Power distribution network overhead line single-phase earth fault positioning method and system

Abstract

The invention belongs to the technical field of power grid grounding fault positioning, and discloses a power distribution network overhead line single-phase grounding fault positioning method and a power distribution network overhead line single-phase grounding fault positioning system. Collecting an electric field signal and a magnetic field signal on the detected overhead line to calculate a voltage instantaneous value, a current instantaneous value and respective full-cycle Fourier amplitude; integrating the product of the voltage instantaneous value and the current instantaneous value in one period, dividing the integral value by the product of the full-cycle Fourier amplitude of the voltage instantaneous value and the current instantaneous value to obtain a ratio coefficient at different positions on the detected overhead line, so as to construct a function of the ratio coefficient with respect to the different positions on the detected overhead line; a single-phase earth fault occurs at the maximum value point of the first derivative of the function. Reverse power transmission is carried out on the basis that a vehicle-mounted power supply is combined with a distribution transformer, the amplitude of an injection signal is enhanced, rapid and accurate positioning of a single-phase earth fault point of the power distribution network is achieved in cooperation with an electric field and magnetic field sensor carried by the unmanned aerial vehicle, and the reliability of power supply is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid grounding fault positioning, and more specifically, relates to a method and system for positioning a single-phase grounding fault of an overhead line in a distribution network. Background Art

[0002] As one of the three major systems of "power generation, transmission, and distribution", the distribution network is directly connected to electricity users. Unlike the transmission network with fewer branches, the distribution network has a complex structure, many branches, and a complex and diverse environment. Therefore, its failure rate is much higher than that of the transmission network. Therefore, the timely location and handling of distribution network line faults can greatly improve the reliability of power supply, thereby improving the power experience of directly connected users. Single-phase grounding faults are the most likely fault form in the distribution network, and most short-circuit faults are developed from single-phase grounding faults.

[0003] The current solution to single-phase grounding faults in distribution networks is mainly the signal injection method, which injects a specific current signal into the line through a signal generator, and the current forms a loop through the generator, the fault line, the fault point, and the earth. However, when the single-phase grounding fault judgment criterion based on the signal injection method is used to identify the fault location, due to the influence of the capacitive current of the overhead line, the difference in the magnetic field signals on both sides of the fault point will be small, which in turn affects the accuracy of the single-phase grounding fault location identification.

[0004] In addition, with the widespread use of drones in power systems, the use of drone-mounted sensors to quickly identify and determine fault location information has also begun to develop during distribution network fault inspections. However, due to the flight distance requirements between drones and overhead lines, the sensors mounted on drones cannot be directly close to overhead lines, making the measured fault signals often very weak, and it is difficult to accurately locate the fault location using existing signal injection methods. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a method and system for locating a single-phase grounding fault of an overhead line in a distribution network, the purpose of which is to improve the accuracy of identifying the position of a single-phase grounding fault of an overhead line in a distribution network.

[0006] To achieve the above object, according to a first aspect of the present invention, a method for locating a single-phase ground fault of an overhead line in a power distribution network is provided, comprising:

[0007] After a single-phase grounding fault occurs in the overhead line of the distribution network, an AC voltage and a current are simultaneously injected into the overhead line under test, and the AC voltage and the current generate an electric field and a magnetic field on the overhead line under test respectively; and the electric field signal and the magnetic field signal on the overhead line under test are collected;

[0008] Based on the electric field signal and the magnetic field signal, respectively calculate the instantaneous voltage value and the instantaneous current value at different positions on the overhead line under test; and respectively calculate the full-cycle Fourier amplitude of the instantaneous voltage value and the instantaneous current value;

[0009] The product of the instantaneous value of the voltage and the instantaneous value of the current within an electric field or magnetic field alternation cycle is integrated to obtain the integral values ​​at different positions on the measured overhead line; the integral value is divided by the product of the full-cycle Fourier amplitude of the instantaneous value of the voltage and the instantaneous value of the current to obtain the ratio coefficient at different positions on the measured overhead line, so as to construct a function of the ratio coefficient between different positions on the measured overhead line; wherein a single-phase grounding fault occurs at the position corresponding to the maximum value of the first-order derivative of the function.

