26 results about "Network equation" patented technology

The invention belongs to the field of short-circuit current calculation, and discloses a fault analysis method based on a power network equation and a related system.Unified modeling of the overall structure of a power system is achieved by obtaining bus information of the power system and constructing a system topological relation model, and the fault analysis accuracy is improved. The adaptation difficulty caused by different system scales and different wiring modes is avoided, and the universality and the expandability of the method are improved; according to the method, an automatic processing mechanism is introduced into the calculation and decomposition of the admittance matrix, so that the positive sequence admittance matrix, the negative sequence admittance matrix and the zero sequence admittance matrix of the power system can be quickly obtained, manual derivation and gradual simplification processes are reduced, the probability of analysis errors is reduced, and the stability of a calculation result is improved; a three-sequence network equation is uniformly adopted in fault calculation to solve a framework, and a direct coupling relation between an admittance matrix and a short circuit operation condition is utilized, so that key to-be-solved quantities such as fault current and voltage can be quickly and accurately obtained, the calculation process is remarkably shortened, and the analysis efficiency is improved.

The invention relates to the technical field of electromagnetic transient simulation, in particular to an electromagnetic transient simulation decoupling method, system and device based on a single-impedance branch and a medium, and the method comprises the steps: dividing a system to be simulated into two subsystems which are connected through the single-impedance branch, and carrying out the equivalent reconstruction to form a reconstructed branch model; establishing a discrete state space equation based on the reconstructed branch model; according to the main step length, the number of sub-steps meeting the stability condition is determined based on a small-step synthesis algorithm, and the main step length is equally divided into differential step lengths; in each main step length interval, performing iterative calculation on the state-space equation by using a differential step length to obtain a branch current and a capacitor voltage at the next moment; and injecting the calculated branch current serving as a known current source into an original network equation, solving in parallel to obtain the port voltage of the subsystem, and completing decoupling calculation and promoting simulation. According to the method, effective decoupling of the universal single-impedance branch can be realized, and the applicability, the numerical stability and the calculation efficiency of parallel simulation are improved.

This invention discloses a method and apparatus for calculating the three-phase asymmetrical short-circuit current in a distribution network considering photovoltaic (PV) power. The method includes: before a fault, using power flow calculations to obtain the node voltage and injected current of each node, including the PV node, during normal operation; equating the power source to a current source and the load to an impedance based on Norton's equivalent; calculating the admittance matrix based on an equivalent circuit model after a three-phase asymmetrical short-circuit fault; and constructing a network equation for the PV short-circuit calculation node impedance suitable for Gaussian iteration; simultaneously establishing nonlinear piecewise expressions for the voltage and current of the renewable energy node; and solving for the current and voltage during a renewable energy fault using an iterative method to obtain the fault short-circuit current. By constructing the admittance matrix and corresponding voltage and current expressions for single-phase-to-ground short circuits and two-phase-to-phase short circuits, and using iterative calculations to derive the final result, the accuracy of the calculation is improved.

The invention belongs to the technical field of transient analysis of a new energy grid-connected system, and particularly relates to a transient overvoltage analysis method of a direct-driven wind power grid-connected system under an asymmetric fault, which comprises the following steps: acquiring three-phase asymmetric voltage and current, and constructing a positive and negative sequence dq control model of positive and negative sequence bisynchronization of a direct-driven wind power plant station; establishing a mapping relation with a symmetric component method, and determining a positive-sequence dynamic reactive current increment and a negative-sequence current suppression coefficient according to a converter control strategy; establishing sequence network boundary conditions under various asymmetric faults; enabling the direct-driven wind power plant to be equivalent to a frequency-related controlled sequence impedance source, and obtaining equivalent sequence impedance of the wind power plant; establishing a sequence network equation considering wind power dynamic support; calculating the current and sequence voltage of the fault point, and obtaining a three-phase voltage through symmetric component inverse transformation; and an overvoltage coefficient is calculated, and a quantitative relational expression between the overvoltage coefficient and the negative-sequence current suppression coefficient is established and applied. The method provides theoretical support for parameter setting and capacity planning of the wind power integration system.

