23 results about "Self impedance" patented technology

The invention provides a non-power-cut test method for mutual inductance parameters of a power transmission line under excitation of different-frequency signals and a related device, and solves the problems of difficulty in accompanying stop and high safety risk of adjacent lines. The method comprises the following steps: selecting one circuit in the same corridor for power failure, connecting the head end with an induced electricity suppression device, and performing three-phase short-circuit grounding at the tail end; injecting a different-frequency sinusoidal current of 45-55Hz into the power failure line; the synchronous measurement device collects head and tail voltage and current of a running line based on a satellite synchronous clock; extracting pilot frequency signals through two-stage notch filtering and Fourier transform; and different-frequency zero-sequence self-impedance and mutual impedance are calculated and converted into power-frequency impedance. According to the invention, accurate test without power failure can be realized, and safety and power supply reliability are guaranteed.

The invention relates to an impedance modeling method and device and computer equipment. Comprising the steps that disturbance voltage is injected to the alternating current side of a main circuit, a first relation between a modulation small signal and an alternating current small signal is obtained through alternating current control topology, the disturbance voltage and a phase angle small signal are correlated through a phase-locked loop, and a second relation between the modulation small signal and an alternating voltage small signal is determined; injecting disturbance voltage to the direct current side of the main circuit, and determining a third relationship between the modulation small signal and the alternating current small signal and a fourth relationship between the direct current small signals based on the alternating current control topology and the direct current control topology; and finally, impedance modeling is carried out in combination with a frequency small-signal model, so that self-impedance and coupling impedance characteristics of an alternating current side and a direct current side can be accurately reflected, and a basis is provided for analyzing system stability and optimizing a control strategy.

The invention discloses a low-voltage transformer area topology identification method and system based on node mutual impedance characteristic identification, and relates to the technical field of power supply and distribution. The identification method comprises the following steps: firstly, synchronously acquiring voltage and current time sequence data of the head end of a transformer area and each user node; constructing and solving a mathematical model based on a circuit superposition principle to obtain a user node mutual impedance coefficient matrix; the impedance feature vector of each user node is extracted, the difference value between the self-impedance and the mutual impedance is calculated, and the difference value is compared with a preset judgment threshold value based on physical parameters, so that the relationship between the upstream and the downstream of the user nodes and the same access point is accurately judged; and finally, reconstructing a complete tree-shaped physical topology of the transformer area. According to the method, only existing measurement data is utilized, extra hardware is not depended on, efficient and accurate automatic identification of the topological structure of the low-voltage transformer area is achieved, and reliable support is provided for refined operation and maintenance such as power distribution network line loss treatment and fault positioning.

The application discloses a new energy multi-station short-circuit ratio calculation method and system, and a storage medium. The method comprises the following steps: performing network topology analysis on a power grid model I containing an external network model to obtain a total topology node set; forming a node admittance matrix according to the device resistance, the electric reactance parameter and the topology node set of the power grid model I, processing the node admittance matrix to obtain a factor table of the node admittance matrix; calculating self-impedance and mutual impedance of nodes corresponding to new energy stations in a node impedance matrix according to the factor table; obtaining short-circuit currents of each node when three-phase short-circuit faults occur, and calculating short-circuit capacities of each node; obtaining new energy multi-station short-circuit ratios of each node according to the short-circuit capacities, the self-impedance and the mutual impedance; and obtaining new energy multi-station short-circuit ratios according to the short-circuit ratios of each node. The application considers the influence of the external network model and the characteristics of a new energy voltage-controlled power supply on the calculation of new energy multi-station short-circuit ratios, and improves the accuracy of the calculation results.

The invention discloses a traction network simplified modeling method and a power flow and fault analysis method. In order to reduce calculation errors caused thereby, additional self-impedance and additional mutual impedance are introduced, and an additional impedance matrix is formed by the additional self-impedance and the additional mutual impedance. An additional admittance matrix may be generated from the additional impedance matrix. And establishing a node admittance matrix of the traction power supply system, fusing the node admittance matrix with the additional admittance matrix to obtain an extended admittance matrix and a node voltage equation of the traction power supply system, solving the equation by using a continuous linear power flow method, and performing proper processing to obtain steel rail potential and traction network voltage and current distribution. The method is further applied to traction power supply system load flow calculation and short circuit analysis. According to the method, computer memory occupancy and modeling time are reduced, and traction power supply system load flow calculation time is effectively shortened. Meanwhile, fault analysis based on the simplified traction network has the advantages of simple calculation, clear concept, high accuracy and the like.

