A method and system for measuring grounding resistance of a power transmission line tower

Abstract

The application discloses a kind of transmission line tower grounding resistance measurement method and system, it is related to high-voltage transmission technical field, the measurement method includes the following steps: first electric signal is sent to coupling injection module, makes coupling injection module to the two lightning arresters of transmission line tower Synchronous injection same second electric signal;Two lightning arresters are collected at the voltage signal and current signal of second electric signal injection place;According to the voltage signal and current signal of collection transmission line tower grounding resistance is calculated.The application is injected into the same second electric signal by coupling injection module to two lightning arresters Synchronous, greatly weaken the circulation between two lightning arresters, so that the ground current component can be better extracted, ground resistance value can be quickly and accurately obtained, improve measurement efficiency, and reduce the error caused by human operation, this kind of measurement mode does not need to insert auxiliary grounding electrode and lay long distance lead, it is convenient to operate, and the scope of application is wide.

Description

Technical Field

[0001] This invention relates to the field of high-voltage power transmission technology, specifically to a method and system for measuring the grounding resistance of power transmission line towers. Background Technology

[0002] As crucial supports and lightning protection facilities for high-voltage transmission lines, the grounding system of transmission towers directly affects the operational safety and lightning protection performance of the transmission lines. Excessive tower grounding resistance prevents lightning current from effectively dissipating into the ground, easily leading to insulator flashover, line tripping, and even equipment damage, posing a serious threat to the safe and stable operation of the power grid. Therefore, accurately and promptly monitoring the state of tower grounding resistance is a vital aspect of transmission line operation and maintenance.

[0003] Currently, the detection of tower grounding resistance mainly employs offline measurement methods such as the "three-electrode method." This method requires two auxiliary grounding electrodes to be installed along a straight line outside the grounding electrode being tested. By injecting a known current and measuring the potential difference, the resistance value can be calculated, yielding relatively accurate results.

[0004] However, this method has significant limitations in the application of transmission towers. During measurement, two auxiliary grounding electrodes need to be inserted and long lead wires need to be laid. The operation is cumbersome and labor-intensive. In some sites, the electrodes cannot be installed due to terrain and soil conditions. The method is inefficient and poses safety hazards. Summary of the Invention

[0005] This invention provides a method and system for measuring the grounding resistance of transmission line towers. It can solve the problems of existing technology, which requires the insertion of two auxiliary grounding electrodes and the laying of long-distance leads, which is cumbersome, labor-intensive, and inefficient due to terrain and soil conditions in some sites. It also poses safety hazards.

[0006] In a first aspect, embodiments of the present invention provide a method for measuring the grounding resistance of transmission line towers, comprising the following steps:

[0007] Send a first electrical signal to the coupling injection module, so that the coupling injection module synchronously injects the same second electrical signal into the two lightning protection wires of the transmission line tower;

[0008] The voltage and current signals injected into the second electrical signal point by the two lightning protection wires were collected;

[0009] The grounding resistance of the transmission line towers is calculated based on the collected voltage and current signals.

[0010] In conjunction with the first aspect, in one implementation, the calculation of the grounding resistance of the transmission line tower based on the collected voltage and current signals includes the following steps:

[0011] The forward current and reflected current are calculated based on the collected voltage and current signals;

[0012] Calculate the frequency domain reflection coefficient based on the forward current and the reflected current.

[0013] Calculate the grounding resistance of transmission line towers based on the frequency domain reflection coefficient.

[0014] In conjunction with the first aspect, in one implementation, the calculation of the forward current and reflected current based on the acquired voltage and current signals includes the following steps:

[0015] Calculate the forward current and reflected current using the following formulas:

[0016] ;

[0017] ;

[0018] ;

[0019] in, This represents the combined impedance of the two lightning protection wires and the transmission line tower.

[0020] , These represent the voltage and current signals collected at the points where the second electrical signal is injected into the two lightning protection wires, respectively.

[0021] and These represent the forward voltage and the reflected voltage, respectively.

[0022] and This represents the forward current and the reflected current.

