14 results about "Forced oscillation" patented technology

The invention discloses a power system forced oscillation source positioning method based on ICEEMDAN-ITEO, and belongs to the technical field of power system stability analysis and control. In a signal adaptive decomposition and modal extraction part, an ICEEMDAN algorithm is utilized to decompose a wide-area measurement signal, suppress modal aliasing and noise interference and obtain a modal component with physical significance; the energy weight of each modal component is calculated by adopting ITEO, the identification capability of the dominant forced oscillation component is enhanced through an adjustable resolution parameter, and the time domain waveform of the dominant forced oscillation component is reconstructed; in the oscillation source judgment part based on the dissipation mode energy flow, the dissipation mode energy flow of each generator port is calculated according to the dominant oscillation mode component, and accurate judgment of a disturbance source is realized through linear fitting of slope characteristics of the dissipation mode energy flow; in the verification and application part of the oscillation source positioning result, the accuracy and robustness of the method in different noise and disturbance scenes are verified through a test system comprising a network-forming fan.

The invention discloses a forced oscillation suppression method combining phase shift compensation and active damping, and belongs to the technical field of stable operation analysis of a power system. According to the forced oscillation suppression method combining phase shift compensation and active damping, most inter-harmonic disturbance sources are suppressed through direct-current voltage phase shift compensation, system damping is improved in a small-amplitude mode by combining active damping control, and the forced oscillation amplitude is suppressed under the condition that system performance is not affected. The mechanism that the inter-harmonic disturbance source triggers forced oscillation of the forced system is elaborated by using an equivalent disturbance equation, the influence of the amplitude of the inter-harmonic disturbance source and the damping of the forced system on the amplitude of forced oscillation is considered, and a forced oscillation suppression strategy of phase shift compensation and active damping is combined. The amplitude of an inter-harmonic disturbance source is suppressed through phase shift compensation, and the weak damping state of a forced system is improved through active damping, so that the amplitude of forced oscillation is suppressed.

The invention discloses a forced oscillation hydrodynamic experiment device for covering a buoyancy block rigid riser, which comprises an actuation module, a physical quantity sensing module, a rigid riser and a buoyancy block model, and is characterized in that the physical quantity sensing module is mounted on an actuation control module, the rigid riser is mounted on the physical quantity sensing module, the buoyancy block model is mounted on the rigid riser, and the buoyancy block model is mounted on the rigid riser. Therefore, the motion response of the rigid riser and the hydrodynamic load of the rigid riser can be measured in real time. The high-Reynolds-number forced oscillation experiment can be carried out on the rigid cylinder covered with the buoyancy block, the hydrodynamic coefficient of the rigid cylinder covered with the buoyancy block in a high-Reynolds-number flow field is obtained, and then a hydrodynamic coefficient library used for forecasting is established. The experimental device is simple in structure and easy to build and disassemble, meanwhile, the rigid stand pipe model is easy to disassemble, other stand pipe accessory structures can be replaced, and the experimental mode is flexible.

This application relates to the field of marine engineering technology, and discloses a floating breakwater with a resonant cavity and its hydrodynamic performance analysis method. The method includes: constructing a floating breakwater model; determining the target length and target width of the resonant cavity, the wave-facing open-type wave-dissipating chamber, and the wave-repelling open-type wave-dissipating chamber on the leeward side; dividing the entire fluid domain of the floating breakwater into multiple regions; obtaining the velocity potential of each region; calculating the wave force of the floating breakwater; using the velocity potential of each region to express the added mass and radiation damping of the floating breakwater when it undergoes unit forced oscillation, so as to construct the motion response equation of the floating breakwater in the frequency domain under wave action; obtaining the transmission coefficient and energy dissipation coefficient of the floating breakwater through the equation set, and evaluating the shielding performance and wave-dissipating performance of the floating breakwater based on each coefficient. The synergy of the resonant cavity and the open-type wave-dissipating chamber can improve the wave-dissipating efficiency, and the analysis method can provide an efficient and reliable basis for the design of breakwaters.

