124 results about "Phasor" patented technology

The invention discloses a broadband oscillation risk prediction method and system based on wide-area broadband measurement, and relates to the technical field of wide-area broadband measurement. The method comprises the following steps: firstly, collecting grid-connected point high-frequency synchronous phasor data by using a PMU device at a photovoltaic field station side, and performing filtering and time mark calibration processing to eliminate noise and ensure time consistency; performing spectrum correlation analysis on wide-area multi-station PMU data based on time mark synchronization, screening broadband oscillation candidate features, and transmitting the broadband oscillation candidate features to a scheduling master station prediction network; and finally, inputting the real-time operation parameters of the power grid and historical oscillation sample data into the network, carrying out risk assessment and trend prediction, and assisting broadband oscillation early warning and prevention and control decision. According to the method, efficient fusion of multi-area equipment data is realized, a full-system broadband dynamic monitoring view angle is formed, the oscillation dynamic state is captured in real time, the risk is pre-judged, the broadband oscillation risk caused by new energy power fluctuation and power electronic equipment transient response can be dealt with, and the dynamic monitoring requirement of a novel power system is met.

The invention discloses a reinforcement learning-based low-voltage power distribution network multi-target collaborative optimization method and system, and the method comprises the steps: S01, taking adjustable equipment of a low-voltage power distribution network as an intelligent agent, and obtaining the historical operation data of a plurality of intelligent agents to form a training data set; step S02, constructing a multi-objective optimization model, and defining a reward function in a phasor form and a multi-objective weight; step S03, performing centralized training on the deep reinforcement learning model, inputting a multi-target weight into a neural network in the training process, performing learning with a maximum accumulated reward according to a reward phasor, and fusing a multi-target weight vector and a Q value vector through a phasor fusion layer; and step S04, acquiring real-time operation data of a plurality of agents in the low-voltage power distribution network, and controlling each agent to act by using a strategy learned by training. According to the invention, multi-target collaborative optimization control can be realized in a distributed photovoltaic large-scale access scene.

The invention discloses a power grid switching operation anti-misoperation verification method and device based on real-time topology, and relates to the technical field of power grid anti-misoperation, and the method comprises the following steps: collecting the phasor data of target equipment and the real-time active power flow direction of a power grid, constructing a real-time directed topological graph, and extracting a to-be-reconstructed sub-graph associated with an operation instruction of the target equipment; converting the target equipment operation instruction into an impedance correction term, constructing an estimated impedance matrix based on the to-be-reconstructed sub-graph, and calculating a corresponding power flow transfer vector; performing double-layer constraint decoupling on the topological structure of the to-be-reconstructed sub-graph to generate a source flow path chain set; and generating a verification result based on the power flow transfer vector, the source flow path chain set and a preset anti-error rule. The method is used for solving the problems of electrical rehearsal real-time lagging and complex topology anti-error logic confusion in a complex power grid environment.

The invention discloses a self-adaptive current-limiting control method and related device for a network construction type energy storage converter under a symmetric fault of a power grid, and belongs to the technical field of network construction type energy storage converter control, and the method comprises the steps: constructing a corresponding fault current dynamic response model based on the network construction type energy storage converter under the symmetric fault of the power grid; generating a self-adaptive current-limiting control strategy based on the voltage drop depth of the power grid; wherein the self-adaptive current-limiting control strategy comprises the steps of carrying out overcurrent steady-state component suppression based on a phasor current-limiting method and carrying out overcurrent transient-state component suppression based on a virtual impedance control method, and self-adaptively adjusting a power instruction to meet a system support requirement in a current-limiting process; a fault current dynamic response model is solved through a self-adaptive current-limiting control strategy, a current-limiting control scheme is obtained, it can be ensured that the converter maintains the networking characteristic in the fault period, steady-state and transient overcurrent is effectively restrained, output current is strictly limited within a safety threshold value, and transient stability of a system is maintained.

The invention relates to the technical field of power systems, in particular to a power grid fundamental harmonic and inter-harmonic detection method and device and a storage medium, and can collect power grid signals, arrange discrete samples into sample vectors, apply a Hanning window to the sample vectors for zero filling DFT, and obtain a frequency index of fundamental waves according to a peak value of frequency spectrum amplitude square; setting a harmonic wave search range according to the frequency index of the fundamental wave, and screening the harmonic waves according to the frequency related threshold to obtain a frequency index set of the fundamental wave and the harmonic waves; calculating a residual error between the power grid signal and the fundamental harmonic reconstruction signal, and calculating a residual error ratio; and performing secondary iteration on the residual error to obtain a TF coefficient corresponding to the inter-harmonic. According to the technical scheme, fundamental wave phasor measurement, harmonic detection and inter-harmonic detection can be completed at the same time, the precision is high, and the detection efficiency is high.

