99 results about "Transient stability analysis" patented technology

The invention relates to the technical field of new energy grid-connected control, in particular to a fault stage transient stability analysis method and system for a following-constructed network type converter series-parallel system, and the method comprises the steps: enabling a constructed network type converter to be equivalent to a controlled voltage source series impedance, enabling a following network type converter to be equivalent to a controlled current source, and enabling the controlled current source to be equivalent to a controlled voltage source series impedance; the whole series-parallel system is equivalent to a scene in which double voltage sources and a single current source are jointly connected in parallel to a PCC point, and a series-parallel system model is constructed; according to the series-parallel system model, respectively representing an active power coupling term of the network-building type converter and a voltage coupling term of the network-following type converter under the condition of considering parallel connection of the network-following type converter and the network-building type converter; according to the coupling term, remodeling an active loop control structure of the network-constructing converter and a phase-locked loop synchronization structure of the network-following converter, and obtaining a transient analysis model of the series-parallel system considering the coupling term; the transient stability of the hybrid system in the power grid fault stage is analyzed through the transient analysis model, and the influence on the transient stability is effectively represented.

The invention discloses a transient stability analysis method for a network-building type energy storage inverter based on torque enhancement control. The transient stability analysis method comprises the following steps: step 1, constructing a network-building type energy storage inverter model based on torque enhancement control; step 2, transient stability analysis of the net-building type energy storage inverter: 2.1, an energy function method, 2.2, influences of parameters on an attraction area, and taking a damping coefficient, line impedance and reference active power which influence a swing equation as variables, so as to obtain the transient stability of the net-building type energy storage inverter; transient power angle instability of the network-building type energy storage inverter is essentially caused by imbalance between the reference active power and the output active power, and the transient stability margin can be improved by reducing the reference active power during the fault period. The method has the beneficial effects that the problems of active power fluctuation and voltage instability of the grid-forming type energy storage inverter are considered, so that the fluctuation can be effectively suppressed and the oscillation can be reduced when the voltage of the system is suddenly changed.

The invention discloses a series-parallel system transient stability analysis and fault ride-through control method considering current limiting, and belongs to the field of power fault analysis. In order to reveal an action mechanism of a current amplitude limiting and converter coupling effect on the transient synchronization stability of the hybrid system, the method comprises the following steps: firstly, considering the influence of control mode switching of a constructed network type converter, and establishing a transient analysis model of the hybrid system considering a current amplitude limiting link; then, based on a phase plane method, analyzing an action rule of converter control parameters on system transient stability, determining an optimal active power reference value and a saturation current phase angle of the grid-forming converter during a fault period, and proposing a fault ride-through control strategy according to the optimal active power reference value and the saturation current phase angle; and finally, verifying the correctness of theoretical analysis and the effectiveness of the proposed control strategy through multi-working-condition simulation.

The invention discloses a modeling and transient stability analysis method for a grid-connected new energy unit. The modeling method comprises the following steps: establishing a nonlinear full-order model of a grid-connected new energy unit system by adopting a state space modeling method, performing order reduction processing on the established nonlinear full-order model, and performing linearization processing on a nonlinear part; according to the system transient synchronization stability analysis method, the problem of constructing the maximum estimation attraction domain of the system is converted into the problem of solving optimization, and the maximum estimation attraction domain of the system is solved by adopting an LMI optimization theory. The influence of a phase-locked loop and a current loop of the system is fully considered when the full-order model is constructed, order reduction processing and linearization processing are performed on the full-order model, the obtained simplified model can accurately simulate the original full-order model, and the difficulty of subsequent transient stability analysis is reduced; an LMI optimization method is adopted to solve the maximum estimation attraction domain of the system, and the constructed maximum estimation attraction domain can accurately reflect the transient stability boundary of the system and is low in conservative property.

