1289 results about "Grounding Malfunction" patented technology

The invention relates to the technical field of power system fault monitoring, and discloses a 10kV voltage transformer ground fault real-time monitoring method and system, and the system comprises a ground fault data collection module, a waveform distortion analysis module, a transient signal detection module and the like. Three-phase current, zero-sequence current and voltage waveform data are collected, a current harmonic component proportion, a zero-sequence current high-frequency transient energy value and the like are analyzed, a fault type is determined by combining a phase difference, and a fault position is positioned according to topological parameters and line impedance. And the temperature of the grounding down lead can be monitored, and the fault probability is evaluated and the threshold value is dynamically adjusted by machine learning. According to the invention, real-time accurate monitoring can be realized, fault types and positions can be accurately diagnosed, potential hidden dangers can be comprehensively monitored, the intelligence of a monitoring system is improved, the operation and maintenance cost and risks are effectively reduced, and safe and stable operation of the 10kV power distribution network is ensured.

The invention discloses a distribution network cable traveling wave fault early warning and positioning method and system, and the method comprises the steps: installing a device in a ring main unit, collecting a high-frequency traveling wave current and a power frequency current, and recognizing a grounding fault through a transient zero sequence comparison method and a high-frequency traveling wave polarity algorithm; weak traveling wave signals generated by insulation defects are monitored to carry out hidden danger early warning; traveling wave arrival time difference is measured through double-end distance measurement, and the position of a fault point is calculated in combination with line parameters; and early warning and positioning results are transmitted to a master station through 4G / 5G and 101 / 104 protocols. The system comprises a data acquisition module, a signal processing module, a fault positioning module, a hidden danger early warning module, a master station communication module and a master station module which work cooperatively. The method and the system are high in positioning precision, can realize accurate fault positioning and hidden danger early warning, support live-line installation, are suitable for various scenes, effectively solve the operation and maintenance problem of the distribution network cable, and improve the power supply reliability.

An electrical fault detection and interruption device includes a switch module coupled between input and output ends of current carrying lines, a GFCI (ground fault circuit interrupter) fault detection module for generating a ground fault signal when detecting a leakage current on the current carrying lines, an AFCI (arc fault circuit interrupter) fault detection module for generating an arc fault signal when detecting harmful arcs on the current carrying lines, a drive module for driving the switch module to disconnect the electrical connection between the input and output ends in response to the ground fault signal and / or arc fault signal, a fault signal transfer module for generate a simulated leakage current signal in response to the arc fault signal, and a monitoring module for generating a harmful arc signal to test whether the electrical fault detection and interruption device is functioning normally.

The invention discloses a stator winding grounding fault arc extinction method and system based on grounding transition resistance. The method comprises the following steps: S1, acquiring fundamental voltage of a neutral point and a machine end after normal operation and a grounding fault in real time; s2, calculating a fault phase potential EA1, and calculating a phase angle delta between the fault phase potential EA1 and the neutral point ground voltage UN1; s3, constructing a generator stator winding grounding fundamental wave fault analysis positioning equation, and substituting the measurement and calculation amount to complete fundamental wave fault positioning; s4, if multiple solutions occur in fundamental wave fault positioning, introducing a low-frequency injection quantity check criterion, and screening out a unique correct transition resistance value; and S5, carrying out arc extinction on the fault point of the neutral point of the generator in a high-resistance grounding mode. According to the method, the accuracy and reliability of fault positioning are remarkably improved, the possibility of misjudgment is eliminated, and an accurate compensation basis is provided for arc extinction.

The invention discloses a power distribution network high-resistance grounding fault detection method and system, and relates to the technical field of power distribution network fault detection. A power distribution network high-resistance grounding fault detection method comprises the following steps: S1, collecting a transient zero-sequence voltage signal of a target feeder line as a to-be-decomposed electric quantity signal; s2, variational mode decomposition is carried out on the to-be-decomposed electric quantity signals, mode functions obtained by decomposing the single to-be-decomposed electric quantity signals are arranged according to the center frequency from low to high, and one-dimensional feature vectors of the to-be-decomposed electric quantity signals are obtained; and S3, inputting the one-dimensional feature vector of the electric quantity signal to be decomposed into a pre-constructed Transform model to obtain a detection result. According to the method, the high-resistance grounding fault and the disturbance condition can be accurately identified, the fault identification accuracy is very high, and the power distribution network fault detection efficiency is improved.