The invention discloses a parallel solving method and system for a system of linear equations of an electric power system based on a Woodbury theory, and belongs to the technical field of large-scale electric power system computation.The method comprises the steps that a coefficient matrix of a network equation of the electric power system is obtained and subjected to block representation; performing truncated singular value decomposition on the non-diagonal block coupling matrix, and realizing low-rank decomposition through an Arnoldi iterative algorithm; carrying out inversion on the coefficient matrix based on a Woodbury matrix identical equation, and carrying out parallel calculation on each block sub-matrix and an intermediate variable; and solving the system of linear equations by using the inversed matrix. According to the method, the low-rank characteristic and parallel computing advantages of the inter-region coupling matrix of the power system are fully utilized, the solving efficiency of the large-scale linear equation set is remarkably improved, and the method is suitable for transient analysis, real-time simulation and other high-performance computing scenes of the power system.

This invention discloses an integrable short-circuit current constraint modeling method and apparatus for power systems. The method constructs a Norton equivalent circuit model by acquiring the electromotive force and subtransient reactance parameters of the synchronous generator before a fault. Through a multi-dimensional constraint transformation strategy, the nonlinear control logic of the inverter power supply is transformed into mixed-integer constraints to obtain the inverter power supply injection current constraint. Based on the node current injection information of the synchronous generator and the inverter power supply injection current constraint, a node admittance matrix of the power system is constructed. Based on the node admittance matrix, network equation constraints of the power system are constructed. The Norton equivalent circuit model, mixed-integer constraints, and network equation constraints are integrated to construct and solve a mixed-integer quadratic constraint optimization model to obtain the short-circuit current value required for power system optimization. This invention solves the problems of mismatched nonlinear control characteristics of high-proportion IBGs and the difficulty of directly embedding existing fault current iterative solvers into upper-level optimization.

The application discloses a fast calculation method and system of a reconfigurable battery network state quantity under time-varying working conditions, and the method comprises the following steps: modeling a reconfigurable battery network topology based on a directed graph to generate a node correlation matrix; determining the voltage-current relationship of a preset working condition battery branch based on a preset battery model and a Norton equivalent circuit; determining the voltage-current relationship of a switch branch according to a preset working condition; obtaining a preset working condition node admittance matrix according to the node correlation matrix, the voltage-current relationship of the preset working condition battery branch and the switch branch, and establishing a network equation to solve the state quantity of the reconfigurable battery network under the preset working condition; judging whether the node admittance matrix needs to be updated according to the current working condition change based on a preset reconfiguration period; if the current working condition changes, updating the node admittance matrix to obtain a corresponding modified network equation, and solving the equation to obtain the state quantity of the reconfigurable battery network under the current working condition. The application has strong universality, considers the accuracy and the calculation cost, and meets the real-time requirement.

This invention discloses a method, apparatus, electronic device, and storage medium for determining node voltages in an electromechanical transient network containing an infinite bus, belonging to the field of power system electromechanical transient simulation technology. The method includes: obtaining the node admittance matrix of the power system to be simulated and the injected current of each grid-connected device except the infinite bus; solving the equivalent impedance matrix based on the node admittance matrix to obtain the self-impedance of the infinite bus and its mutual impedance with each node; calculating the total equivalent voltage drop formed at the infinite bus by each grid-connected device in conjunction with its injected current and corresponding mutual impedance; deriving the injected current of the infinite bus based on the infinite bus voltage phasor, self-impedance, and total voltage drop; and substituting the injected current of the infinite bus and the injected currents of other grid-connected devices into the node admittance matrix to solve the network equations to obtain the voltages of each node. The implementation of this invention can solve the problem of network node voltages deviating from preset standards during transient processes in existing technologies.

The invention discloses a high-proportion photovoltaic access rural power distribution network voltage stability analysis method and system, and the method comprises the following steps: collecting the voltage, current and power of a power generation bus and a load bus, and the node admittance matrix data of a network, and building a network equation through a constant power load model; solving a network equation, and then separating a real part and an imaginary part of the load bus voltage; calculating a partial derivative of the voltage amplitude equation relative to the load bus voltage and the power generation bus voltage, then determining the partial derivative through solving, and obtaining a result of a Jacobian matrix; and deducing a V-Q sensitivity result based on a load bus voltage amplitude equation by using a chain rule. The method does not need to directly depend on a power flow equation, reduces the dependence on a specific balanced operation state, can still obtain a more accurate voltage stability analysis result through the improved method even under the complex condition that the power flow equation is difficult to converge, and provides a reliable basis for subsequent decision making.

