22 results about "Mutual impedance" patented technology

The invention relates to the technical field of transformer detection, in particular to a transformer comprehensive state monitoring method and a transformer monitoring system.The transformer comprehensive state monitoring method comprises the steps that a broadband detection impedance matrix data set is obtained through detection and calculation from multiple ports of a transformer, and then the detection impedance matrix data set is obtained through a neural network and a particle swarm optimization algorithm; obtaining an evaluation parameter vector and an evaluation impedance matrix of each frequency point; correcting the health reference conditions by using each parameter in the evaluation parameter vector, and judging the fault type of the transformer; respectively judging the winding deformation degree and the transformer health degree by utilizing the symmetry of the evaluation impedance matrix and the difference degree between the evaluation impedance matrix and the health reference matrix; the difference between the mutual impedance corresponding to the evaluation impedance matrix and the health reference matrix is calculated, and when the difference is large, an impedance path between two ports corresponding to the mutual impedance is marked as a fault position; the problems that real-time monitoring cannot be achieved through a common transformer detection method, and a detection result is not clear are solved.

The invention discloses a high-frequency transformer litz wire loss prediction method, and relates to the technical field of circuits, and the method comprises the steps: collecting an electromagnetic physical quantity, a structural physical quantity and a thermal physical quantity of a high-frequency transformer, so as to generate a multi-physical-quantity original feature set; carrying out litz wire equivalent copper foil conversion based on the multi-physical-quantity original feature set to obtain litz wire equivalent structure parameters; based on the litz wire equivalent structure parameters, determining three-dimensional magnetic field distribution of the litz wire, and decomposing the three-dimensional magnetic field distribution into a magnetic field component parallel to the strand and a magnetic field component perpendicular to the strand in combination with the litz wire torsion angle so as to generate a magnetic field component representation result; on the basis of the equivalent structure parameters of the Litz wire and the corresponding current harmonic characteristics, calculating the unit length loss of the Litz wire according to the magnetic field component characterization result so as to determine a basic loss value; and superposing the harmonic loss values to the basic loss value through the mutual impedance equivalent circuit of the litz wire to obtain the predicted loss value of the litz wire, thereby improving the loss prediction precision.

This invention discloses a transient stability modeling method for doubly-fed induction generator (DFIG) wind turbines that considers the characteristics of dual-port grid connection. In constructing the mathematical model, this method considers the coupling relationship between the input voltages of the phase-locked loops (PLLs) of the rotor-side converter and the grid-side converter, using the mutual impedance voltage drop as a bridge for the mutual coupling of the two PLLs. The constructed fourth-order transient synchronization model, compared to the traditional second-order transient synchronization model based on a single PLL, can reveal the transient synchronization and stability mechanism of DFIG wind turbines more deeply.

The invention discloses a new energy system transient overvoltage evaluation method based on a multi-station effective short circuit ratio, and the method comprises the steps: calculating a mutual impedance threshold value of a to-be-analyzed new energy station according to a voltage variation threshold value of the to-be-analyzed new energy station in a low-voltage ride-through control strategy; determining all new energy station sets entering low-voltage ride through due to the short-circuit fault of the new energy station to be analyzed based on a mutual impedance threshold value among multiple stations; calculating a multi-station effective short-circuit ratio of the new energy station to be analyzed according to the new energy station set; calculating the transient process maximum voltage of the to-be-analyzed new energy station based on the reactive current coefficient of the to-be-analyzed new energy station in the low voltage ride through control strategy and the multi-station effective short circuit ratio; according to the transient process maximum voltage and a preset overvoltage threshold value, whether the new energy station to be analyzed has transient overvoltage or not is judged.