The invention relates to the technical field of cable positioning, in particular to a one-way grounding fault positioning method based on a signal injection method. The method comprises the following steps: installing an impedance detection unit at a grounding knife switch of a transformer substation, and injecting a controllable AC signal into a power transmission line through a built-in injection coil to enable the line to be in an open circuit state; collecting the injected current signal and performing frequency enhancement to extract the amplitude and phase of a target frequency component; zero-sequence impedance is calculated based on the injection voltage and current, and the zero-sequence impedance is compared with a preset impedance model to judge single-phase grounding; and when a fault is detected, determining a fault distance, a tower position and a grounding phase according to an impedance difference matching result, thereby realizing accurate positioning. According to the invention, by injecting the controllable AC signal into the power transmission line and combining frequency enhancement, phase self-calibration and impedance difference matching analysis, high-sensitivity detection, high-stability signal extraction and high-precision positioning of the single-phase earth fault are realized.

The invention relates to a high-resistance fault detection and line selection method for a power distribution network. The method comprises the steps of generating an original waveform from zero-sequence voltage recording data; performing morphological filtering processing on the original waveform, calculating a curve abrupt change area by adopting a sliding window mode, setting an early warning self-adaptive threshold value, and judging the running state of the power distribution network; carrying out fault detection by adopting a high-resistance grounding fault identification method; analyzing the flow direction after the fault based on the phase distribution, and judging whether the fault point is located at the upstream or downstream of the power distribution terminal, thereby completing the fault line selection. Performing data preprocessing on each waveform, calculating a zero-sequence voltage curve abrupt change area by adopting a sliding window mode, and judging whether the distribution network is in a normal operation state or not by combining a set early warning self-adaptive threshold value; distinguishing capacitor switching interference and a high-resistance grounding fault through a high-resistance grounding fault identification method based on signal difference; the power flow direction after the fault is analyzed based on phase distribution, the threshold setting trouble of a traditional line selection method is avoided, and thus fault line selection is completed.

Disclosed are a single-phase-to-ground protection method and system for an active power distribution network. The method includes: acquiring current and voltage data of a line in real time by means of a power distribution terminal, and calculating active power of the line; recording and storing the active power of the line to form an active power curve; performing data statistics according to the active power curve; calculating a direction compensation coefficient and a zero-sequence current compensation coefficient on the basis of statistical data; and detecting whether a single-phase-to-ground fault occurs to the line, where when the single-phase-to-ground fault occurs to the line, a transient-state zero-sequence direction and a steady-state zero-sequence direction are compensated, or a zero-sequence current is compensated, it is determined that the single-phase-to-ground fault occurs to the line when compensation results satisfy action conditions, and tripping is performed or an alarm is given.

A ground fault detection apparatus is used for an on-board system. The on-board system includes a power source unit, a power storage unit, a conductive path, and a disconnection unit. The conductive path includes a first conductive path, a second conductive path, and a third conductive path. The disconnection unit includes a first disconnection unit and a second disconnection unit. A second load is connected to one path out of the second conductive path and the third conductive path, and a third load is connected to the other path. The ground fault detection apparatus includes a detection unit (a current detection unit and a control circuit) configured to detect a ground fault on at least one of the second conductive path and the third conductive path.

The invention discloses a power distribution network single-phase earth fault positioning method and system based on zero-sequence admittance comparison, and the method comprises the steps: obtaining zero-sequence voltage and zero-sequence current sampling values at two ends of a protected section, and determining whether to start the detection of single-phase earth fault positioning or not based on the break variable of the zero-sequence voltage; if the detection of the single-phase earth fault positioning is started, the two ends respectively calculate respective power frequency zero sequence voltage phasors and power frequency zero sequence current phasors, and send the phasors to the opposite end; respectively calculating zero-sequence admittance values of the home terminal and the opposite terminal based on the power frequency zero-sequence voltage phasors and the power frequency zero-sequence current phasors of the home terminal and the opposite terminal; and respectively calculating a differential admittance value and a brake admittance value, respectively comparing the differential admittance value with an admittance threshold value and the brake admittance value, and judging whether the protected section is a fault section based on a comparison result. The differential admittance serves as the action amount, the brake admittance serves as the floating threshold, the difference between internal and external faults is amplified, and reliability and sensitivity are effectively improved.