The invention provides a mathematical modeling method and system for a straddle-type monorail direct-current traction power supply system, and relates to the field of simulation calculation of an urban rail transit direct-current traction power supply technology, and the method comprises the steps: obtaining basic data of a target straddle-type monorail direct-current traction power supply system, and carrying out the segmentation processing of the basic data, calculating the node number according to the mileage of the traction substation to obtain a substation-node mapping relation; calculating the node number according to the mileage of the traction load to obtain a load-node mapping relation; establishing a node admittance network equation and a node current vector according to the node-branch set, the substation-node mapping relation and the load-node mapping relation; and generating a node admittance matrix according to the node admittance network equation to obtain a whole-line node voltage and branch current distribution result. According to the invention, the ground insulation resistance of each conductor in the direct current traction power supply system is introduced, so that the mathematical model is more in line with the real situation of the direct current traction power supply system of the straddle type monorail traffic.

The application discloses a general electromagnetic transient simulation decoupling method and system for asynchronous motor load, comprising the following steps: determining a single-phase simplified equivalent circuit of an asynchronous motor decoupling model; obtaining an asynchronous motor load-grid electromagnetic transient simulation interface through the single-phase simplified equivalent circuit; and based on the asynchronous motor load-grid electromagnetic transient simulation interface and a d-q model, performing electromagnetic transient simulation on the asynchronous motor load, so that the problem of too many iteration times of full-network equation solving of electromagnetic transient simulation of a power system containing a large number of asynchronous motor loads is solved, and the problems of low simulation efficiency and poor interface numerical stability are solved.

This invention discloses a nationwide integrated power balance method. First, a nationwide integrated balance mathematical model is constructed. Based on this model, the integrated balance network equations characterizing network structural constraints are derived. Second, based on the network equations, a new type of key balance objective for the power system is introduced, deriving an integrated balance dynamic equation consisting of four process forms: natural mutual support for supply guarantee, mutual support for supply guarantee and start-up, natural mutual support for absorption, and mutual support for absorption and start-up. Then, engineering boundary conditions are substituted into the integrated balance dynamic equations, deriving nine integrated balance configurations for engineering practice to achieve nationwide integrated power balance. The new power system integrated balance model and mechanism proposed in this invention effectively solve the fundamental principle problem of nationwide integrated balance. By proposing a basic model for integrated balance engineering practice and eight sub-configurations, the problem of diverse engineering practice scenarios and multiple objectives is effectively addressed.

The invention discloses a short-circuit fault analysis method, device and equipment for a multi-terminal flexible DC system and a storage medium, and the method comprises the steps: determining a node admittance matrix and a node voltage amplitude of the normal operation of the system; applying a short-circuit fault to the system, and correcting a node admittance matrix; performing sequence component transformation on the node voltage phasor and the node current phasor after the short-circuit fault, and constructing a sequence network equation; determining an optimal solution of a node voltage phasor and a node current vector after the short-circuit fault based on the optimal solution of the sequence network equation, taking the optimal solution as an initial value, and determining the optimal solution of the node voltage phasor and the node current vector after the short-circuit fault through a state estimation algorithm; and analyzing the short-circuit fault based on the corrected node admittance matrix, the node voltage amplitude in normal operation and the optimal solution, so that the short-circuit fault can be accurately analyzed, a powerful basis is provided for timely processing of the fault and formulation of a system protection strategy, and improvement of the reliability and stability of the system is facilitated.

Embodiments of the present application provide a seismic data regularization method and device, electronic equipment and storage medium; the method comprises: acquiring actual seismic data collected by an exploration data observation system, the data comprising actual shotpoint coordinates and travel time data in the exploration data observation system, acquiring coordinates of a target shotpoint input by a user, constructing a travel time neural network and a velocity neural network according to the actual shotpoint coordinates and the travel time data, and constructing a neural network equation guided based on an eikonal equation, wherein the eikonal equation is used to link the travel time neural network and the velocity neural network, inputting the actual shotpoint coordinates and the travel time data into the neural network equation guided based on the eikonal equation, and performing neural network training to obtain trained travel time and velocity networks; and inputting the coordinates of the target shotpoint into the trained travel time network to obtain travel time data of the target shotpoint. The method realizes regularization of seismic travel time data and ensures accuracy of data processing.

The application relates to a multi-terminal mixed connection extra-high voltage direct current engineering main loop parameter calculation method and system, which comprises the following steps: on the basis of a network equation of traditional port direct current voltage and direct current, a multi-terminal direct current system network matrix related to valve group port voltage and direct current of each mixed connection converter station in different operation conditions is obtained through matrix transformation; an N-order matrix normalization method is adopted, the multi-terminal direct current system network matrix is solved according to different control modes and in combination with a Newton-Raphson method, direct current parameters under the multi-control mode are obtained; based on the direct current parameters, the position of a converter transformer tap is solved by given triggering and turn-off angles, and converter parameters are calculated. The main loop parameter calculation speed is relatively fast, and the calculation result is high in accuracy.

