40 results about "Network equation" patented technology

The invention discloses a transient optimization control method based on a parallel system of a virtual synchronous machine and a grid-following converter. The method comprises the following steps: 1, constructing a topological structure of the parallel system of the virtual synchronous machine and the grid-following converter; 2, based on the topological structure, establishing a mathematical model of a parallel system, including an active loop equation and a reactive loop equation of a virtual synchronous machine and a phase-locked loop equation of a grid-following converter; 3, constructing an equivalent circuit, a network equation and a transient analysis model of the parallel system based on the mathematical model; 4, on the basis of the equivalent circuit, the network equation and the transient analysis model, determining conditions met by respective balance points of the virtual synchronous machine and the grid-following converter by using a balance point method; and 5, when the power grid has a fault, constructing a transient optimization strategy according to a condition satisfied by the balance point so as to realize transient optimization control of the parallel system. According to the method, the control modes of a virtual synchronous machine power loop and a grid-following type converter phase-locked loop can be improved, so that the transient stability of a parallel system converter is improved.

A low-voltage power distribution network distributed energy storage double-layer optimization method considering distributed power supply access comprises the following steps: constructing a network equation of a distributed power supply and distributed energy storage based on the randomness of distributed power supply output; establishing a double-layer optimization model by considering distributed power supply access and a distributed energy storage configuration strategy; aiming at a distributed power supply and distributed energy storage collaborative double-layer optimization configuration problem, adopting a strategy of combining an improved particle swarm algorithm and a second-order cone-convex relaxation linear programming technology to solve an established double-layer optimization model; and carrying out comprehensive evaluation on the double-layer optimization model based on the distributed power supply and the distributed energy storage. The method can significantly improve the reliability and adaptability of the low-voltage power distribution network system, improve the reliability and flexibility of the low-voltage power distribution network system, ensure effective utilization of local power generation resources and energy storage capability in the low-voltage power distribution network, effectively solve the loss problem caused by access of new energy to the low-voltage power distribution network, and improve the reliability and flexibility of the low-voltage power distribution network system. Economical and stable operation of the low-voltage distribution network is realized.

The invention discloses a transient stability control method and system for a power system with equilibrium point continuation after disturbance, and the method comprises the steps: firstly building a steady-state mathematical expression of each dynamic element, and constructing a solving model of a system equilibrium point in combination with a power network equation; then, a homotopy method is introduced, homotopy parameter values at saddle node bifurcation points are solved, and whether balance points still exist in the system or not is judged; and for the condition of system instability, further deriving the sensitivity of the fault parameter of the homotopy curve at the saddle node bifurcation point to each control variable, and optimizing the adjustment strategy of the adjustable parameter in combination with the sensitivity and the control cost. Through a systematic search method, the optimal control scheme with the lowest cost is determined on the premise that the stability margin is met, and therefore the economical efficiency and effectiveness of control measures are improved. The optimization adjustment direction of each adjustable parameter can be accurately identified, the effectiveness of a control scheme is ensured, and accurate operation is provided for stability recovery of a power system.

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 present invention discloses a method and system for calculating the impact of transient power angle stability based on energy deviation rate. The method includes determining the energy balance fulcrum of the power grid corresponding to each simulation time point after a preset disturbance; for each simulation time point, dividing the nodes in the network equation into two node sets with the energy balance fulcrum as the boundary, and determining the leading or lagging attribute of the node set based on the rotor inertia center angle of the synchronous generator associated with the nodes in the two node sets; determining the time period for calculating the impact of transient power angle stability based on the relative rotor inertia center angle between the leading node set and the lagging node set after the disturbance; calculating the energy deviation rate of the device connected to the grid through each node during the time period based on the grid-connected active power of the device through the connected nodes and the node set attributes at the simulation time point, and taking the sum of the energy deviation rates of the device connected to the grid through each connected node as the impact of the device on the transient power angle stability of the power grid after the disturbance. A corresponding system is also disclosed. The present invention provides an optimization direction for transient power angle stability control decision calculation.

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.