[0010] Furthermore, an AC voltage and a current are simultaneously injected into the overhead line under test, including:

[0011] The battery and inverter are mounted on a maintenance vehicle. The inverter converts the DC voltage and current generated by the battery into AC voltage and current, and then transmits the converted voltage to a distribution transformer through a high-voltage cable for voltage boosting. The boosted AC voltage and current are injected into the overhead line under test. The electric field signal and magnetic field signal are collected by electric field sensors and magnetic field sensors mounted on a drone.

[0012] Furthermore, the frequency of the alternating current generated by the inverter is 60HZ-100HZ.

[0013] According to a second aspect of the present invention, a system for locating a single-phase ground fault of an overhead line in a power distribution network is provided, comprising:

[0014] A signal injection module is used to simultaneously inject an AC voltage and a current into the overhead line under test after a single-phase grounding fault occurs in the overhead line of the distribution network, wherein the AC voltage and the current generate an electric field and a magnetic field on the overhead line under test;

[0015] Electric field sensor, used to collect electric field signals on the overhead line under test;

[0016] A magnetic field sensor is used to collect magnetic field signals on the overhead line under test;

[0017] A fault identification module is used to calculate the instantaneous voltage value and the instantaneous current value at different positions on the measured overhead line based on the electric field signal and the magnetic field signal, and to calculate the full-cycle Fourier amplitude of the instantaneous voltage value and the instantaneous current value; it is also used to integrate the product of the instantaneous voltage value and the instantaneous current value within an electric field or magnetic field alternation cycle to obtain the integral value at different positions on the measured overhead line; the integral value is divided by the product of the full-cycle Fourier amplitude of the instantaneous voltage value and the instantaneous current value to obtain the ratio coefficient at different positions on the measured overhead line, so as to construct a function of the ratio coefficient between different positions on the measured overhead line; wherein a single-phase grounding fault occurs at the position corresponding to the maximum value of the first-order derivative of the function.

[0018] Furthermore, it also includes a drone for carrying the electric field sensor and the magnetic field sensor; and the signal injection module includes a battery and an inverter carried on the maintenance vehicle;

[0019] The inverter is used to invert the DC voltage and current generated by the battery into AC voltage and current; wherein the AC voltage and current are transmitted to the distribution transformer through a high-voltage cable for boosting, and the boosted AC voltage and current are injected into the overhead line under test.

[0020] Furthermore, it also includes a communication unit carried on the drone;

[0021] The communication unit is used to receive and store the electric field signal and the magnetic field signal collected by the electric field sensor and the magnetic field sensor, and send the electric field signal and the magnetic field signal to the fault identification module.

[0022] Furthermore, the electric field sensor is a three-dimensional electric field vector sensor having a six-electrode structure with arc surfaces equally divided.

[0023] Furthermore, the magnetic field sensor is a giant magneto-impedance sensor.

[0024] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0025] (1) Different from the existing method of only detecting the injected current, the present invention provides a new signal injection method for locating the single-phase grounding fault of the overhead line of the distribution network, and simultaneously injects AC voltage and current into the overhead line under test. The injected AC voltage and current generate electric field and magnetic field on the overhead line under test. The instantaneous values ​​of voltage and current at different positions on the overhead line under test are obtained based on the electric field signal and the magnetic field signal. After integrating the product of the instantaneous value of voltage and the instantaneous value of current within a cycle, since the phase of the measured current and the injected voltage in the injected current are consistent, and the phase difference between the capacitive current and the injected voltage in the injected current is 90°, the product of the capacitive current and the injected voltage is 0 after integration within a cycle. In this way, the capacitive current and the measured current in the injected current are separated, and the influence of the capacitive current on the single-phase grounding fault location is eliminated. Based on this, the ratio coefficient function is constructed by the ratio of the integral value and the amplitude product value at different positions on the overhead line under test. The position where the ratio coefficient suddenly changes is the position where the single-phase grounding fault occurs. Therefore, the position corresponding to the maximum value of the first-order derivative of the function is the position where the single-phase grounding fault occurs. The method for locating a single-phase grounding fault of an overhead line in a distribution network of the present invention eliminates the influence of the capacitive current of the overhead line and improves the accuracy of fault location identification.

