91 results about "Ground impedance" patented technology

The invention discloses an insulation resistance and capacitance measuring circuit and method based on monopulse double-edge analysis, and relates to the related field of the electrical insulation online monitoring technology, and the circuit comprises a detected object and an insulation detection circuit. The insulation detection circuit comprises a controlled pulse voltage source, a coupling resistance network, a current sensor, a switch control module, a signal modulation circuit and a processor. The measurement method implemented based on the circuit comprises the following steps: injecting a common-mode voltage pulse into a transmission line of the power transmission system by adopting a pulse transmitter; pulse current response is collected in real time, a current oscillogram is drawn, and a three-point sampling method is introduced to record a current value for insulation impedance parameter calculation; according to a load condition, a double-edge verification method is applied based on a pulse current attenuation characteristic, and insulation impedance parameters including a resistive component and a capacitive component are independently calculated by analyzing a pulse current rising edge and a pulse current falling edge. According to the invention, non-intrusive synchronous monitoring of resistive and capacitive components of line-to-ground impedance is realized, and the detection precision is improved.

The invention discloses a lightning protection system for an environment monitoring station and a use method of the lightning protection system, and relates to the technical field of lightning protection, and the system comprises a multi-stage composite grounding module, an intelligent energy distribution module, a lightning current monitoring module, a surge protection module and a grounding impedance optimization module. Comprising a main grounding body, an auxiliary grounding body and a deeply-buried grounding electrode, the grounding resistance can be remarkably reduced, the lightning current leading-in efficiency can be improved, when lightning current passes through, the multi-stage grounding structure can effectively disperse the current, overload of a single grounding body is avoided, and meanwhile the grounding resistance of the grounding body is improved. The intelligent energy distribution module can dynamically adjust a current distribution strategy between different grounding bodies according to the magnitude of lightning current, ensures that the deeply-buried grounding electrode is preferentially conducted under the condition of strong lightning stroke, starts a parallel discharge mode of the main grounding body and the auxiliary grounding body under the condition of weak lightning stroke, and guarantees the safe operation of the environment monitoring station.

A power transmission tower grounding resistance non-contact measurement method based on the electromagnetic coupling principle comprises the following steps that transmitting and receiving electromagnetic coupling coils are arranged around an iron tower grounding body, and geometric calibration and spatial positioning of a measurement area are completed by combining grounding grid structure parameters and soil conduction characteristics; injecting a high-frequency alternating-current excitation signal into the transmitting coil, and synchronously acquiring the amplitude and phase response of the induced voltage at a receiving coil end; carrying out filtering processing on the induction signal by adopting a time-frequency analysis and phase decoupling algorithm, and solving a function relationship between electromagnetic response and grounding impedance by combining a coupling equivalent model; based on experimental calibration data and scene parameters, a nonlinear mapping model of induction response and grounding resistance is constructed, and real-time inversion calculation is carried out by combining a solving result obtained in the third step. According to the invention, the real-time accurate measurement of the grounding resistance under the conditions of no power failure and no wire breakage is realized, and the safety, the operation convenience and the anti-interference capability in a complex environment in the measurement process are obviously improved.

The invention relates to the field of power systems, in particular to a power cable cross interconnection grounding system live-line maintenance method and system. The method comprises the following steps: firstly, synchronously acquiring cable line load current, three-phase grounding ring current and grounding resistance at the head end and the tail end of a metal sheath of a crossed interconnection unit with ring current abnormity, and generating a real-time data set with a timestamp; extracting cable structure parameters based on a preset cable topology database, and dynamically associating the cable structure parameters with the real-time data set; constructing a multi-conductor transmission line equation model, calculating a theoretical circulation distribution value of each section of sheath, and generating a theoretical circulation map; carrying out matching analysis on the theoretical circulation map and actually measured circulation data, and determining defect types and positions; and finally, according to a defect positioning result, the maintenance operation is executed in an electrified state through the insulating mechanical arm, and the stability of the grounding impedance of the system is maintained through the bypass grounding device. The problems that in the prior art, the live detection function is incomplete, and defects cannot be rapidly and accurately positioned are solved.

