Distribution line fault detecting and positioning device and searching method

Abstract

The invention provides a distribution line fault detection and positioning device and a searching method, the device comprises a transmitter and a receiver, the transmitter injects alternating current and direct current signals to a fault line to reproduce a ground fault, current is output by the transmitter, flows through the fault line, enters the ground at a fault ground point and returns to the transmitter, and the receiver receives the fault line. The transmitter measures direct current impedance and alternating current impedance of a fault line according to received signals, a proper positioning mode is given according to the measured impedance, under the determined positioning mode, the transmitter transmits corresponding signals to the fault line, the receiver analyzes and processes the received current signals and direct current pulse signals at the moment, and the fault line is positioned according to the current signals and the direct current pulse signals. And determining a line fault position. The distribution line fault detection and positioning device and the searching method are reasonable in design, simple to operate, convenient to use and carry, and can quickly solve various fault types such as low-resistance faults, high-resistance faults, arc grounding faults and interphase short-circuit faults.

Description

Technical Field

[0001] The present invention relates to the technical field of power fault detection equipment, and in particular to a 0.4-35kV distribution line fault detection and positioning device and a search method. Background Art

[0002] With the rapid development of science and technology and the continuous rise of social economy, electronic technology has developed rapidly, and computer systems and other electronic information equipment have long been deeply rooted in all walks of life. The widespread application of these electronic devices has made people's requirements for the stability of power line operation higher and higher. Once a problem occurs in the power line, it will cause unnecessary direct and indirect economic losses. Therefore, the normal operation of the transmission and distribution line is directly related to the safe, reliable and stable operation of the power system, and also to the orderly development of the entire national economy.

[0003] The terminal of 6-35kV high-voltage distribution line power transmission is an important part of the power system. The distribution line of Shengli Oilfield is more than 8,000 kilometers long, with many points, long lines, wide areas, many equipments, and a relatively complex operating environment. The accident rate of distribution line accounts for 85% of the power system failures. The manifestations of the fault are mainly single-phase grounding, two-phase short circuit, three-phase short circuit and phase loss. After the high-voltage distribution line fails and stops operating, it can only rely on manual inspection of the equipment on each pole, and the cable heads at both ends of the line must be removed before the megohmmeter can be used for detection. On average, it takes about 2 hours to detect a cable fault, which is time-consuming and laborious. In the event of a hidden fault, it is necessary to use the method of climbing the pole one by one and testing in sections to find the fault. Especially hidden fault points cannot be found even in three to five days. It is difficult to find the fault point, the power staff is inefficient, and the labor intensity is extremely high.

[0004] When a low-resistance fault occurs in a 0.4-35kV cable line, there is no discharge sound at the fault point, and the fault point cannot be located through a handset. The faulty cable needs to be replaced, affecting crude oil production.

[0005] Faults in the low-voltage distribution lines of oil wells and lines for production, offices, and residents, especially those after modification, are caused by irregular wiring, making it difficult for maintenance personnel to find out the exact location of the line path and fault points. Some of the faults require several days or even "breaking walls" to be resolved, greatly affecting oil well production and domestic electricity use.

[0006] At present, the power system uses a small current grounding line selection device, which can quickly find the grounding fault when the line is energized, but it cannot find and locate the broken line and short circuit fault of the power line. In addition, when the power line is not energized, the small current grounding line selection instrument, which is energized to find faults, cannot play a role. Fault query is very difficult and has great limitations. In addition, there are certain misjudgments in the judgment and location of grounding faults.

[0007] In the Chinese patent application with application number: CN202111382320.4, a small current overhead line grounding fault location device and a fault location method are involved. The location device includes a transmitter, an AC sensor and a receiver. The transmitter includes an analog fault signal transmitter and a transmitting wire connected to the transmission line. The AC sensor includes an induction antenna and a processing circuit. The induction antenna includes a ferrite core and an induction coil. The induction antenna receives the electromagnetic signal radiated from the fault point of the transmission line to generate an induced electromotive force. The processing circuit performs signal processing on the induced electromotive force to obtain a sinusoidal signal reflecting the change of the induced electromotive force. The receiver displays the sinusoidal signal as a sinusoidal waveform through a display screen. The beneficial effect of the invention is that the fault location device can change the relative position of the handheld AC sensor and the receiver to observe the sinusoidal signal reflecting the change of the induced electromotive force, thereby determining the specific position of the fault, thereby achieving the effect of locating the fault and improving the accuracy of fault location.

[0008] In the Chinese patent application with application number: CN201620596593.7, a fault location device for a small current grounding system is involved, which includes a voltage sampling module, a current sampling module, a wireless transmission module, a 32-bit ARM processor and a mobile terminal. The voltage sampling module and the current sampling module transmit the transmission line information to the 32-bit ARM processor through the wireless transmission module; the 32-bit ARM processor sends the information to the mobile terminal. The utility model improves the accuracy and work efficiency of fault judgment, reduces production and operation costs and daily maintenance costs, and can timely understand the fault status, quickly determine the fault location, perform data query, and participate in troubleshooting.

[0009] In the Chinese patent application with application number: CN202021472143.X, a grounding fault locating device for a line in an ultra-low frequency and low current grounding system is involved. The fault locating device includes a transmitter and a handheld receiver matched therewith. The transmitter is used to apply an ultra-low frequency pulsating DC signal to the fault line to reproduce the grounding fault. The transmitter is connected to a signal sensor suspended on the faulty power grid through an output connecting line. The signal sensor is used to detect the current signal along the line and is wirelessly connected to the handheld receiver. The output connecting line is wound on the wiring board. The structural design of this utility model is scientific and reasonable, with high practicality. It can quickly determine the grounding fault point of the distribution line, with accurate direction, reducing labor intensity and improving the efficiency of distribution line operation and maintenance.

[0010] In the Chinese patent application with application number: CN201110066090.0, an online positioning method for a small current grounding fault and a positioning device based on the positioning method are involved. The method is applicable to a 3-60kV neutral point non-effectively grounded power grid. When the line is running with a single-phase grounding fault, an AC signal of 130-230Hz (excluding the integral multiple frequency of 50Hz) is injected from the substation PT, the voltage phasor of the injected signal is measured in the substation, the current phasor of the injected signal is measured on the line, and the section position of the fault point is determined according to the phase relationship between the injected signal voltage and the current phasor. The positioning device of the invention consists of two parts: an upper computer and a lower computer. The upper computer device is installed in the substation and is used to inject an AC signal of 130-230Hz (excluding the integral multiple frequency of 50Hz) from the substation PT and measure the voltage phasor of the busbar injected signal. The lower computer device is installed on the line to measure the current phasor of the injected signal. The lower computer uploads the measurement result to the upper computer, and finally the upper computer performs phasor analysis and completes the positioning calculation. The invention has mature technology and high reliability.

[0011] The above existing technologies are greatly different from the present invention and fail to solve the technical problem we want to solve. For this reason, we have invented a new distribution line fault detection and positioning device and search method. Summary of the invention

[0012] The purpose of the present invention is to provide a distribution line fault detection and positioning device and search method which has a short fault query and positioning time, reduces accidental power outage time and power loss, reduces work intensity and cost, improves work efficiency and service quality, and has great practical application value.

[0013] The purpose of the present invention can be achieved through the following technical measures: a distribution line fault detection and positioning device, which includes a transmitter and a receiver. The transmitter injects AC and DC signals into the fault line to reproduce the ground fault. The current is output by the transmitter and flows through the fault line, enters the ground at the fault grounding point and returns to the transmitter. The transmitter measures the DC impedance and AC impedance of the fault line according to the received signal, and selects the corresponding positioning mode according to the measured impedance. In the determined positioning mode, the transmitter transmits the corresponding signal to the fault line. The receiver then analyzes and processes the received AC current signal or DC pulsating signal of the fault line through magnetic field induction to determine the line fault location.

[0014] The purpose of the present invention can also be achieved by the following technical measures:

[0015] The signal injected by the transmitter into the fault line is AC 0-1kV, dual-frequency signal and 0-15kV DC signal, and the DC impedance R, AC impedance Zlr and distributed capacitance C of the fault line are measured, and the corresponding positioning mode is given according to the measured impedance.

[0016] The distribution line fault detection and positioning device also includes a direct connection sensor. When the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 5 kilo-ohms, the transmitter selects high-voltage AC positioning and direct connection output mode to start, and sends out 0-1kV, AC dual-frequency signals. The fault line and the fault point form a loop. The transmitter measures the current value and resistive current content of the fault loop. The direct connection sensor is inserted into the receiver. The receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable for reception. The received signal is processed to obtain the current value and resistive current content. If it is resistive, it is a fault signal, and if it is capacitive, it is not a fault signal. The resistive current content and current value are fixed before the fault point, and are significantly reduced after the fault point, so as to judge the fault point.