[0026] (2) Furthermore, the present invention takes into account that due to the requirement of the flight distance between the UAV and the overhead lines, it is impossible to make the sensors carried by the UAV directly close to the overhead lines, so that the measured fault signals are often very weak. Based on this, the present invention uses a distribution transformer for reverse power transmission. That is, unlike the conventional method of converting high voltage into low voltage and transmitting it to users through a distribution transformer, the present invention uses a distribution transformer to convert the low-voltage AC voltage and current provided by the on-board power supply into high-voltage voltage and current, which greatly improves the voltage and current signals injected into the overhead lines, so that the method of the present invention can be applied to the sensors carried by the UAV to quickly identify and judge the fault location information.

[0027] In addition, the present invention uses the distribution transformer to reverse power and injects signals at the low-voltage end of the distribution transformer, eliminating the need for manual pole climbing and wire hanging operations, which saves manpower on the one hand and ensures the safety of inspection personnel on the other. At the same time, the use of primary energy (batteries and inverters) integrated in the maintenance vehicle also improves the flexibility of the detection location.

[0028] (3) As a preferred embodiment, the frequency of the AC current output by the inverter is 60HZ-100HZ, which improves the reverse power transmission efficiency while avoiding interference from the industrial frequency electromagnetic field (50HZ).

[0029] (4) Preferably, the electric field sensor adopts a three-dimensional electric field vector sensor with six electrodes having equally spaced arc surfaces, which can fully sense the electric field vector components in space, has a wide-band measurement capability within a range of 10 MHz, and has good anti-angle measurement deviation characteristics.

[0030] (5) Preferably, the magnetic field sensor is a giant magneto-impedance sensor, which has the characteristics of high sensitivity, high linearity, high flexibility, wide magnetic field detection range, good three-axis orthogonality, and can self-correct the magnetic field measurement error caused by the change of sensor posture caused by the movement of the drone. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The figure is a schematic diagram of a method for locating a single-phase grounding fault of an overhead line in a distribution network in an embodiment of the present invention.

[0032] Figure 2 The figure is a schematic diagram of the flow direction of the injection signal when the power is reversely transmitted through the distribution transformer in the embodiment of the present invention.

[0033] Figure 3 1 is an equivalent circuit diagram of the system when a single-phase grounding fault occurs in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Example 1

[0036] like Figure 1 As shown, an embodiment of the present invention provides a method for locating a single-phase grounding fault of an overhead line in a distribution network, which mainly includes:

[0037] After a single-phase grounding fault occurs in the overhead line of the distribution network, AC voltage and current are injected into the overhead line under test at the same time. The injected AC voltage and current generate electric field and magnetic field on the overhead line under test respectively; and the electric field signal and magnetic field signal on the overhead line under test are collected;

[0038] Calculating instantaneous voltage values ​​at different positions on the overhead line under test based on the electric field signal, calculating instantaneous current values ​​at different positions on the overhead line under test based on the magnetic field signal; and calculating full-cycle Fourier algorithm amplitudes of the instantaneous voltage value and the instantaneous current value respectively;

[0039] The product of the instantaneous value of voltage and the instantaneous value of current within an electric field or magnetic field alternating cycle is integrated to obtain the integral values ​​at different positions on the measured overhead line; the full-cycle Fourier algorithm amplitude of the instantaneous value of voltage is multiplied by the full-cycle Fourier algorithm amplitude of the instantaneous value of current to obtain the amplitude product values ​​at different positions on the measured overhead line; the integral value is divided by the amplitude product value to obtain the ratio coefficient at different positions on the measured overhead line to construct a function of the ratio coefficient with respect to different positions on the measured overhead line; wherein a single-phase grounding fault occurs at the position corresponding to the maximum value of the first-order derivative of the function.

