A method and device for measuring grounding of a multi-down conductor grounded transmission tower without wire removal

Abstract

The invention discloses a method and a device for measuring the grounding of a multi-down conductor grounded transmission tower without wire removal. The method comprises: firstly, selecting a No. 1 down conductor to set a voltage excitation clamp and a current measuring clamp, and setting a current measuring clamp on the other down conductors; measuring and comparing the current response amplitudes in the other down conductor branches, recording the maximum value and the corresponding down conductor branch number k; then, applying a frequency f to the No. 1 down conductor through the voltage excitation clamp l The voltage excitation is adjusted to make the current amplitude and phase of the No. k down conductor branch consistent with the high-frequency state; the branch resistance of each down conductor and the resistance and inductance of the grounding and lightning arrester loop can be calculated. The present invention can measure the resistance of each down conductor branch and the resistance and inductance of the grounding and lightning arrester loop without removing the wires. If there is a connection problem in the down conductor or grounding body of the transmission tower, it can also be located, which is of great significance for further improving the grounding reliability and ensuring the safety of power transmission.

Description

Technical Field

[0001] The invention relates to the technical field of grounding measurement of power transmission towers, and in particular to a wire-removal-free grounding measurement method and a measuring device for a multi-downlead grounding power transmission tower. Background Art

[0002] With the continuous increase in the voltage level of my country's power transmission lines, the grounding safety performance of transmission towers has received more and more attention. The measurement and maintenance of the grounding status of transmission towers is an important part of the inspection of transmission lines. In recent years, in order to further improve the grounding reliability of transmission towers, most towers have adopted the form of multiple down conductors, that is, multiple points of the towers are connected to the pre-buried underground grounding electrode or grounding network through down conductors. The form of multiple down conductors provides grounding redundancy. At this time, even if some down conductor branches have poor connections, the tower can be guaranteed to be well grounded through the remaining down conductor branches.

[0003] When performing maintenance and inspection on transmission towers, it is necessary to confirm the connection status of all down conductor branches. However, there are few methods for measuring the connection resistance of down conductor branches on transmission towers without removing the wire. Traditional three-pole method, four-pole method and clamp meter method are all grounding resistance measurement methods for transmission towers. Among them, the three-pole method requires additional current and voltage electrodes for auxiliary measurement, and the connection between the down conductor and the tower needs to be untied during the measurement process, and it is impossible to ensure whether the connection status of the down conductor after the connection is restored is reliable. The four-pole method increases the number of auxiliary electrodes on the basis of the three-pole method, which can improve the detection accuracy, but has the same disadvantages as the three-pole method. The clamp meter method has been widely promoted in recent years due to its simple and efficient operation, and this method does not need to untie the down conductor when measuring the transmission tower with a single grounding down conductor. However, the clamp meter method measures the equivalent resistance of the loop. In the face of the redundant grounding loop of the tower with multiple grounding down conductors, this method is difficult to judge the grounding status.

[0004] The invention patent with the publication number CN111141960A discloses a tower grounding resistance test method based on the single-pole method. The present invention only needs to arrange an auxiliary grounding electrode, which can adapt to the tower grounding resistance test requirements in various situations. Compared with the three-pole method, it eliminates the need to arrange a voltage electrode. Compared with the clamp meter method and the loop impedance method, it avoids the test errors caused by poor contact between the tower and the overhead ground wire and a small number of adjacent lightning conductors directly grounded through the tower. At the same time, it can measure the resistance formed by the tower to be tested through the overhead ground wire and other tower grounding devices in the line to the earth, so as to evaluate whether the connection between the tower and the overhead ground wire is good. However, this application mainly faces single-grounding occasions. For towers with multiple down conductors, other down conductors need to be untied, which is cumbersome to operate, and the repeated removal and restoration of down conductors increases the possibility of grounding errors.