[0017] The distribution line fault detection and positioning device also includes an AC booster and a hanging sensor. When the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 200 kilo-ohms, the transmitter selects high-voltage AC positioning and external booster output mode to start, and sends 0-1kV, AC dual-frequency signals to the AC booster. The AC booster boosts the AC dual-frequency signal to AC high voltage and then outputs it to the fault line and the fault point to form a loop. The hanging sensor is hung on the fault line, collects AC current signals and sends them to the receiver. The receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable to receive the AC current signal and determine the fault point based on the obvious change in current before and after the fault point. In addition, the fault finding and locating instrument can find the short circuit (and ungrounded) fault point. First, determine which two phases of the three phases are short-circuited: inject the signal into the middle phase of the power line, and artificially ground any phase on the two sides. If the current signal is monitored, this phase is short-circuited with the middle phase; if there is no current signal, artificial grounding is switched to another phase, and the monitoring method is the same; if there is no current signal on both sides, it is determined that the two phases are short-circuited, and artificial grounding and injection signals are connected to the two phases respectively. At this time, the method of measuring short-circuit faults is the same as that of testing grounding faults.

[0018] When the DC impedance is greater than 5 kilo-ohms and the AC impedance is less than 2 megohms, the transmitter selects the high-voltage DC positioning mode to start, and transmits a 0-15kV DC high-voltage signal to the fault line and the fault point to form a loop. The transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement result. Before the fault point, the current waveform continues to exist, and after the fault point, the current waveform disappears. The receiver first performs a rough segmentation and then accurately locates the fault, thereby quickly determining the fault location.

[0019] After a single-phase grounding fault occurs in a low-current grounding overhead line, fault location is allowed during live operation. The direct-connected sensor is inserted into the receiver. The transmitter selects the high-voltage live mode to start and receives the characteristic signal current value of the measured line vertically directly below the faulty overhead line or directly above the faulty cable. The receiver processes the received signal and displays and judges the horizontal component and vertical component of the measured 5th harmonic current and the current size. When the ratio of the vertical component to the horizontal component of the measured signal is positive, the pointer points to normal, and the larger the ratio, that is, the greater the absolute value, the greater the deflection; when the ratio is negative, the pointer points to the fault, and the larger the ratio, that is, the greater the absolute value, the greater the deflection; the vertical component is greater than the horizontal component in a normal line; the horizontal component is greater than the vertical component in a faulty line. After the line is successfully selected, the specific location of the fault point is gradually found along the fault line to the power user side. Before the fault point, the fault information is displayed as: the horizontal component is greater than the vertical component, and it returns to normal after the fault point: the vertical component is greater than the horizontal component.

[0020] The distribution line fault detection and positioning device also includes an arc grounding adapter. In the DC fixed-point mode, when the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, the arc grounding adapter needs to be connected; the transmitter selects the high-voltage DC positioning mode to start, and inputs a 0-15kV DC high-voltage signal to the fault line and the fault point to form a loop. The transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement result; before the fault point, the signal continues to exist, and after the fault point, the signal disappears; the point where the signal suddenly changes is the location of the fault point.

[0021] When detecting and locating faults in 0.4kV low-voltage lines, when the AC impedance is less than 1 kilo-ohm, the transmitter selects the direct output mode to start, and sends out a 0-1kV, AC dual-frequency signal. The fault line and the fault point form a loop. The transmitter measures the current value and resistive current content of the fault loop. The direct sensor is inserted into the receiver, and the receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable for reception. The received signal is processed to obtain the current value and resistive current content. If it is resistive, it is a fault signal, and if it is capacitive, it is not a fault signal. The resistive current content and current value are fixed before the fault point, and they are significantly reduced after the fault point, so as to judge the fault point.

[0022] When detecting and locating faults in 0.4kV low-voltage lines, when the AC impedance is greater than 1 kilo-ohm, the transmitter selects high-voltage AC positioning and direct output mode to start, and sends 0-1kV, AC dual-frequency signals to the AC booster. The AC booster boosts and rectifies the AC dual-frequency signals and then outputs DC high voltage. The fault point is discharged through the manual discharge button, and the fault point is quickly located by sound, or the discharge cycle and discharge voltage are set through the transmitter.

[0023] When the acceptance test is carried out after the fault is repaired, the transmitter chooses the DC withstand voltage mode to start, and the maximum single execution time is 5 minutes. It will automatically exit at the end of the time, and can also be stopped manually at any time.

[0024] The purpose of the present invention can also be achieved by the following technical measures: a distribution line fault detection and positioning method, the distribution line fault detection and positioning method adopts a distribution line fault detection and positioning device, including:

[0025] Step 1: The transmitter injects AC and DC signals into the fault line to reproduce the ground fault. The current is output by the transmitter and flows through the fault line, enters the ground at the fault grounding point and returns to the transmitter.

[0026] Step 2: The transmitter measures the DC impedance and AC impedance of the fault line according to the received signal, and selects a corresponding positioning mode according to the measured impedance;

[0027] Step 3: In the determined positioning mode, the transmitter transmits the corresponding signal to the faulty line. The receiver then analyzes and processes the received AC current signal or DC pulsating signal of the faulty line through magnetic field induction to determine the line fault location.

[0028] The purpose of the present invention can also be achieved by the following technical measures:

[0029] In step 2, the transmitter injects 0-1 kV AC, dual-frequency and 0-15 kV DC signals into the fault line, measures the DC impedance R, AC impedance Zlr and distributed capacitance C of the fault line, and gives a corresponding positioning mode according to the measured impedance.

[0030] In step 2, when the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 5 kilo-ohms, the transmitter selects high-voltage AC positioning and direct output mode to start; when the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 200 kilo-ohms, the transmitter selects high-voltage AC positioning and external booster output mode to start; after a single-phase grounding fault occurs in a low-current grounding overhead line, fault positioning is allowed during live operation, and the receiver selects high-voltage live mode to start; in DC fixed-point mode, when the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, the transmitter selects high-voltage DC positioning mode to start; when detecting and locating a fault on a 0.4kV low-voltage line, when the AC impedance is less than 1 kilo-ohm, the transmitter selects direct output mode to start; when detecting and locating a fault on a 0.4kV low-voltage line, when the AC impedance is greater than 1 kilo-ohm, the transmitter selects high-voltage AC positioning and direct output mode with an external AC boost rectifier to start.

[0031] In step 3, when the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 5 kilo-ohms, and the transmitter selects high-voltage AC positioning and direct output mode to start, it sends out 0-1kV, AC dual-frequency signal, and the fault line and the fault point form a loop; the transmitter measures the current value and resistive current content of the fault loop, and the direct sensor is inserted into the receiver. The receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable for reception, and the received signal is processed to obtain the current value and resistive current content. If it is resistive, it is a fault signal, and if it is capacitive, it is not a fault signal. The resistive current content and current value are fixed before the fault point, and are significantly reduced after the fault point, so as to judge the fault point.

[0032] In step 3, when the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 200 kilo-ohms, the transmitter selects the high-voltage AC positioning and external booster output mode to start, and sends 0-1kV, AC dual-frequency signal to the AC booster. The AC booster boosts the AC dual-frequency signal to the AC high voltage and outputs it to the fault line and the fault point to form a loop. The suspension sensor is hung on the fault line, collects the AC current signal and sends it to the receiver. The receiver receives it under the faulty overhead line or at the faulty cable, receives the AC current signal, and determines the fault point according to the obvious change of the current before and after the fault point. In addition, the fault finding and locating instrument can find the short-circuit (and ungrounded) fault point. First, determine which two phases of the three phases are short-circuited: inject the signal into the middle phase of the power line, and artificially ground any one of the two phases. If the current signal is monitored, this phase is short-circuited with the middle phase; if there is no current signal, the artificial grounding is changed to another phase, and the monitoring method is the same; if there is no current signal on both sides, it is judged that the two phases are short-circuited, and the artificial grounding and the injection signal are respectively connected to the two phases. At this time, the method for testing short-circuit fault is the same as that for testing ground fault.

[0033] In step 3, when the DC impedance is greater than 5 kilo-ohms and the AC impedance is less than 2 megohms, and the transmitter selects the high-voltage DC positioning mode to start, the DC high-voltage signal is input to the fault line and the fault point to form a loop, and the transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement result. Before the fault point, the current waveform continues to exist, and after the fault point, the current waveform disappears. The receiver first performs rough segmentation and then accurately locates the fault, thereby quickly determining the fault location.

[0034] In step 3, when a single-phase grounding fault occurs in a low-current grounding overhead line, the transmitter selects the high-voltage live mode to start. The transmitter receives the current value of the characteristic signal of the measured line vertically directly below the faulty overhead line or directly above the faulty cable. The receiver processes the received signal, and displays and judges the horizontal component and vertical component of the measured 5th harmonic current and the current size. When the ratio of the vertical component to the horizontal component of the measured signal is positive, the pointer points to normal, and the larger the ratio, that is, the greater the absolute value, the greater the deflection; when the ratio is negative, the pointer points to the fault, and the larger the ratio, that is, the greater the absolute value, the greater the deflection; the vertical component is greater than the horizontal component in a normal line; the horizontal component is greater than the vertical component in a faulty line. After the line is successfully selected, the specific location of the fault point is gradually found along the fault line to the power consumption side. Before the fault point, the fault information is displayed as: the horizontal component is greater than the vertical component, and after the fault point, it returns to normal: the vertical component is greater than the horizontal component.