The invention discloses a simulation method for measuring sequence impedance parameters of a same-tower double-circuit line. The method comprises the following steps: extracting line information based on engineering design data; according to the extracted line information, a simulation model of the power transmission line is constructed, the simulation model is divided into sections according to the consistency of the line information, and corresponding elements are configured; setting a line head end power supply and a head end and tail end wiring mode according to a specified standard, and carrying out short circuit and open circuit tests to measure the voltage and current of the line head end; fourier transform is adopted to extract fundamental frequency components of voltage and current of the head end of the line, and short-circuit impedance and open-circuit impedance of the line are calculated according to the fundamental frequency components of the voltage and the current; and the positive-sequence impedance and the zero-sequence impedance of the lines and the zero-sequence mutual impedance between the lines on the same tower are obtained by using the short-circuit impedance and the open-circuit impedance of the lines. The method solves the problems that single-circuit line parameter measurement simulation cannot accurately represent the coupling characteristics of double-circuit lines on the same tower, and related guide rules have a measurement theoretical basis but do not provide a matched simulation modeling scheme.

The application discloses an alternating current system wide frequency band impedance envelope method, and belongs to the technical field of impedance envelope. The method comprises the following steps: establishing a Norton equivalent circuit of an internal power supply of an alternating current system; according to the relationship between the Norton equivalent circuit of the internal power supply of the alternating current system and the voltage and current of each node, obtaining equivalent impedance of the alternating current system based on a kron reduction theory; and finally, superimposing the equivalent impedance of the alternating current system under each operation mode and the connection node of the external equipment into the same coordinate system, so that the harmonic equivalent impedance of the alternating current system and the mutual impedance between the nodes can be calculated simultaneously, and the concept of the impedance envelope line of the alternating current system is proposed to describe the change range of the impedance when the operation mode of the system changes.

The application discloses a kind of multiple-line direct supply traction network fault location method, electric power instrument and medium, the method includes: collecting the traction network electrical data before failure and the traction network electrical data after failure;According to the electrical data collected, calculate the traction network electrical data variation;According to the traction network electrical data variation, obtain the voltage effective value of downlink traction network;According to the traction network electrical data variation, ground unit reactance, unit self-impedance, unit mutual impedance and other parameters, obtain the fault point voltage variation;According to the fault point voltage variation, obtain the effective value function of downlink traction network voltage variation variation;The effective value function of downlink traction network voltage variation variation is solved, and the fault distance is obtained.The application can timely and accurately identify fault position, further improve fault location accuracy, effectively improve the reliability of traction network operation.

The invention relates to the technical field of rail transit lightning stroke protection and electrical safety analysis, and discloses a method for establishing an equivalent calculation model of a steel rail transmission line, a terminal and a medium. The method is applied to lightning stroke transient analysis of a non-standard I-shaped structural steel rail, and comprises the following steps: firstly, arranging two cylindrical surface current layers outside a steel rail conductor; respectively calculating an impedance parameter of a system formed by the inner cylindrical surface current layer and the steel rail, an impedance parameter of a system formed by the outer cylindrical surface current layer and the ground, and a mutual impedance parameter of the steel rail; analyzing the influence of the skin effect and the magnetic saturation effect on the steel rail impedance parameter by adopting finite element software, and obtaining a steel rail frequency domain impedance parameter matrix finally used for modeling according to an analysis result; and finally, based on the steel rail frequency domain impedance parameter matrix, establishing a time domain transmission line equation containing frequency-dependent parameters. The method can obtain the impedance frequency domain characteristic parameters of the section conductor of the steel rail, analyzes the influence rule of magnetic saturation nonlinearity on the impedance parameters in the steel rail, and establishes a steel rail lightning stroke transient response calculation model.

The application discloses a kind of monitoring method and system of electric power grounding system, applied to resistance detection technical field, method includes: obtaining the position distribution information of each ground body in target electric power grounding system;Based on position distribution information, the mutual impedance information of each ground body is obtained;Determine the target excitation frequency point of ground body;The target excitation signal is applied to corresponding ground body, and corresponding response signal is obtained;Orthogonal demodulation is carried out to the target impedance component extracted from response signal, and resistance response component and reactance response component are obtained;According to resistance response component, the equivalent resistance value of ground body is obtained, and the impedance data of ground body is determined based on reactance response component to process equivalent resistance value;Based on the impedance data of ground body, the resistance monitoring data of target electric power grounding system is obtained.The monitoring method and system of electric power grounding system provided by the application effectively improve the accuracy of resistance monitoring of the electric power grounding system of multiple ground body.