[0005] The invention patent with publication number CN115932400A discloses an online monitoring device and method for the grounding resistance of a transmission line tower, the device comprising: an excitation coil, a measuring coil, a photovoltaic panel and a control unit; the excitation coil, the measuring coil and the photovoltaic panel are connected to the control unit through a cable; the excitation coil and the measuring coil are arranged on the lightning conductor; the control unit converts the DC voltage generated by the photovoltaic panel into a hetero-frequency AC voltage based on the received test instruction and transmits the converted voltage to the excitation coil, so that a voltage signal is generated in the grounding loop of the lightning conductor and the measured tower; the measuring coil obtains the current signal generated in the grounding loop; the control unit obtains the voltage value of the voltage signal and the current value of the current signal, and calculates the equivalent grounding impedance of the measured tower through the voltage value and the current value; however, the application is provided with an excitation coil and a measuring coil on each lightning conductor, which is costly and difficult to be applied in practice, and the corresponding measuring device of the application needs to be arranged on the high-altitude lightning conductor, which has poor reliability and maintainability. Summary of the invention

[0006] Purpose of the invention: In order to overcome the shortcomings of the prior art, the present invention provides a wire-free grounding measurement method for a multi-down conductor grounded transmission tower. The method is used to solve the grounding status detection problem of a transmission tower with multiple down conductors grounded. The method can accurately obtain the connection resistance of each down conductor branch, as well as the resistance and inductance of the grounding and lightning protection line loops, and provide sufficient and reliable information for the operation, maintenance and inspection of the transmission tower. It is of great significance to further improve the grounding reliability and ensure the safety of power transmission. The present invention also provides a wire-free grounding measurement device for a multi-down conductor grounded transmission tower.

[0007] Technical solution: According to a first aspect of the present invention, a method for measuring grounding without removing wires of a multi-down conductor grounded transmission tower is provided, comprising the following steps:

[0008] S1 For a tower with N down conductors, the down conductors are arranged in order of 1, 2...N, and a voltage excitation clamp and a current measuring clamp are arranged on the No. 1 down conductor branch of the transmission tower, and a current measuring clamp is arranged on the remaining down conductor branches; the voltage excitation clamp is used to apply voltage excitation to the down conductor connected thereto, and the current measuring clamp is used to measure the current of each down conductor connected thereto;

[0009] S2 applies a voltage excitation clamp with an amplitude of U to the No. 1 down conductor. h , the initial phase is 0 and the frequency is f h The high frequency voltage excitation u h ; Measure the current i of each down conductor branch through the current measuring clamp 1h ,i 2h ,i 3h …i Nh, and use the frequency tracking algorithm to extract the frequency f in each down conductor branch channel h The current component amplitude I 1h , I 2h , I 3h …I Nh ; Record high frequency voltage excitation u h The amplitude U h , the remaining down conductor branch current I 2h , I 3h …I Nh Maximum I kh , and the corresponding branch number k, and then turn off the voltage excitation, where 2≤k≤N;

[0010] S3 adjusts the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh equal and the phase is 0; record the current amplitude I of No. 1 down conductor after the current regulation is completed 1l and phase θ 1il 、No. 1 down conductor loading voltage u l The amplitude U l and phase θ 1ul , and the frequency of the other down conductor branches is f l Current component amplitude I 2l ,…I (k-1)l , I (k+1)l …I Nl , and then turn off the voltage excitation;

[0011] S4 calculates the branch resistance R1, R2, ... R of each down conductor branch according to the recorded data N , and the total resistance R of the grounding and lightning conductor loop z and inductance value L z .

[0012] Further, including:

[0013] In step S2, a voltage excitation clamp is applied to the No. 1 down conductor with an amplitude of U h , the initial phase is 0 and the frequency is f h The high frequency voltage excitation u h , high frequency voltage excitation u h The frequency is higher than the power frequency 50Hz and avoids the frequency band of background noise. The high-frequency voltage excitation u h It is expressed as:

[0014] u h =U h cos(2πf ht) (1)

[0015] Here, t represents time.