[0023] In conjunction with the first aspect, in one embodiment, calculating the frequency domain reflection coefficient based on the forward current and the reflected current includes the following steps:

[0024] Calculate the frequency domain reflection coefficient using the following formula:

[0025] ;

[0026] ;

[0027] in, Represents the frequency domain reflection coefficient. Indicates the length of the lightning protection wire. Indicates wave speed. Indicates the propagation delay time. Indicates forward current delay alignment of the current. Frequency domain compensation term.

[0028] In conjunction with the first aspect, in one embodiment, the calculation of the transmission line tower grounding resistance based on the frequency domain reflection coefficient includes the following steps:

[0029] Calculate the grounding resistance of transmission line towers using the following formula:

[0030] ;

[0031] , ;

[0032] ;

[0033] in, This represents the equivalent grounding impedance of the transmission line tower. This indicates the low-frequency component of the grounding resistance of transmission line towers. , , This indicates the final grounding resistance of the transmission line tower.

[0034] Secondly, embodiments of the present invention provide a system for measuring the grounding resistance of transmission line towers, comprising:

[0035] The coupling injection module is connected to the two lightning protection wires of the transmission line tower;

[0036] The control module, which is connected to the two lightning protection wires and the coupling injection module of the transmission line tower, is configured as follows:

[0037] Send a first electrical signal to the coupling injection module, so that the coupling injection module synchronously injects the same second electrical signal into the two lightning protection wires of the transmission line tower;

[0038] The voltage and current signals injected into the second electrical signal point by the two lightning protection wires were collected;

[0039] The grounding resistance of the transmission line towers is calculated based on the collected voltage and current signals.

[0040] In conjunction with the second aspect, in one implementation, the calculation of the grounding resistance of the transmission line tower based on the collected voltage and current signals includes:

[0041] The forward current and reflected current are calculated based on the collected voltage and current signals;

[0042] Calculate the frequency domain reflection coefficient based on the forward current and the reflected current.

[0043] Calculate the grounding resistance of transmission line towers based on the frequency domain reflection coefficient.

[0044] In conjunction with the second aspect, in one implementation, the step of calculating the forward current and reflected current based on the acquired voltage and current signals includes:

[0045] Calculate the forward current and reflected current using the following formulas:

[0046] ;

[0047] ;

[0048] ;

[0049] in, This represents the combined impedance of the two lightning protection wires and the transmission line tower.

[0050] , These represent the voltage and current signals collected at the points where the second electrical signal is injected into the two lightning protection wires, respectively.

[0051] and These represent the forward voltage and the reflected voltage, respectively.

[0052] and This represents the forward current and the reflected current.

[0053] In conjunction with the second aspect, in one embodiment, calculating the frequency domain reflection coefficient based on the forward current and the reflected current includes:

[0054] Calculate the frequency domain reflection coefficient using the following formula:

[0055] ;

[0056] ;

[0057] in, Represents the frequency domain reflection coefficient. Indicates the length of the lightning protection wire. Indicates wave speed. Indicates the propagation delay time. Indicates forward current delay alignment of the current. Frequency domain compensation term.

[0058] In conjunction with the second aspect, in one embodiment, the calculation of the transmission line tower grounding resistance based on the frequency domain reflection coefficient includes:

[0059] Calculate the grounding resistance of transmission line towers using the following formula:

[0060] ;

[0061] , ;

[0062] ;

[0063] in, This represents the equivalent grounding impedance of the transmission line tower. This indicates the low-frequency component of the grounding resistance. , , This indicates the final grounding resistance of the transmission line tower.

[0064] The beneficial effects of the technical solutions provided by the embodiments of the present invention include:

[0065] This invention discloses a method and system for measuring the grounding resistance of transmission line towers. The measurement method includes the following steps: sending a first electrical signal to a coupling injection module, causing the coupling injection module to simultaneously inject the same second electrical signal into two lightning protection wires of the transmission line tower; collecting voltage and current signals at the injection points of the second electrical signal on the two lightning protection wires; and calculating the grounding resistance of the transmission line tower based on the collected voltage and current signals. This invention significantly reduces the circulating current between the two lightning protection wires by simultaneously injecting the same second electrical signal into them through the coupling injection module, thereby better extracting the ground current component. This allows for rapid and accurate acquisition of the grounding resistance value, improving measurement efficiency and reducing errors caused by human operation. This measurement method eliminates the need for auxiliary grounding electrodes and long-distance lead wires, making it convenient to operate and widely applicable. Attached Figure Description