The invention discloses a fan blade lightning protection design method and system based on fan grounding resistance, and the method comprises the steps: analyzing a set grounding impedance model, and selecting a most suitable grounding impedance model; designing a fan grounding device according to the most suitable grounding impedance model; optimizing the grounding electrode according to the soil resistivity; based on a target of efficiently guiding and transmitting thunder and lightning, determining materials of a fan blade, a lightning protection lightning arrester and a down lead; through setting a connection mode, the lightning protection lightning arrester, the downlead, the blade root and the fan grounding device are firmly connected in pairs; according to the parameters of the fan blade and the potential difference between the fan blade and the ground, the electric field intensity in the fan blade during lightning stroke is calculated; and optimizing and adjusting the fan blade according to the electric field intensity. The fan blade can be protected from being struck by thunder and lightning, and damage to equipment and personnel is reduced.

The invention belongs to the technical field of electromagnetic detection, and relates to an electromagnetic detection multi-level current emission system for a plateau environment and a control method. The control method comprises the steps of calculating load model impedance; analyzing an MFPWM control process, and determining an optimal control parameter by using an optimization target of transmitting spectrum intensity maximization; and MFPWM optimization control: realizing directional power distribution and independent regulation and control of each frequency component by adjusting the frequency and amplitude of each modulation signal component. A multi-level topological structure is adopted, high output voltage is achieved while switching voltage stress is reduced, and the problems that cost rises and system complexity is too high due to the fact that a traditional H-bridge inverter depends on high power supply voltage are solved; by matching with multi-frequency pulse width modulation optimization control, spectrum energy can be flexibly configured, high-frequency components of transmitted signals are enhanced, and the spectrum energy utilization rate and the signal-to-noise ratio are improved; grounding impedance changes in a high dynamic range can be accurately tracked, and the requirements of deep geological electromagnetic detection in an extreme environment are met.

The invention relates to the technical field of electric data testing, in particular to a data calibration system based on an electric power acquisition terminal, which comprises the steps of acquiring a partial discharge signal; the method comprises the following steps: connecting to a grounding network of an open substation, and injecting calibration signals with preset characteristics into spatial distribution nodes of the grounding network; a calibration signal is controlled, a distributed calibration reference is established by comparing measurement results of different terminals on signals from different calibration nodes, and a gradient calibration parameter distribution strategy is established according to the relation between the distance between the electric power acquisition terminal and each calibration node and the grounding impedance; based on the detection data of the same partial discharge source by at least two power acquisition terminals, calculating the spatial position of the discharge source through the signal arrival time difference and the signal attenuation characteristic, and obtaining the measurement accuracy of each power acquisition terminal; and monitoring the long-term evolution trend of the partial discharge signal, identifying the insulation aging state of the equipment, and dynamically adjusting the calibration parameter of the corresponding power acquisition terminal according to the aging state.

This application provides a power system and a method for detecting a ground impedance. The power system includes a converter and a short-circuit detection apparatus The converter includes a positive bus capacitor and a negative bus capacitor that are connected in series, and a series connection point between the two bus capacitors is a neutral point. The short-circuit detection apparatus is connected to an equivalent neutral point. A ground potential difference of the equivalent neutral point is positively correlated with a ground potential difference of the neutral point. The equivalent neutral point includes a connection end of three phases of output ends of the converter. The short-circuit detection apparatus outputs a first voltage value and a second voltage value to the equivalent neutral point, and obtains a first current value and a second current value of the short-circuit detection apparatus when the first voltage value and the second voltage value are output. The short-circuit detection apparatus obtains a ground impedance of the power system based on the first voltage value, the second voltage value, the first current value, and the second current value, and reports or sends ground impedance abnormality fault information when the ground impedance is less than a specified threshold. According to this application, ground impedances of an alternating current side and a direct current side of the power system can be detected, and a ground impedance detection range is wide.

The invention provides a control method and system for a flexible arc extinguishing device for a grounding fault of a power distribution network. The flexible arc extinguishing device serves as a controlled zero-sequence source, provides required power for total zero-sequence ground impedance of the power distribution network, supports required zero-sequence voltage of the power distribution network, and promotes grounding fault current and voltage to be zero. By designing the virtual damping and virtual inertia control of the zero axis, the motion characteristics of the rotor of the synchronous generator are simulated, and by designing the virtual excitation control of the zero axis, the excitation characteristics of the stator of the synchronous generator are simulated. When a distributed power electronic flexible arc-extinguishing device in a power distribution network commonly dominates the zero-sequence voltage of a zero-sequence network circuit of the power distribution network, the droop characteristic of a synchronous generator is simulated, and a droop control equation of active and reactive power output by the flexible arc-extinguishing device and the frequency and amplitude of the zero-sequence voltage of the power distribution network is designed; and virtual impedance control is added to coordinate the output of the flexible arc extinguishing device. And finally, constructing a power distribution network ground fault arc extinguishing device control system to realize arc extinguishing of the power distribution network ground fault.