[0035] In step 3, when the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, and the transmitter selects the high-voltage DC positioning mode to start, the transmitter transmits a 0-15kV DC high-voltage signal to the fault line and the fault point to form a loop, and the transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement result; before the fault point, the signal continues to exist, and after the fault point, the signal disappears; the point where the signal suddenly changes is the location of the fault point.

[0036] In step 3, the fault of the 0.4kV low-voltage line is detected and located. The AC impedance is less than 1 kilo-ohm. When the transmitter selects the direct output mode to start, the transmitter sends a 0-1kV, AC dual-frequency signal. The fault line and the fault point form a loop. The transmitter measures the current value and resistive current content of the fault loop. The direct sensor is inserted into the receiver. The receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable for reception. The received signal is processed to obtain the current value and resistive current content. If it is resistive, it is a fault signal. If it is capacitive, it is not a fault signal. The resistive current content and current value before the fault point are fixed, and they become significantly smaller after the fault point, so as to judge the fault point.

[0037] In step 3, the fault of the 0.4kV low-voltage line is detected and located. When the AC impedance is greater than 1 kilo-ohm and the transmitter selects high-voltage AC positioning and direct output mode to start, the transmitter sends a 0-1kV, AC dual-frequency signal to the AC boost rectifier. The AC boost rectifier boosts the AC dual-frequency signal and outputs a DC high voltage. The fault point is discharged through the manual discharge button, and the fault point is quickly located by sound, or the discharge cycle and discharge voltage are set through the transmitter.

[0038] The distribution line fault detection and positioning device and search method of the present invention are designed to address the shortcomings of the prior art and combine the actual situation of the power line site. The distribution line fault detection and positioning device is equipped with a large-capacity lithium battery. In addition, the distribution line fault detection and positioning device can inject a signal into the fault line when the power line is out of power, so that the fault phenomenon can be reproduced. Through the detection of the distribution line fault detection and positioning device, various fault types such as low-voltage fault, low-resistance fault, high-resistance fault, and phase-to-phase short-circuit fault of the transmission and distribution line can be solved, and the fault point can be accurately and quickly found and located. Faults such as disconnection and short circuit of the power line can also be quickly and accurately found and located.

[0039] Compared with the prior art, the present invention has the following advantages: reasonable design, simple operation, easy use, and easy to carry. It can quickly solve various fault types such as low-resistance faults, high-resistance faults, arc grounding faults, and phase-to-phase short circuit faults. It can also quickly and accurately judge faults, find and locate the fault points of power lines when the lines are not energized. It also has a 0.4kV low-voltage line detection and positioning mode, providing a complete set of distribution line fault positioning solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Attached Figure 1 It is a schematic diagram of the signal injection technology of the present invention;

[0041] Attached Figure 2 It is a schematic diagram of the structure of the transmitter in the present invention;

[0042] Attached Figure 3 It is a schematic diagram of the receiver structure in the present invention;

[0043] Attached Figure 4 It is a schematic diagram of the structure of the AC booster in the present invention;

[0044] Attached Figure 5 It is a schematic diagram of a transmitter fault diagnosis interface in the present invention;

[0045] Attached Figure 6 It is a schematic diagram of the AC positioning interface of the transmitter in the present invention;

[0046] Attached Figure 7 It is a schematic diagram of the AC positioning interface of the receiver in the present invention;

[0047] Attached Figure 8 It is a schematic diagram of the interface before and after the AC positioning fault of the receiver in the present invention;

[0048] Attached Fig. 9 It is a schematic diagram of the use of the high voltage live mode instrument in the present invention;

[0049] Attached Fig.10 It is a schematic diagram of the high voltage live online positioning display interface of the receiver in the present invention;

[0050] Attached Fig.11 It is a schematic diagram of positioning and tracing of the high voltage live mode in the present invention;

[0051] Attached Fig.12 This is a wiring diagram for the external booster output mode;

[0052] Attached Fig.13 Schematic diagram for wiring the arc ground adapter;

[0053] Attached Fig.14 This is a schematic diagram of the direct output method. DETAILED DESCRIPTION

[0054] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0055] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0056] The distribution line fault detection and location device includes a transmitter, a receiver, a direct-connection sensor, a hanging sensor, an AC booster, an arc-grounding adapter, a wiring board, a transmitting rod and related accessories. The transmitter injects a signal into the fault line to reproduce the grounding fault. The signal is output by the transmitter and flows through the fault line, enters the ground at the fault grounding point and returns to the transmitter.

[0057] The transmitter's working modes include: low voltage detection and positioning, high voltage parameter measurement, high voltage AC positioning, high voltage DC positioning, high voltage DC withstand voltage, and high voltage live positioning.

[0058] The transmitter includes a 480WH lithium battery pack, a digital power amplifier unit, a display control unit, an AC / DC switching element, a DC boost unit and a voltage and current measurement feedback unit. The battery pack is connected to the display control unit and the power supply end of the digital power amplifier unit to provide them with power; the display control unit is connected to the digital power amplifier unit and can be used to select the working mode, indicate the wiring method required for the current working mode, indicate the measurement parameters such as the current output voltage or current, and display the recommended fixed-point method after fault diagnosis; the digital power amplifier unit can be directly boosted by the AC boost unit and then rectified into a DC signal, or output AC signal through AC / DC switching and externally connected to an AC boost transformer for boosting; the measuring end of the DC boost unit (AC boost transformer) is connected to the measuring jack, and the ground end is connected to the grounding jack; the high-voltage output jack can be connected to the line side of the switch cabinet using a short connecting wire, or it can be connected to the terminal post of the transmitting pole through an extended wiring panel, and then the transmitting pole is hung on the fault line, or connected to the AC input jack of the AC booster.

[0059] A protective grounding socket and a test grounding socket are provided on the panel of the transmitter. The protective grounding socket is grounded, and the test grounding socket is grounded or grounded through an AC booster.

[0060] The receiver includes a high-sensitivity current measurement antenna, a high-precision measurement unit, a data calculation processing unit, a human-machine interface unit and a 3000mAH lithium battery. The high-sensitivity current measurement antenna transmits the received current signal and the DC pulsating signal to the high-precision measurement unit, the high-precision measurement unit transmits the signal to the data calculation processing unit for analysis and processing, and the data calculation processing unit transmits the data to the human-machine interface unit for signal display.

[0061] The direct connection sensor is used for AC positioning-direct connection output mode. The direct connection sensor is inserted into the receiver directly below the line to receive the characteristic signal. The sensor detects the injected AC signal and measures the injected current and resistive current content in the line. The measurement results are displayed on the receiver LCD screen.

[0062] The suspension sensor is equipped with a 1500mAH lithium battery and is used for AC positioning with an external booster and DC positioning. It is installed on an insulating rod when in use and needs to be hung on the measured line to measure the characteristic signal. The sensor uses a high-sensitivity sensor and its magnetic circuit does not need to be closed. The sensor detects the current on the line, automatically performs zeroing, converts the analog signal into a digital signal, and transmits it wirelessly. The receiver on the ground receives the wireless signal sent by the suspension sensor and intuitively displays the measurement results on the LCD screen.

[0063] The AC booster is wired in an external booster output mode, the AC input jack is connected to the high-voltage output jack of the transmitter, the test ground input jack is connected to the test ground jack of the transmitter, the test ground output jack is grounded, and the AC output jack is connected to the transmitting rod through the wiring board. When the high-voltage output is started, the transmitter will output a high-voltage AC signal through the built-in booster of the AC boost rectifier or inject a high-voltage DC signal into the fault line through the rectifier output to locate the high-resistance fault. The voltage and current parameters displayed by the transmitter are the actual output of the AC booster.

[0064] When the arc grounding adapter is in DC fixed-point mode and the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, the arc grounding adapter input jack is connected to the transmitter high-voltage output jack, the power jack is connected to the transmitter charging interface, and the high-voltage output jack is connected to the transmitting rod through the wiring board to locate the arc grounding fault.

[0065] The function of the wiring board is to extend the wiring.

[0066] When the transmitting rod is directly connected to the output fault line which is an overhead line, the high voltage output jack of the transmitter is connected to the terminal post of the transmitting rod through the wiring board, and then the transmitting rod is hung on the fault line.

[0067] When the distribution line fault detection and positioning device of the present invention is in operation, the switch of the fault line is first disconnected to put the distribution line in a power-off state; the protective ground wire is connected to the "protective ground" terminal and the earth grid; the test ground wire (a high-voltage wire with a black clamp) is connected to the "test ground" socket and the earth grid; when the test ground and the protective ground are reliably grounded, the interface displays a grounding icon, and if they are not grounded or the grounding resistance is too large, the high-voltage output cannot be started.