The invention discloses a wide-area oscillation source positioning method and system based on physical feature embedding and a graph attention network, and the method comprises the steps: obtaining synchronous phasor data of a power system, carrying out the modal parameter identification of subsynchronous oscillation and / or super-synchronous oscillation based on the synchronous phasor data, constructing a topological graph of the power system, and carrying out the positioning of a wide-area oscillation source. And constructing the oscillation amplitude, the attenuation factor and the phase of each node obtained by identification into a feature vector of each node in a topological graph, inputting the topological graph and the feature vector into a graph attention network, and outputting an oscillation source positioning result, so that high-frequency recording data after an accident does not need to be waited, and the positioning accuracy of the oscillation source is improved only on the basis of synchronous phasor data. The identified modal parameters are used as physical characteristics to be embedded into the graph attention network, and the interpretability of a physical mechanism and the graph structure mining capability of deep learning are fused, so that subsynchronous oscillation and super-synchronous oscillation are accurately positioned.

The invention discloses a new energy box-type substation state abnormity diagnosis method and system, and relates to the technical field of power equipment monitoring. According to the method and the system, through event-triggered high sampling and cross-channel time base self-inspection, multi-source sequence synchronization is ensured, and a consistent time axis is provided for subsequent estimation, so that online analysis under the condition of no power outage is supported; introducing dual-path estimation of RL step fitting and voltage drop robust regression in a transient stage, cooperatively inhibiting a closing peak and outlier data, and obtaining a stable initial value of the contact resistance; in a steady-state stage, adopting Goertzel frequency selection to extract a fundamental wave phasor and performing ohmic purity judgment, and expanding to a resistance-inductance joint model when necessary to remove interference of parasitic inductive reactance on resistance estimation; and then mutual identification and residual constraint are carried out on the temperature and electric power coupling relationship by using a discrete heat RC model, and local write-back correction is carried out on the deviation, so that the consistent closed loop of the electric domain and the heat domain is realized.

A kind of single-phase grounding fault single-end impedance ranging method and system of DG-containing distribution line, method includes: input parameter and DG distribution to equipment, when single-phase grounding fault occurs in distribution network, the zero sequence voltage of equipment rises, it is judged that single-phase grounding fault occurs, and fault ranging calculation is started;Using symmetrical component method to obtain the sequence components of voltage and current at bus, DG access, load access and fault point;On the basis of the sequence components of voltage and current at fault point, the phase angle difference between line fault phase voltage and current is obtained, and the fault distance is calculated according to the phase angle difference.The ranging effect of the method of the application is very good, and it has practicality.

The application relates to a synthesis method of a rotating phasor, which is suitable for the technical field of electrical rotating phasor conversion and is particularly directed to the decomposition and synthesis of an electrical rotating phasor. The method adjusts the initial phase of two amplitude-constant sub-rotating phasors, and then synthesizes a target rotating phasor with adjustable amplitude and initial phase, and has the characteristics of easy generation of the sub-rotating phasor, good flexibility and high reliability. The application mainly utilizes the parallelogram rule of vector operation, reduces the generation difficulty of the sub-rotating phasor by reducing the generation problem of the target rotating phasor with adjustable amplitude and initial phase to the synthesis problem of the two sub-rotating phasors with constant amplitude and adjustable phase, and solves the problem of synthesizing a complex rotating phasor from a simple rotating phasor. The technical scheme provided by the application forms a simple sub-rotating phasor through electromagnetic conversion, and provides a new idea for the synthesis of a complex rotating phasor.

The application discloses a power distribution network fast protection method and device and a computer readable storage medium, wherein the method comprises the following steps: S1, sequentially calibrating branch lines of a radial power distribution network to determine the grades and numbers of the feeder branch lines; S2, constructing a starting criterion by using transformer low-voltage side currents to calibrate the moment of fault occurrence; S3, according to different fault types, selecting characteristic phases and calculating the amplitude and phase angle of the corresponding characteristic phase mutation current phasor; S4, taking the main transformer low-voltage side phasor as a reference phasor, calculating the inner product of the phasor calculated by other lines and the reference phasor respectively, and marking all the lines with inner product greater than the setting value; and S5, finding the line with the highest number and grade among all the marked lines and marking the line as a fault line. The application can solve the contradiction between the four properties of the traditional power distribution network three-section current protection, and well cope with many problems such as high resistance fault and slow backup protection action.

