8 results about "Power system harmonics" patented technology

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 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 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.

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.