The invention discloses a multi-machine common-bus system grounding fault arc extinction and property identification method based on machine end voltage regulation and control. The method comprises the following steps: S1, machine end arc extinction; s2, low-frequency injection; s3, low-frequency component measurement; s4, grounding transition resistance calculation: through the low-frequency components of the terminal voltage and the current of each generator at the first moment, calculating the ground impedance Zi1 during a grounding fault; calculating the ground impedance Zi2 after the fault is stable through the low-frequency components of the terminal voltage and the current at the second moment; calculating the grounding transition resistance Rgi of each generator when any generator fails by integrating the Zi1 and the Zi2; s5, fault identification: if Rgi is greater than or equal to a set threshold value, identifying the fault as an instantaneous fault, and if Rgi is less than the set threshold value, identifying the fault as a permanent fault; if a generator is identified as a permanent fault, the generator can be identified as a fault unit. According to the method, the problem of poor economical efficiency of existing fault arc extinction and fault identification in a multi-machine common-mother system can be solved.

The invention relates to the field of grounding technology and electrical measurement, and discloses a grounding electrode current diffusion characteristic and environment correlation analysis method, which comprises the following steps: acquiring a ground electricity state vector representing soil electrochemical characteristics; constructing and calibrating a state phase space evolution model for describing time-space evolution of the vector; an adaptive dynamic analysis closed loop is executed, a state vector at the next moment and uncertainty are predicted through the model, an adaptive sensing protocol is generated based on the uncertainty to guide new data collection, a prediction result is corrected through new data, and a corrected state vector is obtained; and finally, based on the continuous corrected state vector, analyzing the causal association between the environment and the state, reconstructing three-dimensional complex conductivity distribution, and determining current diffusion characteristics such as grounding impedance through numerical calculation. According to the method, the limitation of static evaluation in the prior art is solved, and the dynamic prediction of the performance of the grounding system and the physical tracing of the abnormal cause are realized.

The invention discloses a photovoltaic inverter ground impedance fault detection system and method. The system comprises a PID repair circuit and an acquisition circuit. The PID repair circuit is connected in parallel to two sides of the inverter, and the PID repair circuit is suitable for being equivalent to an LR circuit connected between the negative end of the direct current side of the inverter and the ground in a non-working state; and the acquisition circuit is suitable for detecting the inductive voltage of the LR circuit, so that when the inductive voltage abrupt change value of the LR circuit is detected to be greater than a set voltage threshold value, the inverter is affirmed to have a grounding fault. According to the method, the photovoltaic inverter ground impedance fault detection system is adopted to carry out ground fault judgment in an inverter grid-connected state. The method has the beneficial effects that under the condition that the direct current bus is stable, the ground fault of the inverter is identified on line by detecting the voltage change on the equivalent inductor of the secondary side of the PID power supply, the identification speed of the ground fault is increased, and the damage risk of a switch tube under the ground fault is reduced.

The utility model provides a grounding impedance detection circuit. The detection circuit comprises a voltage input circuit, a first voltage division circuit, a to-be-detected power supply housing, a second voltage division circuit and an impedance detection circuit. The output end of the voltage input circuit is connected with the input end of the first voltage division circuit; the output end of the first voltage division circuit is connected with a to-be-tested power supply shell; the input end of the second voltage division circuit is connected with the to-be-tested power supply shell; the output end of the second voltage division circuit is connected with the input end of the impedance detection circuit; when the voltage output by the impedance detection circuit is not lower than a preset threshold value, it is determined that the to-be-detected power supply shell is not grounded; and when the voltage output by the impedance detection circuit is lower than a preset threshold value, determining that the to-be-detected power supply shell is grounded. Voltage is input through the voltage input circuit, the first voltage division circuit and the second voltage division circuit are used for voltage division, whether the to-be-detected power supply shell is grounded or not is determined according to output of the impedance detection circuit, and the purpose of effectively and accurately detecting the grounding condition of an electronic product is achieved.