A power transmission line fault locating method and system based on traveling wave front fitting, and a storage medium and an electronic device. The method mainly comprises the following steps: on the basis of electrical parameters and control parameters of an actual project, constructing an electromagnetic transient simulation model for a power transmission system, setting metallic grounding faults along the entire length of a power transmission line at preset step sizes, and performing simulation (S1); recording fault occurrence moments, and, at a preset sampling frequency, collecting a voltage at an installation position of a fault locating device under each fault condition, so as to calculate a line-mode fault voltage under each fault condition (S2); performing function fitting on the line-mode fault voltage calculated at each fault position to obtain a fitting coefficient (S3); performing power function fitting on the fault positions and the fitting coefficients under various preset step size conditions to obtain a fault positioning function (S4); and when a power transmission line protection device of the actual project detects a line fault, performing fitting on a voltage collected by the fault locating device at a target sampling frequency to obtain a fitting coefficient, and substituting the fitting coefficient into the fault locating function to calculate a fault distance (S5).

The invention relates to an AC-DC integrated grounding fault positioning method and system, and the method comprises the steps: collecting the potential change data of a DC power supply system and the frequency characteristic data of an AC power supply system, and determining the electrical signal characteristics of stray current corrosion; decomposing the electric signal by using wavelet transform, and extracting direct-current and alternating-current components; determining a fault type according to the component amplitude; analyzing the potential gradient and the stray current flow direction in combination with a line topological structure, and determining the position of a fault point; measuring resistance to determine a grounding loop, and analyzing the correlation between corrosion distribution and electrical parameter characteristics; evaluating the influence of corrosion on the grounding path in combination with the material resistivity; according to the method, faults can be accurately recognized, fault points can be accurately positioned, the corrosion degree and the influence of the corrosion degree on the system can be evaluated, and effective support is provided for safe operation and maintenance of a subway power supply system.

The invention provides a power distribution network zero sequence mutual inductor wiring polarity on-line proofreading method and system. The method comprises the following steps that 1, an active inverter is directly connected between a phase line of a power distribution network or a neutral point of a grounding transformer and the ground, or is connected between the phase line of the power distribution network or the neutral point of the grounding transformer and the ground through a boosting transformer; step 2, performing closed-loop control on the active inverter to inject zero-sequence current into the power distribution network; 3, in the injection process, judging whether the wiring polarity of the zero-sequence mutual inductor is wrong or not; 4, if only one of the zero-sequence voltage transformer and the zero-sequence current transformer has a wiring polarity error, correcting by modifying a software flag bit; and step 5, each power distribution terminal and the accessory device thereof complete online calibration of the wiring polarity of the zero sequence mutual inductor. By applying the technical scheme, the problem that the grounding fault section positioning research and judgment result is wrong due to the wiring polarity error of the zero-sequence mutual inductor of the power distribution terminal and the accessory device thereof can be avoided, and the method has good engineering application value.

The invention relates to relay protection technology, specifically a method, system, and medium for fault arc suppression in distribution networks using closed-loop self-healing control. When a fault is detected in the distribution network, transient changes in the measured and virtual phase currents of each phase are obtained. The Pearson correlation coefficient between these changes is calculated to identify the target fault phase. The neutral point-to-ground voltage value is retrieved, and the target fault phase's voltage is adjusted to zero based on this value. The current from the fault phase, when its voltage is zeroed, is acquired. An injected current is then compensated at the neutral point to match this value, ensuring both the ground fault current and the fault phase voltage are reduced to zero. This method enhances the applicability of arc suppression for grounding faults in distribution networks.

The invention discloses a cable insulation abnormity and latent fault early warning method and device based on electrical quantity, and the method comprises the steps: synchronously monitoring the zero-sequence voltage and current of a power distribution network in real time, starting a fault or disturbance analog quantity data cache when a condition is satisfied, and generating a wave recording file; feature frequency band transient fault information is extracted, ground fault judgment is completed, and the fault type is judged; recording and calculating instantaneous fault effective data, and judging whether the instantaneous grounding fault frequency in a preset time limit exceeds a threshold value or not; defining an insulation deterioration degree evaluation index, determining the evaluation grade of the fault, and giving an alarm; initially positioning a cable insulation abnormity and latent fault section; and comparing the waveform of the wave recording file, expanding the section nodes for checking, and if no error exists, carrying out latent fault early warning. The method solves the problem that the power supply reliability is reduced due to the fact that the insulation state of the power distribution network cable is difficult to monitor, many faults are disposed afterwards and unplanned power failure occurs, does not need to additionally add other equipment including a sensor, and has wide practical application value.