The invention relates to a power distribution network harmonic analysis method and system, and the method comprises the steps: constructing a digital twinborn model of a power distribution network region, and selecting transformers in the region as analysis objects one by one; for each analysis object, various working conditions are simulated by changing the transformation ratio of the analysis object in a digital twin model, and voltage and current waveforms are collected and subjected to Fourier decomposition to obtain harmonic phasors; thirdly, performing phase reduction on the phasor data, separating a real part from an imaginary part to construct a matrix, and solving a harmonic coefficient matrix by using a least square method to realize error minimization; separating linear and nonlinear parts of the harmonic current, and calculating a harmonic emission capability parameter and a harmonic current risk parameter for quantitative evaluation; according to the method, all transformers are traversed and analyzed, and systematic harmonic evaluation of the whole power distribution network area is finally realized.

Certain aspects of the present disclosure provide techniques for determining a topology of an electric vehicle supply equipment (EVSE) network. An example method includes obtaining, for a first time period, for each of a plurality of pieces of equipment of the EVSE network, a respective magnitude of a respective current phasor, wherein for each of one or more pieces of equipment of the plurality of pieces of equipment, a respective phase angle of the respective current phasor is unknown; and determining, based on at least the respective magnitude of the respective current phasor for each of at least one piece of equipment of the one or more pieces of equipment, a respective subset of lines of the EVSE network to which the respective piece of equipment is coupled.

This invention discloses a method, system, and apparatus for extracting the fundamental phasor of fault transient current, relating to the field of power system fault transient current analysis. The method involves acquiring N transient sampled currents and dividing them into M subsets according to a preset partitioning strategy. The discrete Fourier transform (DFT) output of each subset is then determined. Combining the DFT output expressions of each subset, the first DFT output corresponding to the first exponentially decaying DC offset component and the second DFT output corresponding to the second exponentially decaying DC offset component under the target subset are determined. Finally, the DFT output of the current fundamental phasor is determined by combining the DFT output expression and output results of the target subset, thus obtaining the fundamental phasor. This scheme pre-establishes a preset fault transient current discrete model and sets a preset partitioning strategy, achieving high-precision and rapid extraction of the fundamental phasor, which is beneficial for improving the reliability of power system relay protection.

This invention relates to the field of transformer mode switching technology, and particularly to a mode switching method and system for a dry-type phase-shifting transformer adapted to the Panama power supply. The method includes: real-time acquisition of voltage and current signals from the input and output sides of the dry-type phase-shifting transformer, and calculation of the phase shift angle and output voltage amplitude as characteristic quantities; construction of a phasor relationship model and identification of the current power grid supply mode; establishment of a joint matching criterion for phase shift angle and voltage amplitude to determine the current operating mode and target mode; generation of a mode switching sequence based on mode differences; and adjustment of the operating state according to the switching sequence until the amplitude, frequency, and phase of the output voltage all meet the rated power supply parameters of the Panama power supply. This invention effectively solves the problems of existing methods not being specifically adapted to the Panama power grid and having substandard power supply parameters, achieving precise adaptation and ensuring normal equipment operation and stable power supply to the power system.

A frequency-independent phasor calculation method suitable for pumped storage unit protection, the electrical quantity of the pumped storage unit is sampled to form electrical quantity sampling values; the response signal corresponding to the time domain signal of the electrical quantity sampling values is obtained by using Hilbert transform, the data window length in the Hilbert transform is determined by using the lower limit of the frequency range to be protected during the starting of the pumped storage unit, and the amplitude and phase of the electrical quantity are determined by using the time domain signal and the response signal; the over-current protection phasor and the negative sequence protection phasor are calculated by using the electrical quantity. The method provided by the application only needs to select a fixed data window according to the lower limit of the frequency, greatly improves the response speed, has higher calculation accuracy without frequency measurement, and has stronger noise and higher harmonic resistance.

