14 results about "Substitution method" patented technology

The invention relates to a reliability evaluation method and system for a flexible AC / DC power distribution network containing an optical storage system in the field of flexible AC / DC power distribution networks. The method comprises the following steps: collecting photovoltaic data, energy storage data, AC / DC bus data and the like in real time; constructing a multi-time scale dynamic topology model, and establishing a failure probability distribution function; load flow calculation based on an improved forward-backward substitution method; adopting an N-1 + N-1-1 composite fault screening strategy to simulate a typical disturbance scene; establishing a vulnerability evaluation matrix to calculate power failure probability and other indexes; designing an optimal scheduling strategy based on model predictive control; multi-time-scale reliability evaluation is carried out; and outputting an evaluation report and a topology reconstruction suggestion. The system comprises a data acquisition unit, a dynamic modeling unit and the like, and an evaluation and analysis unit is internally provided with an algorithm module and is configured with an FPGA acceleration card. The method breaks through the limitation of traditional steady state evaluation in the technology level, improves the load flow calculation speed in the calculation efficiency level, reduces the operation cost in the application value level, improves the energy storage efficiency, and provides support for reliability evaluation of a novel power system.

The invention relates to the technical field of power distribution network fault recovery, in particular to a power distribution network local load segmented transfer method based on line bearing capacity evaluation and a parallel tabu search algorithm. Obtaining a power distribution network coefficient, distributed photovoltaic and energy storage equipment output, a load demand and fault position information; calculating the power flow distribution of the power distribution network after the fault occurs and before transfer by adopting a forward-backward substitution method, defining a safety margin index, and screening out a transferable safety line set; a power distribution network load transfer model fusing high voltage priority, important user priority and loss load priority is constructed, and based on a transferable safety line set, a parallel tabu search algorithm is adopted to perform optimization in a safety solution space to obtain an optimal transfer scheme; and calculating a fault rate based on the load rate of the line after transfer, and marking a high-risk line exceeding a threshold value. According to the invention, an effective load transfer scheme can be provided immediately after the power distribution network has a fault, so that the power failure loss after the fault occurs is reduced, and the user satisfaction is improved.

The invention provides a transformer area two-stage distribution robust line loss optimization method considering wind and light uncertainty, and belongs to the technical field of new energy. Firstly, a day-ahead-real-time two-stage line loss optimization method is constructed, and in the day-ahead stage, a K-means clustering algorithm and a conditional generative adversarial network are combined to generate a multi-scene sample set capable of reflecting the uncertainty of wind and light output; in a real-time stage, based on a day-ahead optimization result and updated output information, a multi-scene distribution robust optimization model is utilized to realize joint correction of line loss and economic dispatching; in the optimization solution process, a forward-backward substitution method is adopted to embed the load flow calculation model so as to accurately reflect the line transmission loss of the transformer area power distribution network; secondly, a distributed robust optimization method based on scene generation is constructed, historical wind and light data are utilized, a diversified scene set is generated through K-means clustering and a conditional generative adversarial network, and distributed robust optimization planning and correction are carried out in different scenes.

The present application relates to a kind of resource optimization method based on RIS auxiliary wireless energy-carrying backscattering communication system, belong to low-power Internet of Things technical field, the present application is aimed at the problem that transmission performance is poor caused by obstruction obstruction and channel perturbation, consider transmission time constraint, energy collection constraint, the maximum interference power constraint allowed by main receiver, channel uncertainty constraint and intelligent metasurface phase shift constraint, construct energy efficiency maximization resource management model based on bounded channel uncertainty, utilize worst criterion method and Cauchy inequality to convert original non-convex optimization problem containing parameter uncertainty into deterministic problem;By variable substitution method, continuous convex approximation method, block coordinate descent method and semi-positive definite programming method, the deterministic problem is converted into convex problem solution, the present application can effectively improve system total energy efficiency, while reducing main user interruption probability, improve signal propagation path.