[0066] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0067] Figure 1 This is a first flowchart of the method for measuring the grounding resistance of transmission line towers according to an embodiment of the present invention;

[0068] Figure 2 This is a second flowchart of the method for measuring the grounding resistance of transmission line towers according to an embodiment of the present invention;

[0069] Figure 3 This is a schematic diagram of the structure of the power transmission line tower grounding resistance measuring device according to an embodiment of the present invention;

[0070] Figure 4This is a schematic diagram of a single-sided signal injection of the power transmission line tower grounding resistance measuring device according to an embodiment of the present invention;

[0071] Figure 5 This is a schematic diagram of the dual-signal simultaneous injection of a power transmission line tower grounding resistance measuring device according to an embodiment of the present invention.

[0072] In the diagram: 10, lightning protection wire; 20, transmission line tower; 30, coupling injection module; 40, control module; 50, signal acquisition module; 60, signal processing module; 70, high-precision synchronization module; 80, communication module. Detailed Implementation

[0073] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] As crucial supports and lightning protection facilities for high-voltage transmission lines, the grounding system of transmission line towers directly affects the operational safety and lightning protection performance of the transmission lines. Excessive grounding resistance in transmission line towers will prevent lightning current from effectively dissipating into the ground, easily leading to insulator flashover, line tripping, and even equipment damage, posing a serious threat to the safe and stable operation of the power grid.

[0075] Currently, offline measurement methods such as the "three-electrode method" are commonly used to measure the grounding resistance of transmission line towers. This method requires two auxiliary grounding electrodes to be installed along a straight line outside the tower being tested. The resistance value is calculated by injecting a known current and measuring the potential difference. Although the results obtained by this method are relatively accurate, it has significant limitations in detecting the grounding resistance of transmission line towers. This method requires the installation of two auxiliary grounding electrodes and the laying of long-distance leads, which is cumbersome, labor-intensive, and in some locations, the electrodes cannot be installed due to terrain and soil conditions. It is inefficient and poses safety hazards. Furthermore, this method requires measuring the grounding resistance of transmission line towers offline, which affects the normal operation of the line.

[0076] In current designs, two lightning protection wires 10 are typically installed on the transmission line tower 20, connected by the tower body. When a signal is injected into one of the lightning protection wires 10, current will be generated in both lightning protection wires 10 simultaneously. , .

[0077] like Figure 4 As shown, the two lightning protection wires are considered as a set of multi-conductor transmission lines, and the current in the two lines is... , Perform mode decomposition.

[0078] The common-mode current is:

[0079]

[0080] This component is manifested as the portion of the current flowing together from both lines towards the ground, i.e., the ground current component. .

[0081] Differential mode current is expressed as:

[0082]

[0083] This component manifests as a circulating current formed between the two lightning protection wires, i.e., the loop current component.

[0084] Because the earth resistance is much greater than the resistance between lightning protection wires, the component of the ground current... Much smaller than the circulating current component ,Right now:

[0085]

[0086] By transforming the formulas for common-mode current and differential-mode current, the lightning conductor current is obtained:

[0087]

[0088]

[0089] At this point, the majority of the current is differential mode current. The common-mode component accounts for a very small percentage.

[0090] Since it hardly participates in the earth's electrical conduction process, the component of the ground current is too small to be extracted, and thus cannot reflect the characteristics of the grounding resistance.

[0091] Based on the above, signals are synchronously injected into the double lightning protection lines to ensure that their amplitudes are equal and their phases are consistent. .

[0092] like Figure 5 As shown, at this time, the differential mode current...

[0093]

[0094] common mode current

[0095]

[0096] That is, the circulating current is completely suppressed, and all the injected energy enters the ground grid in common mode, significantly amplifying the ground current component and effectively improving the signal-to-noise ratio during the measurement process.