The invention discloses a distributed grounding fault line selection device and method, and relates to the technical field of grounding fault processing, and the device comprises an intelligent grounding mechanism, a pole-mounted circuit breaker, an intelligent feeder terminal, a zero-sequence current transformer, and a preprocessor. The pole-mounted circuit breaker is used for controlling the closing and opening of a line where the pole-mounted circuit breaker is located; the zero-sequence current transformer is used for monitoring the zero-sequence current value of the line where the zero-sequence current transformer is located; the preprocessor is used for collecting a zero-sequence current value signal of the zero-sequence current transformer and sending an alarm signal to the intelligent grounding mechanism and the intelligent feeder terminal; the intelligent grounding mechanism can receive the alarm signal, transfer a single-phase grounding fault current and determine a phase and a line where a single-phase grounding fault is located; and the intelligent feeder terminal can receive the alarm signal and control the pole-mounted circuit breaker to be switched off. The method has the effect of improving the timeliness of opening of the feeder where the single-phase earth fault is located.

The invention provides a fault processing device and method compatible with arc suppression coil operation, and relates to the technical field of power supply equipment, the device comprises an arc suppression coil module and an intelligent grounding module, and the arc suppression coil module and the intelligent grounding module are connected in parallel; the arc suppression coil module comprises a first front circuit breaker, a first grounding transformer, an arc suppression coil and a first current limiting resistor, the wire inlet end of the first front circuit breaker is connected with a bus of the power distribution system, the output line of the first front circuit breaker is connected with the wire inlet end of the first grounding transformer, and the neutral point of the first grounding transformer is connected with one end of the arc suppression coil. The other end of the arc suppression coil is connected with a current-limiting resistor I, and the other end of the current-limiting resistor I is grounded; the intelligent grounding module comprises a front circuit breaker II, a fault phase selection sub-module and a fault line selection sub-module, a bus of the power distribution system is connected with a wire inlet end of the front circuit breaker II, the fault phase selection sub-module is connected with the front circuit breaker II in series and then is grounded, and the fault line selection sub-module is connected with the fault phase selection sub-module in parallel.

The invention discloses a power distribution network single-phase earth fault section positioning method based on multi-source data fusion, and the method comprises the steps: obtaining a power distribution cloud master station, dispatching remote signaling data, obtaining power distribution terminal grounding, bus grounding, small-current grounding line selection, arc suppression coil and bus voltage information through data cleaning, and carrying out the positioning of a single-phase earth fault section. Any information of a power distribution terminal grounding alarm signal, bus grounding and small current grounding line selection is used as a grounding research and judgment trigger condition; and after any information of a power distribution terminal grounding alarm signal, bus grounding and small current grounding line selection triggers grounding fault section research and judgment, the power distribution cloud master station respectively researches and judges a grounding fault section by adopting three kinds of information of grounding fault alarm information, a zero-sequence current remote measurement value and grounding fault recording. According to the method, the in-station line selection result, the relation between the neutral point grounding mode and the zero-sequence current, the terminal wave recording file and the terminal alarm information are considered at the same time, and the grounding fault section positioning method which is high in reliability, practicability and accuracy is comprehensively obtained.

The invention discloses a charging pile ground fault intelligent monitoring method based on deep learning. The charging pile ground fault intelligent monitoring method comprises the following steps: S1, acquiring and storing electrical signals of a charging pile in a working state; s2, preprocessing the electrical signal to form a standardized data set; s3, extracting features by using a converter encoder, and obtaining local details and global dependence; s4, generating a candidate solution population, initializing parameters, and performing partial training to calculate an objective function; s5, based on an improved squirrel search algorithm, optimizing the candidate solution and obtaining an optimal hyper-parameter; and S6, carrying out full-quantity training on a converter encoder, constructing and deploying a detection model, and carrying out real-time detection and classification on faults. According to the invention, through combination of deep learning and an intelligent optimization algorithm, high-precision real-time monitoring and intelligent classification of the ground fault of the charging pile are realized.

The invention relates to the technical field of power system fault detection and diagnosis, in particular to a neutral point non-effective grounding power distribution network secondary overline fault detection method, device and equipment and a computer storage medium. According to the method for detecting the secondary overline fault of the neutral point non-effectively grounded power distribution network, an overline different-phase secondary fault equivalent circuit model is established, a fault electrical quantity analytical expression is solved, the characteristics of each stage of the secondary grounding fault under different fault phase sequences are analyzed, and the fault detection accuracy is improved. Corresponding different-phase secondary overline grounding fault detection logic is provided, the accuracy and reliability of the secondary grounding fault detection method are improved, and the method has positive significance in improving the power supply safety of the power distribution network.

