69 results about "Phase line" patented technology

The invention discloses a main station big data-based low-voltage transformer area topology hierarchy identification method and system, and the method comprises the steps: constructing a multi-dimensional voltage feature vector through the voltage time sequence data, collected by a main station side, of a transformer area general meter and a user ammeter, and forming an electrical feature matrix through feature extraction; and on the basis, judging the station area affiliation and the phase line affiliation of the user electric meter through similarity calculation. Then, generating a stable consensus cluster based on multi-time window clustering and the copolymerization matrix, and mapping the cluster into a virtual electric meter box node; constructing a minimum spanning tree and carrying out directionalization to obtain an initial radial topological structure; further introducing an electrical consistency criterion based on correlation of voltage drop and subtree current, performing multi-candidate structure optimization on the preliminary topology, and finally obtaining an optimal transformer area topology hierarchical structure consistent with a physical rule; high-precision automatic identification of the low-voltage transformer area topology can be realized without manual participation, and effective support is provided for digital operation and maintenance of a power distribution network.

The embodiment of the invention provides a transformer no-load closing angle control method, electronic equipment, a storage medium and a program product. The method comprises the following steps: periodically sampling three-phase voltages at a power supply side of a transformer, and determining a zero crossing moment when the phase voltage is changed from a negative value to a positive value according to respective sampling data for each phase in the three phases; based on the zero point moment of each phase, a preset switching-on angle and the total delay required from the switching-on instruction sending to the actual conduction of the main circuit, the target moments at which the switching-on instructions of the three phases should be sent out are calculated respectively, and corresponding switching-on trigger signals are output at the target moments of the phases respectively; and in response to the closing trigger signal of each phase, combined switch circuits arranged in the three-phase line are respectively driven, and each group of combined switch circuit comprises an MOS (Metal Oxide Semiconductor) tube and a dry reed relay which are connected in parallel, so that the MOS tube is conducted to establish an initial current path.

The invention relates to the technical field of ice melting, and discloses a low-frequency ice melting method and device for a power distribution network and a medium. The method comprises the following steps: selecting a 10kV power distribution network ice-melting line section, determining a power taking point and a short-circuit tail end of an ice-melting three-phase line, and obtaining line parameters to determine ice-melting power and total ice-melting power of a wire per unit length; calculating the low-frequency impedance characteristic of the power distribution network line according to the line cross section area, and determining a power-frequency ice-melting current effective value; calculating a power frequency ice melting voltage required by the line based on the ice melting power; determining the lowest ice melting frequency according to a preset proportion based on the power frequency ice melting voltage by taking no over-excitation of the branch line distribution transformer as a constraint; determining a voltage output and a power output of the ice melting device based on the minimum ice melting frequency; and judging whether the load side of the branch transformer has an electric shock risk or not, and carrying out power distribution network line ice melting operation. Reactive power output can be effectively saved, phase line switching operation of direct current ice melting is avoided, and ice melting efficiency is effectively improved.

The invention relates to the technical field of power protection cabinets, in particular to a phase sequence detection and protection circuit and device for a power protection cabinet and the power protection cabinet. An acquisition and calculation unit in the circuit acquires a phase sequence parameter sample of a three-phase line, calculates a phase sequence deviation angle, and calculates a normal index by comparing the difference between a single deviation angle and an overall average deviation angle. The sequence construction unit is provided with a plurality of load grades, sorts normal indexes according to the load grades, constructs a normal index sequence of the power supply protection cabinet, and constructs a reference normal index sequence based on a normal index mean value of historical qualified samples. The protection trigger unit calculates the correlation between the normal index sequence and the reference sequence to obtain an abnormal index; and if the abnormal index is greater than a preset threshold value, judging that the phase sequence is abnormal and triggering a protection action. According to the scheme, through multi-dimensional data analysis and historical reference comparison, accurate phase sequence anomaly detection and graded protection are realized, and the safety and reliability of the power supply protection cabinet are remarkably improved.

