wire is grounded one by one. The test operation is simple and convenient, and there is no need to lay out the wire, but there is an inherent deviation, which is mainly the resistance increment generated by other base towers in parallel. If this inherent deviation can be quantitatively eliminated, the grounding resistance of the base tower can be obtained simply and conveniently through the "clamp meter method". Summary of the invention

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

[0005] To achieve the above object, the present invention provides the following technical solution: a method for correcting the test result of a tower grounding resistance using a clamp meter method, comprising the following steps: 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: using a three-pole method to test any base tower, and obtaining a three-pole method 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 base 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); In the formula, R (i-1) Represents the ground resistance of the i-1th base tower tested by the three-pole method; R (i+1) Indicates the ground resistance of the i+1th base tower tested by the three-pole method; R n Indicates the three-pole method ground resistance test of the nth 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 by combining them: (2); In the formula, Indicates the three-pole method ground resistance test of the n-1th base tower; Step S4: Substitute the grounding resistance of any base 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.

[0006] Further, in step S1, it is determined whether the grounding resistance of the base tower meets the use conditions of the clamp meter method, and 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, the clamp meter method is used to test the grounding 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 one by one to obtain the actual grounding resistance of all base towers.

[0007] Further, in step S2, the grounding resistance of all base towers is tested by the clamp meter method, and 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, and the remaining grounding down conductors should be disconnected from the tower body of the base tower, and the disconnected grounding wires are connected in parallel with the retained grounding wires with metal wires; a clamp-type grounding resistance tester is used to clamp the retained grounding down conductor, and the internal power supply E of the clamp-type grounding resistance tester excites current I in the loop, and the loop resistance is obtained according to Ohm's law. In the test, the current test resistance is regarded as the base tower test grounding resistance r iAccording 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 ; Among them, E is the power supply voltage; I is the loop current.

[0008] Further, in step S3, the three-pole method grounding resistance test of any base tower is obtained, and the specific process is as follows: The ground resistance tester includes four connection ports, namely C1, P1, C2, and P2. C1 and P1 are connected to the grounding down conductor, the voltage electrode P and the current electrode C are connected to P2 and C2 in the ground resistance tester, and the voltage electrode P and the current electrode C are arranged 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 Represents the straight-line distance between the grounding device G and the voltage pole 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.

[0009] Further, in step S4, a new set of simultaneous equations is obtained, and the specific process is as follows: Assume R i =A, the obtained R i =A is substituted into equation (2) to obtain the new system of simultaneous equations: (3); In the formula, It indicates the grounding resistance of the ith base tower tested by the three-pole method, which is a certain value.

[0010] 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 three-pole method grounding resistance of any base tower 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 group is formed, which can reduce the n-order simultaneous equation group to an n-1-order simultaneous equation group. By solving the simultaneous equation group, the grounding resistance of all base towers can be obtained, which significantly improves the testing efficiency of the grounding resistance of the base tower. (2) The method of the present invention can eliminate the inherent deviation of the grounding resistance test of the base tower by the clamp meter method, obtain the grounding resistance of the base tower 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

[0011] Figure 1 This is the flow diagram of the present invention.

[0012] Figure 2 This is a schematic diagram of the test results of the clamp meter method of the present invention.

[0013] Figure 3 It is a schematic diagram of the test results of the three-pole method of the present invention. DETAILED DESCRIPTION

[0014] The present invention is further described in detail below with reference to implementation cases and accompanying drawings.

[0015] like Figure 1 As shown, a method for correcting the test result of the tower grounding resistance using a clamp meter method comprises the following steps: 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: using a three-pole method to test any base tower, and obtaining a three-pole method test grounding resistance of any base tower; 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 of the base tower tested. i The result of connecting the parallel value of the grounding resistance of any base tower with the three-pole method in series, so the grounding resistance r of the i-th base tower clamp meter test is i The ground resistance R of the i-th base 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); In the formula, R (i-1) Represents the ground resistance of the i-1th base tower tested by the three-pole method; R (i+1) Indicates the ground resistance of the i+1th base tower tested by the three-pole method; R n Indicates the three-pole method ground resistance test of the nth 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 by combining them: (2); In the formula, Indicates the three-pole method ground resistance test of the n-1th base tower; Among them, the clamp meter grounding resistance 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; 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; Step S4: Substitute any grounding resistance obtained by the three-pole method test of the base tower 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.