The invention discloses a distribution network feeder line grounding fault line selection and positioning method based on IF-AHP, and belongs to the technical field of grounding fault line selection and positioning, and the method comprises the steps: S1, collecting alarm signals of first terminal equipment, and obtaining target bus information based on the alarm signals of the first terminal equipment; s2, measuring the measurement data of a second terminal device on the feeder line side corresponding to the target bus, and calculating the score of the second terminal device based on the measurement data; s3, establishing a first hierarchical model based on IF-AHP, and calculating a combination weight of factors in the first hierarchical model; and S4, calculating a comprehensive score based on the score of the second terminal device and the combined weight of the factors in the first level model, obtaining a zero-sequence current change coefficient of any two adjacent second terminal devices on the feeder line with the highest comprehensive score before and after the occurrence of the grounding fault, and obtaining a grounding fault range based on the zero-sequence current change coefficient. The problems that the grounding fault range cannot be accurately positioned, so that the troubleshooting and repairing efficiency of the grounding fault of the feeder line of the distribution network is low are solved.

The invention relates to the technical field of power system protection, in particular to an underground power distribution network single-phase grounding protection system and method based on a signal injection method. The system comprises a signal acquisition module, a measurement and control protection module and an online monitoring module. According to the invention, by injecting the independent direct current signal and combining a zero-sequence fundamental wave time sequence identification algorithm and a traveling wave distance measurement method, rapid detection, high-precision positioning and selective protection of the single-phase earth fault of the underground low-voltage power distribution network are realized, and the method is suitable for complex environments such as coal mines and metal mines; through insulation value on-line monitoring and electric leakage protection, the ground insulation value level of a line is reflected to the voltage change of an additional direct current signal and a reactor neutral point. A zero-sequence fundamental wave time sequence identification model is adopted for electric leakage fault judgment so as to judge the fault type. By outputting a relay signal, on-off control is performed on a protected branch, so that a fault line can be quickly cut off when a fault occurs, and equipment and a bus are protected from being damaged by the fault.

The invention relates to the technical field of power distribution network fault detection, and discloses a power distribution network high-resistance grounding fault intelligent detection method, system and device and a medium, and the method comprises the steps: collecting a power distribution network line transient signal which comprises a transient zero-sequence voltage signal and a transient zero-sequence current signal; preprocessing the transient signal and extracting a multi-dimensional feature set for representing high-resistance grounding fault characteristics, wherein the multi-dimensional feature set comprises a transient energy feature, a wavelet entropy feature and a harmonic component feature; and inputting the extracted multi-dimensional feature set into a pre-trained machine learning model, and simultaneously outputting a judgment result of the high-resistance grounding fault and an estimated value of the grounding resistance through the machine learning model. According to the method, the transient energy, the multi-scale wavelet entropy, the odd harmonic amplitude and the phase, which are derived from different analysis domains and have complementary physical meanings, are deeply fused, so that the problem that a single feature is weak in characterization capability and easy to fail under the conditions of high noise and high resistance is effectively solved.

The invention discloses a centralized FA broken line positioning criterion anti-interference method considering noise interference, and the method comprises the steps: collecting the data of each node of a power distribution network line in real time, building a sequence component network model under a single-phase broken line ungrounded fault, carrying out the dynamic threshold analysis of an electrical quantity through employing a sliding time window algorithm, and setting an electrical quantity mutation criterion. And constructing an anti-interference criterion, determining whether to trigger fault positioning or not through the anti-interference criterion when sudden change of electrical quantity occurs, determining a fault section in combination with topology analysis when fault positioning is performed, and controlling upstream and downstream switches to isolate the fault and transfer the fault to a non-fault section. According to the scheme, various noise interferences in the power distribution network are effectively suppressed, the accuracy of fault signal judgment is improved, and the conditions of misjudgment and missed judgment are reduced; secondly, considering different conditions of the power distribution network, performing targeted setting and adjustment on a sequence component network model, an anti-interference criterion threshold value and the like, so that the method can adapt to a complex power distribution network operation environment, and the reliability of fault positioning is improved.