The invention discloses a current differential protection adaptability analysis method for an alternating current line of a new energy network flexible direct output system, and belongs to the technical field of power system relay protection. Establishing a system fault equivalent model based on a low-voltage ride-through control strategy of power electronic equipment at two sides of the outgoing line; according to different asymmetric fault types and a fault point boundary condition equation, deriving mathematical models of positive-sequence, negative-sequence and zero-sequence currents on the two sides of a fault phase line; calculating a differential current and a braking current, and establishing a function relationship between the differential current and the braking current and the VSG internal potential reference value, the transition resistance and the current sequence component ratio; and the action sensitivity of protection under different working conditions is judged by comparing the current differential protection ratio braking coefficient setting value with the current differential protection ratio braking coefficient setting value. The association rule of the current differential protection refusal risk and the low-pass control parameters under the high transition resistance fault is disclosed, a basis is provided for protection setting and control strategy optimization of a network construction flexible direct output system, and the problems that a protection adaptability analysis method is weak and the influence rule of the control parameters is not clear yet are solved.

The application discloses a kind of wind power variable pitch system power grid fault detection method, system, terminal and medium, it is related to wind power generation technical field, its technical scheme main point is: by obtaining three-phase line voltage value detected by pitch driver, and based on the cosine law relationship between line voltage and phase voltage Mapping relationship is established, without increasing any external hardware voltage measurement module, only using the line voltage detection capability that driver has inside, i.e. By setting upper and lower threshold and comparing with line voltage, according to the preset judgment logic, it can be identified whether there is single-phase voltage anomaly in power grid and locate abnormal phase.Cose law reveals the inherent vector relationship between line voltage and phase voltage, when a certain phase voltage drops or rises, the two line voltages containing the phase will change simultaneously, while the third line voltage remains unchanged, by comparing the relative size of the three line voltages and the threshold, the abnormal phase can be uniquely determined.

The application discloses a kind of three-phase rectifier multiple switch tube open-circuit fault diagnosis methods based on voltage deviation, belong to power electronic converter fault diagnosis technical field.Method includes: obtaining relevant signal for diagnosis;According to three-phase voltage, three-phase current, three-phase inductance value, three-phase equivalent resistance value and switching period, the actual value of three-phase line voltage is calculated;According to DC voltage and the duty cycle of switch tube on three-phase bridge arm, the expected value of three-phase line voltage is calculated;Difference is obtained between the expected value and actual value of three-phase line voltage;The deviation value of three-phase line voltage is compared with first preset threshold and second preset threshold, to determine the polarity of the deviation value of three-phase line voltage;Wherein, first preset threshold is less than second preset threshold;The polarity of the deviation value of three-phase line voltage is combined with voltage phase, to determine fault switch tube.The application can quickly diagnose for various situations of multiple switch tube fault, including single switch fault, two switch tubes in succession fault, two switch tubes simultaneous fault.

The application provides a phase precision debugging method, which comprises the following steps: firstly, processing a debugging board and a positive sample plate for each LTCC combined substrate, obtaining initial phase precision of a beam forming matrix through the debugging board, and then designing a surface phase line of the positive sample plate according to the initial phase precision to realize coarse adjustment of the phase precision; secondly, printing the corrected surface phase line on the surface of the positive sample plate; and finally, cutting the debugging phase line on the surface of the positive sample plate to change the path length of the signal, and then to improve the phase precision and realize fine adjustment of the phase precision. As can be seen, the application can concentrate the phase errors of all components in the system by printing the phase line on the surface of the positive sample plate, and then eliminate or reduce the phase errors by debugging the surface printed phase line, so that the operation is simple and convenient, the reliability of the system is not affected, and other devices and circuits are not needed, which can ensure the overall structure of the system unchanged and solve the phase precision problem through debugging.