The invention relates to the technical field of ocean engineering, and discloses an energy dissipation floating breakwater with a resonance type cavity and a hydrodynamic performance analysis method of the energy dissipation floating breakwater. Respectively determining target lengths and target widths of the resonant cavity, the wave head side perforated wave dissipation chamber and the wave back side perforated wave dissipation chamber; the whole fluid domain of the floating breakwater is divided into a plurality of areas; solving the speed potential of each region; calculating the wave force of the floating breakwater, and expressing the additional mass and radiation damping when the floating breakwater performs unit forced oscillation by utilizing the speed potential of each region so as to construct a motion response equation of the floating breakwater in a frequency domain under the action of waves; the transmission coefficient and the energy dissipation coefficient of the floating breakwater are obtained through the equation set, and the shielding performance and the wave dissipation performance of the floating breakwater are evaluated according to all the coefficients. The cooperation of the resonant cavity and the perforated wave dissipation chamber can improve the wave dissipation efficiency, and the analysis method can provide an efficient and reliable basis for the design of the breakwater.

In absence of electrical approaches for realization of highly stable RF oscillator, opto-electronic oscillators (OEO) techniques are provided, where self-forced oscillation techniques using long optical delays demonstrate significant short-term and long-term frequency stability. Fully integrated opto-electronic oscillator chip (IOEC) may be the most efficient realization of an RF frequency synthesizer in terms of operation frequency (covering microwave and millimeter wave), size (<10 cm3), ruggedness to environmental effects of temperature (−40 to 80 C), vibration (up to 40 g), low timing jitter (<5 fs for 40 GHz carrier), and wall-plug efficiency (output power >10 dBm from under 1 W power). A free-running III-V (primarily InP) based multi-mode laser (MML) diodes is designed with large mode number (e.g., over 60 modes) and intermodal oscillation frequency compatible with desired RF carrier signal (e.g., 1-40 GHz).

The application discloses a power system forced oscillation positioning method based on a space-time attention mechanism, solves the problems of complex space-time dependence on an accurate model, noise sensitivity and insufficient positioning accuracy in a multi-source or complex oscillation scene in the prior art, and realizes high-precision single-source forced oscillation positioning; the method comprises the following steps: acquiring power system node time series data, and preprocessing to obtain a standardized space-time input matrix; a weighted normalized adjacency matrix is constructed based on a topological structure; the space-time input data is linearly mapped to a high-dimensional space to obtain a high-dimensional feature tensor; node attributes and time series encoding are embedded to obtain a space-time embedded feature tensor; a space-enhanced feature tensor is obtained based on the adjacency matrix; time dimension attention calculation and feature aggregation are performed on the space-enhanced tensor to obtain a space-time fusion feature tensor; global average pooling and full connection classification are performed on the space-time fusion tensor to output node oscillation source probability distribution and locate the oscillation source position.

This application discloses a method for identifying and locating forced oscillations using multimodal information fusion and an autoencoder. First, the logarithmic change in voltage amplitude and the change in active power are calculated from the collected data and fused using the entropy weight method to comprehensively characterize the oscillation signal. Then, the fused signal is decomposed into modal components of different frequencies using a fully integrated empirical mode decomposition and adaptive noise (CEEMDAN) algorithm, reducing data complexity. Zero-padded Hanning window fast Fourier transform (ZP-Hanning-FFT) is used to improve spectral resolution, calculate the frequency, amplitude, and energy of the modal components, and output the identification results, thus improving identification accuracy. Next, the mean, standard deviation, and energy of the modal components are calculated, and multi-scale convolution is used to extract feature information at different scales, which is then input into the autoencoder for training, improving the localization accuracy.

The invention discloses an energy storage suppression method and device for forced power oscillation, a program and a medium, and relates to the technical field of power system stability control, and the method comprises the following steps: when forced power oscillation occurs in a system, executing oscillation mode analysis to identify a dominant oscillation mode, and quantifying forced oscillation response characteristics under distributed disturbance injection; modeling is carried out based on isomorphic characteristics of an energy storage system and a disturbance source on a power grid power injection level, and an energy storage reverse phase compensation power reference value required by oscillation suppression is calculated; the method comprises the following steps: for a distributed energy storage collaborative scene, fusing wide area measurement system data, and constructing a power distribution model with energy storage resource global optimization configuration as a target when oscillation is completely suppressed; a feedback control module is introduced for calculation errors, and energy storage output power is dynamically corrected through real-time oscillation state information until oscillation is completely converged; and maintaining the dynamic power output of the energy storage system until the distributed disturbance source is removed. And the transient stability margin of the power system is obviously improved.