[0016] Further, including:

[0017] In step S3, the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor is adjusted. l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh equal and the phase is 0, where the frequency f l A frequency band below 50Hz that avoids background noise.

[0018] Further, including:

[0019] In step S3, the frequency of the k-th down conductor is set to f l The current component amplitude I kl Adjust to I kh The frequency tracking algorithm and PI controller are combined to realize I kl Adjust to I kh are equal and have a phase of 0.

[0020] Further, including:

[0021] In step S4, the branch resistances R1, R2, ... R of each down conductor branch are calculated according to the recorded data. N , where the calculation method of the branch resistance R1 of the No. 1 down conductor branch is:

[0022]

[0023] Further, including:

[0024] In step S4, the branch resistances R1, R2, ... R of each down conductor branch are calculated according to the recorded data. N , where the branch resistance R2, ...R N The calculation method is:

[0025]

[0026] Further, including:

[0027] In step S4, the total resistance R of the grounding and lightning protection line loop is calculated based on the recorded data. z and inductance value L z The calculation method is:

[0028]

[0029] Izq =I 1l sinθ 1il (5)

[0030] Among them, I zd and I zq Represent the cosine and sine components of the ground and lightning conductor loop current responses, respectively;

[0031]

[0032] Among them, I z and θ z represent the amplitude and phase of the grounding and lightning conductor loop current responses respectively; therefore,

[0033]

[0034] On the other hand, the present invention also provides a wire-removal-free grounding measurement device for a multi-down conductor grounded transmission tower, the device comprising: a controller, a voltage excitation clamp, and multiple current measuring clamps, the voltage excitation clamp being arranged on No. 1 down conductor branch of the transmission tower, and the current measuring clamp being arranged on each down conductor branch of the transmission tower, the controller being used to control and adjust the relevant values ​​of the voltage excitation clamp and the current measuring clamp, and calculate the branch resistance of each down conductor branch, as well as the total resistance and inductance of the grounding and lightning protection line loops.

[0035] Further, including:

[0036] The controller includes an extraction module for extracting the frequency f in each down conductor branch channel by using a frequency tracking algorithm. h The current component amplitude I 1h , I 2h , I 3h …I Nh , and record the high frequency voltage excitation u h The amplitude U h , each down conductor branch current I 2h , I 3h …I Nh Maximum I kh , and the corresponding branch number k, and then turn off the voltage excitation;

[0037] The adjustment module is used to adjust the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor. l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh equal and the phase is 0, and record the current amplitude I of No. 1 down conductor after the current regulation is completed 1l and phase θ 1il 、No. 1 down conductor loading voltage ul The amplitude U l and phase θ 1ul , and the frequency of the other down conductor branches is f l Current component amplitude I 2l ,…I (k-1)l , I (k+1)l …I Nl , and then turn off the voltage excitation;

[0038] The calculation module is used to calculate the branch resistance R1, R2, ... R of each down conductor branch according to the data recorded in the extraction module and the adjustment module. N , and the total resistance R of the grounding and lightning conductor loop z and inductance value L z .

[0039] Further, including:

[0040] In the calculation module, the total resistance R of the grounding and lightning protection line loop is calculated based on the recorded data. z and inductance value L z The calculation method is:

[0041]

[0042] I zq =I 1l sinθ 1il (5)

[0043] Among them, I zd and I zq Represent the cosine and sine components of the ground and lightning conductor loop current responses, respectively;

[0044]

[0045] Among them, I z and θ z represent the amplitude and phase of the grounding and lightning conductor loop current responses respectively; therefore,

[0046]

[0047] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0048] (1) The present invention only needs one voltage excitation clamp and multiple current measuring clamps, uses fewer instruments, has low cost, is easy to apply in practice, and can accurately obtain the connection resistance of each down conductor branch and the resistance and inductance of the grounding and lightning protection line loops through simple calculations, providing sufficient and reliable information for the operation and maintenance of transmission towers. The measurement method is highly efficient and accurate.