This invention discloses a method for detecting the health status of a new energy vehicle power supply, belonging to the field of power supply technology. The invention first extracts abnormal current signals from the phase line current signals of the three-phase inverter of the new energy vehicle power supply at different scale windows. It then extracts amplitude dispersion values ​​from the frequency domain, calculates the three-phase frequency domain cumulative values, generates frequency domain amplitude dispersion weights, and constructs a multi-scale frequency domain feature matrix and weight matrix. Next, it extracts effective abrupt change values ​​from the time domain, calculates the three-phase time domain cumulative values, generates time domain abrupt change weights, and constructs a multi-scale time domain feature matrix and weight matrix. Finally, it fuses the feature matrix and weight matrix of the same dimension, inputs them into a fault detection neural network for processing, and outputs the power supply health status. This invention improves the sensitivity and accuracy of early power supply fault identification, effectively reducing the probability of false positives and false negatives.

The invention discloses a method and system for calculating split-phase line loss of a metering box based on an intelligent measurement switch, and the method comprises the steps: searching meters through an RS485 bus after the intelligent measurement switch is powered on, and recognizing the types of single-phase and three-phase electric energy meters in the metering box; acquiring voltage data of the single-phase meter, determining an access phase through stability verification, and caching split-phase power supply and subordinate electric energy meter data for the three-phase meter at an initial moment; after correcting the abnormal data of the electric energy, performing phase-splitting classification summation on the data of the electric energy meter according to phase affiliation; dynamically setting a calculation period according to split-phase load fluctuation, and independently calculating a three-phase line loss rate by adopting a slip method when a monitoring time point meets a condition; and comparing the line loss rate with a preset parameter, dividing three levels of abnormities, and reporting the abnormities in a differentiated manner, and realizing abnormities traceability through electric energy proportion analysis and equipment real-time state monitoring. The method improves the calculation precision of the split-phase line loss, balances the calculation efficiency and resource consumption, optimizes the operation and maintenance response efficiency, and is suitable for the fine management of the line loss of the low-voltage distribution network metering box.

The application discloses a wind farm power collection line fault branch determination method and device, a storage medium and an electronic equipment. The method comprises the following steps: acquiring first fault current data sets corresponding to each phase line at the end of each power collection line within a preset time range after a fault occurs; performing power collection line route selection processing based on the first fault current data sets to determine a target power collection line where the fault occurs; acquiring second fault current data sets and fault voltage data sets corresponding to each phase line at the end of the target power collection line within the preset time range after the fault occurs; and performing power collection line branch route selection processing based on the second fault current data sets and the fault voltage data sets to determine a target branch of the target power collection line where the fault occurs. The power collection line fault branch determination method can accurately determine the power collection line fault branch, save the cost of determining the fault branch, and improve the efficiency of determining the fault branch.

The application discloses a two-phase operation characteristic analysis method for a flexible low-frequency power transmission system, and the method aims at the flexible low-frequency power transmission technology, takes the steady-state operation characteristics of the flexible low-frequency power transmission system in a two-phase operation mode as a research object, establishes each sequence equivalent network and a composite sequence network diagram in combination with a system control strategy, and obtains the voltage, current and three-phase instantaneous power characteristics of the low-frequency power transmission system based on the two-phase operation mode. The method can be used for analyzing the steady-state operation characteristics of the low-frequency power transmission system in the two-phase operation mode when a single-phase line is cut off, is simple to implement, is favorable for simplifying the analysis process, and has practical value for guiding engineering design.

A system and method of identifying the source in a three-phase power system, wherein a zero-sequence circuit is coupled between the phase lines and the neutral line at a point of interconnection. The zero-sequence circuit to: (i) injects a known shunt current change into the point of interconnection and (ii) ceases injection of the known shunt current change into the point of interconnection. Neutral current values are obtained while the known shunt current change is injected and at least one of (i) before the known shunt current change is injected and (ii) after the known shunt current change is injected and ceased. A determination is made as to whether the source is on the first side of the point of interconnection or the second side of the point of interconnection based on the known shunt current change and the neutral current values.

