148 results about "Phase line" patented technology

The invention relates to the technical field of three-phase current data processing, in particular to an electric energy quality intelligent monitoring method and system for a four-fusion integrated terminal. The method comprises the following steps: acquiring a current sequence and a monitoring phase corresponding to each phase line; calculating the suspected abnormal degree of the current monitoring point in the current sequence of the monitoring phase, and judging whether the current monitoring point is an abnormal monitoring point or not; if the current monitoring point is an abnormal monitoring point, acquiring a continuation curve; calculating a continuation distribution characteristic value of the abnormal monitoring point according to each data point in the continuation curve; correcting the continuation distribution characteristic value based on the distance between trough points of the crest of the continuation curve and the height of the crest to obtain a corrected continuation distribution characteristic value; obtaining the current abnormal degree of the abnormal monitoring point based on the suspected abnormal degree of the abnormal monitoring point and the corrected continued distribution characteristic value; and judging whether the electric energy quality is abnormal according to the current abnormal degree. According to the invention, the electric energy quality of the four-fusible integrated terminal can be accurately monitored.

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 invention discloses a wiring detection method for an intelligent electric energy meter and a related product, and the method comprises the steps: obtaining the measurement data of a phase line collected by the intelligent electric energy meter in a preset time period, the measurement data comprises phase current data, and each sampling point in the phase current data comprises an A-phase current and a C-phase current; determining the number of sampling points of abnormal phase current in the phase current data; and determining the wiring fault type of the intelligent electric energy meter according to the ratio of the sampling point number of the abnormal phase current to the sampling point number of the effective phase current in the phase current data. By means of the method, wiring errors such as misconnection of the current loop of the intelligent electric energy meter can be accurately recognized.

The invention provides an energy storage converter low-voltage ride-through control method and an energy storage converter, and relates to the field of low-voltage ride-through control, and the method comprises the steps: obtaining a three-phase line voltage of a power grid; based on the three-phase line voltage, calculating a coordinate transformation angle by using a phase-locked loop method of a second-order generalized integrator to obtain a first coordinate transformation angle; based on the three-phase line voltage, calculating a coordinate transformation angle by using a phase-locked loop method of BC phase line voltage zero crossing point detection to obtain a second coordinate transformation angle; calculating an absolute value of a difference value between the first coordinate transformation angle and the second coordinate transformation angle to obtain a transformation angle difference value; judging a power grid voltage drop condition; and determining a target coordinate transformation angle and target reactive current positive sequence and negative sequence component given values according to the power grid voltage drop condition and the transformation angle difference value. According to the method provided by the invention, the low-voltage ride-through requirements under different power grid voltage drop conditions can be met, and the low-voltage ride-through capability and the system stability of the energy storage converter are improved.

The invention discloses a least square improvement-based nearest projection point ambiguity resolution method. The method comprises the following steps of: constructing a relation model between ambiguity phase differences corresponding to various baselines of a double-long-baseline phase interferometer; grid division is carried out on the field angle of the double-long-baseline phase interferometer, and a phase difference fuzzy graph is constructed; expanding the relation model of the double-long-baseline phase interferometer to a multi-long-baseline interferometer, constructing a baseline vector, a theoretical fuzzy phase difference vector and a fuzzy number vector, and determining a hyperplane perpendicular to a phase line in the phase difference fuzzy graph; starting point fuzzy phase difference vectors of all phase lines and phase difference projection points of the phase lines on a hyperplane are determined based on the phase difference mode fuzzy graph; and performing least square fitting on an actually measured fuzzy phase difference vector corresponding to the actually measured multi-snapshot target signal, searching a fitted fuzzy phase difference vector with the minimum variance, determining the nearest phase difference projection point, and obtaining a corresponding fuzzy number vector to realize ambiguity resolution.