[0097] Based on the synchronous injection of signals on the dual lightning protection lines, such as Figure 1 As shown, the present invention provides a method for measuring the grounding resistance of transmission line towers, comprising the following steps:

[0098] Step S10: Send a first electrical signal to the coupling injection module 30 so that the coupling injection module 30 synchronously injects the same second electrical signal into the two lightning protection wires 10 of the transmission line tower 20.

[0099] Step S20: Collect the voltage and current signals injected into the second electrical signal point by the two lightning protection wires 10;

[0100] Step S30: Calculate the grounding resistance of the transmission line tower 20 based on the collected voltage and current signals.

[0101] The method for measuring the grounding resistance of transmission line towers involves sending a first electrical signal from the control module 40 to the coupling injection module 30. The control module 40 includes a signal acquisition module 50 and a signal processing module 60.

[0102] The signal acquisition module 50 is used to acquire current and voltage signals on the transmission line tower 20.

[0103] The signal processing module 60 is used to process the current and voltage signals acquired by the signal acquisition module 50 and calculate the grounding resistance of the transmission line tower 20.

[0104] Preferably, in some embodiments, the control module 40 further includes a high-precision synchronization module 70 for providing a unified time reference for the system.

[0105] Furthermore, the high-precision synchronization module 70 adopts a BeiDou / GPS dual-mode timing method to provide a unified time reference for the entire system, ensuring the timing consistency of pulse injection, signal acquisition and multi-device collaborative operation.

[0106] Preferably, in some embodiments, the control module 40 further includes a communication module 80. By setting the communication module 80, the injection timing can be controlled and the working mode can be adaptively adjusted. The communication module 80 is also connected to the background monitoring platform to interact with the background monitoring platform.

[0107] The coupling injection module 30 includes a pulse drive unit, a coupling converter, and a safety isolation unit. It is responsible for coupling a pulse excitation first electrical signal of a specific waveform to the two lightning protection wires 10 during a preset monitoring window period to form a test signal source. The coupling converter is based on the Rogowski coil principle. The input and output sides transmit signals through magnetic coupling, without direct electrical connection, thus blocking the threat of primary-side faults to secondary-side equipment.

[0108] This invention employs the pulse injection principle. Since the pulse excitation first electrical signal outputs energy only within a short window of 0-500µs, its peak power is ≤50W. Continuous injection is unnecessary, reducing energy loss by an order of magnitude compared to traditional continuous wave injection methods (power levels typically ≥500W). Based on the low power requirement, the drive circuit uses high-frequency switching devices and miniature energy storage capacitors, and the coupling converter uses a nanocrystalline alloy magnetic core for miniaturization. The overall module is compact and lightweight, making it suitable for complex outdoor environments.

[0109] During operation, the control module 40 sends a first electrical signal to the coupling injection module 30. After receiving and processing the first electrical signal, the coupling injection module 30 synchronously injects the same second electrical signal with equal amplitude and consistent phase into the two lightning protection wires 10 of the transmission line tower 20. The signal acquisition module 50 acquires the voltage and current signals of the two lightning protection wires 10 and sends the acquired voltage and current signals to the signal processing module 60. The signal processing module 60 analyzes and calculates the grounding resistance of the transmission line tower.

[0110] This invention injects the same second electrical signal into two lightning protection wires simultaneously through a coupling injection module, which greatly reduces the circulating current between the two lightning protection wires. This allows for better extraction of the ground current component, enabling rapid and accurate acquisition of grounding resistance values, improving measurement efficiency, and reducing errors caused by human operation. Even in complex terrain or harsh weather conditions, it can achieve online high-precision monitoring.

[0111] like Figure 2 As shown, in one embodiment, calculating the grounding resistance of the transmission line tower based on the collected voltage and current signals includes the following steps:

[0112] Step S110: Calculate the forward current and reflected current based on the collected voltage and current signals;

[0113] Step S120: Calculate the frequency domain reflection coefficient based on the forward current and the reflected current;

[0114] Step S130: Calculate the grounding resistance of the transmission line tower based on the frequency domain reflection coefficient.