The invention relates to the technical field of visible light communication systems, in particular to a visible light communication system modeling method and system discovered by adopting a neural network equation. The method comprises the following steps: acquiring a sending code element, and acquiring a real receiving code element from the sending code element through a visible light communication model; inputting the sending code element into a neural network to obtain a predicted receiving code element, and calculating a data error according to a predicted receiving code and a real receiving code element; constructing a candidate symbol library according to the sending code element and the predicted receiving code element; constructing a differential transfer function comprising a weighting coefficient according to the predicted receiving code element and the candidate symbol library, and calculating transfer loss; introducing regularization constraint loss based on a differential transfer function; calculating the total loss according to the data error, the transmission loss and the regularization constraint loss; optimizing neural network parameters and weighting coefficients until the total loss is converged; according to the method, the system can be modeled under relatively high precision.

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 invention discloses an electric power system transient state frequency stability influence degree calculation method comprising the following steps: determining an influence degree calculation time period according to an equipment active frequency dynamic response time scale; determining a dominant time point set of each node according to the node frequency of each time point in the time period; non-empty nodes in the dominant time point set are incorporated into a dominant node set; for each node in the dominant node set, calculating the active sensitivity of each time point node to a branch connected with the node according to a network equation corresponding to each time point in the node dominant time point set, and calculating the active sensitivity of each time point node to the branch connected with the node according to the frequency of the node at each time point in the dominant time point set and the active sensitivity of the node to the branch connected with the node; calculating the transient frequency stability influence degree of the node in the time period on the node; calculating the transient frequency stability influence degree of the nodes in the time period on the power grid according to the transient frequency stability influence degree of the nodes in the dominant node set in the time period; meanwhile, the invention discloses a corresponding system. The method provides an optimization direction for transient frequency stability control decision calculation.

The embodiment of the invention provides a seismic data regularization method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring actual seismic data acquired by an exploration data observation system, the data comprising actual shot point coordinates and travel time data in the exploration data observation system, acquiring coordinates of a target shot point input by a user, constructing a travel time neural network and a speed neural network according to the actual shot point coordinates and the travel time data, and calculating the speed of the target shot point according to the travel time neural network and the speed neural network. A travel time neural network and a speed neural network are established, a travel function equation guidance-based neural network equation is constructed, the travel function equation is used for connecting the travel time neural network and the speed neural network, and according to the travel function equation guidance-based neural network, the actual shot point coordinates and travel time data are input, and neural network training is performed to obtain a trained travel time network and a trained speed network; and according to the trained travel time network, inputting coordinates of a target shot point to obtain travel time data of the target shot point. According to the method, the regularization of the seismic travel time data is realized, and the accuracy of data processing is ensured.

The present invention discloses a method and system for solving the low-rank update of the power system network equation, which relates to the technical field of power systems. By obtaining the node operation data of the power system, the node operation data is used to construct the power system network equation to generate the power system network equation; the nodal admittance matrix in the power system network equation is subjected to hierarchical non-diagonal block low-rank decomposition to construct a left low-rank basis large matrix; based on the left low-rank basis large matrix, the nodal admittance matrix is decomposed to construct a target nodal admittance large matrix; based on the target nodal admittance large matrix, the low-rank solution of the power system network equation is performed to generate the solution data of the power system. The present invention performs low-rank update and solution on the power system network equation based on the hierarchical non-diagonal low-rank structure, and can only update the changed part instead of recalculating the entire system when the parameters or structure of the power system change, and can quickly adapt and reduce the consumption of computing resources, thereby significantly improving the computing efficiency.

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 present application provides a method for transient simulation of a power system based on virtual admittance, comprising: obtaining the node voltage and phase angle value of each dynamic element in the power system to be simulated at the current moment; calculating the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element, and calculating the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element; using the virtual admittance matrix to correct the network equation of the current time step to obtain a new network equation; using the new network equation to perform transient simulation of the power system at the current time step until the simulation convergence condition is met. The simulation method proposed in the present invention uses a virtual admittance matrix to correct the network equation of the system, thereby improving the convergence of transient simulation. In particular, for systems with new energy grid connection, it can achieve equivalent transformation of the whole system simulation model with the goal of improving convergence, thereby solving the problem of non-convergence of simulation.