[0049] (2) The present invention provides a method for measuring the grounding of a multi-down conductor grounded transmission tower without removing the wires. The method can be implemented on the basis of the traditional clamp meter method through certain modifications. The branch resistance of each down conductor and the resistance and inductance of the grounding and lightning conductor loops can be measured without removing the grounding down conductors. This is helpful for maintenance personnel to fully grasp the grounding information of the transmission tower. For example, if there is a problem with the connection between the grounding down conductor or the grounding body and the lightning conductor on the transmission tower, it can also be located. This is of great significance for further improving grounding reliability and ensuring power transmission safety.

[0050] (3) The present application is a portable measuring device that can be carried by maintenance personnel to measure each tower one by one, and has strong feasibility and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a front view schematic diagram of a transmission tower with four down conductors according to an embodiment of the present invention;

[0052] Figure 2 is a schematic top view of a transmission tower with four down conductors according to an embodiment of the present invention;

[0053] Figure 3 It is a schematic diagram of a voltage excitation clamp and a current measurement clamp connected to four down conductors of a transmission tower according to an embodiment of the present invention;

[0054] Figure 4 is an equivalent circuit diagram of a transmission tower according to an embodiment of the present invention;

[0055] Figure 5 is an equivalent circuit diagram of a transmission tower in a high frequency state according to an embodiment of the present invention;

[0056] Figure 6 is a voltage regulation control block diagram according to an embodiment of the present invention;

[0057] Figure 7 It is the phasor diagram of the No. 1 down conductor branch according to the embodiment of the present invention;

[0058] Figure 8 The present invention discloses a flow chart of grounding measurement without wire removal for a multi-downlead grounded transmission tower according to an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] like Figure 8 As shown, the present invention first provides a method for measuring grounding without removing wires of a multi-down-lead grounded transmission tower. Specifically, the method comprises the following steps:

[0061] S1 For a tower with N down conductors, the down conductors are arranged in order of 1, 2...N, and a voltage excitation clamp and a current measuring clamp are set on the No. 1 down conductor branch of the transmission tower, and a current measuring clamp is set on the remaining down conductor branches.

[0062] Therefore, the present application only needs to set up one voltage excitation clamp and one current measuring clamp on the No. 1 down conductor branch of the transmission tower, and one current measuring clamp on the remaining down conductor branches, without setting up a voltage excitation clamp.

[0063] S2 applies a voltage excitation clamp with an amplitude of U to the No. 1 down conductor. h , the initial phase is 0 and the frequency is f h The high frequency voltage excitation u h ; Measure the current i of each down conductor branch through the current measuring clamp 1h ,i 2h ,i 3h …i Nh , and use the frequency tracking algorithm to extract the frequency f in each down conductor branch channel h The current component amplitude I 1h , I 2h , I 3h …I Nh ; Record high frequency voltage excitation u h The amplitude U h , the remaining down conductor branch current I 2h , I 3h …I Nh Maximum I kh , and the corresponding branch number k, and then turn off the voltage excitation, where 2≤k≤N.

[0064] In step S2, a voltage excitation clamp is applied to the No. 1 down conductor with an amplitude of U h , the initial phase is 0 and the frequency is f h The high frequency voltage excitation u h The frequency should be much higher than the power frequency of 50Hz and should avoid the frequency band of background noise. It is recommended to set it to 2kHz. At this time, the high-frequency voltage excitation u h It can be expressed as:

[0065] u h =U h cos(2πf h t) (1)

[0066] Here, t represents time.

[0067] S3 adjusts the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh equal and the phase is 0; record the current amplitude I of No. 1 down conductor after the current regulation is completed 1l and phase θ 1il 、No. 1 down conductor loading voltage u l The amplitude U l and phase θ 1ul , and the frequency of the other down conductor branches is f l Current component amplitude I 2l ,…I (k-1)l , I (k+1)l …I Nl , and then turn off the voltage excitation.

