Power line fault on-line monitoring and positioning system

Abstract

The invention relates to the technical field of power line detection, in particular to a power line fault monitoring and positioning system, which comprises a tuning circuit, and a tuning frequency selection unit and a fault positioning unit which are respectively connected with the tuning circuit, the tuning circuit is connected with an electric power circuit through a capacitance type mutual inductor and a current type mutual inductor end screen medium, and is used for extracting a transient traveling wave signal; the tuning frequency selection unit determines the tuning frequency of the tuning circuit according to the transient traveling wave signal for extracting fault features; the tuning circuit further comprises a voltage branch container, taps used for adjusting the voltage division ratio of the voltage branch container are arranged in the voltage branch container, and the tuning circuit is used for extracting voltages of different proportions and determining voltage distribution information of the electric power circuit. And the fault positioning unit is used for determining the fault phase of the power line according to the fault characteristics and the voltage distribution information. According to the invention, multiple fault features and voltage distribution information are comprehensively utilized, and rapid and accurate monitoring and positioning of power line faults are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power line detection, and more specifically to an online monitoring and positioning system for power line faults. Background Art

[0002] Line fault, as the name implies, means there is a problem with the line. Common faults are prone to poor contact between the busbar and other equipment lines, which causes the line operation to be interrupted and the equipment cannot work according to the expected indicators, that is, the equipment does not achieve the function it should achieve.

[0003] The fault characteristics of the power system refer to the comprehensive quantity of the type, location and degree of the fault of the equipment and system obtained after the signal reflecting the fault symptoms is processed. The basic characteristics of the power system fault are:

[0004] ① The current increases, that is, the current in the electrical equipment connecting the short-circuit point and the power supply increases. ② The voltage drops, that is, the voltage on the electrical equipment around the fault point decreases, and the closer the electrical distance to the fault point, the more serious the voltage drop, and even drops to zero. ③ The phase difference between the voltage and current at the beginning of the line will change. ④ The ratio between the voltage and current at the beginning of the line, that is, the measurement impedance, will change.

[0005] The busbar is an important device for the concentration and distribution of electric energy, and is one of the important components of the power system. If a busbar fails, all components connected to the busbar will be forced to be removed, causing power outages for a large area of ​​users, serious damage to electrical equipment, and even the destruction of the stable operation of the power system, leading to the collapse of the power system, with very serious consequences. The causes of busbar failures include: welding of busbar insulators and circuit breaker bushings, failure of voltage transformers installed on the busbar and current transformers installed between the busbar and the circuit breaker, damage to the supporting insulators of busbar disconnectors and circuit breakers, misoperation of operators, etc. Whether the substation operation is normal is related to the safety and stability of the entire power system, but due to the large number of equipment and complex operation, substation failures occur frequently, which also makes it difficult to repair and maintain the equipment. Timely troubleshooting can ensure the safe operation of the power system.

[0006] With the rapid development of power systems, the stability and reliability of power grids have become the focus of the power industry. When the power grid suffers from faults, operations or lightning strikes, transient traveling wave signals will be generated. These signals propagate along the transmission line at a speed close to the speed of light and are refracted and reflected at places where the wave impedance is discontinuous. Traveling wave protection or transient quantity protection and traveling wave fault location technology are based on the traveling wave transmission theory of power grids. In order to achieve effective traveling wave protection or transient quantity protection, it is first necessary to effectively extract transient high-frequency signals, and this process depends on whether the transformer can correctly transmit and transform high-frequency transient quantities.

[0007] However, traditional transformers have obvious deficiencies in transmitting and transforming high-frequency voltage signals, which limits the ability to quickly locate and detect power line faults. In addition, with the growing demand for rapid isolation of faulty lines in power systems, traditional circuit breakers are gradually unable to meet this safety requirement in terms of functionality. Therefore, it is particularly important to develop a device that can quickly locate, detect and isolate power line faults.

[0008] In the prior art, some patents have proposed different solutions. For example, the invention patent with publication number CN110082596A proposes a distance protection fault impedance calculation method and system based on high-frequency transient quantities. This method collects cable data, including high-frequency harmonics in current and voltage, to calculate the distance percentage from the fault point to the protection installation, thereby locating the fault.

[0009] The invention patent with publication number CN109541400A discloses a method for non-contact acquisition of transient voltage traveling wave signals. It uses the principle of spatial electromagnetic induction and does not require physical contact with the high-voltage cable. It can safely, quickly and accurately collect and process transient voltage traveling wave signals after a high-voltage cable fault.

