674 results about "Virtual impedance" patented technology

The invention discloses a power grid power flow risk control method based on topology analysis, and relates to the technical field of power flow risk control, and the method comprises the following steps: obtaining first data of a power grid in real time, and constructing a node admittance matrix; when a switch displacement signal or distributed power supply power mutation is detected, topology reconstruction is carried out based on a node admittance matrix, and a dynamic topological graph is generated; establishing a fault current characteristic matrix based on the dynamic topological graph in combination with the bidirectional power flow characteristics of the active power grid; establishing an adaptive risk early warning model based on the dynamic topological graph and the fault current characteristic matrix, and outputting the overload probability and the voltage out-of-limit risk index of each branch; and performing analysis according to the branch overload probability and the voltage out-of-limit risk index, and generating a multi-target optimization control instruction set. Through adaptive topology adjustment, load flow calculation and a risk early warning model, automatic power grid optimization control can be realized, and in combination with convergence verification of a virtual impedance observer, effectiveness of topology adjustment and control operation is ensured.

The invention discloses a network construction type VSG output power decoupling method based on voltage signal composite feedforward, relates to the technical field of power electronic control, and provides a network construction type converter grid-connected system and a method for realizing converter output power decoupling through converter output voltage signal composite feedforward for network construction type VSG power synchronous control. Comprising a network construction type VSG power control module, a power grid parameter detection unit, a line impedance observer, a virtual impedance voltage drop feedforward loop and a voltage signal secondary feedforward loop. According to the composite feed-forward control strategy, virtual impedance and voltage amplitude and power angle compensation are combined, the coupling effect of active power and reactive power is remarkably weakened, efficient decoupling is achieved, and the method is suitable for a complex power grid environment.

The invention discloses an energy storage system real-time diagnosis and networking control method and system based on digital twinning and deep learning, and the method comprises the steps: collecting the electrical, thermal and aging state data of an energy storage battery cluster through a multi-mode sensor, constructing a multi-physics field coupled digital twinborn model by using a graph neural network and a long short-term memory network; performing synchronous mapping on battery cluster operation data acquired in real time and the digital twinborn model to generate a state evolution sequence in the battery cluster with advanced prediction capability; based on the state evolution sequence, predicting a dynamic stability boundary of the key node of the power grid and a possible instability risk time period in the future; and according to the dynamic stability boundary and the instability risk time period, generating a cooperative adjustment instruction of the output voltage amplitude, the phase and the virtual impedance of the network construction type energy storage equipment. According to the embodiment of the invention, the diagnosis reliability, the control foresight and the operation safety of the energy storage system in a complex power grid environment can be improved.

The invention relates to the technical field of resonance suppression, and discloses an active damping control LC resonance suppression method and device. The method comprises the following steps: performing parameter identification processing based on bus voltage to obtain an inductance value, a capacitance value and a resonance frequency of an LC circuit; extracting a resonant current component of the current signal based on the resonant frequency; calculating damping power according to the resonance current component, and converting the damping power into a voltage compensation instruction under an alpha-beta coordinate system; generating a PWM control signal according to the voltage compensation instruction and a voltage reference instruction; and performing on-off control on the inverter based on the PWM control signal, and injecting power opposite to the resonant current component into the LC circuit to generate a virtual damping effect. Virtual impedance characteristics are seamlessly integrated into inverter control, rapid response of the whole process from resonance detection to power injection is ensured, the resonance peak value is effectively suppressed, and the current quality is improved.

The invention provides a GFM converter fault ride-through control method and system. According to the method, when the voltage drop of a power grid is detected, the power angle stability and the voltage supporting capability during a fault period are enhanced by adaptively adjusting active and reactive power reference values; meanwhile, when the output current exceeds a set threshold value, the virtual resistor and the reactance are dynamically injected, the transient impact current is rapidly suppressed, and dual limitation on the fault current is achieved. The control system comprises a voltage and current acquisition unit, a fault detection module, a self-adaptive power instruction control module, a dynamic virtual impedance control module and an instruction generation module, and all the modules operate cooperatively to form a complete closed-loop control structure. According to the method, the operation stability and the power grid supporting capacity of the GFM converter in weak power grid and fault scenes can be improved, and the requirements of power grid specifications such as GC0137 and the like are met.

The invention discloses a power grid cross-correlation harmonic suppression method, device and equipment and a storage medium, and the method comprises the steps: carrying out the wavelet packet decomposition of a subnet electric signal, and obtaining the harmonic component of a subnet at each frequency band; calculating the harmonic phase difference between the subnets according to the cross-correlation function between the harmonic components of the subnets and the topological impedance matrix, and calculating the total harmonic distortion rate according to the harmonic components of the subnets in the frequency bands; constructing a harmonic transfer equation according to the harmonic phase difference between the subnets and the equivalent output impedance of the inverter so as to calculate the harmonic responsibility proportion of the subnets; solving the double-layer game model based on the total harmonic distortion rate, the reference value of the total harmonic distortion rate and the harmonic responsibility proportion of the subnet, and obtaining the output of the governance equipment; and inputting the output of the treatment equipment into the fuzzy controller to obtain the impedance adjusting quantity of the subnet, and adjusting the virtual impedance according to the impedance adjusting quantity to update the harmonic backflow path. According to the invention, harmonic suppression among multiple subgrids during high-permeability distributed grid connection is realized, and the operation stability of the power grid is improved.