The embodiment of the invention discloses a distribution transformer electrical parameter complex field on-line synchronous vector monitoring device and method, and the device comprises a high-precision synchronous vector measurement and collection module and a controller, and the high-precision synchronous vector measurement and collection module is connected with the controller. The high-precision synchronous vector measurement and acquisition module is used for being connected with a neutral line at the low-voltage side of the distribution transformer to be measured and a three-phase line at an outlet, and is used for measuring and synchronously acquiring a zero-sequence voltage vector and a neutral line current vector at the low-voltage side of the distribution transformer to be measured. The controller is used for determining the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral current vector, so as to determine the load loss and the short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance, namely, the zero-sequence voltage vector and the neutral current vector are simply and synchronously measured on the low-voltage side of the distribution transformer. Therefore, on-line monitoring of short-circuit complex impedance and electrical parameters can be realized, and problems in the prior art are solved.

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 discloses an AE-KDE-based transformer area phase line loss data anomaly detection method, system and device, and relates to the technical field of intelligent power detection. The method comprises the steps of obtaining a line loss data set of a target station area, performing data preprocessing on the line loss data set to obtain a plurality of sub-data sets, and storing split-phase line loss time sequence data in the sub-data sets; respectively inputting the split-phase line loss time sequence data stored in the sub-data set into a pre-trained prediction model, and outputting a prediction value of each piece of split-phase line loss time sequence data; and calculating a weighted residual error between the predicted value and an actual value of the line loss data set, and judging whether the line loss of each split phase is abnormal or not by utilizing a statistical density estimation method according to a weighted residual error calculation result. The method can achieve the precise monitoring and positioning of the line loss abnormity of each phase, improves the detection precision, and facilitates the stable operation of a power grid and the efficient allocation of resources.

The present invention belongs to the technical field of matrix converters, and discloses a three-phase four-leg three-level direct matrix converter and an SVPWM modulation method. The topology consists of 24 bidirectional switches and 8 flying capacitors. Each of the four legs A, B, C, and N includes 9 output switching states and 6 output voltages. There are a total of 6561 switching states, and the output phase line voltages altogether include six output voltages. The present invention proposes a novel SVPWM modulation method. This method mainly transforms the control of the output voltage from the conventional αβ coordinate system to the abc coordinate system, while the input current is still modulated separately in the αβ coordinate system. The biggest advantage of using the abc coordinate system is that through coordinate translation, the three-level modulation can be simplified to two-level modulation, greatly reducing the increase in algorithm complexity caused by the increase in the number of levels.

The invention relates to a controllable voltage source arc extinction method, control equipment and a computer storage medium, and the method comprises the steps: S1, obtaining three-phase voltage change data outputted after the fault of a power distribution network occurs when the power distribution network has a grounding fault; s2, generating three phase voltage increment matrixes in one-to-one correspondence with the three phase lines according to the three-phase voltage change data; s3, performing sorting conversion on each phase voltage increment matrix to obtain three multi-dimensional data matrixes in one-to-one correspondence with the three phase voltage increment matrixes; s4, performing similarity analysis according to the three multi-dimensional data matrixes to obtain a first similarity coefficient capable of representing the similarity of the phase A and the phase B, a second similarity coefficient capable of representing the similarity of the phase B and the phase C and a third similarity coefficient capable of representing the similarity of the phase A and the phase C; and S5, determining a fault phase according to the first to third similarity coefficients. The fault phase determination method can be simplified, and the fault phase determination efficiency can be improved.

The invention discloses a BP neural network-based single-phase disconnection fault positioning method and apparatus, and a medium. The method comprises the steps of collecting a single-side disconnection fault feature set of a power distribution network; mapping the fault feature set to a high-dimensional feature space through a preset kernel function to obtain a mapping result, and screening out a feature subset from the broken line fault feature set based on the mapping result; inputting the feature subset into a preset fault positioning model, searching an optimal model parameter of the fault positioning model by adopting a particle swarm optimization algorithm, and determining a target fault positioning model based on the optimal model parameter; and collecting the electrical characteristic quantity of the single side of the power distribution network, inputting the electrical characteristic quantity into the target fault positioning model to determine an output model output result, and determining the position of the single-phase disconnection fault based on the model output result. According to the invention, the position of the broken line fault can be accurately and rapidly positioned.

