21 results about "Power system harmonics" patented technology

The invention discloses an electric power system harmonic propagation analysis method and device and a storage medium, and belongs to the technical field of electric power system harmonic analysis, and the method comprises the steps: inputting a to-be-predicted operation condition parameter and a harmonic voltage parameter into a trained regression prediction model, obtaining a corresponding prediction cross admittance matrix, and obtaining a prediction cross admittance matrix; the predicted cross admittance matrix is applied to harmonic propagation analysis of the power system; wherein the regression prediction model is integrated with Bagging based on a decision tree; according to the method, by improving the data set quality and optimizing the model hyper-parameters, the harmonic source cross admittance matrix which is self-adaptive to the operation condition and is established by adopting the decision tree-based regression device and the Bagging element regression device can meet the harmonic analysis precision requirements under different operation conditions, and harmonic propagation of the power system can be analyzed more accurately; the analysis efficiency is improved, and a feasible technical path is provided for online monitoring or rapid evaluation.

The invention discloses a harmonic stability evaluation method, device and equipment applied to a renewable energy power system and a medium, the method is applied to the technical field of power system harmonic, and the method comprises the steps: carrying out the impedance aggregation processing of topological structure data, and obtaining a harmonic impedance model; processing the renewable energy equipment data based on a Nyquist stability criterion to obtain a stability boundary condition of the power system; constructing a node admittance matrix based on the harmonic impedance model and the stability boundary condition; processing the node admittance matrix by using a Fourier technology to obtain impedance spectrum data, and processing the impedance spectrum data based on a modal impedance maximum value analysis method to obtain resonance modal characteristics; processing the resonance mode characteristics and the real-time operation condition to obtain a time domain verification result; and carrying out harmonic stability evaluation based on a time domain verification result. According to the method provided by the invention, the technical problem of harmonic stability evaluation distortion caused by incomplete measurement data can be solved.

The invention discloses a capacitor voltage transformer harmonic error prediction method based on NRBO-BP, and belongs to the technical field of modeling prediction. The method comprises the steps of analyzing harmonic transmission characteristics, adjusting stray capacitance numerical values to simulate different operating environments, performing simulation to obtain harmonic error data, optimizing initial weight and bias of a BP neural network by using an NRBO algorithm, constructing a harmonic error prediction model, and finally predicting 2-60 times of harmonic errors by taking typical harmonic errors as characteristic parameters. The performance of the model is evaluated by adopting a mean absolute error, a root-mean-square error and a decision coefficient, wherein the NRBO algorithm comprises the steps of population initialization, Newton-Raphson search and TAO trap avoidance; the method solves the problems of low model precision and susceptibility to environmental interference in the existing CVT harmonic error prediction, effectively improves the measurement precision of the CVT in the harmonic frequency band, and provides reliable technical support for harmonic analysis of a power system.

The invention relates to the technical field of harmonic suppression and reactive compensation of a power system, in particular to a harmonic and reactive compensation system and method, and the system comprises a detection and analysis module, a control decision module, a compensation execution module, a man-machine interaction and communication module, and a fault pre-judgment and protection diagnosis module. Through an H-bridge cascade topology and microsecond-level response optimization mechanism, accurate and rapid generation and injection of compensation current are realized, the precision and efficiency of harmonic suppression and reactive compensation are effectively improved, meanwhile, the switching loss under a low-load working condition is reduced, and through multi-parameter real-time monitoring, hierarchical risk pre-judgment and multi-level accurate diagnosis, the real-time performance of the system is improved. Early warning and grading protection of power electronic device fault premonition are achieved, the fault position is accurately positioned, a standardized maintenance report is generated, and the safety, reliability and operation and maintenance convenience of system operation are greatly improved.

The invention relates to the technical field of power systems, and discloses a power system harmonic impedance partitioning method based on a Leiden community partitioning algorithm, which comprises the following steps: obtaining harmonic impedance data; performing feature extraction on the harmonic impedance data to generate a multi-dimensional feature matrix; outputting harmonic impedance characteristics after dimension reduction; calculating the Euclidean distance between the buses based on the harmonic impedance characteristics after dimension reduction, and constructing a harmonic impedance difference edge weight matrix; combining the power grid topology adjacency matrix and the harmonic impedance difference edge weight matrix, and utilizing a Leiden community division algorithm to carry out clustering partition; and outputting the partition label of each bus to form a power grid harmonic impedance partition result. According to the power system harmonic impedance partitioning method based on the Leiden community partitioning algorithm, a power grid is divided into a plurality of regions with similar dynamic characteristics according to impedance similarity, basic data support is provided for grid-side impedance regulation and oscillation risk management, and cross-band dynamic stability analysis and regional collaborative management are achieved.