[0040] Different from the existing method of only detecting the injected current, the present invention provides a new signal injection method for locating the single-phase grounding fault of the overhead line of the distribution network, and simultaneously injects AC voltage and current into the overhead line to be measured, and the injected AC voltage and current generate electric field and magnetic field on the overhead line to be measured. The instantaneous values ​​of voltage and current at different positions on the overhead line to be measured are obtained based on the electric field signal and the magnetic field signal. After integrating the product of the instantaneous value of voltage and the instantaneous value of current within one cycle, since the phase of the measured current and the injected voltage in the injected current are consistent, and the phase difference between the capacitive current and the injected voltage in the injected current is 90°, therefore, the product of the capacitive current and the injected voltage is 0 after integration within one cycle, thus realizing the separation of the capacitive current and the measured current in the injected current, and eliminating the influence of the capacitive current on the single-phase grounding fault location. Based on this, the ratio coefficient function is constructed by the ratio of the integral value and the amplitude product value at different positions on the overhead line to be measured, and the position where the ratio coefficient suddenly changes is the position where the single-phase grounding fault occurs, therefore, the position corresponding to the maximum value of the first-order derivative of the function is the position where the single-phase grounding fault occurs. The method for locating a single-phase grounding fault of an overhead line in a distribution network of the present invention eliminates the influence of the capacitive current of the overhead line and improves the accuracy of fault location identification.

[0041] In order to enable the method of the present invention to be applied to the fault inspection of the UAV distribution network, as a further design of the present invention, when the AC voltage and current are injected into the overhead line under test at the same time, the present invention provides a signal injection method based on the vehicle-mounted power supply and the UAV-mounted sensor to greatly increase the AC voltage and current injected into the overhead line, such as Figure 2 As shown, specifically including:

[0042] The battery and inverter are carried on the maintenance vehicle. The inverter converts the DC voltage and current generated by the battery into AC voltage and current, and then transmits them to the distribution transformer through a high-voltage cable for boosting. The boosted AC voltage and current are transmitted to the overhead line under test. Among them, the electric field signal and magnetic field signal are collected by the electric field sensor and magnetic field sensor carried on the drone.

[0043] In the embodiment of the present invention, the AC voltage and current are fed back to the 10 kV overhead line under test through the distribution transformer.

[0044] Preferably, the frequency of the AC current output by the inverter is 60HZ-100HZ, which improves the reverse power transmission efficiency while avoiding interference from the industrial frequency electromagnetic field (50HZ).

[0045] In the embodiment of the present invention, the battery is carried by the maintenance vehicle, and the capacity can reach 80 ah. The vehicle-mounted inverter moves with the vehicle during maintenance, fully ensuring flexibility and portability.

[0046] The present invention takes into account that due to the requirement of the flight distance between the UAV and the overhead lines, it is impossible to make the sensors carried on the UAV directly close to the overhead lines, so that the measured fault signals are often very weak. Based on this, the present invention uses a distribution transformer for reverse power transmission. Under normal circumstances, the high voltage is converted into a low voltage and transmitted to the user through the distribution transformer. The present invention uses a distribution transformer to convert the low-voltage AC voltage and current provided by the on-board power supply into a high-voltage voltage and current, which greatly improves the voltage and current signals injected into the overhead lines, so that the method of the present invention can be applied to the sensors carried by the UAV to quickly identify and judge the fault location information.

[0047] In addition, the present invention uses the distribution transformer to reverse power and injects signals at the low-voltage end of the distribution transformer, eliminating the need for manual pole climbing and wire hanging operations, which saves manpower on the one hand and ensures the safety of inspection personnel on the other. At the same time, the use of primary energy (batteries and inverters) integrated in the maintenance vehicle also improves the flexibility of the detection location.

[0048] Example 2

[0049] The embodiment of the present invention provides a single-phase grounding fault location system for overhead lines in a power distribution network, which mainly includes:

[0050] The signal injection module is used to inject AC voltage and current into the overhead line under test at the same time after a single-phase grounding fault occurs in the overhead line of the distribution network. The injected AC voltage and current generate electric field and magnetic field on the overhead line under test accordingly.