[0068] In step S3, the frequency tracking algorithm is used to extract the frequency f in the k-th down conductor. l The current component amplitude is adjusted to adjust the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor. l , the frequency in the down conductor is f l The current component amplitude I kl Adjust to I kh are equal and have a phase of 0, where the frequency f l The frequency is low and should avoid the frequency band of background noise. It is recommended to set it to 20Hz.

[0069] And in step S3, the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor is adjusted l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh The current of the k-th down conductor branch can be controlled by combining the frequency tracking algorithm with the PI controller.

[0070] S4 calculates the branch resistance R1, R2, ... R of each down conductor branch according to the recorded data N , and the total resistance R of the grounding and lightning conductor loop z and inductance value L z .

[0071] In step S4, the branch resistances R1, R2, ... R of each down conductor branch are calculated based on the recorded data. N , where the calculation method of the branch resistance R1 of the No. 1 down conductor branch is:

[0072]

[0073] In step S4, the branch resistances R1, R2, ... R of each down conductor branch are calculated according to the recorded data. N , where branch resistance R2,…R N The calculation method is:

[0074]

[0075] In step S4, the total resistance R of the grounding and lightning protection line loop is calculated according to the recorded data. z and inductance value L z The calculation method is:

[0076]

[0077] I zq =I 1l sinθ 1il (5)

[0078] Among them, I zd and I zq Represent the cosine and sine components of the ground and lightning conductor loop current responses respectively.

[0079]

[0080] Among them, I z and θ z Represent the amplitude and phase of the grounding and lightning conductor loop current response respectively.

[0081]

[0082] The present invention is described below by taking the grounding resistance measurement of a transmission tower with four down conductors as an example, and the situations of other multiple down conductors are similar:

[0083] Figure 1 A schematic diagram of a transmission tower with four down conductors is given. Figure 2 A top view of a transmission tower with four down conductors is given. Figure 3 The schematic diagram of the voltage excitation clamp and current measurement clamp connected to the four down conductors of the transmission tower is shown in the figure. The equivalent circuit diagram of the transmission tower is shown in the figure Figure 4 As shown in the figure, R1, R2, R3 and R4 are the resistances of the 1st, 2nd, 3rd and 4th down conductor branches respectively. z and L z They are the total resistance and inductance of the grounding and lightning protection wire loops respectively.

[0084] First, a voltage excitation clamp with an amplitude of U is applied to the No. 1 down conductor. h , the initial phase is 0 and the frequency is f h The high frequency voltage excitation u h ,for:

[0085] u h =U h cos(2πf h t) (11)

[0086] Due to the high frequency, the inductive reactance of the grounding and lightning conductor loop is much larger than the branch resistance of each down conductor. At this time, it can be considered that the grounding and lightning conductor loops are disconnected. Figure 4 In high frequency state, it can be equivalent to Figure 5 .from Figure 5 It can be seen that at this time the circuit is in a state where R2, R3 and R4 are connected in parallel and in series with R1. h The initial phase is 0. At this time, the initial phase of the current response of each down conductor branch is also 0. The current of each down conductor branch can be expressed as:

[0087] i mh =I mh cos(2πf h t), m=1…4 (12)

[0088] Without loss of generality, assume that the current response amplitude of branch 2 in each down conductor branch is I 2h Maximum, at this time k = 2. The high-frequency voltage across the resistance of the No. 2 down conductor branch can be expressed as:

[0089] u 2h =U 2h cos(2πf h t)=I 2h R2 cos(2πf h t) (13)

[0090] Next, adjust the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor. l , the frequency of the No. 2 lead is f l The current component amplitude I 2l Adjust to I 2h The current of the No. 2 down conductor branch can be controlled by combining the frequency tracking algorithm with the PI controller, such as Figure 6 shown.