This invention proposes a method for determining the impact of harmonic source types on monitoring points in power grids, belonging to the field of harmonic source tracing technology in power systems. The method involves acquiring various harmonic source currents and constructing harmonic source feature vectors; acquiring harmonic data for a specified time period T at monitoring point M, setting n sampling points, and constructing a normalized vector for each sampling point; multiplying the normalized vector of each sampling point with the feature vector of each harmonic source to determine the dominant harmonic source type for each sampling point; statistically analyzing the number of sources to determine the main harmonic sources at each monitoring point; if the number of sources is equal, it is determined that multiple sources are jointly affecting the source. This solution aims to solve the problems of difficult unified processing of harmonic sources and difficulty in extracting effective information from massive amounts of data, achieving accurate attribution determination.

The present application relates to a kind of wide frequency power grid harmonic fast extraction method based on multiscale collaborative measurement, belong to the field of power system harmonic analysis, including: construct multi-window parallel data buffer, utilize smooth transition function dynamically calculate the confidence weight of each window;Adopt adaptive window function strategy to load rectangular window and Blackman window respectively, and preliminary obtain full-band spectrum parameter in combination with zero padding FFT, introduce phase alignment algorithm based on time zero point to eliminate the phase drift caused by non-synchronous sampling;For random interference, use stability filtering mechanism to carry out effectiveness check.The present application realizes the unity of wide frequency harmonic transient fast locking and steady-state high-precision measurement by organically combining multi-window parallel processing with S-shaped smooth transition mechanism, significantly improves the dynamic adaptability and anti-noise reliability of measurement, and provides reliable technical foundation for new type power system wide frequency oscillation monitoring and control.

The invention relates to a harmonic and inter-harmonic time domain detection method in a noise environment, and belongs to the technical field of power system harmonic measurement. The method comprises the following steps of: firstly, acquiring a harmonic sampling signal of a power system, performing variational mode decomposition on the acquired signal, and performing parameter optimization by adopting an optimization algorithm according to the number of modes and a penalty factor of variational mode decomposition; then, according to the correlation coefficient of each modal component and an original signal, selecting a proper modal component to carry out signal reconstruction, and carrying out parameter identification on the reconstructed signal by adopting a Prony algorithm to obtain information such as amplitude and frequency of each modal component. The detection method provided by the invention has good noise immunity, and can obtain the time domain information of the collected signal under the condition of strong noise.

The application discloses a kind of wide dynamic range signal measurement error calibration method and system, the present application includes on harmonic signal measurement experimental platform for specified harmonic different amplitude, different temperature is tested multiple times and the amplitude data of harmonic signal measurement device output is collected;Nonlinear parametrization function about amplitude correction parameter vector L is constructed and fitting error function;Combining the amplitude data collected and nonlinear parametrization function and fitting error function, amplitude correction parameter vector L is iteratively solved based on gradient descent method and substituted into nonlinear parametrization function to obtain temperature correction function, whether continue to iteratively solve amplitude correction parameter vector L according to the correction result of temperature correction function is judged.The present application aims to solve the error problem influenced by temperature change in power system harmonic signal measurement, and improve the accuracy and reliability of harmonic signal measurement in power system by effective error correction.

The invention relates to a broadband power grid harmonic rapid extraction method based on multi-scale cooperative measurement, and belongs to the field of power system harmonic analysis, and the method comprises the steps: constructing a multi-window parallel data buffer, and dynamically calculating the confidence coefficient weight of each window through a smooth transition function; respectively loading a rectangular window and a Blackman window by adopting a self-adaptive window function strategy, preliminarily acquiring full-band spectrum parameters by combining zero-padding FFT (Fast Fourier Transform), and introducing a phase alignment algorithm based on a time zero point to eliminate phase drift caused by asynchronous sampling; for random interference, a stability filtering mechanism is adopted to carry out validity verification. According to the method, multi-window parallel processing and an S-shaped smooth transition mechanism are organically combined, so that the unification of broadband harmonic transient fast locking and steady-state high-precision metering is realized, the dynamic adaptability and anti-noise reliability of measurement are remarkably improved, and a reliable technical basis is provided for broadband oscillation monitoring and control of a novel power system.

