10 results about "Frequency instability" patented technology

The invention discloses a frequency response prediction method and system under an anticipated fault of a power system, and the method comprises the steps: generating sample data in different operation modes and fault scenes through the simulation of the power system, carrying out the normalization processing, and dividing the sample data into a training set and a test set; constructing and training a physical guidance neural network model; in an online state, inputting a power grid operation mode and anticipated fault information at a future moment into the trained physical guidance neural network model, predicting a system frequency response curve, and judging whether a frequency instability risk exists or not according to the frequency response curve; according to the method, the physical guidance neural network and the data driving method are combined, the problems that a traditional data driving model is poor in interpretability and depends on a large amount of data are effectively solved, accurate prediction of the power system frequency response under the anticipated fault is achieved, and prediction efficiency and reliability are remarkably improved.

The invention discloses a steady-state wind power grid-connected power system frequency instability risk quantitative evaluation method considering an active disturbance probability, and belongs to the field of power system stability analysis. The method comprises the following steps: inputting steady-state power flow information of each grid-connected power generation cluster into an XGBoost-based speed regulation system frequency modulation parameter identification model to obtain frequency modulation parameters, and obtaining a primary frequency modulation polynomial equivalent analysis model of each cluster; simplifying a calculation formula of an inertia center frequency deviation extreme value based on an active-frequency open-loop decoupling model; setting a multi-level inertia safety boundary by referring to various active disturbance occurrence probabilities; and establishing a piecewise linear thought-based steady-state frequency stability margin quantitative evaluation index for online evaluation of the inertia level of the system, and analyzing the steady-state system frequency stability margin and the frequency instability risk in real time. According to the method, the influence of wind power integration on the frequency response process of the power system is considered, online real-time accurate evaluation of the system frequency stability margin in a steady state is realized, and a reference basis is provided for formulating frequency stability control measures.

The present application relates to the field of hybrid energy storage system control, in particular to a hybrid energy storage black start coordination control method and system based on frequency rate of change prediction; state data of a power system at the current time and operation data of a hybrid energy storage system are collected; the operation data of the hybrid energy storage system is input into an improved equivalent state of charge model to calculate the equivalent state of charge at a future time; the state data of the power system and the equivalent state of charge at the future time are input into an improved frequency rate of change prediction model to calculate the frequency rate of change at the future time; according to the frequency rate of change at the future time and the equivalent state of charge at the future time, a stability index at the future time is calculated; the present application overcomes the risk of rated frequency instability of the power system caused by load mutation and control delay, and significantly improves the frequency stability and recovery success rate during the black start process.

This invention relates to the fields of laser technology and quantum sensing technology, specifically an alkali metal vapor laser for array-type atomic magnetometers. This laser aims to solve the problems of low power, wide linewidth, mediocre beam quality, and frequency instability in existing lasers for measuring extremely weak magnetic fields. The main components include a semiconductor laser pump source, fast and slow axis collimating mirrors, a coupling lens, an alkali metal vapor chamber, a front cavity mirror and a rear cavity mirror, a polarization beam splitter, a built-in F-P cavity, and a λ / 4 waveplate. The semiconductor laser pump source provides a narrow-linewidth pump laser after linewidth compression. The fast and slow axis collimating mirrors are used for collimation and shaping of the pump beam. The coupling lens couples the pump light into the alkali metal vapor chamber, which provides the gain medium for laser formation. The front and rear cavity mirrors are used to form laser resonance and perform mode selection. The polarization beam splitter separates the laser from the pump light and controls the laser polarization direction. The λ / 4 waveplate is used for converting linearly polarized light to circularly polarized light.

The invention relates to the technical field of power system safety and stability control, and provides a generator tripping / load shedding dynamic adjustment method and system for isolated network frequency instability, and the method comprises the steps: detecting the power flow section power, the frequency change rate and a fault signal of a power system in real time, calculating the power shortage according to the power flow section power, and determining the state of an isolated network according to the fault signal; calculating the current stability condition of the system according to the frequency change rate and the power vacancy; according to the preset isolated network action logic of the stability control device, the trigger threshold value, the delay time and the priority of generator tripping / load shedding are dynamically adjusted, photovoltaic output and non-critical loads are preferentially cut off, and operation of a thermal power generating unit is reserved to the maximum extent. According to the method, the frequency of the isolated network can be quickly recovered to a stable range, the frequency stability of the isolated network is remarkably improved, and the reliability and robustness of the system are enhanced.