The invention provides a transient stability analysis method for a grid-connected system. The method comprises the following steps: establishing a mathematical model of a heterogeneous new energy grid-connected system comprising a network construction type new energy unit, a network following type new energy unit, a synchronous generator and a receiving end power grid, and defining a state variable set of the system; solving a stable equilibrium point and an unstable equilibrium point of the system according to the operation condition of the system; and by taking the unstable equilibrium point as a starting point, calculating by adopting a numerical integration method or a numerical continuation method to obtain a stable manifold starting from the unstable equilibrium point. The method provided by the invention realizes global and accurate depiction of the transient stability domain, overcomes the defects that a traditional small signal linearization method can only analyze local stability and a traditional energy function method depends on an artificial construction function and is limited in applicability, fundamentally changes an analysis normal form of the transient stability domain, and improves the analysis accuracy of the transient stability domain. And a more effective analysis tool is provided for safe and stable operation of the high-permeability new energy grid-connected system.

The invention discloses a new energy unit grid-connected system transient stability boundary acquisition and stability analysis method, and the method comprises the steps: solving a phase trajectory of a system under different parameters through an ode23tb solver in Matlab for boundary acquisition, judging a parameter value, exceeding a set range, of the trajectory to be unstable, obtaining a point set enabling the system to be transient-stable, and carrying out the transient stability of the system; and fitting the boundary of the region by using Matlab, and drawing an attraction domain or / and a parameter feasible domain capable of ensuring transient stability of the system. According to the stability analysis, whether the system has a balance point or not and whether a stable balance point and a state variable are located in an attraction domain or not are judged, and a system transient stability analysis result is obtained. According to the method, the attraction domain of the system and the parameter feasible domain capable of ensuring the transient stability of the grid-connected system can be quickly solved, a new thought is provided for new energy grid-connected transient stability analysis, and the defects of existing new energy grid-connected transient stability analysis and research are overcome.

The invention relates to the technical field of converter analysis, in particular to a converter transient stability analysis method and system considering HPFR structure influence. The method comprises the steps that an HPFR structure is considered, and a transient response large disturbance dynamic model of a virtual synchronous generator under large disturbance is constructed; based on the constructed transient response large-disturbance dynamic model, analyzing the transient stability of the system by adopting an extended equal-area method to obtain a VSG dynamic response characteristic jointly influenced by a gain coefficient and a cut-off frequency in a speed regulation link; based on VSG dynamic response characteristics, a phase diagram analysis method is adopted to evaluate a gain coefficient and a cut-off frequency in a speed regulation link, and a value interval of the gain coefficient and the cut-off frequency in the speed regulation link is obtained; and optimizing a gain coefficient and a cut-off frequency in a speed regulation link of the virtual synchronous generator, so that a power angle value of the system is smaller than a power angle value of the system tending to be unstable under a fault condition. The method has the characteristics of high analysis precision, difficulty in conservative judgment result and the like.

The invention discloses a transient stability analysis method, device and system for a new energy power system, and belongs to the technical field of new energy power generation, and the method comprises the steps: setting a network-type converter of the new energy power system as a voltage source in a normal state, and switching the network-type converter into a current source in a fault state; and representing a first transient analysis model corresponding to the grid-forming converter and a second transient analysis model corresponding to the grid-forming converter by using a curved surface, thereby determining respective power angle stable regions of the two converters, analyzing actual power angles of the new energy power system when different power grid voltages drop, observing power angle swing tracks of the converters, and calculating the power angle stability of the new energy power system. And therefore, transient weak converters corresponding to different power grid voltage sags can be accurately reflected. Compared with the prior art, the method can accurately describe the power angle stable areas of the grid-forming converters, simulates the new energy power system under various fault conditions, provides a powerful basis for preventing system instability in advance, and improves the operation reliability of the new energy power system.

The invention discloses a data analysis method and device for space state expansion of a wind turbine generator, and relates to the technical field of electric digital data processing. The method comprises the steps that a unit state equation is listed for unit state quantities, and meanwhile, nonlinear time-varying items of key parameters such as filter inductance, capacitance, line impedance and power grid impedance are introduced; adding model error terms introduced by unmodeled parts such as a dead zone, power tube internal resistance and voltage drop, parasitic parameters and the like, considering random disturbance terms such as state sampling errors, external disturbance and the like, and establishing an extended state space model of the multi-class new energy unit; partial non-key state and control link influence are ignored, and a new energy unit order reduction model for balancing transient stability analysis rapidity and accuracy is established; and combining a Lyapunov stability theory to summarize a transient stability analysis problem of the system into a maximum attraction domain estimation problem of the system, so that accurate data support is provided for subsequently exploring a mapping relationship between the maximum estimation attraction domain and system parameters and state response characteristics under typical working conditions.