The application discloses a harmonic suppression method based on frequency adaptive resonance control and belongs to the field of power system harmonic suppression. In view of the problem that SVG under a traditional control strategy is difficult to effectively suppress harmonics, a resonance control strategy is designed based on an internal model theorem and is applied to a voltage control link of SVG. Meanwhile, in order to adapt to the uncertainty of harmonic frequency, a recursive least square method is introduced to identify the harmonic frequency, the resonance control parameter is dynamically adjusted, and the harmonic compensation bandwidth of the SVG device is widened. The simulation result shows that the suppression method provided by the application is simple in operation, can effectively eliminate the (intermediate) harmonic of the offshore wind power system without additionally adding electrical primary equipment, and has strong robustness and adaptability.

The application discloses an active damping virtual resistance adaptive method and system based on a linear assumption, and the method comprises the following steps: in the current iteration period, the harmonic voltage measured value at the common connection point of the active damping device is acquired, the absolute error between the harmonic voltage measured value and the harmonic voltage target value is calculated, if the error amount is less than or equal to the error threshold, it is determined that the system has converged, and the final setting value is output; if the error amount is greater than the error threshold, it is determined that the system has not converged, a theoretical straight line is formed by the connecting line of the coordinate origin and the current working point, based on the linear relationship corresponding to the straight line, the next iteration virtual resistance value that makes the harmonic voltage close to the target value is calculated through the variable step adjustment strategy, and the next iteration period is entered, and iteration is continuously carried out until the system converges; the application has the advantages that the application does not depend on the power grid impedance model, has the online adaptive capacity, can be quickly and accurately set, and effectively suppresses the power system harmonic resonance.

The application discloses a power harmonic and interharmonic analysis and detection method based on parameter optimization MSST and HT, and belongs to the technical field of power system harmonic detection. The application comprises the following steps: collecting original power signals and performing multiple synchronous compression transformation with different iteration numbers; calculating time-frequency entropy under different iteration numbers, and determining the optimal iteration number according to the change of the time-frequency entropy; performing multiple synchronous compression transformation and mode decomposition on the signals by using the optimal iteration number, and obtaining a series of inherent mode function components; and performing Hilbert transformation on each component, and extracting instantaneous frequency and instantaneous amplitude. The application realizes adaptive optimization of the iteration number of MSST by introducing information entropy as an evaluation index, solves the problem that the iteration number needs to be set according to experience in the traditional method, reduces the calculation cost while ensuring the time-frequency energy concentration degree, and improves the harmonic detection precision.

The application discloses a kind of power system harmonic impedance frequency characteristic measurement method, device, equipment and medium, for solving the technical problems of low efficiency, processing delay and simulation real-time insufficient of harmonic impedance measurement.It includes: when receiving the sweep starting instruction sent by user, generate the disturbance current signal of multiple frequency points using preset sweep parameter;The disturbance current signal is injected into the injection node of the electromagnetic transient simulation model of power system, and with preset simulation time step as sampling interval, the voltage time domain data of injection node and the current time domain data formed by disturbance current signal are continuously collected;The voltage time domain data is subjected to fast fourier transform, and the voltage complex spectrum is obtained, and the current time domain data is subjected to fast fourier transform, and the current complex spectrum is obtained;The equivalent impedance of multiple frequency points is calculated using voltage complex spectrum and current complex spectrum;Harmonic impedance frequency characteristic curve is generated using the equivalent impedance of multiple frequency points.

The invention discloses a coupled harmonic source positioning method and system based on SSA-VMD and a Spearman correlation coefficient, relates to the technical field of harmonic analysis and control of a power system, and solves the problems that it is difficult to construct an improved 0-1 planning algorithm and a double constraint design, and it is also difficult to construct a coupling harmonic source through an SSA-VMD optimal decomposition model in combination with a dynamic search space adjustment and double-index screening mechanism. And the technical problem of current signal reconstruction is solved. Comprising the following steps: firstly, optimizing PMU configuration through an improved 0-1 planning algorithm; constructing an optimal decomposition model, and screening effective modal components in combination with permutation entropy and symbol transfer entropy; then, extracting a harmonic current sequence of a matched frequency through fast Fourier transform, and introducing a time weight coefficient to construct an improved Spearman correlation coefficient to calculate the correlation between harmonic voltage and current; and finally, determining the position of the coupled harmonic source by combining the correlation sorting, the node load type, the historical harmonic data and the topology importance.

Signal processing methods based on compressed sensing (CS) theory, intended to solve storage space and communication limitations in a Nyquist sampling framework, have attracted increased attention in recent years. In conventional harmonic detection, sparse bases are typically represented by a discrete Fourier transform (DFT) matrix. Harmonic non-synchronous sampling inevitably leads to spectral leakage and fence effect. To address this issue, we present an improved CS model for harmonic detection in power systems. A windowing technique is introduced in the compression sampling process. The fixed-point continuation algorithm combined with interpolation technique is used to directly extract harmonic parameters from the sparse coefficients without reconstructing the original signal. The proposed harmonic detection method, using an improved CS model, can achieve an accuracy comparable to that of the windowed interpolation FFT algorithm.