[0051] Electric field sensor, used to collect electric field signals on the overhead line under test;

[0052] A magnetic field sensor is used to collect magnetic field signals on the overhead line under test;

[0053] A fault identification module is used to calculate the instantaneous value of voltage at different positions on the measured overhead line based on the electric field signal, and to calculate the instantaneous value of current at different positions on the measured overhead line based on the magnetic field signal; and to calculate the full-cycle Fourier algorithm amplitude of the instantaneous voltage value and the instantaneous current value respectively; and to integrate the product of the instantaneous voltage value and the instantaneous current value within a cycle to obtain the integral value at different positions on the measured overhead line; after multiplying the full-cycle Fourier algorithm amplitude of the instantaneous voltage value with the full-cycle Fourier algorithm amplitude of the instantaneous current value, the amplitude product value at different positions on the measured overhead line is obtained; the integral value is divided by the amplitude product value to obtain the ratio coefficient at different positions on the measured overhead line, so as to construct a function of the ratio coefficient with respect to different positions on the measured overhead line; wherein a single-phase grounding fault occurs at the position corresponding to the maximum value of the first-order derivative of the function.

[0054] As a preferred implementation, the distribution network overhead line single-phase grounding fault location system in the embodiment of the present invention further includes a drone for carrying an electric field sensor and a magnetic field sensor, and the signal injection module includes a vehicle-mounted power output device. The vehicle-mounted power output device includes a battery and an inverter mounted on a maintenance vehicle.

[0055] The inverter is used to invert the DC voltage and current generated by the battery into AC voltage and current; the AC voltage and current are transmitted to the distribution transformer through high-voltage cables for boosting; the boosted AC voltage and current are transmitted to the overhead line under test.

[0056] In the embodiment of the present invention, the electric field sensor is a three-dimensional electric field vector sensor, which adopts a six-electrode structure with arc surfaces equally divided, can fully sense the electric field vector components in space, has a broadband measurement capability within the range of 10MHz, and has good anti-angle measurement deviation characteristics. In the embodiment of the present invention, the magnetic field sensor is a giant magneto-impedance sensor, which has the characteristics of high sensitivity, high linearity, and high flexibility, and can detect magnetic fields in the range of 10-10 to 10-2T; the three-axis orthogonality is good, and it can self-correct the magnetic field measurement error caused by the change of sensor posture caused by the movement of the drone.

[0057] Preferably, it also includes a communication unit carried on the drone, which is used to receive and store electric field signals and magnetic field signals collected by the electric field sensor and the magnetic field sensor, and send the electric field signals and magnetic field signals to the fault identification module.

[0058] In the embodiment of the present invention, the fault identification module is Figure 2 The ground data processing device, the UAV, and the electric field sensor, the magnetic field sensor and the communication unit carried on the UAV constitute the vehicle-mounted current output device.

[0059] like Figure 3As shown in FIG. 1 , an equivalent circuit diagram of a distribution network system when a single-phase grounding fault occurs in an embodiment of the present invention, U AB is the line voltage of the AB phase line, U BC is the line voltage of BC phase line, U CA is the line voltage of the CA phase line, C is the total ground capacitance of the entire line, C1 is the ground capacitance of the line before the fault, C2 is the ground capacitance of the line after the fault, and R is the resistance value of the single-phase grounding fault. The method or system for locating the single-phase grounding fault of the overhead line of the distribution network of the present invention performs fault locating, and the calculated position of the ratio coefficient mutation is at R, so it can be determined that the single-phase grounding fault occurs at R.

[0060] The present invention adopts a vehicle-mounted power output device for reverse power transmission, which can greatly improve the strength of the injected signal. In conjunction with the electric field and magnetic field sensors carried by the drone, it can achieve rapid and accurate positioning of the single-phase grounding fault point in the distribution network, thereby improving the reliability of power supply.

[0061] In summary, the on-board current output device is combined with the distribution transformer for reverse power transmission, the amplitude of the injected signal is strengthened, and the signal-to-noise ratio is improved to the maximum extent possible. When cooperating with the drone to locate the single-phase grounding fault of the distribution network, the electric field sensor and the magnetic field sensor are used to capture the fault signal (injected current and voltage), and the ratio coefficient is used to determine the location of the fault point. During the entire maintenance process, there is no need for manual climbing of poles and hanging wires. Only remote control of the drone is required for non-contact measurement, which reduces the difficulty of the inspection personnel's work, improves the inspection efficiency, and can better ensure the safety of the inspection personnel.