[0068] To connect the output line of the faulty line, you can use a short connecting line (high-voltage wire with a red clamp) to connect the "high-voltage output" terminal and the line side of the switch cabinet according to the on-site conditions. If it must be connected to an overhead line, use a terminal block to extend the wiring. Connect the high-voltage plug to the "high-voltage output" terminal, and crimp the wire nose at the other end to the terminal post of the insulating hanging pole. Then hang the hanging pole on the faulty line to detect the line fault status and provide a suitable fixed-point method.

[0069] The "display control unit" is controlled through a human-machine friendly interface to send instructions to the "digital power amplifier unit" to output an AC 0-1kV dual-frequency signal (to avoid interference from 50Hz and distributed capacitance, the AC power supply output frequency is designed to be a dual-frequency signal) and a DC 0-15kV DC signal to the high-voltage output end, and the line DC impedance R, AC impedance Zlr, and distributed capacitance C are measured. The signal is fed back to the "digital power amplifier unit" through the "voltage and current measurement feedback unit" and displayed on the "display control unit" to the human-machine interface, showing the measured DC impedance and AC impedance, and giving a suitable positioning mode based on the measured impedance.

[0070] High-voltage AC positioning: When the AC impedance is less than 5 kilo-ohms, select "High-voltage AC positioning" -- "Direct output" mode -- Start on the transmitter control panel, and send AC dual-frequency signal instructions to the "digital power amplifier unit" and then to the "internal AC step-up transformer" through the internal "display control unit" to output 0-1kV through the test line to the fault line and the fault point to form a loop. The transmitter "display control panel" displays the "current value and resistive current content" of the fault loop. If it is resistive, it is a fault signal, and if it is capacitive, it is not a fault signal. The resistive current content and current value before the fault point are fixed, and they become significantly smaller after the fault point.

[0071] The working principle of the receiver is to use ultra-low frequency AC current signal long-distance measurement technology, 24-bit high-precision ADC and high-gain antenna to realize wireless induction detection of injected characteristic signals. The receiver is vertically placed directly below the line or directly above the cable for reception. The receiver's "high-sensitivity measurement antenna" feeds the received signal back to the "high-precision measurement unit" and then to the "data calculation and processing unit" for processing. Finally, the "current value and resistive current content" are displayed on the "human-machine interface display" to be consistent with the transmitter signal. The meaning of the measured value is the same as that of the transmitter. The receiver current value is the value calculated at a distance of 10m from the overhead line. The value increases proportionally when the distance is shortened, and decreases proportionally when the distance is increased.

[0072] High-voltage AC positioning (external booster output): When the AC impedance is less than 200 kilo-ohms, select "High-voltage AC positioning" -- "External booster output" mode -- Start on the transmitter control panel, and send an AC 1kV dual-frequency signal command to the "digital power amplifier unit" and then to the "internal AC boost transformer" signal to the high-voltage output to the "high-voltage boost rectifier". The AC boost rectifier boosts the voltage to AC high voltage through the booster, and then passes the test line to the fault line and the fault point to form a loop. The transmitter "display control panel" displays the voltage and current parameters as the actual output of the AC booster. The fan radius indicates the current size, with a maximum of 33mA. In addition, the fault finding and locating instrument can find the short circuit (and ungrounded) fault point. First, determine which two phases of the three phases are short-circuited: inject the signal into the middle phase of the power line, and artificially ground any phase on the two sides. If the current signal is monitored, this phase is short-circuited with the middle phase; if there is no current signal, artificial grounding is switched to another phase, and the monitoring method is the same; if there is no current signal on both sides, it is determined that the two phases are short-circuited, and artificial grounding and injection signals are connected to the two phases respectively. At this time, the method of measuring short-circuit faults is the same as that of testing grounding faults.

[0073] Turn on the power of the suspension sensor (unplug the direct-connected sensor), turn on the power of the receiver, and press the [Mode] key to set it to high-voltage AC positioning mode to display the suspension sensor measurement data, communication status and battery power interface. The receiver is vertically placed directly below the line or directly above the cable for reception. The receiver's "high-sensitivity measurement antenna" feeds the received signal back to the "high-precision measurement unit" and then to the "data calculation and processing unit" for processing. The current size is displayed on the human-machine interface.

[0074] High-voltage DC positioning: When the AC impedance is less than 2 megohms, the transmitter control panel selects the "high-voltage DC positioning" mode - start, and sends a command to the "digital power amplifier unit" through the internal "display control unit" to output the DC high-voltage signal through the "DC boost unit", and forms a loop through the test line to the fault line and the fault point. The transmitter "display control panel" displays the pulsating DC voltage and current signals.

[0075] The working principle of the receiver is to hang the hanging sensor on the line through the insulating rod along the line to detect the injected current. The sensor adopts a high-sensitivity sensor, and its magnetic circuit does not need to be closed, which greatly facilitates the hanging and taking operations. The sensor detects the current on the line, automatically performs zeroing operation, converts the analog signal into a digital signal and transmits it wirelessly. The receiver on the ground receives the wireless signal sent by the hanging sensor and displays the measurement results intuitively on the LCD screen. Before the fault point, the current waveform continues to exist, and after the fault point, the current waveform disappears. It can be roughly segmented first, and then accurately located, so as to quickly determine the fault location.

[0076] The receiver's 24-bit high-precision ADC and high-gain antenna enable wireless induction detection of injected characteristic signals. The receiver is placed vertically just below the line or just above the cable for reception. The receiver's "high-sensitivity measurement antenna" feeds the received signal back to the "high-precision measurement unit" and then to the "data calculation and processing unit" for processing. Finally, the "current waveform" is displayed on the "human-machine interface display" to be consistent with the transmitter signal.

[0077] High voltage live: After a single-phase grounding fault occurs in a low-current grounded overhead line, fault location is allowed during live operation. Ultra-low frequency AC current signal long-distance measurement technology, 24-bit high-precision ADC and high-gain antenna are used to achieve wireless induction detection of injected characteristic signals. The receiver is vertically located directly below the line or directly above the cable for reception. The receiver's "high-sensitivity measurement antenna" feeds the received signal back to the "high-precision measurement unit" and then to the "data calculation and processing unit" for processing. Finally, the "horizontal and vertical components of the measured 5th harmonic current and the current size" are displayed on the "human-machine interface display" for judgment.

[0078] Low voltage detection and positioning: suitable for fault detection and positioning of 0.4kV low voltage lines.

[0079] Low resistance is the same as “high voltage AC positioning” – “direct output”.

[0080] When the AC impedance is greater than 1 kilo-ohm, select "high voltage AC positioning" -- "direct output" mode -- start on the transmitter control panel, and send AC dual-frequency signal instructions to the "digital power amplifier unit" through the internal "display control unit" to output AC 0-1kV to the AC boost rectifier through the "internal AC boost transformer", first pass through the booster to boost, and then pass through the rectifier silicon stack to output 0-5100V DC high voltage, through the manual discharge button, the fault point is discharged, and the fault point is quickly located by sound. Or set the discharge cycle and discharge voltage through the transmitter main program.

[0081] When used for high-voltage AC positioning-direct output mode, insert the direct connection sensor into the receiver. When used for high-voltage AC positioning external booster and high-voltage DC positioning mode positioning, the suspension sensor is installed on the insulating rod and hung on the measured line to measure the characteristic signal. The receiver wirelessly receives the heterodyne signal injected by the transmitter in the vertical direction of the line or cable. In the DC positioning mode, when the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, the arc grounding adapter needs to be connected. Before the fault point, the signal continues to exist, and after the fault point, the signal disappears. The point where the signal suddenly changes is the location of the fault point.

[0082] The fault finding method using the distribution line fault detection and positioning device of the present invention comprises the following steps:

[0083] A. High-voltage parameter measurement: The fault line is in a power-off state, the protective ground wire is connected to the "protective ground" terminal and the earth network, and the test ground wire (high-voltage wire with a black clamp) is connected to the "test ground" socket and the earth network; the output line of the fault line can be connected to the "high-voltage output" terminal and the line side of the switch cabinet using a short connection line according to the on-site situation, or the wiring board can be used to extend the wiring and connect the "high-voltage output" terminal to the faulty overhead line. To detect the line fault state, use DC and AC methods respectively, measure the line DC impedance R, AC impedance Zlr, and distributed capacitance C, and give the corresponding fixed-point method. The details are shown in Table 1.