This invention discloses a method, apparatus, electronic device, and storage medium for determining node voltages in an electromechanical transient network containing an infinite bus, belonging to the field of power system electromechanical transient simulation technology. The method includes: obtaining the node admittance matrix of the power system to be simulated and the injected current of each grid-connected device except the infinite bus; solving the equivalent impedance matrix based on the node admittance matrix to obtain the self-impedance of the infinite bus and its mutual impedance with each node; calculating the total equivalent voltage drop formed at the infinite bus by each grid-connected device in conjunction with its injected current and corresponding mutual impedance; deriving the injected current of the infinite bus based on the infinite bus voltage phasor, self-impedance, and total voltage drop; and substituting the injected current of the infinite bus and the injected currents of other grid-connected devices into the node admittance matrix to solve the network equations to obtain the voltages of each node. The implementation of this invention can solve the problem of network node voltages deviating from preset standards during transient processes in existing technologies.

This application discloses a method and device for measuring parameters of a double-circuit transmission line. It involves periodically acquiring voltage and current signals from the beginning and end of each phase of the double-circuit transmission line. Two sets of voltage moduli and two sets of current moduli are generated based on the voltage and current signals. The resistance and inductance moduli are calculated from the first set of moduli, and then inverse phase-mode transformation is performed to obtain the resistance and inductance phase parameters. A phase sequence transformation is then performed to obtain the positive-sequence self-impedance, zero-sequence self-impedance, and zero-sequence mutual impedance of the double-circuit transmission line. Similarly, the capacitance moduli of the double-circuit transmission line are calculated from the second set of moduli, and then inverse phase-mode transformation is performed to obtain the capacitance phase parameters. A phase sequence transformation is then performed to obtain the positive-sequence self-capacitance, zero-sequence self-capacitance, and zero-sequence mutual capacitance of the double-circuit transmission line. This method enables simultaneous measurement of positive-sequence impedance and zero-sequence impedance and capacitive reactance parameters of the line without power outages or changes to the transmission line's operating mode. It offers high measurement accuracy and is simple and cost-effective.

The present application relates to the technical field of matcher device, especially to a matcher device suitable for high pressure working environment, which aims at the problem that the existing radio frequency matcher cannot be adapted and optimized for the high pressure environment formed by the injection of sulfur hexafluoride into a sealed tank, is prone to abnormal operation or even stoppage failure under the action of high pressure in the tank, and cannot meet the use requirements of special experimental scenes, and proposes the following technical scheme: a matcher shell is provided with two groups of baffles; two groups of capacitors are arranged between the two groups of baffles, and adjusting mechanisms are arranged at two ends of the capacitors respectively, the adjusting mechanisms are used for adjusting the capacitance value of the capacitors to dynamically adjust the self impedance of the matcher; and a circuit board is installed in the matcher shell. The matcher can be used in high pressure working environment, is safe and convenient, and has good social and economic benefits.

The invention relates to an output impedance modeling method and device suitable for a network construction type new energy converter and a storage medium, a multi-frequency voltage disturbance signal is injected into a converter grid-connected point, the multi-frequency voltage disturbance signal comprises at least one positive sequence frequency component and one negative sequence frequency component, modeling is carried out based on a two-phase static coordinate system and a two-phase rotating coordinate system, and the output impedance is obtained. Representing the voltage and current of the grid-connected point of the converter as time-domain complex vector signals, and sequentially performing power calculation, power tracking control loop modeling, voltage control loop modeling and current control loop modeling to obtain complex vector expression of PWM control reference voltage; a PWM control reference voltage is associated with a PWM bridge arm output voltage, an equation is established, and an output impedance matrix of the converter is obtained and comprises positive sequence self-impedance, negative sequence self-impedance, positive-negative sequence mutual impedance and negative-positive sequence mutual impedance; the invention discloses a method-based implementation device and a storage medium. According to the invention, rapid modeling and impedance verification can be realized for converters with different control parameters.