The invention is suitable for the technical field of line fault diagnosis, and provides a method, a system and equipment for detecting a single-phase broken line fault of a power distribution network based on a line voltage amplitude, and the method comprises the steps: collecting a zero-sequence voltage and a three-phase line voltage of each detection point in the power distribution network; whether the zero-sequence voltage effective value of any detection point is larger than a preset starting threshold value or not is judged, if yes, the ratio of the maximum value to the minimum value of the three-phase line voltage amplitude of the current detection point is calculated, and the standard deviation of the three-phase line voltage amplitude of the current detection point is calculated; and if the ratio is greater than a preset ratio threshold value and the standard deviation is greater than a preset standard deviation threshold value, determining that a single-phase disconnection fault occurs in a line section covered by the current detection point, and the fault section is located between the current detection point and an adjacent downstream detection point, thereby realizing rapid and accurate identification of the single-phase disconnection fault.

The invention discloses a distribution network line loss abnormal position identification method and system considering load distribution, and the method comprises the steps: carrying out the clock synchronization of all line loss sensing equipment, and collecting the electric energy related data on the same time section; calculating a branch line loss rate, a transformer area total loss rate and a split-phase line loss rate by adopting a layered split-phase mode based on the electric energy related data; substituting the load data and the power distribution network parameters into a pre-trained neural network model to obtain an actual line loss rate prediction value; based on the branch line loss rate, the transformer area total loss rate, the split-phase line loss rate and the actual line loss rate prediction value, determining a high loss range; and an abnormal electric energy meter is determined by applying an energy conservation law and electric energy meter relative error analysis in a high-loss range, and then a line loss abnormal position is determined. According to the method, a layered and split-phase mode is adopted, load distribution characteristics are considered through the trained neural network model, the actual line loss rate is predicted, misjudgment or missed judgment of the line loss abnormal position is avoided, and the line loss abnormal position is accurately and rapidly positioned.

The invention discloses a three-phase circuit lightning stroke identification method and device, relates to the technical field of power system positioning, and aims to accurately judge the lightning stroke type and the lightning stroke position, conveniently identify the line accident reason and quickly position the line fault caused by the lightning stroke. The method comprises the following steps: fitting a relationship between a lightning peak value on a line and a transmission distance according to a finite difference time domain method; a transient magnetic field generated by lightning stroke is induced through a PCB differential ring, and induced electromotive forces generated at the two ends of the transient magnetic field are sampled; when the induced electromotive force is greater than a set threshold value, recording current waveform data of a three-phase line; and judging an output lightning stroke type according to the current waveform data and whether the polarities of the three-phase current head waves are the same or not, and judging a lightning stroke position in combination with a relationship between a lightning peak value and a transmission distance. The lightning stroke type and the lightning stroke position can be accurately judged, and line accident reasons can be conveniently identified and line faults caused by lightning stroke can be rapidly positioned.

The application provides a power line carrier signal synchronization method and device based on a MIMO system, the method comprising the steps of: obtaining cross-correlation sequences by cross-correlating power line signals of three phase lines; determining target sampling points according to comparison results of cross-correlation values of current sampling points of the three phase lines and cross-correlation thresholds; calculating first autocorrelation results of the target sampling points according to the cross-correlation sequences of the corresponding phase lines of the target sampling points; determining second autocorrelation results according to the first autocorrelation results; if the number of the target sampling points is equal to one, the second autocorrelation result of the current sampling point is equal to the first autocorrelation result of the target sampling point; if the number of the target sampling points is greater than or equal to two, the first autocorrelation results of the target sampling points are combined to obtain the second autocorrelation results; and completing frame synchronization by comparing the second autocorrelation result of the current sampling point with an autocorrelation threshold. The application calculates autocorrelation of the target sampling points, effectively improving synchronization accuracy and reliability.