[0010] Although these technologies have improved the efficiency of fault detection and location to a certain extent, there are still some limitations. For example, some methods require changes to the primary system wiring, which poses a safety hazard, or require the application of standard lightning wave signals at multiple voltage level outlets, which is complex and costly. Therefore, this application aims to propose a new technical solution to solve the problems existing in the prior art and improve the efficiency and safety of rapid location detection and isolation of power line faults. Summary of the invention

[0011] In view of this, the present application provides a power line fault monitoring and positioning system to solve the above problems.

[0012] The technical solutions provided by this application are as follows:

[0013] A fault monitoring and locating system for a power line, comprising a tuning circuit, a tuning frequency selection unit and a fault locating unit respectively connected to the tuning circuit; the tuning circuit is connected to the power line through a capacitive transformer and a current transformer end screen medium, and is used to extract a transient traveling wave signal related to the fault; the tuning frequency selection unit determines the tuning frequency of the tuning circuit according to the transient traveling wave signal, and is used to extract fault characteristics, including transient characteristics, mode component propagation characteristics, fault transition resistance and power quality characteristics;

[0014] The tuning circuit also includes a voltage divider, wherein a tap for adjusting the voltage divider ratio of the voltage divider is provided inside the voltage divider, and the tuning circuit is used to extract voltages of different proportions and determine voltage distribution information of the power line; the fault locating unit is used to determine the fault phase of the power line according to the fault characteristics and the voltage distribution information.

[0015] In one possible implementation, the tuning circuit further includes one or more LC resonant networks and filters formed by one or more capacitors and inductors connected in series;

[0016] The LC resonant network is used to adjust the resonant frequency of the tuning circuit to match a preset transient voltage signal frequency band;

[0017] The filter is connected between the LC resonant network and the fault location unit, and is used to filter out signals in non-target frequency bands. The fault location unit is used to receive transient voltage traveling wave signals in a specific frequency band.

[0018] In one possible implementation, the tuning circuit further includes a voltage-controlled oscillator, a phase detector, and a feedback network;

[0019] The phase detector is used to compare the phase difference between the output signal of the voltage controlled oscillator and the reference signal, generate a control voltage for adjusting the frequency of the voltage controlled oscillator, and synchronize the phase of the output signal of the voltage controlled oscillator with the reference signal;

[0020] The feedback network is connected between the voltage controlled oscillator and the phase detector, and is used to transmit the control voltage generated by the phase detector to the voltage controlled oscillator for frequency locking;

[0021] The voltage-controlled oscillator is connected to the LC resonant network and is used to adjust the resonant frequency of the LC resonant network according to the control voltage.

[0022] In one possible implementation, the capacitive voltage transformer is directly connected to the power line to obtain a voltage signal on the power line and convert the obtained voltage signal into a low voltage signal suitable for monitoring;

[0023] The end screen medium of the current transformer is used to capture the magnetic field information related to the current change; the current transformer provides a current signal through the secondary side output, and the current signal includes a transient traveling wave signal generated when a fault occurs.

[0024] In one possible implementation, the tuning circuit is also used to extract transient traveling wave signals and obtain traveling wave information through phase mode transformation, multiplying the three-phase voltage and current by the Karenbel transformation matrix or the Clarke matrix to transform them into line mode components α, β and zero mode components 0; and determining the arrival time of the initial traveling wave based on the instantaneous phase and frequency of each component.

[0025] In one possible implementation, the tap set inside the capacitive voltage divider is used to divide the capacitive voltage divider into a high voltage capacitor region C1 and a medium voltage capacitor region C2; the voltage divider ratio is expressed as:

[0026] V out =V in ×C2 / (C1+C2)

[0027] Where V in is the input voltage, C1 is the capacitance value of the high voltage capacitor area, C2 is the capacitance value of the medium voltage capacitor area, V out is the extracted voltage.

[0028] In one possible implementation, the voltage distribution information includes voltage variation, voltage drop, voltage flicker, voltage harmonics, voltage measurement point distribution, and voltage geographical distribution of the power line from the source to the load end.

[0029] In one possible implementation, the transient traveling wave signal related to the fault extracted by the tuning circuit includes the sudden change information of the voltage and current generated when the fault occurs.