The invention discloses an electric power system low-frequency oscillation type identification and tracing method based on measurement, and relates to the technical field of electric power system low-frequency oscillation monitoring. Comprising the following steps: acquiring measurement data of a plurality of generators in a power system through a synchronous phasor measurement unit (PMU); performing detrending processing on the measurement data, and calculating the deviation value of each measurement relative to the steady state trend; performing spectral analysis on the at least one deviation value, and extracting a dominant oscillation frequency of the system; filtering the deviation value by using a band-pass filter, and extracting a characteristic signal taking the dominant oscillation frequency as a central frequency band; calculating a port oscillation energy component of each generator based on the filtered characteristic signal; according to the trend characteristic of the port oscillation energy component, identifying whether the low-frequency oscillation type of the system is weak damped oscillation or forced oscillation; and calculating the port oscillation energy flow of each generator based on the filtered characteristic signal, and preliminarily positioning the unit generating the oscillation source according to the comparison result of the change slope of the port oscillation energy flow.

The invention discloses a system weak point identification method and system for forced oscillation, and the method comprises the steps: collecting the time series data of the rotor angle, angular velocity and voltage phase / frequency of a generator of a power system based on a PMU, and constructing a measurement matrix and a time derivative matrix after preprocessing the collected data; constructing a feature matrix, solving a coefficient matrix, obtaining a state transition matrix and an input matrix from the coefficient matrix, and extracting to obtain a system dynamic equation; calculating a sensitivity matrix to represent the influence of the input on the system state; defining an output matrix, and calculating an influence matrix; quantifying the total contribution of each input to oscillation based on the sensitivity matrix and the influence matrix, and completing the recognition of the system weak point; the method can extract the dynamic equation of the system without depending on specific parameter information of the power system, identifies the weak point of the system through quantitative analysis, and improves the simplicity and reliability of the method.

The invention belongs to the technical field of forced oscillation, and provides a pulse oscillation technology system error-based multi-point calibration method, which comprises the steps of theoretical impedance data calculation, fitting data collection, compensation curved surface fitting model construction and impedance data correction. According to the method, the compensation curved surface fitting model is constructed, so that the measurement accuracy in high-frequency and high-impedance ranges is improved, errors caused by factors such as system asymmetry can be processed, more accurate calibration can be realized for full-frequency bands and various impedance ranges, physiological conditions of different patients can be adapted, and the reliability of measurement results is ensured.

The application discloses a power grid synchronous broadband forced oscillation detection and positioning method and system and a medium. The method comprises the following steps: obtaining oscillation data sequences and a power system topology graph of a power grid, and inputting the pre-trained multi-task graph sequence network to obtain an oscillation source positioning detection result. The oscillation data sequences are input into a convolution layer, a pooling layer and an output feature obtained by a created embeddable sequence autoregressive module. The power system topology graph is input into a multi-task graph sequence network to perform information transmission, and a node feature of each node is obtained through a gated recurrent unit (GRU). Then, the method is input into a graph-level detection branch and a node-level detection branch to realize event type classification of an oscillation source and positioning of the oscillation source. The application aims to reduce the interference of other information on broadband oscillation information, dynamically analyze data from two dimensions of time and space, and quickly and accurately realize broadband oscillation source positioning.

The present application belongs to the field of direct connection hypersonic inlet / isolator ground wind tunnel experiment, and particularly relates to a forced oscillation generating device for hypersonic inlet / isolator and a design method thereof. Step 1: determining the static pressure and Mach number of the incoming flow gas; Step 2: based on the static pressure and Mach number of the incoming flow gas in step 1, determining the material adopted by the shell of the oscillation generating device and the oscillation back pressure generating mechanism; Step 3: based on the material selected in step 2, determining the type of the driving device in the oscillation back pressure generating mechanism; Step 4: based on the type of the driving device in step 3, determining the transmission ratio of the gear and the throttling ratio range of the rotating blade in the oscillation back pressure generating mechanism; Step 5: based on the transmission ratio and the throttling ratio in step 4, processing the forced oscillation device experimental piece and installing it on the ground wind tunnel experiment table, selecting the throttling ratio and the oscillation frequency and conducting the experiment, and the forced oscillation device will generate the expected oscillation back pressure at the outlet of the isolator. To solve the problem of flow separation in the inlet in the prior art, and further affect the power and control performance of the aircraft.