The embodiment of the invention discloses a composite material airplane electrical return network impedance checking method based on voltage drop constraint. The method comprises the following steps: determining an electrical return network design scheme of a composite material airplane; performing impedance checking on the newly obtained electrical return network design scheme to judge whether the newly obtained electrical return network design scheme meets the requirement or not; if not, determining a new electrical return network design scheme, and judging whether the newly obtained electrical return network design scheme meets the requirement or not; and carrying out impedance checking on the newly obtained electrical return network design scheme to judge whether the newly obtained electrical return network design scheme meets the requirement or not, namely solving the maximum impedance of the newly obtained electrical return network design scheme, substituting the obtained maximum impedance value into the aircraft power supply system simulation model as grounding impedance, and calculating the impedance of the newly obtained electrical return network design scheme. Determining the voltage value of the electrical load of each observation point; and obtaining a judgment result of a voltage drop constraint condition according to the voltage value, and further determining whether the newly obtained electrical return network design scheme meets the requirement or not.

The invention discloses a transformer substation electromagnetic interference source modeling and positioning method based on multi-physics field coupling, relates to the technical field of interference positioning, is used for solving the problem of insufficient positioning precision of an electromagnetic interference source, and aims at solving the problem of low positioning precision of the electromagnetic interference source by collecting grounding potential data of a grounding grid monitoring node, calculating a potential deviation index and judging whether discharge abnormality exists or not. And when an abnormality occurs, accessing a historical database to call grounding impedance data of the marked grounding electrode, analyzing an impedance fluctuation trend, detecting a discharge current amount in each discharge direction, marking the grounding electrode by combining a discharge imbalance characteristic, dividing and screening an abnormal corrosion area, and obtaining surface magnetic field data and surface temperature data of each divided area. A discharge concentration coefficient is calculated through magnetic field distribution characteristics and a surface temperature coefficient, a positioning index is generated in combination with discharge path data, a discharge positioning area is screened, and the corrosion positioning precision and maintenance effectiveness of the grounding grid are improved.

The present invention discloses an insulation detection method for a charging device, comprising the following steps: A1, after the electric vehicle is connected to the charging pile, the charging pile starts to perform insulation detection, and respectively measures the DC+ to ground impedance R+ and the DC- to ground impedance R-; A2, accumulating the number of insulation detection times n, and respectively calculating the difference Δ between the measured R+, R- and the insulation impedance standard value r R+ , Δ R‑ , and then calculate Δ R+ , Δ R‑ The square values ​​of each are saved; A3, respectively R+ , Δ R‑ The square value of each and the total square of DC+ to ground resistance S R+ 、DC-to-ground resistance total square sum S R‑ Accumulate and assign the accumulated values ​​to S respectively R+ , S R‑ ; A4, then calculate the standard deviation S of DC+ impedance to ground 正 , Standard deviation of DC-to-ground impedance S 负 , and according to the calculated S 正 , S 负 The present invention can effectively avoid the risk of electric shock caused by aging of insulating materials during charging.

This invention discloses a method and system for assessing the grounding resistance status of transmission towers, relating to the field of grounding measurement technology for transmission towers. The method includes: acquiring a grounding impedance characteristic sequence and a three-dimensional environmental characteristic sequence; calculating the comprehensive environmental influence intensity index for each cycle; calculating the response lag coefficient for the current cycle; calculating the dominant weight index of environmental effects for the current cycle; constructing and training two types of hidden Markov models, independent and joint, to obtain the independent observation probability and joint observation probability of each hidden state in the current cycle; based on the independent and joint observation probabilities, obtaining the corrected observation probability of each hidden state in the current cycle; based on the corrected observation probabilities, calculating the confidence level of each hidden state in the current cycle, and determining the grounding resistance status for the current cycle. This invention can dynamically distinguish between normal current dissipation capacity fluctuations caused by the environment and real anomalies caused by equipment degradation, improving the accuracy of grounding status assessment.