The invention discloses an electric power system saddle node bifurcation point solving method based on a hybrid estimation-correction and secant method, and belongs to the technical field of electric power system stability analysis. The method comprises the following steps: establishing an extended power flow equation set; obtaining an effective initial value through a pre-estimation-correction method; dynamically processing a network equation for a line fault scene; judging a bifurcation point interval based on the linear relation and the sensitivity; and combining a secant method with self-adaptive step length control to realize accurate positioning of the bifurcation point. According to the method, the defect that the numerical value is unstable near the bifurcation point in the traditional method is overcome, the calculation efficiency and robustness are improved, the method is suitable for a complex power system containing faults and new energy, and effective support is provided for stability analysis.

The application belongs to the technical field of new energy grid-connected system transient analysis, and particularly relates to a kind of direct-drive wind power grid-connected system transient overvoltage analysis method under asymmetric fault, comprising: obtaining three-phase asymmetric voltage and current, constructing positive and negative sequence double-synchronous positive and negative sequence dq control model of direct-drive wind power station;Establish the mapping relationship with symmetric component method and determine the positive sequence dynamic reactive current increment and negative sequence current suppression coefficient according to the converter control strategy;Establish the sequence network boundary condition under a variety of asymmetric faults;Equivalent direct-drive wind power station to frequency-dependent controlled sequence impedance source, obtain the equivalent sequence impedance of wind farm;Establish the sequence network equation considering wind power dynamic support;Calculate the current and sequence voltage of fault point and obtain three-phase voltage through symmetric component inverse transformation;Calculate the overvoltage coefficient and establish the quantitative relationship between overvoltage coefficient and negative sequence current suppression coefficient and apply it.The application provides theoretical support for parameter setting and capacity planning of wind power grid-connected system.

The invention discloses a fault positioning method and system, and belongs to the technical field of new energy direct current power distribution network control and protection. The method comprises the following steps: injecting a double-frequency detection signal through a power electronic direct-current transformer of a sound line after a fault occurs; listing a model fault network equation according to the type of the end equipment of the fault line; collecting head end voltage and current signals, and extracting a real part and an imaginary part to construct a real number equation set; adopting an interior point method to solve and obtain fault parameters; and finally calculating the fault distance. The method effectively solves the problem that in the prior art, fault characteristics are weak due to current limiting of power electronic equipment, and bus faults form a protection dead zone and cannot be accurately positioned, and the fault detection precision and the system recovery capability of the new energy direct current power distribution network are improved.

The invention provides a power system time domain simulation method based on Jacobian matrix adaptive updating. Simulation performance is improved under an alternate solution framework. Firstly, system variables are initialized, and a numerical integration method and a nonlinear algebraic equation set iteration format are determined; in the simulation process, comparing the size relation between the number of iterations of each simulation time step and the updating threshold value of the Jacobian matrix, and judging whether the Jacobian matrix needs to be updated or not; solving a state variable and a network algebraic variable based on a nonlinear algebraic equation set iteration format and a network equation; after the calculation of the current time step is finished, adjusting a jacobian matrix updating threshold according to the actual iteration times of the current time step; and judging whether the end time is reached or not, and selecting to execute the next time step simulation or end the calculation. According to the method, by designing a threshold-driven Jacobian matrix updating strategy, the matrix updating frequency is flexibly adjusted, the calculation speed is increased while convergence is guaranteed, and the simulation performance requirement of a power system can be met.

The invention discloses a bearing transient temperature field calculation method considering lubricating oil circulation flow, and relates to the field of bearing temperature field simulation. An original thermal grid model simplifies lubricating oil and a lubricating system, so that the model obviously underestimates the thermal inertia of a bearing system, and the accuracy of temperature field calculation is influenced. The method comprises the following steps of: 1, forming a bearing lubricating system by an oil tank, a bearing and an oil collecting device, marking each temperature node on the bearing lubricating system, and establishing a bearing transient thermal network equation set according to each temperature node and heat exchange generated by circulating flow of lubricating oil in the bearing lubricating system; and 2, solving the bearing transient thermal network equation set by using a fourth-order Runge-Kutta method, obtaining the temperature of each node, and generating a bearing transient temperature field. The method is used for obtaining the transient temperature field of the bearing.