The application relates to an impedance modeling method, device and computer equipment. The method comprises the following steps: injecting a disturbance voltage to an AC side of a main circuit, obtaining a first relationship between a small signal modulation and an AC current small signal through an AC control topology, and determining a second relationship between the small signal modulation and an AC voltage small signal through a phase-locked loop associated with the disturbance voltage and a phase angle small signal; injecting the disturbance voltage to a DC side of the main circuit, determining a third relationship between the small signal modulation and the AC current small signal and a fourth relationship between DC current small signals based on the AC control topology and a DC control topology; and finally, combining a frequency small signal model to perform impedance modeling, so as to accurately reflect self-impedance and coupling impedance characteristics of the AC side and the DC side, and provide a basis for analyzing system stability and optimizing a control strategy.

The utility model discloses anti-howling wireless sound equipment based on impedance matching. The anti-howling wireless sound equipment comprises a howling suppression circuit arranged between a wireless receiver and a power amplifier board, the howling suppression circuit comprises an impedance detection module, a microcontroller and a programmable impedance adjustment module which are connected in sequence; the impedance detection module is connected with an audio input line, detects an impedance value of an input audio signal in real time, and transmits detection data to the microcontroller; the microcontroller analyzes and processes the received impedance data, and calculates an impedance adjustment parameter according to a preset matching rule; the programmable impedance adjusting module dynamically adjusts the impedance value of the programmable impedance adjusting module according to the impedance adjusting parameters output by the microcontroller; according to the utility model, the dynamic accurate matching of the output signal impedance of the wireless receiver and the input impedance of the power amplifier board can be realized, a positive feedback loop formed by signal reflection is eliminated, the howling problem caused by impedance mismatching is solved, and the defect of signal distortion caused by the fact that a fixed parameter RC filter circuit cannot dynamically cope with interference is avoided.

The invention provides a method and a device for judging a grounding fault of a two-phase power transmission line, and relates to the technical field of power systems. The distance protection method for the ground fault of the two-phase power transmission line comprises the following steps: determining a zero-sequence compensation coefficient of the two-phase power transmission line according to actually measured self-impedance and actually measured mutual impedance of the two-phase power transmission line; under the condition that the two-phase power transmission line breaks down, the sum current of the operation phase is determined according to the actually measured two-phase current of the operation phase in the two-phase power transmission line and a preset sum current calculation mode; according to the zero sequence compensation coefficient, the actually measured two-phase current, the sum current, the actually measured three-phase voltage on the power supply side bus of the two-phase power transmission line, the working voltage calculation mode and the polarization voltage calculation mode, the working voltage and the polarization voltage of the operation phase are determined; and determining whether the two-phase power transmission line has a grounding fault according to the grounding fault judgment mode in combination with the sum current, the working voltage and the polarization voltage.

The invention discloses a receiving-end power grid operation optimization method and system considering multi-infeed short-circuit ratio constraint. The method comprises the following steps: determining a multi-feed-in short-circuit ratio at a feed-in point based on direct-current actual power of each loop, equivalent self-impedance of the feed-in point and mutual impedance among different feed-in points; by taking the multi-infeed short-circuit ratio as a security constraint, constructing a multi-source collaborative optimization scheduling model for overall planning of multi-type energy and direct-current infeed; and based on a preset constraint condition, solving the objective function to determine a scheduling scheme which minimizes the objective function. The multi-infeed short-circuit ratio is used as the security constraint to be embedded into the optimization model so as to quantify and improve the direct current power bearing capacity of the power grid, and the problem of how to improve the stability of a receiving end system during large-scale direct current infeed is solved.