[0030] The tuning frequency selection unit is used to determine the corresponding tuning frequency according to the characteristics of the transient traveling wave signal to match the frequency characteristics of the traveling wave signal when a fault occurs;

[0031] The tuning circuit is also designed to respond to a matching tuning frequency and only allow traveling wave signals related to the fault to pass.

[0032] In one possible implementation, it also includes online monitoring units respectively arranged on the main line and each branch line of the power line;

[0033] Each of the online monitoring units includes three voltage and traveling wave sensors, evenly distributed on three AC potentials of the main line and branch line of the power line, for real-time monitoring of voltage and traveling wave signals;

[0034] By comparing the voltage drops at different monitoring points, the faulty line and faulty phase are determined; in the case of a single-phase grounding fault, the voltage of the faulty phase drops, and the voltage of the non-faulty phase increases; in the case of a two-phase grounding fault and the resulting phase-to-phase fault, the voltages of both faulty phases drop, and the voltage of the non-faulty phase increases; in the case of a three-phase short circuit fault, the voltages of all three phases drop.

[0035] In one possible implementation manner, after determining the fault phase, the fault location unit is further used to:

[0036] According to the determined fault phase, based on the fault traveling wave propagation time difference positioning method, the time difference of transient traveling waves recorded at each monitoring point on the fault phase is compared to determine the distance of the fault point relative to each monitoring point and perform fault location.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The beneficial effects of this technical solution are mainly reflected in the following aspects:

[0039] The present application can effectively extract fault-related transient traveling wave signals in power lines by combining a tuning circuit with a capacitor transformer and a current transformer end screen medium, and can realize high-sensitivity monitoring of power line faults. The fault location unit can accurately determine the fault phase of the power line based on the fault characteristics and voltage distribution information in the transient traveling wave signal, which helps to quickly respond to and repair the fault, reduce power outage time, and improve the reliability and stability of the power grid.

[0040] The tuning frequency selection unit can determine the tuning frequency of the tuning circuit according to the transient traveling wave signal, thereby extracting a variety of fault characteristics including transient characteristics, mode component propagation characteristics, fault transition resistance and power quality characteristics, providing comprehensive data support for fault analysis. In summary, this application comprehensively utilizes a variety of fault characteristics and voltage distribution information to achieve rapid and accurate monitoring and positioning of power line faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the structure of a power line fault monitoring and locating system provided in an embodiment of the present application.

[0042] Figure 2 A schematic diagram of the structure of a tuning circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] The present application provides a power line fault monitoring and positioning system, such as Figure 1As shown in , the fault monitoring and location system of the power line consists of a tuning circuit, a tuning frequency selection unit and a fault location unit. The tuning circuit is connected to the power line through the capacitor transformer and the current transformer end screen medium, and is used to extract the transient traveling wave signal related to the fault. The voltage divider in the tuning circuit is equipped with a tap for adjusting the voltage divider ratio, allowing the system to extract voltages of different proportions to determine the voltage distribution information of the power line. The voltage distribution information is directly related to the stability and power supply quality of the power system. By monitoring the voltage change, voltage drop, voltage flicker, voltage harmonics, voltage measurement point distribution and voltage geographical distribution of the power line from the source to the load end, the operating status of the power line can be fully understood, and potential faults and problems can be discovered and handled in a timely manner.

[0045] In the embodiment of the present application, the voltage distribution information includes but is not limited to the following aspects:

[0046] (1) Voltage changes, including voltage changes of power lines under different load conditions, such as the instantaneous value, average value and change trend of voltage.

[0047] (2) Voltage drop, including measuring the voltage drop in power lines due to resistance and reactance.

[0048] (3) Voltage flicker is a rapid change in voltage within a short period of time, which is usually caused by the start or stop of large loads and poses a threat to the stability of the power system.

[0049] (4) Voltage harmonics refer to voltage waveform distortion caused by nonlinear loads or power electronic equipment. Long-term existence will damage power equipment and reduce power supply quality.

[0050] (5) Distribution of voltage measurement points: The distribution of voltage measurement points helps to understand the voltage status of power lines and provides a reference for fault diagnosis and maintenance.

[0051] (6) Voltage geographical distribution: Voltage geographical distribution information helps to identify areas with weak power supply, optimize power resource allocation, and improve power supply reliability.

[0052] Specifically, the voltage divider is divided into a high voltage capacitor area C1 and a medium voltage capacitor area C2, and the voltage division ratio is expressed as:

[0053] V out =V in ×C2 / (C1+C2)

[0054] Where V in is the input voltage, C1 is the capacitance value of the high voltage capacitor area, C2 is the capacitance value of the medium voltage capacitor area, V out is the extracted voltage.