The invention belongs to the technical field of energy storage and grid connection, and particularly relates to a non-linear modeling method for a network-building type energy storage converter based on a mixed potential function, which comprises the following steps of: in an analysis model of the mixed potential function, determining a group of complete mixed variables of branch current and voltage by a non-energy-storage element and a capacitor; the method comprises the following steps: calculating a product of a current potential function of a non-energy-storage element and a voltage and a current on a capacitor according to an energy relation of system elements according to an inductive current and a capacitor voltage in an energy storage grid-connected system, and further deriving a mixed potential function of the system; and constructing a nonlinear model of the energy storage grid-connected system according to the determined hybrid potential function of the energy storage system. According to the method, the transient stability behavior of a nonlinear circuit is considered from the perspective of energy, the Lyapunov function construction difficulty of a high-order nonlinear system is reduced, and the problem that the transient stability analysis difficulty of the nonlinear system is large under the condition that the system is subjected to large disturbance can be solved.

The invention provides a voltage source converter grid-connected system parameter feasible region construction method and device, and relates to the field of power system transient stability analysis, and the method comprises the steps: constructing a grid-connected system simplified mathematical model according to a topological structure of a voltage source converter grid-connected system; deriving the simplified mathematical model of the grid-connected system to obtain a second-order equivalent dynamic equation; and performing numerical integration and equal area calculation on the second-order equivalent dynamic equation to determine a voltage source converter grid-connected system parameter feasible region. According to the method, the parameter feasible region of the voltage source converter in the whole fault process can be constructed aiming at the transient synchronous stability problem caused by the weak connection system of the voltage source converter in the whole fault process.

The invention relates to a power system transient stability analysis method based on spherical geometry, and the method comprises the following steps: 1, carrying out the dimension reduction processing of a high-dimensional multi-machine power system, and obtaining the projection of a global manifold in a unit projection sphere of a three-dimensional phase space through a contraction projection transformation method; and step 2, two groups of spherical coordinates SAIs which are symmetrical about the center of the sphere can be obtained by constructing and observing a geometric distribution situation graph of the SAIs of the high-dimensional multi-machine power system on the sphere, and a spherical triangle area formed by three SAIs on the same hemisphere is used for defining a spherical surface curved surface triangle area SAST as an SAIs evaluation parameter. The problem that the stability degree cannot be effectively distinguished due to the fact that the indexes are the same when different faults exist in an existing power system transient stability analysis method is solved, simulation results show that evaluation parameters provided by the method have the advantage of being higher in accuracy, and the transient stability degree of the system can be effectively judged.

The invention provides an electric power system transient stability analysis method and device. The method comprises the following steps: acquiring operation data of a to-be-analyzed electric power system; inputting the operation data into a transient stability analysis model to obtain a transient stability analysis result of the to-be-analyzed power system output by the transient stability analysis model; wherein the transient stability analysis model is obtained by training a deep learning neural network of a Transform architecture on the basis of sample data with transient stability and sample data with transient instability. According to the method, a neural network transient stability analysis model is constructed by combining a deep learning neural network of a Transform architecture aiming at the transient stability analysis problem under a stability domain concept, and compared with an existing transient stability analysis model, the calculation amount can be greatly reduced, and the real-time or near-real-time transient stability analysis requirement of a power system can be met.

The invention discloses a method for analyzing transient stability of a hybrid synchronous control grid-forming inverter considering damping influence, and belongs to the field of DC / AC converters, the method comprises the following steps: dividing a power angle interval to be analyzed into a plurality of sub-intervals, constructing an explicit damping-power angle function in each sub-interval, further quantifying the damping influence, and calculating the transient stability of the hybrid synchronous control grid-forming inverter. And depicting a transient stability boundary of the network-constructing inverter system. According to the method, the damping influence is quantified, the defect that a traditional equal-area method is too conservative is overcome, meanwhile, compared with a traditional transient stability analysis method needing iteration, the method does not need to solve a nonlinear differential equation through complex numerical iteration, an explicit transient stability boundary can be obtained, and the method is suitable for being used for transient stability analysis. And the method is also used for the grid-forming inverter with droop control and virtual synchronous machine control of a linear damping item, and an effective method with high analyzability and low complexity is provided for transient stability analysis of the grid-forming inverter. And the method has good practical application value.