This invention discloses an ultra-high stability laser system based on dual-path independent composite frequency stabilization and sum-frequency modulation, belonging to the field of precision laser spectroscopy and frequency control technology. The system includes two seed lasers (1560 nm and 1064 nm), a dual-wavelength common-cavity ultra-stable module, two acousto-optic frequency shift and dual-reference absolute frequency stabilization modules, and a nonlinear sum-frequency modulation (SFG) module. Full-time-scale frequency noise suppression is achieved through a three-stage cascaded closed loop consisting of a MHz fast loop, a kHz slow loop, and a Hz extremely slow loop. An acousto-optic modulator is placed in the sampling optical path fed into the ultra-stable cavity, and physical decoupling of the fast and slow loops is achieved through radio frequency bridging. The extremely low-frequency error signal detected by NICE-OHMS is fed back to the PPMgOLN crystal temperature or AOM driving frequency to compensate for the thermally induced drift of the nonlinear crystal. The system ultimately outputs a 633 nm laser power of not less than 50 mW, with a short-term frequency instability better than 5 × 10⁻⁶ mW. ‑15 @1 s.

The invention discloses a hybrid energy storage inertia support optimization method based on real-time frequency change rate dynamic decoupling distribution, and the method comprises the steps: monitoring the power grid frequency change rate of a target hybrid energy storage system in real time, and generating a total inertia power demand; based on the total inertia power demand, determining a super capacitor power distribution weight; obtaining an optimized power value of the super capacitor and an optimized power value of the energy storage battery according to the constructed objective function; based on the optimized power value of the super capacitor and the power value of the energy storage battery, correcting the power distribution weight of the super capacitor; and generating a super-capacitor inertia time constant and an energy storage battery inertia time constant based on the corrected super-capacitor power distribution weight. According to the method, the problem of frequency instability caused by insufficient inertia of a high-proportion new energy power grid is solved; the stability level of the power grid frequency is remarkably improved, the service life of the energy storage battery is greatly prolonged, and the whole life cycle operation and maintenance cost is reduced.

The invention belongs to the technical field of cable fault positioning, and particularly relates to an intelligent cable fault positioning method and system based on a wave reflection method, and the method comprises the steps: injecting a pulse signal into a to-be-detected cable, and obtaining a time domain reflection discrete sequence according to a sampling cut-off moment determined based on a minimum theoretical wave velocity; calculating a heuristic propagation wave velocity according to the maximum reflection pulse in the sequence, and determining a real-time attenuation constant and a real-time propagation wave velocity based on the rationality of the heuristic propagation wave velocity; variational mode decomposition is carried out on the sequence, and a kurtosis screening index based on a central moment is utilized to select a fault sensitive mode component; correcting the Talbot energy of the modal component in combination with a real-time attenuation constant and a local frequency instability index to obtain a time-varying frequency weighted energy spectrum; and calculating a fault positioning distance according to the energy spectrum peak moment. According to the invention, through adaptive adjustment of the wave velocity parameter and the time-varying frequency weighted energy spectrum, accurate positioning of the aging cable and the fault in a complex noise environment is realized.

The present application belongs to the technical field of power system restoration control, and discloses a power coordination control method of a hybrid energy storage auxiliary black start system and related devices. The method obtains the total active power demand of the black start system, decomposes it into three time scale components of fundamental wave, medium frequency and high frequency, dynamically allocates it to lithium batteries and super capacitors, and then corrects the allocated power based on temperature, operation time and rated parameters. Finally, the frequency change rate and the DC voltage change rate are calculated according to the actual power instruction and the system parameters, and the controller outputs the control quantity. The method overcomes the contradiction between the energy and the power density of a single power source, cooperatively improves the response speed and the continuous power supply capacity, effectively suppresses the voltage frequency instability risk caused by the load input, and significantly improves the reliability and efficiency of the black start through the improved hybrid energy storage coordination control.

The invention discloses a method, a device, a medium and equipment for eliminating microwave landing system ground antenna scanning beam frequency instability, and relates to the technical field of microwave landing system measurement. Frequency scanning is carried out through signals formed by multiple beams, parameters of the signals can be more comprehensively grasped through self-correlation detection, and the measurement accuracy is improved. The method also can solve the problem of amplitude and phase detection based on a non-uniform sampling method, converts the detected unstable frequency into a Nyquist frequency signal through Fourier transform, solves the problems of scanning gain reduction and unstable performance caused by the deviation of a scanning angle from the unit beam direction, effectively improves the beam direction, and improves the detection precision. The method is advantaged in that wave beam scanning accuracy is improved, after unstable frequency characteristics are identified, signals with required frequency are finally separated, microwave landing guiding equipment is guided to output stable wave beam scanning microwave frequency, and elimination of ground antenna scanning wave beam frequency instability is realized.