[0055] When a fault occurs in a power line, the tuning circuit captures the transient traveling wave signals generated by the fault. The tuning frequency selection unit determines the tuning frequency of the tuning circuit based on these signals and extracts the fault characteristics. The above fault characteristics include transient characteristics, mode component propagation characteristics, fault transition resistance and power quality characteristics. The fault location unit determines the fault phase of the power line based on the fault characteristics and voltage distribution information.

[0056] In some embodiments, the above-mentioned fault monitoring and positioning system is deployed in a high-voltage power line network. The network covers a wide area and the lines are long, so the accuracy and response speed of fault monitoring and positioning are extremely high. By installing data acquisition terminals at the ends of the main line and the branch line, the tuning circuit extracts the transient voltage traveling wave signal of a specific frequency band through the LC resonant network and the filter, and obtains the traveling wave information through phase mode transformation. The fault location unit accurately locates the fault phase and the fault point according to the time difference of the arrival of the traveling wave and the voltage distribution information, which significantly improves the fault response speed and the reliability of the power grid.

[0057] In other embodiments, the above-mentioned fault monitoring and positioning system also includes online monitoring units respectively arranged on the main line and each branch line of the power line. Each online monitoring unit includes three voltage and traveling wave sensors, which are evenly distributed on the three AC potentials of the power line, and are used to monitor the voltage and traveling wave signals in real time. By comparing the voltage drops at different monitoring points, the system can determine the fault line and the fault phase. Among them, in the case of a single-phase grounding fault, the voltage of the fault phase drops, and the voltage of the non-fault phase increases. In the case of a two-phase grounding fault and the resulting phase-to-phase fault, the voltages of the two fault phases both drop, and the voltage of the non-fault phase increases. In the case of a three-phase short circuit fault, the voltages of the three phases all drop. This distributed monitoring method improves the monitoring range and accuracy of the system, making fault positioning more accurate and reliable.

[0058] In a specific application scenario, the above-mentioned fault monitoring and positioning system can also be applied to a complex power distribution network. The network includes a mixed line of overhead lines and cables, and the neutral point is not directly grounded. The fault monitoring and positioning system monitors the voltage and traveling wave signals in real time through an online monitoring unit, and determines the fault line and fault phase by comparing the voltage drops at different monitoring points. The fault positioning unit compares the time difference of the arrival of the transient traveling waves recorded at each monitoring point on the fault phase based on the fault traveling wave propagation time difference positioning method, determines the distance of the fault point relative to each monitoring point, and locates the fault. In this embodiment, the system can accurately identify and locate single-phase grounding faults, two-phase grounding faults and the phase-to-phase faults and three-phase short-circuit faults caused by them, which greatly improves the maintenance efficiency and power supply reliability of the distribution network.

[0059] Below, each unit of the fault monitoring and positioning system is described in detail.

[0060] like Figure 2As shown in , the above tuning circuit specifically extracts transient traveling wave signals related to power line faults. It is connected to the power line through the end screen medium of the capacitive transformer and the current transformer, and can capture the sudden change information of voltage and current generated when the fault occurs. These signals include transient characteristics, mode component propagation characteristics, fault transition resistance and power quality characteristics, which are used for subsequent fault type judgment and location.

[0061] Among them, transient characteristics are sudden changes in voltage and current when a fault occurs, and these sudden changes are usually manifested as fast rising edges of traveling wave signals. By analyzing these transient characteristics, the initial moment of the fault can be determined. The propagation characteristics of the modulus component involve the propagation characteristics of traveling waves in power lines. By analyzing the propagation speed and attenuation characteristics of traveling waves, the distance between the fault point and the monitoring point can be inferred. The fault transition resistance refers to the resistance value of the fault point, which has an important influence on the reflection and attenuation of the traveling wave signal. By measuring the reflection coefficient of the traveling wave signal, the size of the fault transition resistance can be estimated. Power quality characteristics include voltage drop, voltage flicker, voltage harmonics, etc. These characteristics can provide additional information about the health of the power line and assist in fault identification.

[0062] Specifically, the capacitive voltage transformer is directly connected to the power line to obtain the voltage signal on the power line and convert the obtained voltage signal into a low voltage signal suitable for monitoring. The end screen medium of the current transformer is used to capture the magnetic field information related to the current change and provide a current signal through the secondary side output, which includes the transient traveling wave signal generated during the fault.