The invention discloses a protection method for a low-voltage power grid, the low-voltage power grid comprises a transformer area intelligent terminal and a plurality of intelligent switches, the transformer area intelligent terminal and the plurality of intelligent switches are connected through power lines, and the method comprises the following steps: establishing a longitudinal communication network between the transformer area intelligent terminal and the plurality of intelligent switches; determining a branch level of the low-voltage power grid according to the voltage, the current, the power, the electric energy and the alternating-current zero crossing point; drawing an electrical topological relation of the plurality of intelligent switches based on the branch hierarchy; establishing a transverse communication network of the plurality of intelligent switches based on the electrical topological relation; and when the power line has a short circuit or a grounding fault, the fault area is cut off through the corresponding intelligent switch, the fault information is broadcasted and the fault area is positioned through the transverse communication network, and the fault information is reported to the station area intelligent terminal through the longitudinal communication network. According to the protection method, the fault area can be accurately positioned, so that the emergency situation of the low-voltage power grid can be efficiently and quickly handled in real time.

The invention belongs to the technical field of power transmission and distribution of a power system, and particularly discloses a DR-MMC alternating-current and direct-current hybrid grid-connected system single-pole grounding fault ride-through method. The DR-MMC alternating-current and direct-current hybrid grid-connected system is constructed based on an offshore alternating-current wind power plant, an alternating-current collection submarine cable, an offshore direct-current wind power plant, a direct-current collection submarine cable, an offshore converter station, a direct-current sending-out submarine cable and an onshore converter station, and a connecting transformer valve side winding of the onshore converter station adopts high-resistance grounding. Judging whether the direct-current submarine cable has a single-pole grounding fault or not; and reducing the voltage instruction value and the power instruction value under the condition that the single-pole grounding fault occurs in the direct-current submarine cable, so that the transmission power of the grid-connected system is maintained at the preset transmission power, and the voltage and the current of the grid-connected system are maintained in a safe range. For a DR-MMC alternating current and direct current hybrid grid-connected system single-pole grounding fault, efficient and reliable fault ride-through can be realized through the method and the device.

The invention discloses a transmission line disconnection fault identification method and device based on multi-stage current comparison, and the method comprises the steps: extracting the zero-sequence current data of a fault line and the tripping signal data and reclosing signal data of a protection device from a fault recording file or a protection recording file obtained from the two sides of the fault line, the fault process of the line is divided into a plurality of stages; calculating per unit values of the current fundamental frequency amplitudes of the two sides of the fault line in each stage by taking the maximum value in the current fundamental frequency amplitudes of the stage before the fault as a current amplitude reference value; and judging the disconnection condition of the faulty line based on comparing the per-unit value with the disconnection fault judgment coefficient kdx and the grounding judgment coefficient kjd. According to the invention, the fault process is divided into a plurality of stages, and each time period in which the line may be disconnected or grounded is fully considered; the method can efficiently and accurately judge the line breaking fault of the line and whether the condition of grounding after line breaking exists, and does not cause misjudgment with the grounding fault.

The invention discloses a ground fault positioning and multi-solution screening method for a stator winding of a pumped storage unit, and belongs to the field of relay protection. The method is combined with a special structure of a stator winding of a variable-speed pumped storage unit, and a function relationship between a fault winding potential and a fault position is established by taking a slot potential as an analysis unit. In a phasor plane, by drawing a three-phase ground voltage phasor and a neutral point voltage phasor, an included angle relation between a fault point voltage phasor and the neutral point voltage phasor and a phasor triangle relation are utilized to determine an alternative fault point. And then, an optimization model for fault positioning is established, and a homonuclear molecule optimization algorithm is adopted for solving, so that accurate positioning of a plurality of alternative fault points is realized. And finally, third harmonic voltage information is introduced as auxiliary information, and a unique solution is screened out from the plurality of alternative fault points. The method is high in reliability, small in positioning result error and suitable for the positioning requirement of the variable-speed pumped storage unit stator grounding fault.

A ground fault circuit interrupter (GFCI) device includes a ground fault detection module for detecting a ground fault in a neutral line of a plurality of current carrying lines and generating a ground fault signal in response thereto, including a neutral line detection coil having a magnetic core made of a silicon steel and through which the current carrying lines pass; a leakage current detection module for detecting the ground fault signal and detecting a leakage current signal on the current carrying lines, and generating a zero sequence current fault signal in response to either signal; and a drive module for receiving the zero sequence current fault signal and driving a switch module to disconnect the electrical connection of the current carrying lines in response thereto. The GFCI device can avoid false tripping when high frequency currents flow through the current carrying lines, improving user experience and enhancing safety.

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.