The invention discloses an overhead line current accurate measurement system and method based on an MEMS sensor array. The system comprises a three-phase line device located on an overhead line. The A-phase line device comprises three TMR sensors, one MEMS sensor and one data processing module, and the B-phase line device and the C-phase line device respectively comprise one MEMS sensor; all the TMR sensors and the MEMS sensors are located on the same vertical plane of the overhead line; on the vertical plane, the three TMR sensors are arranged on the concentric circle of the A-phase line, the sensor TMRa is located on the vertical line of the center connecting line of the BC-phase line, and the sensors TMRb and TMRc are both located on the center connecting line of the BC-phase line; and the data processing module of the A-phase line device calculates the three-phase current of the overhead line according to the measurement data of each sensor and the mutual position relation set when each phase line is in a static state. According to the invention, accurate detection of each phase current of the overhead line by using the TMR is realized.

The invention relates to the technical field of distribution line fault detection, in particular to a distribution line fault on-line detection method, device and system, and the method comprises the steps: obtaining the actual current of each phase line in a distribution line, and obtaining the line mode current of the distribution line through employing Karembert; calculating a peak saliency coefficient of each data segment and a first saliency value of each data segment to obtain a lightning fault saliency value of the line mode current so as to calculate a line mode current abnormal value of the distribution line; obtaining an actual current abnormal value of the distribution line according to the difference degree of any two phases of lines with respect to the actual current and the range condition of the actual current of each phase of line; and obtaining a lightning stroke fault evaluation value of the distribution line according to the line mode current abnormal value and the actual current abnormal value of the distribution line, and detecting the fault of the distribution line. The fault detection precision of the distribution line can be improved.

The invention relates to the field of testing, and discloses an inter-phase short-circuit fault diagnosis method, device, system and equipment, and a storage medium. In the system, a frequency converter is connected with a motor through a three-phase line, and at least two phases of lines are respectively and correspondingly provided with a current sensor; the method comprises the following steps: determining the current change rate of each phase line based on the current signal of each current sensor under the condition of detecting that a power device of the frequency converter has a fault or the frequency converter outputs overcurrent, and detecting whether the current change rates of at least two phase lines in the current change rates of the phase lines are greater than a current change rate threshold value or not; performing inter-phase short-circuit fault diagnosis based on the current change rate detection result to obtain a diagnosis result; the diagnosis result is the position where there is no interphase short circuit fault or there is an interphase short circuit fault, and a fault protection strategy corresponding to the diagnosis result is determined for fault protection. The problem of low accuracy of inter-phase short-circuit fault diagnosis is solved, and the reliability and availability are improved by using a proper fault protection strategy.

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 provides a method and system for detecting abnormity of a load switch of a low-voltage meter box, and the method comprises the steps: obtaining the target parameter information of a target low-voltage meter box, and screening the meter information in the target parameter information; the number of meters in the screened target parameter information is determined, if the number of meters in the screened target parameter information is larger than a preset first number threshold value, phase-by-phase checking is conducted on phase lines of the meters according to a preset checking standard, and a corresponding checking result is obtained; and determining whether the load switch corresponding to the meter is abnormal or not according to the troubleshooting result, and if so, outputting a corresponding alarm signal. The low-voltage load switch with poor contact can be found in time, loss of national assets caused by electric charge loss is avoided, electric appliance fire accidents are avoided, manpower and material resources can be saved, economic losses of an electric power department are reduced, and electric fire safety accidents are avoided.