The invention relates to the technical field of intelligent control and robots, in particular to a multi-site robot equipment online state monitoring method based on the Internet of Things, which comprises the following steps: in response to a communication signal sent by robot equipment, determining communication link connectivity between the robot equipment and a monitoring system; monitoring a phase line current signal of a joint motor in the robot equipment, and determining a target frequency band energy ratio of the phase line current signal and a calculated joint speed change rate calculated based on the phase line current signal; based on the target frequency band energy ratio and the calculated joint speed change rate, the actual physical operation state of the robot equipment is determined; and according to the state contradiction degree between the communication link connectivity and the actual physical operation state, the reliable online state of the robot equipment is determined. According to the invention, the robot communication interruption state and the real offline state can be accurately distinguished.

The invention provides a power line carrier signal synchronization method and device based on an MIMO system. The method comprises the steps that power line signals of three phase lines are subjected to cross-correlation to obtain a cross-correlation sequence; determining a target sampling point according to a comparison result of the cross-correlation values of the current sampling points of the three phase lines and a cross-correlation threshold value; calculating a first self-correlation result of the target sampling point according to the cross-correlation sequence of the phase lines corresponding to the target sampling point; determining a second autocorrelation result according to the first autocorrelation result; if the number of the target sampling points is equal to one, the second self-correlation result of the current sampling point is equal to the first self-correlation result of the target sampling point; if the number of the target sampling points is greater than or equal to two, combining the first self-correlation results of the target sampling points to obtain a second self-correlation result; and comparing the second self-correlation result of the current sampling point with a self-correlation threshold to complete frame synchronization. According to the invention, autocorrelation calculation is carried out on the target sampling point, and synchronization accuracy and reliability are effectively improved.

An off-line overhead line single-phase grounding fault positioning method based on AC signal injection, after single-phase grounding fault occurs, the fault line is isolated and an AC voltage signal is simultaneously injected into the three-phase line by using a signal generating device; the fault branch is determined according to the zero sequence admittance angle difference of different branches at the branch point, and then the fault direction is determined by using the zero sequence admittance angle difference of different detection points of the fault branch; the present application is a modification of the fault off-line positioning method based on the signal amplitude difference on both sides of the fault point, and comprehensively utilizes the zero sequence admittance angle information of the fault branch and the non-fault branch, the upstream and downstream of the fault point as a new single-phase grounding fault positioning idea, avoiding the problems of the line capacitance shunt effect of the signal amplitude difference method on both sides of the fault point and the low measurement accuracy of the non-contact signal measurement method. Compared with the existing signal amplitude difference positioning method, it is not affected by the system structure and operation mode, can tolerate higher transition resistance, has wider application range and higher reliability.

The invention discloses a voltage harmonic suppression method and device for offshore wind power through a hybrid commutation sending-out system, terminal equipment and a storage medium, and belongs to the field of offshore wind power, and the method comprises the steps: collecting a three-phase line voltage waveform of a diode uncontrolled rectification unit in the hybrid commutation sending-out system, carrying out the Fourier analysis, obtaining a line voltage fundamental component, and carrying out the voltage harmonic suppression of the three-phase line voltage waveform; the total harmonic distortion amount is calculated; whether the total harmonic distortion amount exceeds a preset threshold value or not is judged, if yes, the voltage at a PCC point in the hybrid commutation sending-out system is measured, and PCC voltage is obtained through measurement; and according to the PCC voltage, controlling an auxiliary converter in the hybrid commutation sending-out system to inject harmonic current into a diode uncontrolled rectification unit so as to eliminate the harmonic component of the PCC point voltage in the hybrid commutation sending-out system, and if not, maintaining the current operation state of the auxiliary converter unchanged. According to the invention, the problem of voltage harmonic waves existing in the hybrid commutation sending-out system in the prior art can be solved.