The application discloses a power grid real-time event detection and positioning method and system based on synchronous phasor data. Firstly, linear regression and Chebyshev detector are used for abnormal detection and cleaning of PMU synchronous phasor data, and a DBSCAN clustering algorithm is used for detecting clustering change points to classify events. Then, PMU data is statistically analyzed from five dimensions, and PMU scores are calculated. Finally, subgraph construction and scanning are performed to obtain the event location. The simulation results prove the effectiveness of the application in event detection, classification and positioning. The results of industrial data prove the necessity of abnormal detection and the effectiveness of the event detection algorithm. The application can provide a very effective PMU-based power grid real-time event detection tool, and can help power system operators to improve decision-making efficiency.

The invention discloses a distribution network synchronous phasor measurement method and system based on a situation awareness technology, and relates to the technical field of power system state estimation and uncertainty modeling, and the method comprises the steps: collecting and synchronously obtaining the multi-node phasor data of a power distribution network, and constructing a state input vector for situation prediction; a neural network model with uncertain output is constructed, and a predicted value and a confidence interval are obtained based on multiple times of sampling; an interlayer uncertainty regularization mechanism is introduced into model training, and the relative change range of standard deviation output by each layer is limited. According to the method, the synchronous phasor measurement data of the power system and the uncertainty perception modeling are deeply fused, so that the accurate prediction of the operation situation of the power distribution network can be realized, the confidence level information can be output, and the uncertainty propagation in the model can be dynamically controlled; the method greatly improves the stability, reliability and interpretability of a prediction result, and has good engineering application prospects and technical innovation values.

The invention discloses a low-voltage transformer area wrong wiring user identification method and system based on extended Kalman filtering. The method comprises the following steps: collecting the residual current of a tested transformer area and the load current phasor of each user in the transformer area; constructing an initial state vector and a covariance matrix based on extended Kalman filter (EKF); performing EKF prediction and updating steps based on the transformer area residual current and load current phasors, dynamically estimating a state vector, and determining fault coefficients of each user at different moments; and calculating a steady-state fault coefficient corresponding to each user based on the fault coefficient of each user in the preset time period, and determining a wrong wiring user based on the steady-state fault coefficient. According to the method, high-precision fault identification can be provided in a multi-user and multi-phase scene by utilizing the nonlinear state estimation capability of the EKF and combining intelligent distribution transformer terminal configuration and intelligent electric meter data; the method can process nonlinear dynamics, can adapt to load changes and noise interference, and has higher adaptability and reliability compared with a traditional method.

The invention discloses a power distribution network planning auxiliary method and system based on multi-source data, and the method comprises the steps: injecting a predetermined frequency disturbance signal into a power grid, and collecting the response data of all power equipment; quantifying the response data of each power device to obtain a sensitivity and cluster interaction index; based on the sensitivity and the cluster interaction index, judging whether the corresponding power equipment is marked as an excitation source or not; calling the access positions of all excitation sources and the sensitivity in each resonance frequency band, determining electrical path parameters between the excitation sources and the circuit breaker based on the resonance frequency bands and the access positions, and sequentially inputting the sensitivity of each excitation source in each resonance frequency band and the electrical path parameters into a pre-constructed harmonic phasor superposition model to obtain a harmonic phasor superposition model; obtaining a harmonic voltage split-phase quantity generated by the excitation source at the circuit breaker mounting point under the corresponding resonance frequency band; hidden fault risks are identified and eliminated in the planning stage, and the operation safety of the power grid is remarkably improved.

The invention discloses a converter frequency coupling impedance test and calculation method and system. The method comprises the following steps: selecting a disturbance source form according to the type of a to-be-tested converter, and constructing an impedance test circuit of a steady-state working point; a steady-state working point of the converter is simulated by adjusting parameters of a controlled source for the impedance test circuit, and a positive-sequence harmonic disturbance signal and a negative-sequence harmonic disturbance signal are injected in a superposed manner, so that a response signal is obtained; performing spectral analysis on the positive-sequence harmonic disturbance signal, the negative-sequence harmonic disturbance signal and the response signal, and calculating phasors and phase differences of power frequency and harmonic components; based on the phase difference, performing phase correction on a coupling component in the response signal to obtain a correction result; and calculating equivalent harmonic impedance by using a correction result, and outputting a frequency coupling matrix of the harmonic impedance of the converter in the full frequency band. By implementing the method provided by the invention, the impedance measurement requirements of various converters are met, so that the limitations of unclear initial phase, lack of physical concept of coupling impedance, difficulty in four-quadrant impedance measurement and calculation and the like in the traditional technology are overcome.