The invention provides a transient stability prevention and control method and device based on an agent model, and the method comprises the steps: inputting a plurality of operation data of a power system into a pre-constructed transient stability analysis model, and obtaining a transient stability analysis result of each operation data outputted by the transient stability analysis model, each operation data comprises the initial active power of the generator; according to the transient stability analysis result, determining transient instability operation data, and calculating the sensitivity of each generator in the transient instability operation data through an integral gradient algorithm; determining an adjustment strategy for the initial active power of each generator based on the sensitivity; according to the invention, a feasible solution is provided for monitoring of the stability situation of the power system and control decision after instability, the safe and stable operation capability of the power system is further improved, and support is provided for preventing large-scale accidents of a power grid.

The invention provides an electric power system transient stability analysis method and device based on supervised comparative learning. The method comprises the following steps: grouping operation data of a to-be-analyzed electric power system according to physical attributes; each group of operation data obtained through grouping is input into a corresponding encoder of a Transform architecture for feature extraction, feature vectors of each group of operation data output by each encoder are obtained, and each encoder of the Transform architecture is obtained through training of a supervised contrast learning algorithm; and performing feature splicing on the feature vectors, and inputting the feature vectors into the decoder to obtain a transient stability analysis result of the to-be-analyzed power system output by the decoder. According to the method, the transient stability analysis model is optimized through the multi-channel feature extraction framework and the supervised contrast learning method, so that the learning ability, the expression ability and the generalization ability of the transient stability analysis model are improved.

The invention discloses a synchronous inverter voltage control method and system based on a minimum boundary, and the method comprises the steps: obtaining the electric data of a synchronous inverter, and constructing an energy function; performing transient stability analysis on a VSG mechanical equation based on the energy function; and controlling the transient stability of the VSG mechanical equation by using a minimum convergence control mode. According to the method, the influence of a damping coefficient on a mechanical equation under VSG control is considered, energy function construction based on a Lyapunov method is improved, and a solving method for critical energy Vcr and transient energy Vcl at the fault clearing moment is improved. Compared with a traditional Lyapunov energy function, the conservative property of the new method is reduced, and the transient voltage stability of the grid-connected inverter under the VSG control strategy is effectively improved.

The invention relates to a multi-mode seamless switching control method of a PCS energy storage converter and related equipment, and the method comprises the following steps: collecting the current operation state parameters of the PCS energy storage converter; obtaining a potential switching mode corresponding to a mode switching trigger condition based on a matching relationship between the current operation state parameter and the preset mode switching trigger condition; performing transient stability analysis on the PCS energy storage converter based on the potential switching modes to obtain a transient response characteristic curve of each potential switching mode; performing priority ranking on the potential switching modes based on the transient response characteristic curve to obtain a switching priority sequence; and performing multi-mode seamless switching control on the PCS energy storage converter on the basis of the switching priority sequence, thereby solving the technical problem that in a multi-mode PCS control strategy, dynamic sensing and analysis capability for a real-time operation state is lacked, so that a switching decision is lagged or misjudged.

The invention relates to the technical field of power system safety assessment, and discloses an optical storage and charging micro-grid power distribution network safety assessment method, system and device based on continuous loading capacity assessment and a medium, and the method comprises the steps: building a probability distribution model of an optical storage and charging micro-grid through data preprocessing; calculating a continuous loading capacity index considering the time sequence characteristics; establishing a power flow model of the power distribution network, and performing voltage, thermal and transient stability analysis; carrying out probability safety evaluation by adopting Monte Carlo simulation; and optimizing the acceptance capability of the optical storage and charging micro-grid based on the security constraint. Accurate and efficient evaluation of the safety level of the power distribution network is achieved, and effective technical support is provided for safe operation of the power distribution network under high-proportion new energy access.