[0115] In one embodiment, calculating the forward current and reflected current based on the acquired voltage and current signals includes the following steps: calculating the forward current and reflected current according to the following formula:

[0116] ;

[0117] ;

[0118] ;

[0119] in, This represents the combined impedance of the two lightning protection wires and the transmission line tower. , These represent the voltage and current signals collected at the points where the second electrical signal is injected into the two lightning protection wires, respectively. and These represent the forward voltage and the reflected voltage, respectively. and This represents the forward current and the reflected current.

[0120] In one embodiment, calculating the frequency domain reflection coefficient based on the forward current and the reflected current includes the following steps: calculating the frequency domain reflection coefficient according to the following formula:

[0121] ;

[0122] ;

[0123] in, Represents the frequency domain reflection coefficient. Indicates the length of the lightning protection wire. Indicates wave speed. Indicates the propagation delay time. Indicates forward current delay alignment of the current. Frequency domain compensation term.

[0124] In one embodiment, calculating the grounding resistance of the transmission line tower based on the frequency domain reflection coefficient includes the following steps: calculating the grounding resistance of the transmission line tower according to the following formula:

[0125] ;

[0126] , ;

[0127] ;

[0128] in, This represents the equivalent grounding impedance of the transmission line tower. This indicates the low-frequency component of the grounding resistance of transmission line towers. , , This indicates the final grounding resistance of the transmission line tower.

[0129] like Figure 3As shown, this invention provides a system for measuring the grounding resistance of transmission line towers, comprising: a coupling injection module connected to two lightning protection wires of the transmission line tower; and a control module connected to the two lightning protection wires and the coupling injection module, configured to: send a first electrical signal to the coupling injection module, causing the coupling injection module to synchronously inject the same second electrical signal into the two lightning protection wires of the transmission line tower; collect voltage and current signals at the injection points of the second electrical signal on the two lightning protection wires; and calculate the grounding resistance of the transmission line tower based on the collected voltage and current signals.

[0130] This invention injects the same second electrical signal into two lightning protection wires simultaneously through a coupling injection module, which greatly reduces the circulating current between the two lightning protection wires. This allows for better extraction of the ground current component, enabling rapid and accurate acquisition of grounding resistance values, improving measurement efficiency, and reducing errors caused by human operation. Even in complex terrain or harsh weather conditions, it can achieve online high-precision monitoring.

[0131] like Figure 2 As shown, in one embodiment, the calculation of the grounding resistance of the transmission line tower based on the collected voltage and current signals includes the following steps: calculating the forward current and reflected current based on the collected voltage and current signals; calculating the frequency domain reflection coefficient based on the forward current and reflected current; and calculating the grounding resistance of the transmission line tower based on the frequency domain reflection coefficient.

[0132] In one embodiment, calculating the forward current and reflected current based on the acquired voltage and current signals includes: calculating the forward current and reflected current according to the following formula:

[0133] ;

[0134] ;

[0135] ;

[0136] in, This represents the combined impedance of the two lightning protection wires and the transmission line tower. , These represent the voltage and current signals collected at the points where the second electrical signal is injected into the two lightning protection wires, respectively. and These represent the forward voltage and the reflected voltage, respectively. and This represents the forward current and the reflected current.

[0137] In one embodiment, calculating the frequency domain reflection coefficient based on the forward current and the reflected current includes: calculating the frequency domain reflection coefficient according to the following formula:

[0138] ;

[0139] ;

[0140] in, Represents the frequency domain reflection coefficient. Indicates the length of the lightning protection wire. Indicates wave speed. Indicates the propagation delay time. Indicates forward current delay alignment of the current. Frequency domain compensation term.

[0141] In one embodiment, calculating the grounding resistance of the transmission line tower based on the frequency domain reflection coefficient includes: calculating the grounding resistance of the transmission line tower according to the following formula:

[0142] ;

[0143] , ;

[0144] ;

[0145] in, This represents the equivalent grounding impedance of the transmission line tower. This indicates the low-frequency component of the grounding resistance. , , This indicates the final grounding resistance of the transmission line tower.