The utility model provides a simple clamp for testing sound velocity and sound attenuation of a solid material through an insertion substitution method, and belongs to the technical field of material testing. The simple clamp for testing the sound velocity and sound attenuation of the solid material through the insertion substitution method comprises a base. End heads are arranged at the two ends of the base, through holes are formed in the two end heads, the two through holes are coaxially formed, and the two round pipes and the two through holes are coaxially formed. When the device is used and a solid material needs to be tested, the tested material is placed between the two round pipes, then the two round pipes can slide, the two round pipes get close to each other to clamp and limit the tested material, the transmitting transducer and the receiving transducer penetrate through the two through holes respectively, and the transmitting transducer and the receiving transducer are connected with the two through holes under the coaxial action of the two round pipes and the two through holes. The coaxiality among the transmitting transducer, the receiving transducer and the test material can be improved, and then the test accuracy can be improved.

The invention discloses a method for identifying the stability of an EMC (Electro Magnetic Compatibility) measurement system at any two time points, the EMC measurement system refers to an EMC radiation disturbance CDNE substitution method measurement system, a national standard sample is used as a test sample, a t test method is used for carrying out statistical analysis on repetitive test results of the EMC measurement system at the two time points, and the stability of the EMC measurement system at any two time points is identified. And the stability is evaluated. The method is simple to operate, can be used for self-evaluation of the stability of the EMC measurement system, and gets rid of dependence of stability detection of the EMC measurement system on external quality management activities such as calibration and capability verification.

The invention discloses a double-station RCS (radar cross section) scaling test system and a test method for an electrically large-size target in an indoor compact range. The system comprises a transmitting feed source, a receiving feed source, a transmitting compact range parabolic reflecting surface, a receiving compact range parabolic reflecting surface, a transmitting compact range movable bracket, a receiving compact range movable bracket, a target to be measured, a target placement turntable, a vector network analyzer, a three-port power divider and a control and data processing center, the to-be-measured target comprises two types: one type is a calibration body, and the other type is a scaling target model; and calculating and processing to obtain an RCS value of the scaled target model through a known RCS of the calibration body, a receiving feed source output intermediate frequency signal obtained by measurement of the calibration body and a receiving feed source output intermediate frequency signal obtained by measurement of the scaled target model by utilizing a substitution method. The system is simple in structure and convenient to install, and the testing efficiency is improved.

The present invention proposes a two-stage combined frequency regulation optimization method for thermal energy storage based on weight coefficient correction. First, aiming at the frequency regulation assessment rules, a mathematical model of frequency regulation performance index is established, and the Big-M method and variable substitution method are used to linearize the conditional constraints and absolute value constraints in the index model, thereby constructing a first-stage optimization model considering frequency regulation performance. On this basis, in order to reduce the over-limit of energy storage SOC and the deep charge and discharge conditions, a second-stage optimization model is constructed with the minimum deviation of energy storage SOC as the goal, so as to establish a two-stage combined frequency regulation optimization model for thermal energy storage. Therefore, the two-stage combined frequency regulation optimization method proposed by the present invention can improve the frequency regulation performance of the combined thermal energy storage system, effectively reduce the deep charge and discharge conditions of the energy storage and the loss of service life, and improve the sustainability of the energy storage auxiliary frequency regulation service.

The present invention relates to a method for predicting the natural frequency of a stiffened conical shell, comprising the following steps: S1-S2, writing the vibration control equations of the conical shell and the concentric annular plate into a dynamic stiffness matrix related to the internal force and displacement thereof; S3, discretizing the conical shell into a plurality of sub-segments, and splicing the plurality of substructures in the stiffened conical shell by utilizing two boundary conditions of displacement continuity and force balance between the ribs and the conical shell sub-segments; S4, on the premise of obtaining the dynamic stiffness of the overall calculation model, performing a correction and substitution method on the matrix elements corresponding to each degree of freedom in the dynamic stiffness matrix; S5, obtaining a curve of the dynamic stiffness matrix determinant of the overall model varying with frequency by solving the determinant of the overall stiffness matrix, and identifying and obtaining the natural frequency of the overall structure through the maximum and minimum values in the frequency response curve, quickly evaluating the natural frequency of tail structures such as the conical shell, and improving the safety and reliability of equipment containing the conical shell structure.