The invention relates to the technical field of electric power system transient state analysis, in particular to a double-high-characteristic electric power transient state stability analysis method, system and device and a medium. The nonlinear part of the model is limited in an adjustable neighborhood of a given balance point so as to construct a Lyapunov function; the estimation of a Lyapunov function time derivative is improved by introducing a non-uniform limiting condition, and the conservative property is reduced; meanwhile, the construction of the Lyapunov function and the lower limit estimation of the fault clearing time are subjected to collaborative optimization, so that more accurate fault clearing time estimation is obtained; according to the method, the optimal Lyapunov function and parameters are solved by using the semi-definite programming problem, the method effectively adapts to the complex dynamic characteristics of high-proportion renewable energy and power electronic equipment, and the transient stability analysis precision and reliability of a power system are improved.

The invention discloses a power grid stability risk boundary generation method based on a large model. The power grid stability risk boundary generation method can dynamically simulate the recovery process of a power grid under load fluctuation or fault disturbance. By introducing transient stability analysis, the recovery time of the power grid after load fluctuation or disturbance can be accurately calculated, and the time boundary of system recovery is provided. When a fault or load fluctuation occurs, the power grid can rapidly recover stable operation, and a long-time unstable state is avoided. In addition, the maximum stable load, the minimum safe load and the overload threshold value are calculated. According to the method, the recovery capability and the stability risk boundary of the power grid can be rapidly calculated, and accurate real-time data support is provided for power grid dispatching and optimization. Compared with the traditional transient stability analysis, the calculation method provided by the invention has lower calculation cost, can update the stability risk boundary of the power grid in real time, and remarkably improves the dispatching and operation efficiency of the power grid.

The invention relates to the technical field of power grids, and discloses a power system transient stability simulation sample generation method and device, and the method comprises the steps: obtaining initial samples of a power system in different operation scenes, and the initial samples comprise initial feature vectors and transient stability quantitative indexes; extracting a steady-state feature vector and a preset fault vector in the initial feature vector; based on the steady-state feature vector and the transient stability quantitative index, determining a generation sample type of a sample needing to be generated; determining a preset fault type of the sample needing to be generated based on the preset fault vector; inputting the generated sample type and the preset fault type into a preset generator model, and generating a corresponding first transient stability simulation sample; and combining the first transient stability simulation sample with the initial sample to obtain a second transient stability simulation sample. According to the method, the required transient stability simulation sample of the power system can be generated in a targeted manner, and reliable high-quality sample data is provided for transient stability analysis of the system.

The invention provides a method, a system, a medium and equipment for determining the maximum direct current feed-in power of a receiving-end power grid, and relates to the technical field of transient stability analysis of an electric power system.The method for determining the maximum direct current feed-in power of the receiving-end power grid comprises the steps of obtaining a voltage dynamic response parameter after the receiving-end power grid breaks down; according to the voltage dynamic response parameters, whether the transient voltage of each bus of the receiving-end power grid is stable or not is judged; under the condition that the transient voltage of each bus of the receiving-end power grid is determined to be stable, the maximum feed-in power of the receiving-end power grid is determined, the method can flexibly adapt to variable operation conditions, and the applicability is high; and under the condition that the transient voltage of each bus of the receiving-end power grid is determined to be stable, the maximum feed-in power of the receiving-end power grid is calculated, so that a scientific basis is provided for safe dispatching and operation of a power system.

The application discloses a transient stability prevention control measure generation method and a related system, including the following steps: in a predicted fault scenario, a machine learning model is used to predict the transient stability of the current operation mode of a power system, the input of the machine learning model including various electrical characteristics related to the transient stability of the power system; the operation mode predicted as unstable is taken as an explained sample, a model explanation method is used to determine the influence degree of each electrical characteristic in the explained sample on the transient stability; candidate control units are determined according to the influence degree, and the candidate control units are adjusted, and the machine learning model is used to predict the transient stability of the adjusted operation mode until an operation mode predicted as stable is obtained, so that transient stability prevention control measures are generated. The method improves the explainability of the data-driven transient stability analysis model, the overall scheme requires a short time, and is suitable for online application.