[0084] Table 1 High voltage parameter measurement fault diagnosis table

[0085]

[0086] By measuring the DC impedance, AC impedance, and distributed capacitance of the line to the ground, the fault type is determined and the appropriate positioning method is given. The high-voltage output of the transmitter is connected to the transmitting rod through the wiring panel and connected to the three phases A, B, and C. The test ground and the protection ground are grounded separately. Select the "Fault Diagnosis" mode when starting up, the equipment will perform parameter tests and give a fixed-point method. For low-resistance faults, the high-efficiency AC positioning method is recommended first. For high-resistance and arc grounding faults, the DC positioning method is recommended. When the arc is grounded, it is prompted to connect the arc grounding adapter. When it is determined that there is a grounded line PT, it is prompted to release the line PT first.

[0087] B. High-voltage AC positioning: It is suitable for low-resistance line faults. It can quickly locate the fault point without climbing the pole. The high-voltage output of the transmitter is connected to the transmitting pole through the wiring panel to the three phases A, B, and C. The test ground and the protection ground are grounded separately. Select the "high-voltage AC positioning" mode when turning on the machine. After confirming safety, start the high-voltage output. The transmitter will inject a specific current signal of a certain frequency into the fault line. The current is emitted by the transmitter, flows through the fault line, enters the ground at the grounding point, and returns to the transmitter through the earth. Directly below the overhead line, the receiver is inserted into a direct-connected sensor to detect the injected AC signal and measure the injected current and resistive current content in the line. Due to the existence of distributed capacitance, the current value before the fault point is the synthesis of resistive current and capacitive current, and the current value after the fault point is all capacitive current (resistive current content is 0%) and the value becomes smaller. Comparing the current value and resistive current content before and after the fault will cause obvious changes. Based on this, the position before and after the fault can be judged. Rough segmentation can be performed first, and then precise positioning can be performed to quickly determine the fault location.

[0088] C. High-voltage DC positioning: In the DC fixed-point mode, when the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, an arc grounding adapter needs to be connected; the transmitter selects the high-voltage DC positioning mode to start, and transmits a 0-15kV DC high-voltage signal to the fault line and the fault point to form a loop. The transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement results; before the fault point, the signal continues to exist, and after the fault point, the signal disappears. The point where the signal mutation occurs is the location of the fault point.

[0089] This mode requires climbing a pole, and can accurately locate difficult faults such as high-resistance grounding and arc grounding of the line. The high-voltage output of the transmitter is connected to the transmitting pole through the wiring panel to the three phases A, B, and C, and the test ground and the protective ground are grounded respectively. If the fault diagnosis is arc grounding, the high-voltage output needs to be connected to the line through an arc grounding adapter. Select the "DC injection" mode when turning on the power, and start the high-voltage output after confirming safety. The transmitter will inject an ultra-low frequency pulsating DC signal into the faulty line. The signal flows through the line to the fault point and into the ground. The hanging sensor is installed on the insulating pole. Climb the pole to hang the sensor on the fault phase to detect the signal. Another person holds a receiver under the line to receive the signal. When it is located in the fault section, the waveform is an obvious rectangular wave, and the non-fault section is an irregular curve with a very small amplitude. By judging the fault branch and dichotomy, the fault point is gradually approached and located.

[0090] D. DC withstand voltage: This mode is mainly used for verification after fault repair and DC test transmission. After the fault is successfully located and repaired, select the "DC withstand voltage" mode, start the high-voltage output after confirming safety, and start the withstand voltage test. It will stop automatically after 5 minutes, and can also be stopped manually at any time. It is recommended to do a DC withstand voltage test before and after the repair. The withstand voltage is low before the repair, and the withstand voltage is significantly improved after the repair. Because the output power is large during DC withstand voltage, you should avoid executing the DC withstand voltage function multiple times in a row.

[0091] E. High voltage live: After a single-phase grounding fault occurs in a low-current grounded overhead line, fault location is allowed during live operation. Hold the instrument horizontally directly below the line, keeping the instrument panel perpendicular to the line direction and perpendicular to the ground. Select the line at the position of each outgoing line on the power supply side, and the distance between adjacent lines must be greater than 100m. Normal line: the vertical component is greater than the horizontal component; fault line: the horizontal component is greater than the vertical component, and the sign is displayed. After the line selection is successful, the specific location of the fault point is gradually found along the fault line to the power consumption side. Before the fault point, it is manifested as fault information: the horizontal component is greater than the vertical component, and it returns to normal after the fault point: the vertical component is greater than the horizontal component. If the fault line has branches, the fault branch line is also judged according to the above method: the vertical component of the normal branch is greater than the horizontal component, and the horizontal component of the fault branch is greater than the vertical component.

[0092] Another method of fault location is to determine the fault point by comparing the current size. The current size at the fault location will change significantly, with a large current before the fault and a small current after the fault.

[0093] F. Low voltage AC positioning

[0094] 1. Wiring: First, turn off the switch of the faulty line to make the line power-off and remove all loads on the line. Use a grounding cable to connect the transmitter's "protective ground" to the earth grid; use a high-voltage wire with a black clamp to connect the "test ground" terminal to the N phase of the faulty line and connect it to the test ground or earth grid. Use a red high-voltage wire or extension wire to connect the "high-voltage output" to the faulty line under test (taking L-phase fault as an example).

[0095] Turn on the power of the transmitter, select the "low voltage AC positioning" mode, and start the high voltage output. Select the "low voltage AC" working mode for the receiver and connect the direct connection sensor. Inspect along the line. If the current value or resistive current content changes suddenly, it means that the fault point has been crossed.

[0096] The following are several specific embodiments of the present invention.

[0097] Example 1

[0098] In a specific embodiment 1 of the present invention, Figure 12 to Figure 14 As shown, attached Fig.12This is a wiring diagram for the external booster output mode; Fig.13 This is the wiring diagram of the arc grounding adapter; Fig.14 The diagram is a schematic diagram of the direct output mode. The distribution line fault detection and positioning device includes a transmitter ①, a receiver ②, a direct sensor ③, a hanging sensor ④, an AC booster ⑤, an arc grounding adapter ⑥, a wiring board ⑦, a transmitting rod ⑧ and related accessories. The working principle is: Figure 1 As shown, the transmitter ① injects a signal into the fault line to reproduce the ground fault, and the current is output by the transmitter ① and flows through the fault line, enters the ground at the fault grounding point and returns to the transmitter ①; when used for AC positioning-direct output mode, the direct connection sensor is inserted into the receiver, and when used for AC positioning with an external booster and DC positioning mode, the suspension sensor is installed on the transmitting rod ⑧ and hung on the measured line to measure the characteristic signal, and the receiver is held in the vertical direction of the line or cable to wirelessly receive the different frequency signal injected by the transmitter ①; in the DC fixed point mode, when the transmitter ① prompts an arc grounding fault or continuously prompts overcurrent protection, it is necessary to connect the arc grounding adapter ⑥; before the fault point, the signal continues to exist, and after the fault point, the signal disappears. The point where the signal suddenly changes is the location of the fault point.

[0099] The working modes of transmitter① include: low voltage detection and positioning, high voltage parameter measurement, high voltage AC positioning, high voltage DC positioning, and high voltage DC withstand voltage.

[0100] like Figure 2 As shown, the transmitter ① includes a 480WH lithium battery pack, a digital power amplifier unit, a display control unit, an AC / DC switching element, a DC boost unit, and a voltage and current measurement feedback unit, wherein the battery pack is connected to the display control unit and the power supply end of the digital power amplifier unit to provide power for them; the display control unit is connected to the digital power amplifier unit, and can be used to select the working mode, indicate the wiring method required for the current working mode, indicate the current output voltage or current and other measurement parameters, and display the recommended fixed-point method after fault diagnosis; the digital power amplifier unit can be directly boosted by the DC boost unit and then inverted into an AC signal, or output AC signals through AC / DC switching and externally connected to an AC boost transformer ⑤ for boosting; the measuring end of the DC boost unit (AC boost transformer) is connected to the measuring jack, and the ground end is connected to the grounding jack; the high-voltage output jack can be connected to the line side of the switch cabinet using a short connecting wire, or it can be connected to the terminal of the transmitting rod ⑧ through the wiring board ⑦ to extend the wiring, and then the transmitting rod ⑧ is hung on the fault line, or connected to the AC input jack of the AC booster ⑤.

[0101] A protective grounding socket and a test grounding socket are provided on the panel of the transmitter ①. The protective grounding socket is grounded, and the test grounding socket is grounded or grounded via an AC booster ⑤.

[0102] like Figure 3As shown, the receiver includes an antenna, an amplifying unit, a processing unit, a human-machine interface unit and a 6700mAH lithium battery. The antenna is used to receive signals and connect to the amplifying unit for amplification. The signal output by the amplifying unit is connected to the processing unit for analysis and processing. The human-machine interface unit connected to the processing unit displays the processed signal and controls the processing unit.

[0103] Direct-connect sensor, used for AC positioning - direct output mode, insert the direct-connect sensor into the receiver just below the line to receive the characteristic signal.

[0104] The suspension sensor is equipped with a 1500mAH lithium battery and is used for AC positioning with an external booster and DC positioning. It is installed on an insulating rod when in use and needs to be hung on the measured line to measure characteristic signals.