The invention provides a method and a device for diagnosing abnormality of harmonic voltage measured values of high, medium and low voltage sides of a transformer, which can verify and identify the accuracy of phase measurement of the harmonic voltage at the three sides by using the phase and sequence characteristics of the harmonic voltage at the high, medium and low voltage sides of the transformer and the connection group data of the transformer. Furthermore, in combination with the three-side harmonic voltage and current phasors and the winding harmonic impedance reduced to the high-voltage side, on the basis of a transformer equivalent circuit model, the same-order harmonic sequence voltage theoretical values of the other two sides can be calculated by taking the harmonic sequence voltage passing verification on one side as the reference, and the theoretical values are compared with the actually measured values, so that the theoretical values of the same-order harmonic sequence voltage are obtained. And effective identification of three-side harmonic voltage amplitude measurement accuracy is realized. According to the method, the accuracy of the phase and amplitude data can be reliably discriminated even in a scene in which the multi-side measurement is possible to be abnormal, so that a solid and credible data basis is provided for subsequent harmonic traceability analysis and precise treatment measures.

The application discloses an energy integral differential protection method and system based on a distribution parameter model, which comprises the following steps: collecting three-phase voltage and three-phase current instantaneous values of a line at a local side and an opposite side in real time; calculating three-phase current calculation values of the local side at the same time based on the three-phase voltage and three-phase current instantaneous values of the opposite side; calculating three-phase current difference currents based on the three-phase current instantaneous values of the local side collected in real time and the three-phase current calculation values of the local side at the same time; calculating three-phase differential current operating quantities based on the three-phase current difference currents; and forming an energy integral differential protection operating criterion by using the three-phase differential current operating quantities, and performing differential protection when the three-phase differential current operating quantities meet the differential protection operating criterion. The application solves the problems of frequency deviation and harmonics of traditional Bergeron phasor differential protection after faults of power electronic devices such as new energy and flexible direct current, and improves the differential protection operating performance in a new energy power transmission scene.

This invention discloses a modeling and application method for a state-space small-signal model of a direct-drive permanent magnet wind power grid-connected system under AC asymmetric operating conditions. The modeling method includes establishing mathematical models of each core component of the direct-drive permanent magnet wind power grid-connected system; converting the mathematical models of the AC-DC-AC power converter and filter circuit to obtain the corresponding dq-sequence dynamic phasor models; processing the mathematical models of the wind turbine shaft system, permanent magnet synchronous generator, phase-locked loop, and turbine-side converter control system at the steady-state operating point to obtain a linear time-invariant model; processing the mathematical models of the phase sequence separation stage, grid-side converter control system, and the dq-sequence dynamic phasor model to obtain a linear periodic time-varying model; and integrating the linear time-invariant model and the linear periodic time-varying model to obtain the state-space small-signal model. The state-space small-signal model obtained by this invention can accurately and completely characterize the small-disturbance characteristics of a direct-drive permanent magnet wind power grid-connected system under AC asymmetric operating conditions.

A method for mapping a surface using signals transmitted from a single transmitter comprises: receiving signals transmitted from the single transmitter, where each signal has a different propagation path; determining a motion of an antenna of the receiver; generating phasor sequences, where each phasor sequence represents a hypothesis based on antenna motion and a direction of arrival estimate for each received signal; compensating the received signals, local signals, or correlation results from correlating the received signals with the local signals using the phasor sequences based on the hypotheses to generate compensated correlation results; determining a preferred hypothesis in the hypotheses for each received signal that optimizes each correlation result; identifying a direction of arrival for each received signal using the determined hypothesis; determining a point of reflection from the direction of arrival of each received signal; and combining the points of reflection into one or more reflective surfaces.

The application provides a power distribution system synchronous phasor information processing method in an unbalanced and noisy environment, and belongs to the technical field of synchronous phasor measurement, and comprises the following steps: S1: establishing an alternating current signal dynamic state estimation model of a power distribution system; S2: in a three-phase power distribution system in an unbalanced and noisy interference environment, a recursive filtering method is used to calculate a phasor estimation value; S3: a mutually orthogonal voltage component signal is established by using a second-order generalized integrator phase-locked loop; S4: a linearization treatment is performed on a nonlinear system state equation, and a discrete state equation and an observation equation are designed; S5: estimation and correction combination recursion is adopted to perform time updating; and S6: state quantity estimation value filtering is performed, and the estimation value is corrected by using a variance matrix to perform measurement updating. The application can process power distribution system synchronous phasor information in an unbalanced and noisy interference environment, improve estimation accuracy, reduce estimation error, shorten convergence time, and provide accurate data for fault diagnosis.