The invention belongs to the field of electric power, and discloses a high-voltage cable grounding system induced current vector synthesis analysis method and device, and the method comprises the steps: synchronously collecting grounding current signals of a three-phase metal sheath of a high-voltage cable and synthesis current signals of each phase wire core through double Rogowski coils with consistent linearity, the synthesized current signal is a superposition value of the running current and the circulating current component; carrying out point-by-point subtraction on the synthetic current sampling value and the grounding current sampling value which are in the same phase so as to counteract a ring current component in the synthetic current signal; absolute values of the difference signals are obtained and summed, and a summed value is converted into a real operation current value through a preset segmented calibration curve; respectively carrying out discrete Fourier transform on the grounding current signal and the difference signal, representing by complex numbers of the two signals under power frequency, and calculating a quotient represented by the complex numbers to obtain a phase difference between the grounding current signal and the difference signal; and determining the system state of the high-voltage cable grounding system based on the operation current value and the phase difference.

The invention discloses a method for judging a broken line fault of a distribution network line, which comprises the following steps of: respectively selecting a head end and a tail end of the distribution network line, and respectively placing signal injection equipment and line detection equipment at the head end and the tail end; and the signal injection device sends a test signal, and after the signal detection device receives the test signal, the signal detection device processes and analyzes the test signal, and judges whether the line has a fault according to the signal loss condition. According to the invention, the broken line fault can be rapidly identified. The protection device only needs to diagnose the signal information of the tail end of the line, and can quickly identify the line breakage fault of the specified line and protect the action after the line breakage according to the change of the signal amplitude of the tail end of the line before and after the line breakage and in combination with a signal loss accumulated threshold value. The scheme is not influenced by a line operation state and a line voltage amplitude phase, and communication sampling of information at two ends is not needed. Secondly, the scheme can be used for phase line breakage detection and also can be used for neutral line or ground line breakage detection.

The invention relates to a corona discharge characteristic test clamp, system and method for an airborne three-phase line, and the clamp comprises a bottom plate which is of a long-plate-shaped structure, the two ends of the bottom plate are symmetrically provided with adjusting frame assemblies in a sliding manner, and the three-phase line is slidably installed between the top ends of the pair of adjusting frame assemblies at intervals; the support plates are fixedly installed on the bottom plate at intervals and located between the pair of adjusting frame assemblies, a pair of side grooves and a middle groove are formed in the top end of each support plate at intervals, the middle grooves are located between the pair of side grooves, and the middle grooves and the pair of side grooves are all used for installing three-phase lines in a penetrating mode; the three-phase lines are distributed in a triangular shape. According to the testing method, whether corona discharge occurs or not is judged by comprehensively utilizing two angles of time domain and frequency domain, when the amplitude of the obtained signal is higher than or equal to 20% of the average noise and the frequency of the signal meets 400Hz or an integral multiple of 400Hz, corona discharge can be judged to occur, the testing result is reliable, and the testing accuracy is high. And a scientific and accurate basis can be provided for electrical judgment of corona discharge of the aviation cable in a high-voltage electrical circuit.

The invention relates to the technical field of motor fault detection, in particular to a motor fault diagnosis method and system. The method comprises the following steps: S1, collecting a three-phase line voltage signal of a motor; s2, carrying out de-noising processing on the collected line voltage signal; s3, after Clarke transformation, converting into a space vector representation on an alpha-beta two-dimensional plane; s4, extracting feature parameters of multiple dimensions, and constructing a high-dimensional feature vector; s5, performing standardization and dimension reduction processing on the high-dimensional feature vector, introducing a principal component analysis method, performing operation state clustering on the multi-dimensional data by adopting a fuzzy C-means clustering algorithm, and automatically dividing the multi-dimensional data into a normal state category, an abnormal state category and a fuzzy abnormal category; s6, for data samples in abnormal states and fuzzy anomalies, constructing a graph structure and inputting the graph structure into the trained graph attention network for fault type diagnosis; s7, generating alarm information or an archiving report; according to the invention, various fault types in the operation process of the motor can be identified and alarmed.