[0063] The application of mutual inductors enables the system to quickly respond to faults in high-voltage transmission line networks. By capturing transient traveling wave signals and voltage distribution information, the system can locate faults within 5 minutes after the fault occurs. The application of mutual inductors can also be extended to complex distribution networks, including overhead lines and cable hybrid lines. The system can accurately identify and locate various types of faults, greatly improving the maintenance efficiency and power supply reliability of the distribution network.

[0064] The above tuning circuit is further used to extract transient traveling wave signals and obtain traveling wave information through phase mode transformation. The system multiplies the three-phase voltage and current by the Karen Bell transformation matrix or the Clarke matrix to transform them into line mode components α component, β component and zero mode component 0 component. According to the instantaneous phase and frequency of each component, the fault monitoring and location system can determine the time of arrival of the initial traveling wave and locate the fault accordingly.

[0065] The design of the tuning circuit includes an LC resonant network consisting of one or more series-connected capacitors and inductors, and a filter. The LC resonant network is used to adjust the resonant frequency of the tuning circuit to match the preset transient voltage signal band. The filter is connected between the LC resonant network and the fault location unit to filter out signals in non-target frequency bands, ensuring that the fault location unit only receives transient voltage traveling wave signals in a specific frequency band.

[0066] Furthermore, the above tuning circuit may also include a voltage-controlled oscillator, a phase detector and a feedback network, which work together to achieve phase synchronization between the output signal of the voltage-controlled oscillator and the reference signal. The phase detector compares the phase difference between the output signal of the voltage-controlled oscillator and the reference signal, and generates a control voltage for adjusting the frequency of the voltage-controlled oscillator. The feedback network transmits the control voltage generated by the phase detector to the voltage-controlled oscillator to achieve frequency locking. This mechanism ensures that the system can accurately capture and analyze the fault traveling wave signal.

[0067] The above-mentioned tuning frequency selection unit is specifically used to determine the tuning frequency of the tuning circuit according to the transient traveling wave signal, so as to extract the fault characteristics. With the help of the tuning frequency selection unit, characteristic signals related to the fault are extracted from the complex power line signal, including transient characteristics, mode component propagation characteristics, fault transition resistance and power quality characteristics. By accurately matching the frequency characteristics of the traveling wave signal when the fault occurs, it is ensured that the tuning circuit only responds to the traveling wave signal related to the fault, thereby improving the accuracy and efficiency of fault monitoring.

[0068] Compared with the prior art, the technical solution provided by the embodiment of the present application has the following beneficial effects:

[0069] The beneficial effects of the technical solution can be explained from the following aspects:

[0070] By extracting fault-related transient traveling wave signals through tuning circuits, it is possible to respond quickly to small changes in the power line, thus improving the sensitivity and accuracy of fault detection. The system not only extracts transient characteristics, but also comprehensively considers the propagation characteristics of the mode component, the fault transition resistance and the power quality characteristics, making the fault analysis more comprehensive and improving the accuracy of fault diagnosis. The tuning frequency selection unit can automatically adjust the tuning frequency according to the transient traveling wave signal, so that the system can adapt to different power line conditions and fault types, enhancing the applicability and flexibility of the system. By adjusting the voltage divider ratio of the voltage divider through the tap inside the voltage divider, the system can extract voltages of different proportions, accurately determine the voltage distribution information of the power line, and provide an important basis for fault location. The fault location unit combines the fault characteristics and voltage distribution information to quickly and accurately determine the fault phase of the power line, shorten the fault handling time, and improve the reliability and stability of the power system.

[0071] 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 power line fault monitoring and positioning system, characterized in that: It includes a tuning circuit, a tuning frequency selection unit and a fault location unit respectively connected to the tuning circuit; the tuning circuit is connected to the power line through a capacitive transformer and a current transformer end screen medium, and is used to extract a transient traveling wave signal related to the fault; The tuning frequency selection unit determines the tuning frequency of the tuning circuit according to the transient traveling wave signal, so as to extract fault characteristics, including transient characteristics, mode component propagation characteristics, fault transition resistance and power quality characteristics; The tuning circuit also includes a voltage divider, wherein a tap for adjusting the voltage divider ratio of the voltage divider is provided inside the voltage divider, and the tuning circuit is used to extract voltages of different proportions to determine voltage distribution information of the power line; The fault locating unit is used to determine the fault phase of the power line according to the fault characteristics and voltage distribution information.