[0091] The frequency tracking algorithm used is specifically expressed as:

[0092]

[0093] Wherein, i2 is the ground current of the No. 2 down conductor branch obtained by the current measuring clamp, and LP represents the low-pass filter.

[0094] The applied voltage u l The calculation method is:

[0095] u l =U h cos(π2f l +tθ1 u l ) (16)

[0096] After the current regulation is completed, there is

[0097] i 2l =I 2l cos(2πf f t) (17)

[0098] Obviously, the voltage across the resistor of the No. 2 down conductor branch is

[0099] u 2l =U 2l cos(2πf f t)=I 2l R2cos(2πf f t)=U 2h cos(2πf f t) (18)

[0100] It can be seen from formula (15) that after the current regulation is completed, the voltage amplitude and phase across the No. 2 down conductor branch resistor are consistent with formula (13), only the frequency is different. Figure 7 The No. 1 down conductor branch is given at f h and f l The phasor diagram under frequency excitation, since the current phase of No. 1 down conductor is θ 1il 、No. 1 down conductor loading voltage u l The phase is θ 1ul , at this time there is

[0101] U h -I 1h R1=U l cosθ 1ul -I 1l R1 cosθ 1il (19)

[0102] According to formula (16), the branch resistance R1 of the No. 1 down conductor branch can be solved as follows:

[0103]

[0104] Furthermore, after calculating R1, combined with Figure 5 The branch resistance R2, ...R4 can be solved as

[0105]

[0106] Finally, the total resistance R of the grounding and lightning protection line loop z and inductance value L z The current data for solving the problem is obtained in step S3. According to Kirchhoff's law of current, it is obvious that the grounding and lightning conductor loop current i z satisfy

[0107] i z =i 1l -(i 2l +i 3l +i 4l ) (twenty two)

[0108] i 1l 、i 2l and i 3l The phase is the same and both phases are 0. Combining formula (19) can solve the grounding and lightning protection line loop current response i z The cosine and sine components of

[0109]

[0110] I zq =I 1l sinθ 1il (twenty four)

[0111] Furthermore, the current response i z The amplitude and phase of

[0112]

[0113] By combining equations (16), (22) and (23), we can calculate the total resistance R of the grounding and lightning protection line loop: z and inductance value L z

[0114]

[0115] The present invention provides a method for measuring the grounding of a multi-down conductor grounded transmission tower without removing the wires. The method can be implemented through certain modifications on the basis of a traditional clamp meter method. The branch resistance of each down conductor and the loop resistance and inductance of the grounding and lightning conductor can be measured without removing the grounding down conductor. This is beneficial for maintenance personnel to fully grasp the grounding information of the transmission tower. For example, if there is a connection problem between the grounding down conductor or the grounding body and the lightning conductor on the transmission tower, it can also be located. This is of great significance for further improving grounding reliability and ensuring power transmission safety.

[0116] On the other hand, the present invention also provides a wire-removal-free grounding measurement device for a multi-down conductor grounded transmission tower, the device comprising: a controller, a voltage excitation clamp, and multiple current measuring clamps, the voltage excitation clamp being arranged on No. 1 down conductor branch of the transmission tower, and the current measuring clamp being arranged on each down conductor branch of the transmission tower, the controller being used to control and adjust the relevant values ​​of the voltage excitation clamp and the current measuring clamp, and calculate the branch resistance of each down conductor branch, as well as the total resistance and inductance of the grounding and lightning protection line loops.