The invention discloses a vehicle network model modeling method and system under the working condition that a pantograph cuts a magnetic line of force, and relates to the technical field of modeling. Comprising the following steps: constructing a unit length lumped tau-type circuit of a traction network based on self-impedance and earth admittance of a contact line, self-impedance and earth admittance of a steel rail and mutual impedance between the contact line and the steel rail; carrying out cascade connection on the unit length lumped tau-type circuit; motional electromotive force generated when the train runs serves as an equivalent voltage source, one end of the equivalent voltage source is connected with a contact line in sliding connection with the pantograph in the chain type lumped tau-shaped network model, the other end of the equivalent voltage source is connected with the top end of a train model, the bottom end of the train model is connected with a steel rail, and a train network model under the working condition that the pantograph cuts magnetic lines of force is obtained. The invention provides a train network model modeling method for cutting magnetic lines by a pantograph of a high-speed train. The influence of the cutting magnetic lines by the pantograph on each line of the train and a traction power supply system at different running speeds of the train can be obtained through simulation.

The invention relates to a same-tower double-circuit alternating-current transmission line zero-sequence parameter estimation method based on internal faults. The method comprises the following steps: establishing different mathematical models according to line length differences, adopting a single-section pi lumped parameter model for medium-short distance transmission lines to approximate a distributed parameter model, and adopting a distributed parameter model for medium-long distance transmission lines, therefore, the electromagnetic characteristics during the single-phase earth fault can be accurately represented. Based on voltage and current measurement data at two ends of the line, establishing a parameter equation set in a fault state by combining a Kirchhoff's law, and performing linear approximate processing on a nonlinear equation by using Taylor series expansion; through algebraic operation and matrix solution, an explicit analytical expression of a zero-sequence parameter is deduced, and precise calculation without iteration is realized. According to the method, zero-sequence parameters such as zero-sequence self-impedance and mutual impedance are estimated based on the single-phase earth fault of the same-tower double-circuit line, and the method is suitable for online identification of the zero-sequence parameters of transmission lines with different lengths and has the characteristics of high calculation efficiency, clear physical significance and high engineering applicability.

This invention discloses a novel online location method for critical branches in power systems based on impedance short-circuit ratio. The method includes: defining an expression for calculating the impedance short-circuit ratio of any connected device; obtaining a node impedance matrix for calculating the impedance short-circuit ratio of the connected device; taking the self-impedance corresponding to the access node of the connected device in the diagonal elements of the node impedance matrix as its Thevenin equivalent impedance; expressing the change in Thevenin equivalent impedance caused by branch switching using a low-order update formula, and calculating the sensitivity of the Thevenin equivalent impedance to the admittance of each branch; defining the branch influence factor and its constituent critical branch online judgment matrix according to the low-order update formula and sensitivity expression, thereby achieving critical branch location at both the device and system levels. This invention fills the current research gap in the field of critical branch location using impedance short-circuit ratio, and can provide a certain reference for the safe and stable operation of future new power systems. It is simple to implement, highly applicable, and has significant value in engineering design.

The application discloses a configuration method of a distributed phase modifier. The technical scheme is as follows: determining the minimum value and the change rate of the power factor of each new energy cluster at the side of a collecting station, and comparing the minimum value and the change rate with corresponding judgment thresholds respectively; according to the comparison results, the new energy clusters are divided into two groups, for one group satisfying the threshold requirements in the minimum value and the change rate, using the self-impedance and the equivalent impedance of the power grid as the analysis calculation amount, calculating the upper limit value of the influence of each new energy cluster in the group on the power grid voltage; for the other group, using the judgment threshold of the minimum value of the power factor and the equivalent impedance of the power grid as the analysis calculation amount, calculating the upper limit value of the influence of each new energy cluster in the group on the power grid voltage; solving the equivalent reactance of the power grid access formed by the phase modifier; and according to the equivalent reactance of the power grid access, combining the type of the phase modifier, obtaining the access requirements of the phase modifier. The configuration method can effectively suppress voltage fluctuation.