[0146] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0147] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0148] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A method of measuring a ground resistance of a transmission line tower, characterized by, The method comprises the following steps: sending a first electrical signal to the coupling injection module to make the coupling injection module synchronously inject a same second electrical signal to the two lightning arresters of the transmission line tower; collecting voltage signals and current signals at the positions where the second electrical signal is injected to the two lightning arresters; calculating forward current and reflected current of the current according to the collected voltage signals and current signals; calculating a frequency domain reflection coefficient according to the forward current and the reflected current of the current according to the following formula: ； ； wherein denotes the length of the lightning conductor, denotes the wave speed, denotes the propagation delay time, denotes the frequency domain reflection coefficient, denotes the frequency domain compensation term for the forward current delay alignment to the current; calculating an equivalent grounding impedance of the transmission line tower according to the frequency domain reflection coefficient according to the following formula: ； ； wherein Zeq represents the ground equivalent impedance of the line tower, Ztot represents the combined impedance of the two conductors and the line tower; , Ztot represents the combined impedance of the two conductors and the line tower; Ztot represents the combined impedance of the two conductors and the line tower; 2. The method for measuring the grounding resistance of a transmission line tower according to claim 1, characterized in that, The method for calculating the forward current and the reflected current of the current according to the collected voltage signals and current signals comprises the following steps: calculating the forward current and the reflected current of the current according to the following formula: ； ； ； wherein, , respectively represent the acquired voltage signal and the current signal at the injection of the second electrical signal on the two lightning conductors. and Vf and Vr represent the forward voltage and the reflected voltage of the voltage, respectively; and denote the forward current and the reflected current of the current.

3. The method for measuring the grounding resistance of a transmission line tower according to claim 1, characterized in that, The method for calculating the grounding resistance of the transmission line tower according to the frequency domain reflection coefficient comprises the following steps: The weight function is calculated according to the following formula : ， ； wherein represents the low-frequency component of the grounding resistance of the transmission line tower, .

4. A system for measuring the ground resistance of a power line tower, characterized in that, The method comprises: a coupling injection module connected to the two lightning arresters of the transmission line tower; a control module connected to the two lightning arresters of the transmission line tower and the coupling injection module, configured to: sending a first electrical signal to the coupling injection module to make the coupling injection module synchronously inject a same second electrical signal to the two lightning arresters of the transmission line tower; collecting voltage signals and current signals at the positions where the second electrical signal is injected to the two lightning arresters; calculating forward current and reflected current of the current according to the collected voltage signals and current signals; calculating a frequency domain reflection coefficient according to the forward current and the reflected current of the current according to the following formula: ； ； wherein denotes the length of the lightning conductor, denotes the wave speed, denotes the propagation delay time, denotes the frequency domain reflection coefficient, denotes the frequency domain compensation term for the forward current delay alignment to the current, calculating an equivalent grounding impedance of the transmission line tower according to the frequency domain reflection coefficient according to the following formula: ； ； wherein Zeq represents the ground equivalent impedance of the line tower, Ztot represents the combined impedance of the two conductors and the line tower; , Ztot represents the combined impedance of the two conductors and the line tower; W represents the weight function.

5. The transmission line tower grounding resistance measurement system according to claim 4, wherein the forward current and the reflected current of the current are calculated from the acquired voltage signal and the current signal. The method for calculating the forward current and the reflected current of the current according to the collected voltage signals and current signals comprises the following steps: The method comprises: ； ； ； wherein, , respectively represent the acquired voltage signal and the current signal at the injection of the second electrical signal on the two lightning conductors; and Vf and Vr represent the forward voltage and the reflected voltage of the voltage, respectively; and denotes the forward current and the reflected current of the current.

6. A system for measuring grounding resistance of a transmission line tower according to claim 4, wherein the grounding resistance of the transmission line tower is calculated according to the frequency domain reflection coefficient by the following equation, ###0001### wherein, R is the grounding resistance of the transmission line tower, Z0 is the characteristic impedance of the transmission line, ZL is the load impedance of the transmission line, and ZT is the impedance of the transmission line tower. calculating the forward current and the reflected current of the current according to the following formula: The weight function is calculated according to the following equation : ， ； wherein represents the low frequency component of the ground resistance, .

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