This invention relates to the field of power supply testing and automated detection technology, specifically to a multi-channel parallel electrical parameter testing system for power adapters. The system includes a parallel test loop, a multi-channel signal acquisition module, a state assessment and quantization module, an intelligent scheduling decision module, and a dynamic decoupling execution module. It acquires real-time electrical parameter signals from each test channel and extracts them to form a multi-dimensional electrical state sequence. A cross-impedance matrix between channels is constructed. Based on a matrix perturbation model, nonlinear coupling analysis is performed to generate electrical crosstalk entropy and predict the system failure risk value. Then, based on a comparison of the electrical crosstalk entropy with a preset safety threshold, a target scheduling strategy is determined, and the parallel test loop and test load are reconstructed and adjusted in timing. This invention achieves stable operation in a high-density parallel testing environment.

The invention discloses a low-voltage distribution network power supply line electric leakage fault positioning method and device and a storage medium, and relates to the technical field of power grid power supply safety. The positioning method comprises the following steps: acquiring historical electrical quantity data of a target station area in a normal operation state, further calculating equivalent mutual impedance among user nodes, and determining an anomaly judgment threshold value; acquiring actually measured electrical quantity data of the target station area when the electric leakage fault occurs, and further calculating current equivalent mutual impedance among the user nodes; comparing the current equivalent mutual impedance with a corresponding anomaly determination threshold to identify an abnormal mutual impedance; for each user node, counting the number of identified abnormal mutual impedance in the current equivalent mutual impedance between the user node and all other user nodes; and determining the user node with the maximum number of abnormal mutual impedance as a priority troubleshooting object of the electric leakage fault. According to the method, the problem of large calculation error of a virtual impedance method depending on strong hypothesis is solved, and the troubleshooting efficiency is improved.

The application discloses a high-frequency transformer Litz wire loss prediction method, and relates to the technical field of circuits, which comprises the following steps: collecting electromagnetic physical quantities, structural physical quantities and thermal physical quantities of a high-frequency transformer to generate a multi-physical quantity original feature set; performing Litz wire equivalent copper foil conversion based on the multi-physical quantity original feature set to obtain Litz wire equivalent structural parameters; determining the three-dimensional magnetic field distribution of the Litz wire based on the Litz wire equivalent structural parameters, and decomposing the three-dimensional magnetic field distribution into a magnetic field component parallel to the strand and a magnetic field component perpendicular to the strand in combination with the Litz wire twist angle to generate a magnetic field component representation result; calculating the unit length loss of the Litz wire according to the magnetic field component representation result based on the equivalent structural parameters of the Litz wire and the corresponding current harmonic characteristics to determine a basic loss value; and superimposing each harmonic loss value on the basic loss value through the mutual impedance equivalent circuit of the Litz wire to obtain a predicted Litz wire loss value, so that the loss prediction precision is improved.

The invention belongs to the technical field of multi-core mobile cable electrical parameter calculation, and discloses a general solving method for multi-core mobile cable electrical parameters based on field-circuit collaborative analysis. The method comprises the following steps: firstly, acquiring structural parameters and material electrical parameters of the multi-core mobile cable, injecting a multi-frequency harmonic signal into the cable, collecting first and tail end voltage and current time domain signals, and extracting each frequency phasor through Fourier transform; simplifying an impedance and admittance matrix based on a cable structure and conductor layout, and solving mutual admittance between a conductor core and a shielding layer by using a measurement phasor; further calculating other mutual admittance and mutual impedance based on an electromagnetic field analytical method; and finally, substituting all mutual parameters into a phasor equation, and solving the self-impedance and the residual mutual impedance of each conductor. According to the method, through field-circuit collaborative analysis, the efficiency of an analytical method and the precision of a numerical method are considered, the complete electrical parameters of the multi-core mobile cable under the broadband can be rapidly and accurately obtained, and the method is suitable for system simulation, protection setting and fault analysis of power transmission and communication cables and has good engineering applicability and calculation efficiency.