[0105] like Figure 4 As shown, the AC booster ⑤, under AC positioning, the AC input jack is connected to the high-voltage output jack of the transmitter, the test ground input jack is connected to the test ground jack of the transmitter, the test ground output jack is grounded, and the AC output jack is connected to the transmitter rod ⑧ through the wiring board ⑦ to locate the high-resistance fault.

[0106] When the arc grounding adapter ⑥ is in DC fixed-point mode and the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, the arc grounding adapter input jack is connected to the transmitter ① high-voltage output jack, the power jack is connected to the transmitter ① charging interface, and the high-voltage output jack is connected to the transmitter rod ⑧ through the wiring board ⑦ to locate the arc grounding fault.

[0107] The function of the wiring board ⑦ is to extend the wiring.

[0108] Transmitter pole⑧, when the directly connected output fault line is an overhead line, the high-voltage output jack of transmitter① is connected to the terminal of transmitter pole⑧ through the extension wiring of terminal board⑦, and then transmitter pole⑧ is hung on the fault line.

[0109] Example 2

[0110] The steps for fault location are as follows:

[0111] A. Fault diagnosis: By measuring the DC and AC impedance of the line to the ground, as well as the distributed capacitance and other parameters, the fault type is determined and the appropriate positioning method is given. The high-voltage output of the transmitter ① is connected to the transmitting rod ⑧ through the wiring board ⑦, and connected to the three phases A, B, and C. The test ground and the protection ground are grounded separately. Select the "fault diagnosis" mode when turning on the machine, and the equipment will perform parameter testing. Detect the fault status of the line, use DC and AC methods respectively, measure the DC impedance R, AC impedance Zlr, and distributed capacitance C of the line, and give a suitable positioning method.

[0112] The fault diagnosis interface is as follows: Figure 5As shown, according to the fault characteristics of the line, the appropriate positioning mode is given: for low-resistance faults, the high-efficiency AC positioning method is recommended first, and the DC positioning method is recommended for high-resistance and arc grounding faults. When the arc is grounded, it is prompted to connect the arc grounding adapter. When it is determined that there is a grounded line PT, it is prompted to release the line PT first.

[0113] B. AC positioning: It is suitable for low-resistance line faults. It can quickly locate the fault point without climbing the pole. The high-voltage output of transmitter ① is connected to the transmitting pole ⑧ through the wiring board ⑦ to the three phases A, B, and C. The test ground and the protection ground are grounded separately. Select the "AC injection" mode when turning on the machine. After confirming safety, start the high-voltage output. Transmitter ① will inject a specific current signal of a certain frequency into the fault line. The current is emitted by transmitter ①, flows through the fault line, enters the ground at the grounding point, and returns to transmitter ① through the earth. Directly below the overhead line, the receiver is inserted into the direct-connected sensor to detect the injected AC signal and measure the injected current and resistive current content in the line. Due to the existence of distributed capacitance, the current value before the fault point is the synthesis of resistive current and capacitive current, and the current value after the fault point is all capacitive current (resistive current content is 0%) and the value becomes smaller. Comparing the current value and resistive current content before and after the fault will cause obvious changes. Based on this, the position before and after the fault can be judged. Rough segmentation can be performed first, and then precise positioning can be performed to quickly determine the fault location.

[0114] As attached Figure 6 As shown, take the measured value 77 (90%, 170mA) 100V as an example:

[0115] 77 is the normalized value = resistive current content × output current ÷ 2. 100% is 100 for 200mA. 90% is the resistive current content. 100% means that the current current value is all resistive current, and the current line is completely resistive to the ground; 0% means that the current current value is all capacitive current, and the current line is completely capacitive to the ground, without fault. 170mA is the injected current value. 100V is the output voltage value. The sector radius indicates the current size, and the maximum direct connection mode is 200mA. The sector angle indicates the resistive current content.

[0116] As attached Figure 7 As shown in the figure, the meaning of the receiver measurement value is the same as that of the transmitter. The current value is calculated at a distance of 10m from the overhead line. The value increases proportionally with a shorter distance and decreases proportionally with an increased distance. The sector radius indicates the current magnitude, with a maximum of 200mA. The sector angle indicates the resistive current content. The real-time sector area is filled in green, corresponding to the real-time value. The memory sector area is not filled, corresponding to the memory value. If any of the current values ​​or resistive current content values ​​before and after the fault suddenly decreases, it means that the fault point has been crossed.

[0117] As attached Figure 8As shown, before the fault: the current value is the transmitter output current; it will change due to the distance between the direct sensor and the overhead line, but it will not change suddenly; the resistive current content is >50%. After the fault: the current value becomes smaller; the resistive current content decreases by <30% or the jump is unstable. The adjacent fault current enters the place vertically: due to the sharp shortening of the distance, the current value is inversely proportional to the distance, which is much larger than the transmitter current. This characteristic is used to locate the specific grounding pole; the resistive current content remains basically unchanged.

[0118] Fault location steps:

[0119] 1. Direct output mode wiring, set the transmitter to AC positioning - direct output mode, and start high voltage output.

[0120] 1. Near-end verification: Measure directly below the cable at a distance of about 50 meters on both sides of the transmitter. The side with a larger current value and resistive current content is the fault side. The sum of the currents at both ends is approximately equal to the transmitter current.

[0121] 2. Segment location: To quickly approach the fault point, it is recommended to perform 50% segmentation. Select the midpoint of the fault side line to detect the characteristic signal. If the fault current and resistive current content values ​​remain basically unchanged, it means that the fault point is still downstream; if any of the two parameters suddenly decreases, it means that the fault point has been crossed. After this segmentation is successful, continue 50% segmentation in the section where the fault point is located. The segments are getting shorter and shorter, and the fault point is gradually approached until the fault location is accurately found.

[0122] 3. Accurate location: When the fault current enters the ground vertically (<5 meters), the current value will increase as the distance shortens. When the AC sensor is close to the fault current entry point, the current value is very large (>5A), and the resistive current content value remains basically unchanged. This indicates that the pole is the fault grounding point.

[0123] 4. If there are branches in the line, the focus should be on the branch to determine whether the fault occurs in the trunk or the branch. If it is determined to be a branch fault, continue to locate the branch line in sections. If the cable of the branch line fails, the cable fault tester should be used to measure the distance and locate the point.

[0124] Example 3

[0125] In this embodiment, the external booster output, the voltage and current parameters displayed by the transmitter are the actual output of the AC booster. The sector radius indicates the current size, with a maximum of 33mA. Turn on the power of the suspension sensor (unplug the direct-connected sensor), turn on the power of the receiver, press the [Mode] key to set it to high-voltage AC positioning mode, and display the suspension sensor measurement data, communication status and battery power interface as shown in the attached figure. Fig. 9 The sector radius indicates the current size, with a maximum of 33mA.

[0126] Install the hanging sensor on the insulating pole, climb the pole and hang it on the measured line for measurement. Method for judging the fault phase and before and after the fault: hang the three-phase lines A, B, and C respectively. If the current value or resistive current content of one phase line is twice that of the other two phase lines, then this line is the fault line and is upstream of the fault.

[0127] When the current and resistive current content measured in the three-phase line are not significantly different, the following processing is required: If the measured three-phase currents are all around 11mA, reaching the maximum output capacity of the transmitter, it means that the distributed capacitance is large and needs to be further segmented to reduce the influence of the distributed capacitance. If segmentation is not possible, use the high-voltage DC positioning method. If the measured three-phase currents are all small (less than 6mA), it means that there is no fault or fault in this section of the line

[0128] The resistance is very high, and the AC method is not applicable. If a ground fault is confirmed, a high-voltage DC positioning method is required. When using the high-voltage DC positioning mode, if there is a grounded PT on the line, the grounded PT needs to be removed before using the DC positioning method.

[0129] DC positioning: This mode requires pole climbing and can accurately locate difficult faults such as high-resistance grounding and arc grounding of the line. The high-voltage output of the transmitter ① is connected to the transmitting pole ⑧ through the wiring board ⑦ to the three phases A, B, and C, and the test ground and the protective ground are grounded separately. If the fault diagnosis is arc grounding, the high-voltage output must be connected to the line through the arc grounding adapter ⑥. Select the "DC injection" mode when turning on the power, and start the high-voltage output after confirming safety. The transmitter will inject an ultra-low frequency 1Hz pulsating DC signal into the faulty line. The lower the frequency, the less it is affected by the distributed capacitance of the system. In theory, pure DC signals have the strongest ability to resist the influence of distributed capacitance, but it is difficult to avoid the influence of geomagnetism when using pure DC signals. After theoretical calculations and practical verification, low-frequency signals can meet most field testing needs.