The present application relates to a kind of brushless motor starting drag stage phase line contact bad diagnosis method and device, belong to brushless motor controller fault diagnosis technical field.The present application method includes: first, execute pre-starting stationary diagnosis, confirm MOS tube and phase line no short circuit or complete open circuit fault after, enter starting drag stage;In drag stage, controller executes 12 commutations, each commutation lasts 20ms, total diagnosis time length 240ms;During, three-phase current is continuously collected, and each phase current value is restored according to commutation sector;The unbalance coefficient K of three-phase current is calculated;If K is greater than preset threshold value, then determine that phase line contact is bad, immediately stop and store fault, prohibit starting.The present application is only optimized by software algorithm, under the premise that any hardware cost is not increased, the fast, accurate diagnosis to phase line implicit fault is realized, and the existing stationary diagnosis technology forms complete complement, and the safety and reliability of brushless motor control system are significantly improved.

The application discloses a power distribution method and power distribution equipment for automatic compensation of reactive power, and belongs to the technical field of reactive power compensation of electric power systems. The method generates target compensation quantities of reactive power of each phase by collecting current and voltage signals of three-phase lines, updates capacity values of compensation units through a capacity coefficient, generates multiple sets of compensation unit combinations in combination with the target compensation quantities and the capacity values, and extracts a target compensation unit combination from the multiple sets of compensation unit combinations based on a safety coefficient. Further, the capacity coefficient is corrected by calculating voltage fluctuation rates and compensation efficiencies after compensation, and the safety coefficient is updated by collecting working parameters of each compensation unit. The application can effectively improve the reliability of the compensation units by predicting capacity changes of the compensation units, and further improve the accuracy of reactive power compensation of three-phase lines.

The invention discloses a power grid phase non-impact intelligent switching method and device, the device comprises an H-bridge circuit, the midpoints of the left and right half bridges of the H-bridge circuit are connected with corresponding phase lines and neutral lines through LC filter circuits, and the two ends of the left and right half bridges are connected with a load through a static switch after being connected with a supporting capacitor in parallel, and the method comprises the following steps: calculating the three-phase voltage unbalance degree; the moment when the unbalance degree exceeds a threshold value serves as a decision moment, load equivalent impedance is calculated according to load current and voltage time sequence data, the impact cost of each phase is calculated according to the load equivalent impedance and phase voltage and load voltage at the decision moment, and the phase with the minimum impact cost serves as a target phase; and performing double closed-loop control on the target phase H-bridge circuit to enable the output voltage to track the load voltage at the decision moment, if the time when the difference value is smaller than the safety threshold meets the requirement, closing the static switch of the target phase, then controlling the output voltage of the target phase H-bridge circuit to be transited to the real voltage of the target phase, and turning off the static switch of the original phase. According to the invention, real non-impact switching of the sensitive load is realized.

The invention relates to a phase line serial number identification method, system and device, equipment, a medium and a product. The method comprises the following steps: acquiring a current change sequence of a first phase line of an alternating current power supply and a current change sequence of to-be-identified equipment; judging whether the current change sequence of the alternating current power supply is matched with the current change sequence of the to-be-identified equipment; under the condition that the current change sequence of the alternating current power supply is matched with the current change sequence of the to-be-identified equipment, determining that the phase line serial number of the to-be-identified equipment is consistent with the first phase line; wherein the current change sequence comprises the change moment of the current effective value in the preset time period and the variable quantity corresponding to the change moment. By adopting the method, the reliability of phase line identification can be improved.

A system and method of identifying the source in a three-phase power system, wherein a zero-sequence circuit is coupled between the phase lines and the neutral line at a point of interconnection. The zero-sequence circuit to: (i) injects a known shunt current change into the point of interconnection and (ii) ceases injection of the known shunt current change into the point of interconnection. Neutral current values are obtained while the known shunt current change is injected and at least one of (i) before the known shunt current change is injected and (ii) after the known shunt current change is injected and ceased. A determination is made as to whether the source is on the first side of the point of interconnection or the second side of the point of interconnection based on the known shunt current change and the neutral current values.