The invention relates to the technical field of acoustic engineering, in particular to an equivalent substitution method and system for sound propagation analysis of a volume sound source in a complex sound field environment. The method comprises the following steps: establishing a finite element model of a volume sound source containing complex boundary conditions by utilizing engineering software, carrying out truncation processing on a computational domain, and calculating and obtaining sound pressure and normal vibration velocity on a closed integral surface surrounding the volume sound source; based on the sound pressure and the normal vibration velocity, performing external sound field solution on the closed integral surface by adopting a free field sound radiation integral mode to obtain sound pressure distribution on at least two layers of enveloping surfaces located on the outer side of the volume sound source; arranging a plurality of equivalent point sound sources in the volume sound source, constructing an equivalent source solution equation by taking the sound pressure on at least two layers of envelope surfaces as a matching target, and calculating the source intensity of each equivalent point sound source; and based on the positions of the equivalent point sound sources and the corresponding source intensities of the equivalent point sound sources, accumulative calculation of the volume sound sources in a complex sound field environment is realized by adopting a channel propagation method based on the point sound sources, so that propagation analysis is carried out.

The invention provides a system and a method for calibrating dynamic characteristics of a microphone based on a substitution method principle, and relates to the technical field of detection sensing. Based on a substitution method principle, a digital closed-loop control sound horn traveling wave tube calibration device is established, and sound attenuation of sound wave conduits with different lengths under a full frequency band is obtained through a system full frequency band dynamic calibration method, so that a measurement result of a monitoring system can be corrected. In the field of aero-engine acoustic microphones, within an allowable error range, a measurement result of a noise measurement monitoring system can be corrected, that is, the correction amount and a value measured in an experiment are added to obtain a final correction value, the test precision is improved, and the test cost is reduced. The method provides more accurate data for subsequent exploration of the relationship between the sound pressure and other physical quantities, and is suitable for the condition that a standard microphone cannot be obtained due to condition limitation.

The present invention relates to a method for optimizing symbiotic radio network resources under separation channel uncertainty, and belongs to the field of mobile communication technology. The present invention addresses the problem of transmission link instability caused by the limited signal processing capability of backscattering devices in symbiotic radio networks. Considering constraints such as the minimum energy collection of backscattering devices, the maximum transmission power of the main base station, the transmission time / reflection coefficient of the backscattering devices, the uncertainty of all link channels, and the service quality of the main base station and the backscattering devices, a throughput maximization robust resource allocation model based on separation channel uncertainty and nonlinear energy collection model is constructed. The worst-case criterion, Lagrangian duality theory, continuous convex approximation method, and variable substitution method are used to transform the original resource allocation model into a deterministic convex optimization model for solution. The present invention can effectively improve the total throughput of the system while reducing the transmission interruption probability of the device.

The application discloses the technical field of integrated energy system operation and planning, and relates to a kind of energy system multi-energy flow calculation method, device and storage medium based on topological partition, method includes: to the each subsystem of pre-constructed IES mathematical model is topologically partitioned, each subsystem is decomposed into only containing radial subnetwork topology or ring subnetwork topology minimum sub-block;Determine the connecting node of adjacent sub-block and aggregate to form equivalent topology;Each described sub-block is set to balance node, with balance node as reference, based on the subnetwork topology type of equivalent topology, radial subnetwork topology adopts forward-back substitution method to solve sub-block multi-energy flow, and ring subnetwork topology adopts finite element method to solve sub-block multi-energy flow;Based on the state quantity of the connecting node, the calculation results of each sub-block are mapped to original IES topology according to preset rule, and multi-energy flow calculation result is output.The application can alleviate the technical problems that existing technology cannot meet the calculation requirements of complex mixed topology IES.

The application provides a two-stage distribution robust line loss optimization method considering wind and light uncertainty, and belongs to the technical field of new energy sources. First, a day-ahead-real-time two-stage line loss optimization method is constructed. In the day-ahead stage, a multi-scenario sample set capable of reflecting wind and light output uncertainty is generated by combining a K-means clustering algorithm and a conditional generative adversarial network. In the real-time stage, based on the day-ahead optimization result and updated output information, a multi-scenario distribution robust optimization model is used to realize joint correction of line loss and economic dispatch. In the optimization solving process, a forward-backward substitution method is embedded into a power flow calculation model to accurately reflect line transmission loss of the distribution network in the transformer area. Secondly, a distribution robust optimization method based on scenario generation is constructed. A diversified scenario set is generated by using historical wind and light data through K-means clustering and a conditional generative adversarial network, and distribution robust optimization planning and correction are carried out under different scenarios.