The application discloses a pantograph cutting magnetic line working condition vehicle network model modeling method and system, relates to the modeling technical field, and comprises the following steps: based on the self-impedance and ground admittance of a contact wire, the self-impedance and ground admittance of a steel rail and the mutual impedance between the contact wire and the steel rail, a unit length lumped τ type circuit of a traction network is constructed; the unit length lumped τ type circuit is cascaded; a dynamic electromotive force generated when a train runs is taken as an equivalent voltage source, one end of the equivalent voltage source is connected with the contact wire connected with a pantograph in sliding mode in a chain type lumped τ type network model, the other end is connected with a roof end of a train model, a bottom end of the train model is connected with the steel rail, and a vehicle network model under the pantograph cutting magnetic line working condition is obtained. The application provides a vehicle network model modeling method for a high-speed train pantograph cutting magnetic line, and the influence of the pantograph cutting magnetic line on the train and each line of a traction power supply system under different running speeds of the train can be simulated and obtained.

The invention discloses a global short-circuit ratio gain prediction method and system based on commissioning of a phase modifier, and is applied to the technical field of distributed phase modifier gain prediction, and the method comprises the steps: obtaining the original short-circuit ratio data of a commissioning station, the electrical distance data between global stations, the self-impedance data of the commissioning station, and the mutual impedance data between the commissioning stations; based on the station self-impedance data and the inter-station mutual impedance data, determining an attenuation coefficient of the commissioning station; inputting the original short-circuit ratio data of the commissioning station into the constructed local gain prediction model for processing to obtain local gain data of the commissioning station of the phase modifier; and constructing a short-circuit ratio attenuation prediction model based on the phase modifier commissioning station local gain data, the global inter-station electrical distance data and the attenuation coefficient, and processing the short-circuit ratio attenuation prediction model to obtain a global short-circuit ratio gain. The method provided by the embodiment of the invention can solve the problem that the prediction deviation of the short circuit ratio before and after the current phase modifier is put into operation easily causes the voltage instability of the new energy unit.

The application discloses a method for analyzing electromagnetic scattering characteristics of an electrically large conductor target, and steps of the method comprise: dividing the conductor target to be analyzed into several blocks, expanding each block to obtain a self-impedance matrix; obtaining a new characteristic mode matrix based on the self-impedance matrix; constructing a reduction matrix by using a Galerkin method based on the new characteristic mode matrix; obtaining surface currents of the conductor target based on the reduction matrix; and analyzing electromagnetic scattering characteristics based on the surface currents; the application of the principal component analysis technology with a threshold not only reduces the number of characteristic modes, but also makes the orthogonality between new characteristic mode base functions better. The condition number of the reduction matrix constructed by using the Galerkin method is optimized, the convergence speed of iterative solution of the reduction matrix equation can be significantly accelerated, and the ability of the characteristic mode base function method for analyzing electromagnetic scattering problems of electrically large targets is improved.

The application discloses a kind of for comprehensive energy export system transient stability analysis method and system, belong to electric power system transient angle stability technical field, method includes: based on synchronous machine-wind power-infinite system equivalent model, the self-impedance of synchronous machine, mutual impedance and its phase angle surplus are calculated, and then determine its electromagnetic power.Combining rotor motion equation and wind power, iteration is solved after fault power angle and speed;Accordingly, the existence of transient energy is calculated according to the trend of its change with power angle, to determine the critical stability point of power angle constraint and corresponding critical voltage.Finally, the critical point and critical voltage obtained are used as the quantitative index of evaluating transient stability margin, for guiding the safe and stable operation and control decision of the export system containing high proportion of new energy.The application can quickly and accurately evaluate system stability boundary, provide effective analysis tool for preventing cascading failure caused by large-scale new energy off-grid.

This invention discloses a method and system for identifying low-voltage distribution transformer topology based on node mutual impedance characteristics, relating to the field of power supply and distribution technology. The identification method first synchronously collects voltage and current time-series data of the transformer head and each user node; it then constructs and solves a mathematical model based on the principle of circuit superposition to obtain the user node mutual impedance coefficient matrix; it extracts the impedance feature vector of each user node, calculates the difference between self-impedance and mutual impedance, and compares it with a preset judgment threshold based on physical parameters to accurately determine the upstream and downstream relationships and co-connection points between user nodes; finally, it reconstructs the complete tree-like physical topology of the transformer area. This invention utilizes only existing measurement data and does not rely on additional hardware, achieving efficient and accurate automated identification of low-voltage distribution transformer topology, providing reliable support for refined operation and maintenance such as distribution network line loss management and fault location.