[0130] The signal flows through the line to the fault point and into the ground. The hanging sensor is installed on the insulating pole. The pole is climbed and the sensor is hung on the fault phase to detect the signal. Another person holds a receiver under the line to receive the signal. When it is located in the fault section, the waveform is an obvious rectangular wave, and the non-fault section is an irregular curve with a very small amplitude. By judging the fault branch and dichotomy, the fault point is gradually approached and located.

[0131] DC withstand voltage: This mode is mainly used for verification after fault repair and DC test transmission. After the fault is successfully located and repaired, select the "DC withstand voltage" mode, start the high-voltage output after confirming safety, and start the withstand voltage test. It will stop automatically after 5 minutes, and can also be stopped manually at any time. It is recommended to do a DC withstand voltage test before and after the repair. The withstand voltage is low before the repair, and the withstand voltage is significantly improved after the repair.

[0132] High voltage live: After a single-phase grounding fault occurs in a low-current grounding overhead line, fault location is allowed during live operation. Ultra-low frequency AC current signal long-distance measurement technology, 24-bit high-precision ADC and high-gain antenna are used to realize wireless induction detection of injected characteristic signals without the need for a transmitter to access the fault line. Insert the direct sensor into the receiver, select the "high voltage live" mode, select the line at the position of each outgoing line on the power supply side, and the receiver is perpendicular to the line directly below or directly above the cable to receive the current value of the characteristic signal of the measured line. The "high-sensitivity measurement antenna" of the receiver feeds the received signal back to the "high-precision measurement unit" and then to the "data calculation and processing unit" for processing, and finally displays the "measurement of the horizontal component and vertical component of the 5th harmonic current and the current size" to the "human-machine interface display" for judgment. When the ratio of the vertical component to the horizontal component of the measured signal is positive, the pointer points to normal, and the larger the ratio (absolute value), the greater the deflection; when the ratio is negative, the pointer points to the fault, and the larger the ratio (absolute value), the greater the deflection. Normal line: vertical component is greater than horizontal component; fault line: horizontal component is greater than vertical component, and ! is displayed. After the line is successfully selected, the specific location of the fault point is gradually found along the fault line to the power consumption side. Before the fault point, the fault information is displayed as: horizontal component is greater than vertical component, and after the fault point, it returns to normal: vertical component is greater than horizontal component. Usage is as follows Fig.10 As shown: Hold the instrument horizontally just below the line, keeping the instrument panel perpendicular to the line direction and the ground.

[0133] The display interface of the high voltage live online positioning receiver is as shown in the attached Fig.11 As shown:

[0134] Ratio: The ratio of the vertical component to the horizontal component of the measured signal.

[0135] When the ratio is positive, the pointer points normally, and the larger the ratio (absolute value), the greater the deflection.

[0136] When the ratio is negative, the pointer points to the fault, and the larger the ratio (absolute value), the greater the deflection.

[0137] Current value: The current value of the characteristic signal of the measured line. The current value is the value calculated at a distance of 10m from the overhead line. The value increases inversely with a shortened distance and decreases proportionally with an increased distance.

[0138] Sector: The radius indicates the current amplitude, and the maximum radius indicates a current of 5 A. The radius angle indicates the ratio.

[0139] Positioning steps:

[0140] Step 1: Line selection. Place the instrument at the position of each outgoing line on the power supply side to select the line. The distance between adjacent lines must be greater than 100m. Normal line: the vertical component is greater than the horizontal component; fault line: the horizontal component is greater than the vertical component, and the sign is displayed.

[0141] Step 2: Locate. After the line is successfully selected, the specific location of the fault point is gradually found along the fault line toward the power consumption side. Before the fault point, the fault information is displayed as follows: the horizontal component is greater than the vertical component, and after the fault point, the fault returns to normal: the vertical component is greater than the horizontal component. If the fault line has branches, the fault branch line is also determined according to the above method: the vertical component of the normal branch is greater than the horizontal component, and the horizontal component of the fault branch is greater than the vertical component. Fig.12 As shown:

[0142] Another method of fault location is to determine the fault point by comparing the current size. The current size at the fault location will change significantly, with a large current before the fault and a small current after the fault.

[0143] Low voltage AC positioning

[0144] 1. Wiring: First, turn off the switch of the faulty line to make the line power-off and remove all loads on the line. Use a grounding cable to connect the transmitter's "protective ground" to the earth grid; use a high-voltage wire with a black clamp to connect the "test ground" terminal to the N phase of the faulty line and connect it to the test ground or earth grid. Use a red high-voltage wire or extension wire to connect the "high-voltage output" to the faulty line under test (taking L-phase fault as an example).

[0145] Turn on the power of the transmitter, select the "low voltage AC positioning" mode, and start the high voltage output. Select the "low voltage AC" working mode for the receiver and connect the direct connection sensor. Inspect along the line. If the current value or resistive current content changes suddenly, it means that the fault point has been crossed.

[0146] Compared with the prior art, the present invention has the following advantages: short fault query and location time. It can quickly locate the fault points of hundreds of distribution lines, 60 households in 30 communities, and 15 offices with 100% accuracy, reducing power outage time and power loss, reducing work intensity and cost, improving work efficiency and service quality, and has great practical application value.

[0147] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0148] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. A distribution line fault detection and positioning device, characterized in that: The distribution line fault detection and positioning device includes a transmitter and a receiver. The transmitter injects AC and DC signals into the fault line to reproduce the ground fault. The current is output by the transmitter and flows through the fault line, enters the ground at the fault grounding point and returns to the transmitter. The transmitter measures the DC impedance and AC impedance of the fault line according to the received signal, and selects the corresponding positioning mode according to the measured impedance. Under the determined positioning mode, the transmitter transmits the corresponding signal to the fault line. At this time, the receiver analyzes and processes the received AC current signal or DC pulsating signal of the fault line through magnetic field induction to determine the line fault location.

2. The power distribution line fault detection and positioning device according to claim 1, characterized in that: The signal injected by the transmitter into the fault line is AC 0-1kV, dual-frequency signal and 0-15kV DC signal, and the DC impedance R, AC impedance Zlr and distributed capacitance C of the fault line are measured, and the corresponding positioning mode is given according to the measured impedance.

3. The power distribution line fault detection and positioning device according to claim 2, characterized in that: The distribution line fault detection and positioning device also includes a direct connection sensor. When the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 5 kilo-ohms, the transmitter selects high-voltage AC positioning and direct connection output mode to start, and sends out an AC dual-frequency signal below 1kV. The fault line and the fault point form a loop. The transmitter measures the current value and resistive current content of the fault loop. The direct connection sensor is inserted into the receiver. The receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable for reception. The received signal is processed to obtain the current value and resistive current content. If it is resistive, it is a fault signal, and if it is capacitive, it is not a fault signal. The resistive current content and current value are fixed before the fault point, and are significantly reduced after the fault point, so as to judge the fault point.

4. The power distribution line fault detection and positioning device according to claim 3, characterized in that: The distribution line fault detection and positioning device also includes an AC booster and a hanging sensor. When the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 200 kilo-ohms, the transmitter selects high-voltage AC positioning and external booster output mode to start, and sends 0-1kV, AC dual-frequency signals to the AC booster. The AC booster boosts the AC dual-frequency signal to AC high voltage and outputs it to the fault line and the fault point to form a loop. The hanging sensor is hung on the fault line, collects AC current signals and sends them to the receiver. The receiver receives AC current signals vertically below the faulty overhead line or above the faulty cable, and determines the fault point based on the obvious changes in current before and after the fault point.

5. The power distribution line fault detection and positioning device according to claim 4, characterized in that: When the DC impedance is greater than 5 kilo-ohms and the AC impedance is less than 2 megohms, the transmitter selects the high-voltage DC positioning mode to start, and transmits the 0-15kV high-voltage DC signal to the fault line and the fault point to form a loop. The transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement result. Before the fault point, the current waveform continues to exist, and after the fault point, the current waveform disappears. The receiver first performs rough segmentation and then accurately locates the fault, thereby quickly determining the fault location.

6. The power distribution line fault detection and positioning device according to claim 5, characterized in that: After a single-phase grounding fault occurs in a low-current grounding overhead line, fault location is allowed during live operation. The direct-connected sensor is inserted into the receiver. The transmitter selects the high-voltage live mode to start and receives the characteristic signal current value of the measured line vertically directly below the faulty overhead line or directly above the faulty cable. The receiver processes the received signal and displays and judges the horizontal component and vertical component of the measured 5th harmonic current and the current size. When the ratio of the vertical component to the horizontal component of the measured signal is positive, the pointer points to normal, and the larger the ratio, that is, the greater the absolute value, the greater the deflection; when the ratio is negative, the pointer points to the fault, and the larger the ratio, that is, the greater the absolute value, the greater the deflection; the vertical component is greater than the horizontal component in a normal line; the horizontal component is greater than the vertical component in a faulty line. After the line is successfully selected, the specific location of the fault point is gradually found along the fault line to the power user side. Before the fault point, the fault information is displayed as: the horizontal component is greater than the vertical component, and it returns to normal after the fault point: the vertical component is greater than the horizontal component.