[0117] Further, including:

[0118] The controller includes an extraction module for extracting the frequency f in each down conductor branch channel by using a frequency tracking algorithm. h The current component amplitude I 1h , I 2h , I 3h …I Nh , and record the high frequency voltage excitation u h The amplitude U h , each down conductor branch current I 2h , I 3h …I Nh Maximum I kh , and the corresponding branch number k, and then turn off the voltage excitation;

[0119] The adjustment module is used to adjust the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor. l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh equal and the phase is 0, and record the current amplitude I of No. 1 down conductor after the current regulation is completed 1l and phase θ 1il 、No. 1 down conductor loading voltage u l The amplitude U l and phase θ 1ul , and the frequency of the other down conductor branches is f l Current component amplitude I 2l ,…I (k-1)l , I (k+1)l …I Nl , then turn off the voltage excitation;

[0120] The calculation module is used to calculate the branch resistance R1, R2, ... R of each down conductor branch according to the data recorded in the extraction module and the adjustment module. N , and the total resistance R of the grounding and lightning conductor loop z and inductance value L z .

[0121] Further, including:

[0122] In the calculation module, the total resistance R of the grounding and lightning protection line loop is calculated based on the recorded data. z and inductance value L z The calculation method is:

[0123]

[0124] I zq =I 1l sinθ 1il (5)

[0125] Among them, I zd and I zq Represent the cosine and sine components of the ground and lightning conductor loop current responses, respectively;

[0126]

[0127] Among them, I z and θ z represent the amplitude and phase of the grounding and lightning conductor loop current responses respectively; therefore,

[0128]

[0129] Other technical features of the wire-free grounding measurement device for a multi-down-conductor grounded transmission tower described in the present invention are similar to the wire-free grounding measurement method for a corresponding multi-down-conductor grounded transmission tower, and will not be repeated here.

[0130] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0131] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0132] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for measuring grounding without removing wires of a multi-down conductor grounded transmission tower, characterized in that: The method comprises the following steps: S1 For a tower with N down conductors, the down conductors are arranged in order of 1, 2...N, and a voltage excitation clamp and a current measuring clamp are arranged on the No. 1 down conductor branch of the transmission tower, and a current measuring clamp is arranged on the remaining down conductor branches; the voltage excitation clamp is used to apply voltage excitation to the down conductor connected thereto, and the current measuring clamp is used to measure the current of each down conductor connected thereto; S2 applies a voltage excitation clamp with an amplitude of U to the No. 1 down conductor. h , the initial phase is 0 and the frequency is f h The high frequency voltage excitation u h ; Measure the current i of each down conductor branch through the current measuring clamp 1h ,i 2h ,i 3h …i Nh , and use the frequency tracking algorithm to extract the frequency f in each down conductor branch channel h The current component amplitude I 1h , I 2h , I 3h …I Nh ; Record high frequency voltage excitation u h The amplitude U h , the remaining down conductor branch current I 2h , I 3h …I Nh Maximum I kh , and the corresponding branch number k, and then turn off the voltage excitation, where 2≤k≤N; S3 adjusts the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh equal and the phase is 0; record the current amplitude I of No. 1 down conductor after the current regulation is completed 1l and phase θ 1il 、No. 1 down conductor loading voltage u l The amplitude U l and phase θ 1ul , and the frequency of the other down conductor branches is f l Current component amplitude I 2l ,…I (k-1)l , I (k+1)l …I Nl , and then turn off the voltage excitation; S4 calculates the branch resistance R1, R2, ... R of each down conductor branch according to the recorded data N , and the total resistance R of the grounding and lightning conductor loop z and inductance value L z .

2. The method for measuring grounding without wire removal of a multi-downlead grounded transmission tower according to claim 1, characterized in that: In step S2, a voltage excitation clamp is applied to the No. 1 down conductor with an amplitude of U h , the initial phase is 0 and the frequency is f h The high frequency voltage excitation u h , high frequency voltage excitation u h The frequency is higher than the power frequency 50Hz and avoids the frequency band of background noise. The high-frequency voltage excitation u h It is expressed as: u h =U h cos(2πf h t) (1) Here, t represents time.

3. The method for measuring grounding without wire removal of a multi-downlead grounded transmission tower according to claim 1, characterized in that: In step S3, the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor is adjusted. l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh equal and the phase is 0, where the frequency f l A frequency band below 50Hz that avoids background noise.