2. A power line fault monitoring and positioning system according to claim 1, characterized in that: The tuning circuit also includes one or more LC resonant networks and filters formed by one or more capacitors and inductors connected in series; The LC resonant network is used to adjust the resonant frequency of the tuning circuit to match a preset transient voltage signal frequency band; The filter is connected between the LC resonant network and the fault location unit, and is used to filter out signals in non-target frequency bands. The fault location unit is used to receive transient voltage traveling wave signals in a specific frequency band.

3. A power line fault monitoring and positioning system according to claim 2, characterized in that: The tuning circuit also includes a voltage controlled oscillator, a phase detector and a feedback network; The phase detector is used to compare the phase difference between the output signal of the voltage controlled oscillator and the reference signal, generate a control voltage for adjusting the frequency of the voltage controlled oscillator, and synchronize the phase of the output signal of the voltage controlled oscillator with the reference signal; The feedback network is connected between the voltage controlled oscillator and the phase detector, and is used to transmit the control voltage generated by the phase detector to the voltage controlled oscillator for frequency locking; The voltage-controlled oscillator is connected to the LC resonant network and is used to adjust the resonant frequency of the LC resonant network according to the control voltage.

4. A power line fault monitoring and locating system according to claim 1, characterized in that: The capacitive voltage transformer is directly connected to the power line, and is used to obtain the voltage signal on the power line, and convert the obtained voltage signal into a low voltage signal suitable for monitoring; The end screen medium of the current transformer is used to capture magnetic field information related to current changes; The current transformer provides a current signal through a secondary side output, and the current signal includes a transient traveling wave signal generated when a fault occurs.

5. A power line fault monitoring and locating system according to claim 4, characterized in that: The tuning circuit is also used to extract transient traveling wave signals and obtain traveling wave information through phase mode transformation, multiplying the three-phase voltage and current by the Karenbel transformation matrix or the Clarke matrix to transform them into line mode components α, β and zero mode components 0; and determining the arrival time of the initial traveling wave based on the instantaneous phase and frequency of each component.

6. A power line fault monitoring and locating system according to claim 1, characterized in that: The taps set inside the capacitive voltage divider are used to divide the capacitive voltage divider into a high voltage capacitor area C1 and a medium voltage capacitor area C2; the voltage divider ratio is expressed as: V out =V in ×C2 / (C1+C2) Where V in is the input voltage, C1 is the capacitance value of the high voltage capacitor area, C2 is the capacitance value of the medium voltage capacitor area, V out is the extracted voltage.

7. A power line fault monitoring and locating system according to claim 1, characterized in that: The voltage distribution information includes voltage variation, voltage drop, voltage flicker, voltage harmonics, voltage measurement point distribution, and voltage geographical distribution of the power line from the source to the load end.

8. A power line fault monitoring and locating system according to claim 1, characterized in that: The transient traveling wave signal related to the fault extracted by the tuning circuit includes the information of the sudden change of voltage and current generated when the fault occurs; The tuning frequency selection unit is used to determine the corresponding tuning frequency according to the characteristics of the transient traveling wave signal to match the frequency characteristics of the traveling wave signal when a fault occurs; The tuning circuit is also designed to respond to a matching tuning frequency and only allow traveling wave signals related to the fault to pass.

9. A power line fault monitoring and locating system according to claim 1, characterized in that: It also includes online monitoring units respectively arranged on the main line and each branch line of the power line; Each of the online monitoring units includes three voltage and traveling wave sensors, evenly distributed on three AC potentials of the main line and branch line of the power line, for real-time monitoring of voltage and traveling wave signals; By comparing the voltage drops at different monitoring points, the faulty line and faulty phase are determined; in the case of a single-phase grounding fault, the voltage of the faulty phase drops, and the voltage of the non-faulty phase increases; in the case of a two-phase grounding fault and the resulting phase-to-phase fault, the voltages of both faulty phases drop, and the voltage of the non-faulty phase increases; in the case of a three-phase short circuit fault, the voltages of all three phases drop.

10. A power line fault monitoring and locating system according to claim 9, characterized in that: After the fault location unit determines the fault phase, it is also used to: According to the determined fault phase, based on the fault traveling wave propagation time difference positioning method, the time difference of transient traveling waves recorded at each monitoring point on the fault phase is compared to determine the distance of the fault point relative to each monitoring point and perform fault location.

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