The application discloses a kind of direct current transmission system model verification method, comprising the following steps: step 1) according to the given AC-DC hybrid power system model, establish the equivalent power grid model for direct current transmission system model verification;Step 2) according to power grid flow state information, initialize transient stability simulation to obtain state variable initial value;Step 3) numerical integration method is used to carry out hybrid simulation to the equivalent power grid model, step 4) using interpolation algorithm keeps the sampling period of online phasor measurement unit and simulation step length synchronous, periodically injects measured data to replace the corresponding value obtained by solving network equation in simulation process;Step 5) compare the AC side power curve with the measured power curve, to evaluate the accuracy of direct current transmission system model.The method supports the transient response after multiple disturbances under different power grid operating conditions, and comprehensively analyzes the dynamic characteristics of AC-DC interconnected system.

The invention belongs to the technical field of passive damping, and discloses a passive damping optimization method, system, equipment and medium for power electronic equipment, and the method comprises the steps: obtaining a passive damping circuit parameter, calculating a grid-connected impedance parameter, generating a modulation network equation, and carrying out the impact analysis of a grid-connected resonance peak; performing denominator materialization on the modulation network equation, solving based on an amplitude-frequency expression to obtain a resonance peak value, and performing power loss comprehensive evaluation; and according to a resonance suppression rule and a comprehensive evaluation result, constructing an optimization function considering resonance peak suppression and power frequency loss, and solving to obtain optimized passive damping branch parameters. According to the method, the influence mechanism of the additional damping on the grid-connected voltage can be clarified, the internal relation of the additional damping branch on the grid-connected current peak suppression and the grid-connected voltage peak suppression is disclosed, the resonance peak suppression effect under the large short-circuit ratio range can be comprehensively considered, and the application range of passive damping parameter design is widened.

The application discloses a kind of grid-connected equipment influence degree calculation method and system to power system transient voltage stability, it is related to power system safety and stability analysis field, method includes: by primary time domain simulation obtains network equation during transient, node voltage and the active and reactive power data of grid-connected equipment;For each time point, using network equation calculates the sensitivity of grid-connected equipment power to node voltage;According to node voltage, grid-connected equipment power and sensitivity, the influence degree of grid-connected equipment to node transient voltage stability is calculated;The transient voltage stability influence degree of each grid-connected equipment to all nodes is summarized, and the transient voltage stability influence degree of grid-connected equipment to power system is obtained.The application only needs to evaluate the influence of all grid-connected equipment on the transient voltage stability of power system in different time periods by one simulation, provides decision basis for the optimization control of grid-connected equipment, and improves the calculation efficiency.

The invention discloses a direct-current traction power supply system load flow calculation method based on a ground feedback device, and the method comprises the steps: reading a data file at a t moment, and sorting all-line nodes; based on the first basic configuration parameters, establishing a first equivalent model of the rectifier substation; acquiring a second equivalent model of the ground feedback device based on the second basic configuration parameter according to the working condition of the ground feedback device; and generating a node admittance network equation, performing load flow calculation of the direct-current traction power supply system, and outputting a load flow calculation result of the direct-current traction power supply system at the t moment. According to the load flow calculation method for the direct-current traction power supply system, the operation characteristics and the limiting working condition of the ground feedback device are fully considered, the method can adapt to the engineering scene where the current ground feedback device is widely applied, and the method has high engineering guidance value and practical significance.

The invention relates to the technical field of wind power generation control, and discloses a temperature monitoring method for an electric control system of a wind turbine generator, which comprises the following steps of: 1, dividing physical partitions according to physical space distribution of internal components of an electric control cabinet, and constructing an equivalent thermal network equation of a thermal network node corresponding to each physical partition by utilizing an energy conservation law, determining a heat propagation topology constraint relationship among the heat network nodes; and 2, constructing a sensor health evaluation model on the basis of the thermal propagation topological constraint relationship, and quantifying the data credibility score of each monitoring source by deconstructing the original data of the sensor into a real temperature component, a physical drift deviation component and a random noise component. By adopting the technical scheme of coupling the physical topology constraint and the information health model, the technical effect of separating hardware deviation from real temperature in real time is achieved, high-precision monitoring in a sensor degradation environment is realized, and the problem of false alarm or missing alarm caused by physical drift of the sensor is solved.