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 invention discloses a neutral line fault detection method and an optical storage inverter, and the method comprises the steps: carrying out the calculation of the phase voltage of each phase line when a neutral line does not deviate according to the line voltage between the phase lines in three phase lines and the phase difference between the line voltages; according to the phase voltage of each phase line when the neutral line does not deviate, calculating to obtain a corresponding phase voltage effective value; and comparing the phase voltage effective value obtained by calculation with the phase voltage effective value obtained by sampling so as to determine whether the neutral line has a fault or not. According to the neutral line fault detection method and the optical storage inverter provided by the invention, the detection of faults such as disconnection or non-access of the neutral line is realized under the condition of not additionally adding a hardware circuit or instrument equipment, the coupling with the hardware circuit is reduced, the overall cost and the overall loss are reduced, and the detection reliability is improved.

The invention relates to a power line characteristic current identification method and device and a phase line identification system. The method comprises the following steps: dividing a current signal and a current signal corresponding to a characteristic frequency based on a preset time window and a preset sliding step length to obtain a first time window array and a second time window array, a first identification sequence based on direct current signal identification and a second identification sequence based on characteristic frequency identification are obtained according to the characteristic sequence; and finally, a characteristic current signal can be judged by comparing the first identification sequence and the second identification sequence with the characteristic sequence. According to the embodiment of the invention, through two modes of direct current signal identification and characteristic frequency current signal identification at the same time, accurate identification in different noise or interference environments can be realized, and the accuracy and robustness of identification are significantly improved.

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 present application provides a method for online identifying the parameters of a surface-mounted three-phase AC permanent magnet synchronous motor. The method includes: obtaining the real-time current on the three-phase lines of the motor, and transforming the three-phase current on the motor phase lines into the current in the two-phase αβ-axis coordinate system; combining the current in the two-phase αβ coordinate system with the electrical angle of the motor rotor and transforming it into the current in the DQ-axis coordinate system; substituting the current in the DQ-axis coordinate system into the voltage equation of the motor in the DQ coordinate system; substituting the current in the two-phase αβ coordinate system into the voltage equation with an extended back electromotive force of the motor in the αβ coordinate system; simplifying the motor voltage equation in the DQ coordinate system of the motor; discretizing the voltage equation with an extended back electromotive force of the motor in the αβ coordinate system according to the control period; obtaining the motor parameters in two cases of high speed and low speed. The present application does not inject high-frequency specific pulses, avoiding interference with the operation of the motor.

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 invention provides an inverter-based networking system, and relates to the technical field of power electronic conversion, the inverter-based networking system comprises a first inverter, a second inverter, a dynamic phase line configuration unit, a load and / or a power grid, the first inverter comprises a first phase line, a second phase line and a first neutral line, and the second inverter comprises a third phase line, a fourth phase line and a second neutral line; the dynamic phase line configuration unit is used for configuring the at least one phase line as a phase line of a load and / or a power grid; and connecting the first neutral line and the second neutral line and then configuring the first neutral line and the second neutral line as a neutral line of a load and / or a power grid. The first inverter is used for controlling the output voltage among the first phase line, the second phase line and the neutral line or controlling the grid-connected current of the first phase line and / or the second phase line according to the working mode, and the second inverter is used for controlling the output voltage among the third phase line, the fourth phase line and the neutral line or controlling the grid-connected current of the third phase line and / or the fourth phase line. The networking system can adapt to various user scene requirements.

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.

The present invention discloses a method for phase mismatch detection and fault-tolerant control of a three-phase switched reluctance motor, which relates to the field of motor technology and includes the following steps: S1, determining whether the phase mismatch detection state of the three-phase switched reluctance motor is greater than 0, if not, entering S2, and if so, entering S4; the phase mismatch detection state is 0 before the first execution of S1; S2, determining whether the original three-phase current peak value meets the threshold condition, if so, entering S3, otherwise entering S5; S3, completing the phase mismatch detection; S4, completing the phase current control; S5, determining that the phase mismatch detection failed, rotating the rotor to another position, and performing the next phase mismatch detection. The present invention can implement fault-tolerant control based on the detection results, avoiding performance issues such as increased torque pulsation caused by phase mismatch and the increased workload of reconnecting phase lines.