The present invention provides a transient stability prevention and control method and device based on an agent model, the method comprising: inputting multiple operating data of an electric power system into a pre-built transient stability analysis model, obtaining transient stability analysis results of each operating data output by the transient stability analysis model, wherein each operating data includes the initial active power of a generator; determining transient instability operating data based on the transient stability analysis results, and calculating the sensitivity of each generator in the transient instability operating data by an integral gradient algorithm; and determining an adjustment strategy for the initial active power of each generator based on the sensitivity; the present invention provides a feasible solution to problems such as monitoring the stability status of the electric power system and control decision-making after instability, further improving the safe and stable operation capability of the electric power system, and providing support for preventing large-scale accidents in the power grid.

The application discloses a network-constructing type VSC transient stability analysis method and system considering internal ring dynamic influence, and comprises the following steps: determining the control system of GFM-VSC, determining active power and virtual power angle based on virtual synchronous power outer ring control; determining port node voltage phase and internal potential amplitude based on the active power and virtual power angle; determining the output current amplitude of GFM-VSC based on the internal potential amplitude and virtual power angle; determining whether the saturation link of GFM-VSC is triggered based on the internal potential amplitude and output current amplitude, and determining the saturation link type when it is determined that the saturation link is triggered; and analyzing the transient stability according to the saturation link type.

The present invention discloses a coupled pendulum mapping model of a grid-connected converter and a transient trajectory characterization method thereof. The present invention aims at transient stability analysis of grid-connected multi-grid converters, maps the power-frequency model of a traditional grid-connected converter to a classical coupled pendulum model, and characterizes the transient trajectory of the state quantity of the grid-connected converter after disturbance through the dynamic motion equation of the coupled pendulum, thereby analyzing the transient stability of the multi-grid-connected converter under large disturbance. The method compares the control model of the grid-connected converter with the motion model of the mechanical pendulum system, innovatively transforms the grid-connected transient stability problem of the grid-connected converter into the motion stability problem of the mechanical system, thereby avoiding the construction of complex Lyapunov functions, and at the same time, the analysis method of the coupled pendulum system can be used in electrical systems, providing new ideas for stability analysis of electrical systems.

The invention discloses a power distribution network state detection method and device and a nonvolatile storage medium. The method comprises the steps that real-time operation information of a target power distribution network is acquired, and the real-time operation information comprises fan real-time generated power, photovoltaic unit real-time generated power and electric vehicle real-time charging data; the real-time operation information is input into a preset target state detection model, a state detection result of the target power distribution network is obtained, the target state detection model is obtained based on training of an initial state detection model, and the initial state detection model is a convolutional neural network model; the state detection result comprises a safety state, a warning state, a general emergency state or a serious emergency state. According to the method, the technical problems that the real-time operation state of the power distribution network is inconvenient to identify and the accuracy is reduced due to the fact that transient stability analysis of the security domain and the stability domain is separated in a traditional method, and the source load fluctuation and the uncertainty thereof cannot be effectively handled are solved.

The invention relates to a power system Lyapunov function construction method, device and equipment based on an induction motor, and the method comprises the steps: obtaining the electric quantity data of all generator sets in a power system, and obtaining the stable balance data of the power system in a stable balance state; performing model construction according to the electrical quantity data to obtain a transient stability analysis model of the power system; converting the transient stability analysis model according to the stability balance data to obtain a power flow equation; obtaining trigonometric function data and state data from the power flow equation; and according to the trigonometric function data, determining whether to construct according to the state data and the trigonometric function data, and obtaining a Lyapunov function of the power system. According to the method, the power flow equation is constructed by acquiring the electrical quantities and the stability balance data of all the generator sets in the power system, and the Lyapunov function for constructing the power system is determined according to the trigonometric function data and the state data of the power flow equation, so that the accuracy and the applicability of function construction are improved.

The application discloses a kind of transient stability analysis method and related device considering current limit, establish the mathematical model of hydropower system and photovoltaic power generation system;In view of the current-limiting control of photovoltaic inverter and flexible rectifier during fault, the equation of active power sent by hydro-generator before fault removal is derived according to Thevenin theorem;The analytical expression of critical removal angle of sending-out system is derived by using equal-area rule;With critical removal angle as the key index of transient stability limit of sending-out system, the influence of photovoltaic and flexible current transformer saturation current angle parameter value and water-light generation ratio on the transient stability of sending-out system is evaluated.The water-light generation ratio setting method involved in the application can effectively improve the transient stability of the system, and the research results are expected to provide certain theoretical guidance for the stable operation of future new energy power system.