The invention relates to the technical field of transformer detection, in particular to an impedance matrix data generation method and an impedance detection system.The impedance detection system executes the method to generate impedance matrix data, and the method comprises the steps that whether the transformer is online or not is judged through a voltage transformer and a current transformer; if the on-line voltage signal and the on-line current signal of each port are directly collected on line, calculating the on-line impedance vector and all on-line mutual impedances of the port according to the specific frequency point of the operation of the transformer, and splicing an on-line impedance matrix; otherwise, broadband off-line detection is carried out, and an off-line impedance matrix is spliced; secondly, eliminating external influences of the two impedance matrixes, and marking effective impedance matrix data and invalid impedance matrix data; the problem of monitoring and fault diagnosis omission caused by impedance matrix data frequency point limitation and the problem of monitoring and fault diagnosis result error caused by external influence are solved.

The present disclosure relates to the technical field of traction power supply for electrified railways, and provides a fault distance measurement method and system using a single-line direct supply of traction network rail current. The method comprises: when the current detected at the first end of the target rail is greater than a preset current threshold, obtaining a first current, a first voltage, a second voltage, a first impedance, a second impedance, and a target mutual impedance; and calculating the short-circuit fault distance between the target contact line and the target rail based on the first current, the first voltage, the second voltage, the first impedance, the second impedance, the target mutual impedance, and a preset calculation formula. The embodiment of the present disclosure can eliminate the need to consider the problem of poor accuracy caused by grounding with a large transition resistance, thereby increasing the practicality and calculation accuracy of the present disclosure.

This invention relates to the field of harmonic assessment technology, specifically disclosing a method and system for assessing harmonic immunity of a parallel grid system considering frequency coupling. The method includes: acquiring grid-connected current data for GFL and GFM converters under different background harmonics; calculating the harmonic coupling admittance matrices of the GFL and GFM converters to obtain the harmonic coupling admittance matrix of the parallel system at the common coupling point; calculating the grid-side harmonic coupling admittance matrix based on the harmonic coupling admittance matrix of the parallel system at the common coupling point and the grid line impedance; and calculating the assessment index of the parallel system's ability to resist background harmonic interference based on the grid-side harmonic coupling admittance matrix, thereby achieving the assessment of the harmonic immunity of the parallel system. This invention introduces harmonic mutual impedance, fully considering the influence of harmonic coupling, and effectively improves the accuracy of harmonic immunity assessment in some scenarios.

The application relates to the technical field of rail transit lightning protection and electrical safety analysis, and discloses a method for establishing an equivalent calculation model of a steel rail transmission line, a terminal and a medium. The method is applied to lightning transient analysis of a non-standard I-shaped structure steel rail. First, two layers of cylindrical current layers are arranged outside a steel rail conductor; then, impedance parameters of a system composed of the inner cylindrical current layer and the steel rail, impedance parameters of a system composed of the outer cylindrical current layer and the ground and mutual impedance parameters of the steel rail are calculated; the influence of skin effect and magnetic saturation effect on the impedance parameters of the steel rail is analyzed by using finite element software, and a final steel rail frequency domain impedance parameter matrix used for modeling is obtained according to the analysis result; and finally, a time domain transmission line equation containing frequency variable parameters is established based on the steel rail frequency domain impedance parameter matrix. The application can obtain the frequency domain characteristic parameters of the conductor impedance of a steel rail section, analyze the influence law of magnetic saturation nonlinearity on the internal impedance parameters of the steel rail, and establish a lightning transient response calculation model of the steel rail.