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.

The present invention discloses a method and system for predicting voltage phase jumps in a receiving-end power grid of an asynchronous interconnected system, relating to the field of electric power engineering technology. A network equation is established based on the composition structure, distribution characteristics, and transient characteristics of the receiving-end power grid components of the asynchronous interconnected system to accurately reflect the electrical behavior of the commutation bus phase of the asynchronous interconnected system under different fault conditions. Based on the network equation of the receiving-end power grid of the asynchronous interconnected system, an equivalent model of a single-feed AC / DC system before and after the fault is obtained. The equivalent power supply voltage and impedance of the receiving-end power grid before and after the fault, as well as the mutual impedance change between nodes after the fault, are solved. Finally, based on the phase relationship of the equivalent model of the single-feed AC / DC system before and after the fault, the phase jump of the commutation bus voltage of the receiving-end power grid is calculated. This solves the problem in the prior art that the quantification method for phase jumps is not accurate enough or cannot reflect the dynamic characteristics of phase changes, thereby providing a strong basis for system fault analysis, state monitoring, and dynamic scheduling.

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 invention discloses a method, a system and equipment for calculating the influence degree of grid-connected equipment on transient frequency stability of a power system, and a medium. The method comprises the following steps: determining a network equation, node frequency and active power data of the grid-connected equipment during a transient period through primary time domain simulation; for each time point, calculating the sensitivity of the active power of the grid-connected equipment to the active power of a branch connected with an inflow node according to a network equation; according to the node frequency, the active power of the grid-connected equipment and the sensitivity, calculating the influence degree of the grid-connected equipment on the transient frequency stability of the node; and summarizing the transient frequency stability influence degrees of the grid-connected equipment on all the nodes to obtain the transient frequency stability influence degree of the grid-connected equipment on the power system. According to the method, the influence of all the grid-connected devices on the transient frequency stability of the power system in different time periods can be evaluated only through one-time simulation, a decision basis is provided for optimization control of the grid-connected devices, and the calculation efficiency is improved.

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 a method for obtaining electromagnetic parameters of a magnetic saturation type controllable reactor, and the method specifically comprises the steps: 1, carrying out the grid division of a solution domain of an MSCR, dividing the solution domain into a plurality of grid units, enabling each grid unit to be a magnetic path segment, and obtaining the magnetic resistance of the corresponding magnetic path segment through employing a magnetic flux tube equivalent magnetic path segment; step 2, obtaining a two-dimensional equivalent magnetic network model of the MSCR on the basis of the step 1; 3, acquiring an equivalent magnetic network matrix; 4, constructing an electromagnetic coupling model of the MSCR; and 5, establishing a loop voltage equation set of the MSCR electromagnetic coupling model, obtaining an MSCR electromagnetic network equation set by combining the equivalent magnetic network matrix, and obtaining the working current and magnetic flux of the MSCR according to the MSCR electromagnetic network equation set. According to the method, the problems that in the prior art, when a finite element model is used for parameter acquisition, the requirement for computer resource performance is high and consumed time is long due to the fact that the model is too complex are solved.

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 present application discloses a partitioning and solving method for improving the calculation efficiency of the network equation of a power system. The method includes: constructing a network equation and a directed unweighted graph of the power system; generating an adjacency matrix according to the relationship between nodes in the directed unweighted graph; constructing an objective function based on the adjacency matrix with the goal of minimizing the number of edges used to partition the power system, optimizing and solving the objective function to obtain two node sets and a cut set after partitioning; partitioning each of the partitioned node sets, and generating a clustering tree according to each partitioned node set; traversing each layer in the clustering tree, and using a hierarchical non-diagonal low-rank algorithm to solve the network equation; wherein, parallel computing is performed on the node sets of each layer in the clustering tree. The present application solves the technical problem of low calculation efficiency existing in the prior art.