The application provides a parallel cavity shared radio frequency power supply system and a radio frequency adjusting method for a plasma process, which comprises the following steps: collecting the ground potential of the cavity wall of each parallel process cavity in real time through a detection and adjusting module, dynamically adjusting the ground impedance of each radio frequency coil, and balancing the total ground impedance of each branch; then, completing independent dynamic impedance matching of each branch by a matching module, eliminating the power distribution imbalance problem caused by the inconsistent impedance of each radio frequency coil, keeping the plasma discharge state of the multiple cavities consistent, improving the process uniformity of each cavity, and greatly reducing the equipment cost by using only one radio frequency power supply.

The invention relates to an alternating current ice melting reactive compensation control method considering ground wire impedance change, which belongs to the technical field of alternating current ice melting, and comprises the following steps: S1, connecting a reactive compensation device into an ice melting loop, and injecting ice melting current into an overhead ground wire through an alternating current power supply; s2, measuring the length and the temperature of the ground wire in the ice melting process through a sag and temperature sensing and monitoring assembly; s3, on the basis of the ground wire impedance change model in the ice melting process, ground wire impedance change is calculated according to the ground wire length and the ground wire temperature; s4, substituting the ground wire impedance value into the heat effect theoretical model, and calculating the required reactive compensation capacity in combination with the temperature rise and the current effective value; and S5, based on the optimal array algorithm, controlling the reactive power compensation device to switch the switching capacitor bank array combination of the corresponding reactive power compensation capacity.

Autonomous self-calibration procedure for autonomous loop impedance measuring devices, with a system like the previous one, which comprises an initial stage (8) for obtaining a normalized calibration curve (8.1) of the measuring device and introduction of the normalized values (8.2) in the memory, and a self-calibration stage (9) that includes the phases for obtaining the range (10) of the loop resistance (Rb) of the measuring device, and calculation (14) of the loop impedance values (15).

The present invention provides a processing circuit for a power output terminal, an electronic device and a ground impedance detection method. The processing circuit includes a first voltage source, a first switch unit, a control unit, a second switch unit, an adjustable current source unit and a voltage detection unit. The adjustable current source unit and the second switch unit are connected in series between a second voltage source and the power output terminal. The control unit is respectively connected to the adjustable current source unit, the first switch unit, the second switch unit and the voltage detection unit. The voltage of the first voltage source is greater than the voltage of the second voltage source. The voltage detection unit is connected to the power output terminal through the second switch unit. The present invention can provide a basis for avoiding potential safety hazards and dangers. At the same time, since different ground impedance ranges are associated with the causes of ground impedance, the present invention can judge the causes of ground impedance, which is conducive to timely and accurate response.

A grounding impedance measurement apparatus and method, and an inverter are provided. The measurement apparatus includes a signal source, a coupling impedance network, a voltage division network, a sampling module, and a controller, the coupling impedance network is connected to the signal source, and couples an excitation signal between a direct-current input terminal and an alternating-current output terminal of an inverter; the voltage division network performs voltage division on the voltage between the direct-current input terminal and the alternating-current output terminal to provide a divided voltage; the sampling module is connected to the voltage division network, samples the divided voltage, and acquires a sampled voltage; and the controller is connected to the signal source and the sampling module, respectively, and acquires a grounding impedance of the direct-current input terminal of the inverter.

The utility model provides a kind of ground impedance detection device based on harmonic analysis, belong to ground impedance detection technical field, including main frame assembly, the inner wall of main frame assembly is connected with ground impedance detector, the outer wall of main frame assembly is fixedly connected with limiting component, the outer wall of main frame assembly is provided with honing component, the outer wall of main frame assembly is provided with side support component, the outer wall of main frame assembly is provided with take-up assembly;The utility model is provided with take-up assembly, in use, by take-up motor driving take-up rod rotation, and then realize the orderly winding of the wire connected with probe or ground electrode test point, avoid multiple wires between each other cross each other, improve the accurate detection of ground impedance detector in field use;By the setting of limiting component, in use, start and control rotary motor use, drive press plate rotation, so that multiple spring barrels are above ground impedance detector.