The application is suitable for the technical field of power system frequency measurement, and provides a phasor correction method and device, computer equipment and program product. The method comprises the following steps: for three continuous sampling points, combining the real part function and the imaginary part function of the three sampling points, a first expression about the system frequency and the real part value of the three sampling points is obtained, and a second expression about the system frequency and the imaginary part value of the three sampling points is obtained; according to the similar proportion principle, the first expression and the second expression are integrated to obtain a calculation formula of the system frequency; the current system frequency is calculated by using the real part value and the imaginary part value of the three sampling points and the calculation formula of the system frequency; the real part correction coefficient and the imaginary part correction coefficient are calculated based on the average frequency f avg in a period of time and the reference frequency f0; and the real part function and the imaginary part function of the sampling points are corrected according to the real part correction coefficient and the imaginary part correction coefficient. Thus, the system frequency can be accurately and efficiently calculated, and the system phasor can be corrected.

The application discloses an anti-difference synchronous phasor measurement estimation method and a terminal, and first establishes a Kalman filter model of state variables of a to-be-measured signal; then derives a first Kalman filter observation equation of the state variables according to the Kalman filter model; then establishes a state variable prediction function of the state variables, and performs Kalman gain processing on the state variable prediction function; further establishes a residual function of the state variable prediction function after the Kalman gain processing, integrates the residual function and the first Kalman filter observation equation through linear regression, and then obtains a second Kalman filter observation equation; then establishes a loss function, substitutes the loss function into the second Kalman filter observation equation, and obtains an iterative expression of the state variables; and finally extracts an estimated value expression of a fundamental frequency phasor in the iterative expression. The application introduces the loss function on the Kalman filter observation equation, improves the anti-difference capability, the estimation process is not disturbed by bad data, and the application has good dynamic characteristics.

The application discloses a method and system for simultaneously identifying frequency response matrix of a linear time-invariant system. In the testing process, an excitation signal containing all target frequency components is simultaneously input into corresponding actuators according to the assigned channels, and the phasor form is filled into each column according to the excitation batch. After the intermediate variable is obtained by orthogonal calculation in the time domain using the excitation signal and the collected response data, the frequency response matrix corresponding to each excitation frequency point can be further obtained by algebraic operation. The method can realize simultaneous identification of multiple frequency response matrices of a multiple-input multiple-output system, has the characteristics of increasing excitation times, simple calculation, strong anti-interference ability and the like, can improve the identification efficiency and precision of the frequency response matrix of the multiple-input multiple-output system in engineering, and provides more valuable basic data for a plurality of application technologies including modal analysis, vibration and sound active control and the like.

The invention belongs to the technical field of electronic information, and discloses a current transformer error online monitoring method considering a load effect and a related device. The current transformer error on-line monitoring method comprises the following steps: obtaining a secondary fundamental current phasor value of a current transformer in each branch line of a target bus, constructing an overdetermined regression equation set, introducing an elastic network regression problem to construct a mixed regularization loss function, and calculating the error of the target bus according to the mixed regularization loss function. Solving an elastic network regression problem to minimize a mixed regularization loss function, and obtaining a current transformer impedance parameter matrix of an overdetermined regression equation set; obtaining impedance parameter increments of other current transformers compared with the reference current transformer according to the current transformer impedance parameter matrix; and on the basis of a comparison result of the impedance parameter increment of each current transformer and a preset increment threshold value, obtaining a current transformer error online monitoring result. The technical scheme of the invention can adapt to the on-line error monitoring requirements of the current transformer under complex working conditions.

The invention discloses an external power grid-containing line oscillation power calculation method based on amplitude-frequency modulation decomposition. The method comprises the following steps: constructing a simplified wind power parallel impedance line grid-connected system model; establishing a standard form of an amplitude-frequency modulation signal; preliminarily calculating oscillation power response based on a simplified wind power parallel impedance line grid-connected system model; decomposing the oscillation power response into a power response under amplitude modulation and a power response under frequency modulation; and projecting the power response under amplitude and frequency modulation excitation to an XY coordinate system by using a phasor method to obtain a final oscillation power amplitude expression. According to the method, the power oscillation response on the external power grid voltage source circuit of the wind power grid-connected system can be accurately obtained, meanwhile, the calculation method is simple and easy to use, and power flow analysis of subsynchronous oscillation can be researched easily.