[0062] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for locating a single-phase ground fault of an overhead line in a distribution network, characterized in that: include: After a single-phase grounding fault occurs in the overhead line of the distribution network, an AC voltage and a current are simultaneously injected into the overhead line under test, and the AC voltage and the current generate an electric field and a magnetic field on the overhead line under test accordingly; And collect the electric field signal and magnetic field signal on the overhead line under test; Based on the electric field signal and the magnetic field signal, respectively calculate the instantaneous voltage value and the instantaneous current value at different positions on the overhead line under test; and respectively calculate the full-cycle Fourier amplitude of the instantaneous voltage value and the instantaneous current value; Integrating the product of the instantaneous value of the voltage and the instantaneous value of the current within an electric field or magnetic field alternation cycle to obtain integral values ​​at different positions on the measured overhead line; The integrated value is divided by the product of the full-cycle Fourier amplitude of the instantaneous value of the voltage and the instantaneous value of the current to obtain the ratio coefficient at different positions on the measured overhead line, so as to construct a function of the ratio coefficient between different positions on the measured overhead line; wherein a single-phase grounding fault occurs at the position corresponding to the maximum value of the first-order derivative of the function.

2. The method for locating a single-phase ground fault of an overhead line in a distribution network according to claim 1, characterized in that: Simultaneously inject AC voltage and current into the overhead line under test, including: The battery and inverter are mounted on a maintenance vehicle. The inverter converts the DC voltage and current generated by the battery into AC voltage and current, and then transmits the converted voltage to a distribution transformer through a high-voltage cable for voltage boosting. The boosted AC voltage and current are injected into the overhead line under test. The electric field signal and magnetic field signal are collected by electric field sensors and magnetic field sensors mounted on a drone.

3. The method for locating a single-phase ground fault of an overhead line in a distribution network according to claim 2, characterized in that: The frequency of the alternating current generated by the inverter is 60HZ-100HZ.

4. A distribution network overhead line single-phase grounding fault location system, characterized in that: include: A signal injection module is used to simultaneously inject an AC voltage and a current into the overhead line under test after a single-phase grounding fault occurs in the overhead line of the distribution network, wherein the AC voltage and the current generate an electric field and a magnetic field on the overhead line under test; Electric field sensor, used to collect electric field signals on the overhead line under test; A magnetic field sensor is used to collect magnetic field signals on the overhead line under test; A fault identification module, used to calculate the instantaneous voltage value and the instantaneous current value at different positions on the measured overhead line based on the electric field signal and the magnetic field signal, and to calculate the full-cycle Fourier amplitude of the instantaneous voltage value and the instantaneous current value; and to integrate the product of the instantaneous voltage value and the instantaneous current value within an electric field or magnetic field alternation cycle to obtain the integral value at different positions on the measured overhead line; The integrated value is divided by the product of the full-cycle Fourier amplitude of the instantaneous value of the voltage and the instantaneous value of the current to obtain the ratio coefficient at different positions on the measured overhead line, so as to construct a function of the ratio coefficient between different positions on the measured overhead line; wherein a single-phase grounding fault occurs at the position corresponding to the maximum value of the first-order derivative of the function.

5. The distribution network overhead line single-phase grounding fault location system according to claim 4, characterized in that: It also includes a drone for carrying the electric field sensor and the magnetic field sensor; and the signal injection module includes a battery and an inverter carried on the maintenance vehicle; The inverter is used to invert the DC voltage and current generated by the battery into AC voltage and current; wherein the AC voltage and current are transmitted to the distribution transformer through a high-voltage cable for boosting, and the boosted AC voltage and current are injected into the overhead line under test.

6. The distribution network overhead line single-phase grounding fault location system according to claim 5, characterized in that: Also included is a communication unit carried on the drone; The communication unit is used to receive and store the electric field signal and the magnetic field signal collected by the electric field sensor and the magnetic field sensor, and send the electric field signal and the magnetic field signal to the fault identification module.

7. The distribution network overhead line single-phase grounding fault location system according to claim 4 or 5, characterized in that: The electric field sensor is a three-dimensional electric field vector sensor with six electrodes having arc surfaces equally divided.

8. The distribution network overhead line single-phase grounding fault location system according to claim 4 or 5, characterized in that: The magnetic field sensor is a giant magneto-impedance sensor.

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