The invention relates to the technical field of lightning protection grounding lightning rods, and discloses a centering type lightning protection grounding lightning rod for a base station, which is suitable for lightning protection of GNSS base stations and similar communication base stations, and comprises a vertical rod, a lightning rod, an equipotential connecting plate, a GNSS base station, a control box, a vertical grounding body, a lower lead, a bottom lead and a multi-stage supporting, fixing and pressure injection structure, the lightning rod realizes joint equipotential grounding with the base station and the plurality of vertical grounding bodies through the equipotential connecting plate, the coaxial centering layout is adopted, the grounding impedance is effectively reduced, the rapid reinforcement and stabilization of the vertical grounding bodies are realized and the pull-out resistance of the grounding bodies is improved through the supporting and fixing part and drilling and fixing part structures, and the device also integrates the function of pressure injection of a resistance reducing agent, so that the device is convenient to use. The ground effect is further optimized, the aviation obstruction beacon and the solar power supply panel are integrally designed, the visibility of equipment is improved, the ground performance is excellent, the lightning protection safety of the base station can be remarkably improved, and the ground lightning protection device is suitable for the lightning protection ground requirement of a field GNSS (Global Navigation Satellite System) base station.

Provided are a grounding impedance measurement circuit and a grounding impedance measurement method. The grounding impedance measurement circuit detects a power supply voltage of an isolated alternating current power supply by means of disposing a power supply voltage detection circuit between a live wire and a neutral wire at the isolated alternating current power supply. Furthermore, by forming an alternating current positive half-cycle detection branch and an alternating current negative half-cycle detection branch between the live wire and the neutral wire at the isolated alternating current power supply as well as between a live wire and a neutral wire at a power wire of an electrical device, the grounding impedance value of the live wire and the grounding impedance value of the neutral wire can be accurately detected, such that an output line having an abnormal grounding impedance can be quickly identified.

This application relates to the field of control for safety testing instruments, and discloses a grounding impedance testing circuit and a grounding impedance testing system. The grounding impedance testing circuit includes: a first port, a second port, a suppression module, a detection module, a delay module, a switching module, an output module, and a third port; the suppression module is used to suppress the AC test voltage between the first port and the second port; the detection module is used to detect the circuit state between the first port and the second port, and control the working state of the detection module based on the working state of the switching module and the circuit state detection result; the delay module is used to determine whether to provide a time delay to the switching module based on the working state of the detection module; the switching module is used to detect whether the delay module provides a time delay, and control the working state of the switching module based on the delay detection result; the output module is used to control the output state of the third port based on the working state of the switching module.

The application relates to the technical field of electric data testing, in particular to a data calibration system based on a power collection terminal, which comprises the following steps: collecting partial discharge signals; connecting to a grounding network of an open-type transformer substation, injecting preset characteristic calibration signals at spatial distribution nodes of the grounding network; controlling the calibration signals, establishing a distributed calibration benchmark by comparing the measurement results of different terminals on signals from different calibration nodes, and establishing a gradient calibration parameter distribution strategy according to the distance relationship between the power collection terminal and each calibration node and the grounding impedance relationship; based on the detection data of at least two power collection terminals on the same partial discharge source, calculating the spatial position of the discharge source through a signal arrival time difference and signal attenuation characteristics, and obtaining the measurement accuracy of each power collection terminal; monitoring the long-term evolution trend of the partial discharge signals, identifying the insulation aging state of equipment, and dynamically adjusting the calibration parameters of the corresponding power collection terminal according to the aging state.

A ground monitoring device connectable to the electrical system of an RV, boat or other vehicle or to a remote or shore AC power supply, is configured to monitor the ground impedance by a direct connection to the AC power supply. In one feature, the ground monitoring device can include the capability to disconnect the electrical system of the vehicle from the AC power supply if the impedance exceeds a predetermined threshold.

The present invention discloses a method for selecting a grounding line and confirming a grounding point range in a low-voltage circuit, which relates to the field of power grid protection technology and includes the following steps: obtaining impedance parameters of the circuit power supply, equipment, and cable; connecting impedances in series in the circuit according to the measured parameters to make the three-phase impedances equal; installing a high-frequency current generating module and a grounding capacitor at the end of the circuit; creating a grounding impedance matching table for each device and important node according to the measured impedance parameters; the high-frequency current generating module alternately generates AC and DC currents and measures the neutral point and capacitor currents; and determining the grounding phase and grounding range by calculating the impedance based on the measured values. The present invention installs a high-frequency current generating module and a grounding capacitor at the end of the circuit. The high-frequency current generating module is activated when a fault occurs. During phase selection, each module generates high-frequency current in a sequential cycle, enters the fault phase selection and fault location logic, and can achieve accurate fault location, quickly select the grounded phase, locate the grounding point range, and improve the operational reliability of the low-voltage system.