The application provides a method for determining the influence attribution of harmonic source types on monitoring points in a power grid, belongs to the technical field of power system harmonic source tracing, acquires harmonic currents of various harmonic sources, and constructs harmonic source characteristic vectors; harmonic data of a monitoring point M in a specified time period T is acquired, n sampling points are set, and normalized vectors of the sampling points are constructed; the normalized vectors of the sampling points and the harmonic source characteristic vectors are internally connected, and the dominant harmonic source types of the sampling points are determined; the main harmonic sources of the monitoring point are determined by counting the number, and if the number is equal, it is determined that the multiple sources jointly influence. The scheme aims to solve the problems of difficult unified processing of harmonic sources and difficult extraction of effective information from massive data, and realizes accurate attribution determination.

The invention discloses a power system harmonic impedance on-line monitoring method, and relates to the technical field of power system harmonic impedance monitoring, and the power system harmonic impedance on-line monitoring method realizes the accurate and real-time monitoring of the power system harmonic impedance through the five steps of data acquisition, preprocessing, calculation, analysis and alarm prompting. Compared with a traditional monitoring method, the method reduces the influence of noise and interference through data preprocessing and data calculation, and improves the accuracy of harmonic analysis. And data analysis and alarm prompt are introduced, so that the system can identify and solve potential problems in time, and the stability and reliability of the power system are improved. Besides, comprehensive data acquisition and real-time monitoring are adopted in the method, stable operation and management of the power system can be better served, and the efficiency and reliability of the monitoring system are improved.

The invention relates to a harmonic suppression and energy reutilization device and method for a power system, and the device comprises an active filter and a passive filter, and comprises a system management and control module and a harmonic energy recovery module. The system management and control module periodically samples power grid voltage, current and load current signals through an active filter and a passive filter, carries out harmonic analysis on the sampled signals, determines a compensation strategy according to an intelligent control algorithm, dynamically distributes the working states and energy recovery paths of the active filter and the passive filter, and carries out harmonic analysis on the power grid voltage, current and load current signals. Dynamic suppression of broadband harmonic waves is realized; meanwhile, power scheduling and energy conversion management are carried out on the harmonic energy recovery module; and the harmonic energy recovery module rectifies the residual harmonic energy after passing through the active filter and the passive filter and converts the residual harmonic energy into available electric energy. Compared with the prior art, the method has the advantages that harmonic energy is reused, and the system is kept to operate under the optimal harmonic suppression and energy recovery efficiency.

The present disclosure relates to the technical field of power system harmonic analysis, and provides a multi-harmonic source responsibility division method and system based on complex correlation coefficient, which comprises: constructing a linear relationship between harmonic voltage at a point of common coupling and average active power of multiple users; obtaining a time sequence of the voltage at the point of common coupling and a time sequence of active power data of the multiple users, and according to the constructed linear relationship, a sliding analysis is used to screen a sub-sequence with a large complex correlation coefficient between the harmonic voltage and the average active power of each user; a harmonic responsibility division index is constructed and calculated by using the screened sub-sequence, and the change of the harmonic responsibility with time is obtained. According to the change of the complex correlation coefficient with time, a time period with a large background harmonic disturbance is found out, and the error problem caused by the fluctuation of the background harmonic responsibility is avoided. On the basis of considering the size of the user power and the background harmonic responsibility, the change of the harmonic responsibility with time is given by the harmonic responsibility division index, and the accuracy and precision of the division are improved.

The application belongs to the field of intelligent power distribution systems, and provides a design method and system for an online harmonic monitoring system of a power system, which comprises the following steps: collecting voltage signals of transformers in a substation in real time through a voltage transformer; performing frequency domain analysis on the collected voltage signals by applying Fourier transform, and extracting each frequency component in the signals; setting a time window and a time interval, obtaining a frequency corresponding to a frequency component with the largest amplitude in each time interval, and recording the frequency as a highest frequency; obtaining a harmonic super-harmonic frequency difference through the highest frequency, and obtaining a harmonic severe wave band time window through the harmonic super-harmonic frequency difference; obtaining a harmonic severe wave band ratio through the harmonic severe wave band time window, and monitoring the operation of the power system through the harmonic severe wave band ratio. According to the design method of the embodiment of the application, problems can be quickly detected in the early stage of harmonic pollution, and a harmonic filter can be started or load distribution can be adjusted in time, so that the stability of the power system is ensured.