7. The power distribution line fault detection and positioning device according to claim 6, characterized in that: The distribution line fault detection and location device also includes an arc grounding adapter, which needs to be connected when the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection in DC fixed-point mode; The transmitter selects the high-voltage DC positioning mode to start, and transmits a 0-15kV DC high-voltage signal to the fault line and the fault point to form a loop. The transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement result. Before the fault point, the signal continues to exist, and after the fault point, the signal disappears. The point where the signal suddenly changes is the location of the fault point.

8. The distribution line fault detection and positioning device according to claim 7, characterized in that: When detecting and locating faults on 0.4kV low-voltage lines, when the AC impedance is less than 1 kilo-ohm, the transmitter selects high-voltage AC positioning and direct output mode to start, and sends out an AC dual-frequency signal below 1kV. The fault line and the fault point form a loop. The transmitter measures the current value and resistive current content of the fault loop. The direct sensor is inserted into the receiver, and the receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable for reception. The received signal is processed to obtain the current value and resistive current content. If it is resistive, it is a fault signal, and if it is capacitive, it is not a fault signal. The resistive current content and current value are fixed before the fault point, and they are significantly reduced after the fault point, so as to judge the fault point.

9. The power distribution line fault detection and positioning device according to claim 8, characterized in that: When detecting and locating faults in 0.4kV low-voltage lines, when the AC impedance is greater than 1 kilo-ohm, the transmitter selects high-voltage AC positioning and direct output mode to start, and sends 0-1kV, AC dual-frequency signals to the AC booster. The AC booster boosts and rectifies the AC dual-frequency signals and then outputs DC high voltage. The fault point is discharged through the manual discharge button, and the fault point is quickly located by sound, or the discharge cycle and discharge voltage are set through the transmitter.

10. The power distribution line fault detection and positioning device according to claim 2, characterized in that: When the acceptance test is carried out after the fault is repaired, the transmitter chooses the DC withstand voltage mode to start, and the maximum single execution time is 5 minutes. It will automatically exit at the end of the time, and can also be stopped manually at any time.

11. A method for detecting and locating a distribution line fault, characterized in that: The distribution line fault detection and positioning method adopts the distribution line fault detection and positioning device according to claim 1, comprising: Step 1: The transmitter injects AC and DC signals into the fault line to reproduce the ground fault. The current is output by the transmitter and flows through the fault line, enters the ground at the fault grounding point and returns to the transmitter. Step 2: The transmitter measures the DC impedance and AC impedance of the fault line according to the received signal, and selects a corresponding positioning mode according to the measured impedance; Step 3: In the determined positioning mode, the transmitter transmits the corresponding signal to the faulty line. The receiver then analyzes and processes the received AC current signal or DC pulsating signal of the faulty line through magnetic field induction to determine the line fault location.

12. The power distribution line fault detection and positioning device according to claim 11, characterized in that: In step 2, the transmitter injects 0-1 kV AC, dual-frequency and 0-15 kV DC signals into the fault line, measures the DC impedance R, AC impedance Zlr and distributed capacitance C of the fault line, and gives a corresponding positioning mode according to the measured impedance.

13. The power distribution line fault detection and positioning device according to claim 12, characterized in that: In step 2, when the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 5 kilo-ohms, the transmitter selects high-voltage AC positioning and direct output mode to start; when the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 200 kilo-ohms, the transmitter selects high-voltage AC positioning and external booster output mode to start; after a single-phase grounding fault occurs in a low-current grounding overhead line, fault positioning is allowed during live operation, and the transmitter selects high-voltage live mode to start; In the DC fixed-point mode, when the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, the transmitter selects the high-voltage DC positioning mode to start; when detecting and locating faults on 0.4kV low-voltage lines, when the AC impedance is less than 1 kilo-ohm, the transmitter selects the direct output mode to start; when detecting and locating faults on 0.4kV low-voltage lines, when the AC impedance is greater than 1 kilo-ohm, the transmitter selects the high-voltage AC positioning and direct output mode to start.

14. The power distribution line fault detection and positioning device according to claim 13, characterized in that: In step 3, when the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 5 kilo-ohms, and the transmitter selects high-voltage AC positioning and direct output mode to start, it sends out 0-1kV, AC dual-frequency signal, and the fault line and the fault point form a loop; the transmitter measures the current value and resistive current content of the fault loop, and the direct sensor is inserted into the receiver. The receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable for reception, and the received signal is processed to obtain the current value and resistive current content. If it is resistive, it is a fault signal, and if it is capacitive, it is not a fault signal. The resistive current content and current value are fixed before the fault point, and are significantly reduced after the fault point, so as to judge the fault point.

15. The power distribution line fault detection and positioning device according to claim 13, characterized in that: In step 3, when the DC impedance is less than 5 kilo-ohms and the AC impedance is less than 200 kilo-ohms, and the transmitter selects high-voltage AC positioning and external booster output mode to start, it sends a 0-1kV, AC dual-frequency signal to the AC booster. The AC booster boosts the AC dual-frequency signal to AC high voltage and outputs it to the fault line and the fault point to form a loop. The hanging sensor is hung on the fault line, collects the AC current signal and sends it to the receiver. The receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable to receive the AC current signal and determine the fault point based on the obvious change in current before and after the fault point.

16. The power distribution line fault detection and positioning device according to claim 13, characterized in that: In step 3, when the DC impedance is greater than 5 kilo-ohms and the AC impedance is less than 2 megohms, the transmitter selects the high-voltage DC positioning mode to start, and transmits a 0-15kV DC high-voltage signal to the fault line and the fault point to form a loop. The transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal, and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement result. Before the fault point, the current waveform persists, and after the fault point, the current waveform disappears; The receiver first performs rough segmentation and then accurately locates the fault, thereby quickly determining the fault location.

17. The power distribution line fault detection and positioning device according to claim 13, characterized in that: In step 3, when a single-phase grounding fault occurs in a low-current grounding overhead line, the transmitter selects the high-voltage live mode to start. The transmitter receives the current value of the characteristic signal of the measured line vertically directly below the faulty overhead line or directly above the faulty cable. The receiver processes the received signal, and displays and judges the horizontal component and vertical component of the measured 5th harmonic current and the current size. When the ratio of the vertical component to the horizontal component of the measured signal is positive, the pointer points to normal, and the larger the ratio, that is, the greater the absolute value, the greater the deflection; when the ratio is negative, the pointer points to the fault, and the larger the ratio, that is, the greater the absolute value, the greater the deflection; the vertical component is greater than the horizontal component in a normal line; the horizontal component is greater than the vertical component in a faulty line. After the line is successfully selected, the specific location of the fault point is gradually found along the fault line to the power consumption side. Before the fault point, the fault information is displayed as: the horizontal component is greater than the vertical component, and after the fault point, it returns to normal: the vertical component is greater than the horizontal component.

18. The power distribution line fault detection and positioning device according to claim 13, characterized in that: In step 3, when the transmitter prompts an arc grounding fault or continuously prompts overcurrent protection, and the transmitter selects the high-voltage DC positioning mode to start, the transmitter transmits a 0-15kV DC high-voltage signal to the fault line and the fault point to form a loop, and the transmitter receives the pulsating DC voltage and current signals of the fault loop. The hanging sensor is hung on the fault line, detects the current on the fault line for zeroing, converts the analog signal into a digital signal and sends it to the receiver wirelessly. The receiver receives the wireless signal sent by the hanging sensor and displays the measurement result; before the fault point, the signal continues to exist, and after the fault point, the signal disappears; the point where the signal suddenly changes is the location of the fault point.

19. The power distribution line fault detection and positioning device according to claim 13, characterized in that: In step 3, the fault of the 0.4kV low-voltage line is detected and located. The AC impedance is less than 1 kilo-ohm. When the transmitter selects the direct output mode to start, the transmitter sends a 0-1kV, AC dual-frequency signal. The fault line and the fault point form a loop. The transmitter measures the current value and resistive current content of the fault loop. The direct sensor is inserted into the receiver. The receiver is vertically placed directly below the faulty overhead line or directly above the faulty cable for reception. The received signal is processed to obtain the current value and resistive current content. If it is resistive, it is a fault signal. If it is capacitive, it is not a fault signal. The resistive current content and current value before the fault point are fixed, and they become significantly smaller after the fault point, so as to judge the fault point.

20. The power distribution line fault detection and positioning device according to claim 13, characterized in that: In step 3, the fault of the 0.4kV low-voltage line is detected and located. When the AC impedance is greater than 1 kilo-ohm and the transmitter selects high-voltage AC positioning and direct output mode to start, the transmitter sends a 0-1kV, AC dual-frequency signal to the AC booster. The AC booster boosts the AC dual-frequency signal and outputs a DC high voltage. The fault point is discharged through the manual discharge button, and the fault point is quickly located by sound, or the discharge cycle and discharge voltage are set through the transmitter.

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