The invention provides a new energy multi-machine transient synchronous stability collaborative optimization control method and system, and belongs to the field of new energy power generation. The system comprises a plurality of new energy power generation units, a grid-connected converter, a common coupling point and a cooperative control center. The method comprises the steps of collecting common point voltage and current of each converter; calculating mutual impedance voltage influence between the converters; evaluating the transient synchronous stability margin of each power generation unit based on mutual impedance influence; by taking improvement of the overall stability margin of the system as a target, performing collaborative optimization to generate a current instruction of each converter; and converter output is controlled according to the instruction. Through system-level cooperative control, mutual impedance negative interaction during multi-machine parallel connection is quantified and inhibited in real time, the synchronization stability of the new energy multi-machine system under the transient fault of the power grid is effectively improved, and chain instability is prevented.

The application relates to a power distribution network shunt active power filter configuration optimization method and device, computer equipment, a storage medium and a computer program product. The method comprises the following steps: obtaining each harmonic impedance of each branch of a power distribution network, each harmonic mutual impedance between nodes, an association matrix formed between all nodes and all branches, and each harmonic current of each branch when no shunt active power filter is configured; determining a target function of the shunt active power filter configuration of the power distribution network, and taking the target function as a harmonic network loss suppression model, wherein the target function comprises a harmonic network loss function of the power distribution network and a configuration quantity function of the shunt active power filter; and solving the harmonic network loss suppression model in a preset solution range through a multi-objective particle swarm optimization algorithm to obtain a global platonic optimal solution set of the harmonic network loss suppression model. The method can improve the use value and efficiency of the shunt active power filter.

The application discloses a low-voltage distribution network power supply line electric leakage fault positioning method and device and a storage medium, and relates to the technical field of power grid power supply safety. The positioning method comprises the following steps: acquiring historical electrical quantity data of a target station area in a normal operation state, and then calculating equivalent mutual impedances between user nodes and determining an abnormal judgment threshold; acquiring measured electrical quantity data of the target station area when an electric leakage fault occurs, and then calculating current equivalent mutual impedances between the user nodes; comparing the current equivalent mutual impedances with corresponding abnormal judgment thresholds to identify abnormal mutual impedances; for each user node, counting the number of the current equivalent mutual impedances between the user node and all other user nodes that are identified as abnormal mutual impedances; and determining the user node with the largest number of abnormal mutual impedances as a priority investigation object of the electric leakage fault. The application solves the problem of large calculation error of the virtual impedance method depending on strong assumptions, and improves the fault investigation efficiency.

The application relates to an equivalent uplink and downlink current ratio fault location method combined with segmented reactance tables, which uses the uplink and downlink current ratio method combined with segmented reactance tables to replace the reactance ratio method and the common uplink and downlink current ratio method commonly used in the current double-line direct supply operation mode for fault location, divides the double-line direct supply traction network into several sections according to the different unit impedances, and then calculates the reactance value of each section according to the impedance and mutual impedance of each section. The method can not only consider the influence of the lightning protection coil and the power supply line on the location result, but also can guarantee the location accuracy when the number of stations is large, so that the location error is controlled within 250 meters; the method can ensure that the maintenance personnel quickly find the fault point, timely treat the fault, and restore the normal operation of the line, and is very important for the safety, reliability and efficient transportation of the railway system.

The present disclosure relates to the technical field of traction power supply for electrified railways, and provides a fault distance measurement method and system using a single-line direct supply of traction network rail current. The method comprises: when the current detected at the first end of the target rail is greater than a preset current threshold, obtaining the contact wire current, rail current, base voltage, comparison voltage, contact wire impedance, rail impedance, and target mutual impedance; and calculating the short-circuit fault distance between the target contact wire and the target rail based on the contact wire current, rail current, base voltage, comparison voltage, contact wire impedance, rail impedance, target mutual impedance, and a preset calculation formula. The embodiment of the present disclosure can eliminate the need to consider the problem of poor accuracy caused by grounding with a large transition resistance, thereby increasing the practicality and calculation accuracy of the present disclosure.