4. The method for measuring grounding without wire removal of a multi-downlead grounded transmission tower according to claim 1, characterized in that: In step S3, the frequency of the k-th down conductor is set to f l The current component amplitude I kl Adjust to I kh The frequency tracking algorithm and PI controller are combined to realize I kl Adjust to I kh are equal and have a phase of 0.

5. The method for measuring grounding without wire removal of a multi-downlead grounded transmission tower according to claim 1, characterized in that: In step S4, the branch resistances R1, R2, ... R of each down conductor branch are calculated according to the recorded data. N , where the calculation method of the branch resistance R1 of the No. 1 down conductor branch is:

6. The method for measuring grounding without wire removal of a multi-downlead grounded transmission tower according to claim 5, characterized in that: In step S4, the branch resistances R1, R2, ... R of each down conductor branch are calculated according to the recorded data. N , where the branch resistance R2, ...R N The calculation method is:

7. The method for measuring grounding without wire removal of a multi-downlead grounded transmission tower according to claim 6, characterized in that: In step S4, the total resistance R of the grounding and lightning protection line loop is calculated based on the recorded data. z and inductance value L z The calculation method is: I zq =I 1l sinθ 1il (5) Among them, I zd and I zq Represent the cosine and sine components of the ground and lightning conductor loop current responses, respectively; Among them, I z and θ z represent the amplitude and phase of the grounding and lightning conductor loop current responses respectively; therefore, 8. A measuring device corresponding to the method for measuring grounding without wire removal of a multi-down conductor grounded transmission tower according to any one of claims 1 to 7, characterized in that: The device comprises: a controller, a voltage excitation clamp, and a plurality of current measuring clamps. The voltage excitation clamp is arranged on a No. 1 down conductor branch of a transmission tower, and the current measuring clamp is arranged on each down conductor branch of the transmission tower. The controller is used to control and adjust the relevant values ​​of the voltage excitation clamp and the current measuring clamp, and calculate the branch resistance of each down conductor branch, as well as the total resistance and inductance of the grounding and lightning protection line loops.

9. The non-removal wire grounding measurement device for a multi-downlead grounded transmission tower according to claim 8, characterized in that: The controller includes an extraction module for extracting the frequency f in each down conductor branch channel by using a frequency tracking algorithm. h The current component amplitude I 1h , I 2h , I 3h …I Nh , and record the high frequency voltage excitation u h The amplitude U h , each down conductor branch current I 2h , I 3h …I Nh Maximum I kh , and the corresponding branch number k, and then turn off the voltage excitation; The adjustment module is used to adjust the loading voltage u of the voltage excitation clamp installed on the No. 1 down conductor. l , the frequency of the k-th lead wire is f l The current component amplitude I kl Adjust to I kh equal and the phase is 0, and record the current amplitude I of No. 1 down conductor after the current regulation is completed 1l and phase θ 1il 、No. 1 down conductor loading voltage u l The amplitude U l and phase θ 1ul , and the frequency of the other down conductor branches is f l Current component amplitude I 2l ,…I (k-1)l , I (k+1)l …I Nl , and then turn off the voltage excitation; The calculation module is used to calculate the branch resistance R1, R2, ... R of each down conductor branch according to the data recorded in the extraction module and the adjustment module. N , and the total resistance R of the grounding and lightning conductor loop z and inductance value L z .

10. The non-removal grounding measurement device for a multi-downlead grounded transmission tower according to claim 9, characterized in that: In the calculation module, the total resistance R of the grounding and lightning protection line loop is calculated based on the recorded data. z and inductance value L z The calculation method is: I zq =I 1l sinθ 1il (5) Among them, I zd and I zq Represent the cosine and sine components of the ground and lightning conductor loop current responses, respectively; Among them, I z and θ z represent the amplitude and phase of the grounding and lightning conductor loop current responses respectively; therefore,

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