[0016] Among them, in step S1, it is determined whether the grounding resistance of the base tower meets the conditions for using the clamp meter method, and 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 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 actual grounding resistance of all base towers.

[0017] like Figure 2 As shown, in step S2, the grounding resistance of all base towers is tested by the clamp meter method, and 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, and the remaining grounding down conductors should be disconnected from the tower body of the base tower, and the disconnected grounding wires are connected in parallel with the retained grounding wires with metal wires; a clamp-type grounding resistance tester is used to clamp the retained grounding down conductor, and the internal power supply E of the clamp-type grounding resistance tester excites current I in the loop, and the loop resistance is obtained according to Ohm's law. In the test, the current test resistance is regarded as the base tower test grounding 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; Among them, E is the power supply voltage; I is the loop current.

[0018] like Figure 3 In the above, in step S3, the three-pole method for testing the grounding resistance of any base tower is obtained, and the specific process is as follows: The ground resistance tester includes four connection ports, namely C1, P1, C2, and P2. C1 and P1 are connected to the grounding down conductor, the voltage electrode P and the current electrode C are connected to P2 and C2 in the ground resistance tester, and the voltage electrode P and the current electrode C are arranged 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 ; Among them, d GP Represents the straight-line distance between the grounding device G and the voltage pole 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.

[0019] In step S4, a new set of simultaneous equations is obtained, and the specific process is as follows: Assume R i =A, the obtained R i =A is substituted into equation (2) to obtain the new system of simultaneous equations: (3); In the formula, It indicates the grounding resistance of the ith base tower tested by the three-pole method, which is a certain value.

[0020] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for correcting the test results of a tower grounding resistance using a clamp meter, 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: using a three-pole method to test any base tower, and obtaining a three-pole method 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 base 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); In the formula, R (i-1) Represents the ground resistance of the i-1th base tower tested by the three-pole method; R (i+1) Indicates the ground resistance of the i+1th base tower tested by the three-pole method; R n Indicates the three-pole method ground resistance test of the nth 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 by combining them: （2）； In the formula, Indicates the three-pole method ground resistance test of the n-1th base tower; Step S4: Substitute the grounding resistance of any base 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 test results of the tower grounding resistance using the clamp meter method according to claim 1, characterized in that: 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, the clamp meter method is used to test the grounding 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 one by one to obtain the actual grounding resistance of all base towers.

3. The method for correcting the test result of the tower grounding resistance by the clamp meter method according to claim 2 is characterized in that: In step S2, the grounding resistance of all base towers tested by the clamp meter method is obtained, and 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, and the remaining grounding down conductors should be disconnected from the tower body of the base tower, and the disconnected grounding wires are connected in parallel with the retained grounding wires with metal wires; a clamp-type grounding resistance tester is used to clamp the retained grounding down conductor, and the internal power supply E of the clamp-type grounding resistance tester excites current I in the loop, and the loop resistance is obtained according to Ohm's law. In the test, the current test resistance is regarded as the base tower test grounding 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 ; Among them, E is the power supply voltage; I is the loop current.

4. The method for correcting the test result of the tower grounding resistance by the clamp meter method according to claim 3 is characterized by: In step S3, the three-pole method grounding resistance test of any base tower is obtained, and the specific process is as follows: The ground resistance tester includes four connection ports, namely C1, P1, C2, and P2. C1 and P1 are connected to the grounding down conductor, the voltage electrode P and the current electrode C are connected to P2 and C2 in the ground resistance tester, and the voltage electrode P and the current electrode C are arranged 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 Represents the straight-line distance between the grounding device G and the voltage pole 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 test result of the tower grounding resistance by the clamp meter method according to claim 4 is characterized in that: In step S4, a new set of simultaneous equations is obtained, and the specific process is as follows: Assume R i =A, the obtained R i =A is substituted into equation (2) to obtain the new system of simultaneous equations: （3）； In the formula, It indicates the grounding resistance of the ith base tower tested by the three-pole method, which is a certain value.

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