The invention provides a fault ride-through control method and system for a network-forming converter, and relates to the technical field of power electronics. The fault ride-through control method of the network construction type converter comprises the following steps: determining a real-time virtual impedance value corresponding to a control loop based on a virtual admittance control module; in response to the fact that the real-time virtual impedance value is larger than or equal to the reference virtual impedance value of the control loop, transient current output by the network-building type converter is adjusted based on first-stage current limiting, and steady-state current output by the network-building type converter is adjusted based on second-stage current limiting; calculating an active power proportionality coefficient based on the real-time parameter and the reference parameter; calculating a target active power reference value according to the active power proportionality coefficient and the reference active power reference value; and executing power control based on the target active power reference value, and adjusting the output voltage of the network-forming converter. According to the method, when the power grid breaks down, the grid-forming type converter can have the functions of current limiting and transient synchronization stability improving at the same time.

The invention discloses a lithium battery internal short circuit diagnosis method and system based on impedance spectroscopy analysis, and relates to the technical field of lithium battery short circuit diagnosis, and the method comprises the steps: building a standard impedance spectroscopy library based on the identification identity information of a target battery; performing an electrochemical impedance spectrum test on the target battery to obtain a monitoring impedance spectrum; mapping the monitoring impedance spectrum to the standard impedance spectrum library, and judging a spectrum interval of the monitoring impedance spectrum; calculating the offset of the upper adjacent impedance spectrum and the lower adjacent impedance spectrum; calculating to obtain a virtual impedance spectrum; and fusing the virtual impedance spectrum and the monitoring impedance spectrum, extracting an impedance feature set, and carrying out short circuit judgment to obtain a short circuit diagnosis result. The lithium battery internal short circuit diagnosis method solves the technical problem that in the prior art, lithium battery internal short circuit diagnosis is affected by temperature and SOC, and accurate judgment is difficult, and the technical effects of achieving accurate judgment of lithium battery internal short circuit and improving the accuracy and reliability of lithium battery internal short circuit diagnosis are achieved.

The invention relates to the technical field of power grids, and discloses a port green power virtual energy storage aggregation regulation and control method, which comprises the following steps: acquiring an aggregation scene and resource data; generating a power hard constraint mapping and pile division execution reference by calculating a multi-band energy index and identifying a system power transfer characteristic; a local rapid control configuration set is generated by solving a virtual impedance feasible region and combining power hard constraint allocation compensation budget; and fusing a sub-pile execution reference (slow channel) generated based on the power hard constraint with a fast channel execution track obtained after local online execution compensation, performing priority arbitration under the constraint of the power hard constraint, and outputting a final execution power track. According to the invention, a double-layer regulation and control framework of slow channel planning and fast channel compensation is constructed, and through a core link of power hard constraint mapping, coordinated operation of fast and slow channels and safety and stability of the whole system are ensured, and fast and reliable dynamic support capability can be provided for a power grid.

Embodiments of the present invention provide a method and apparatus for suppressing transient current of a grid-forming converter, a computing device, a computer-readable storage medium, and a computer program product. The suppressing method comprises: calculating first virtual impedance on the basis of an actual voltage instantaneous value of a point of common coupling; calculating second virtual impedance on the basis of an actual current maximum amplitude of the point of common coupling; and suppressing the transient current of the grid-forming converter on the basis of the first virtual impedance and the second virtual impedance. In this way, by combining the actual voltage instantaneous value of the point of common coupling and the actual current maximum amplitude of the point of common coupling, transient current can be suppressed at the moment when a fault occurs in a grid-forming converter, thereby avoiding misoperation triggering of a protection apparatus, and ensuring that the grid-forming converter can restore stable operation once the fault is removed.

The invention relates to the technical field of power distribution network analysis, in particular to a distributed energy storage cooperative control system and device for an intelligent power distribution network, in the distributed energy storage cooperative control system and device for the intelligent power distribution network, inverter phase angles and bus voltage fluctuation characteristics are collected in real time through a dynamic virtual impedance parameter library, and a virtual impedance parameter library reflecting a disturbance propagation path is constructed; a lower-layer region dynamic division unit of the double-layer decision control module dynamically divides cooperative control sub-regions based on a virtual impedance deviation value and a preset clustering interval, and improves local disturbance suppression precision in combination with power grid topology constraints, and an upper-layer weight distribution unit generates a dynamic power distribution weight coefficient according to an inverse proportion relation of an equivalent impedance ratio; the overload risk caused by traditional fixed weight distribution and impedance characteristic mismatch is solved; when the energy storage unit is off-network, the power disturbance buffer factor calculation module adjusts the upper limit of output of the remaining units according to the original weight proportion and the equivalent impedance ratio in an equal-ratio scaling mode, and output adjustment and the impedance attenuation direction are maintained to be synchronous.

The invention provides a network construction type photovoltaic energy storage control system and method for improving the supporting capacity of a power grid. The system comprises a data sampling module, a reference power generation module, a VSG module, a voltage feed-forward compensation and virtual impedance control module, a voltage and current closed-loop control module and a PWM generation module. According to the invention, modeling is carried out on a network construction type photovoltaic energy storage control model, then virtual impedance is introduced into VSG reactive voltage control, and a power grid voltage feed-forward compensation model is provided according to a vector diagram, so that the value of the virtual impedance is determined to weaken the influence of voltage drop when a power grid fails and suppress overcurrent. The problem that a photovoltaic energy storage face is insufficient in low-voltage ride-through capacity is solved.

The invention discloses a micro-grid electric energy quality global optimization method, which comprises the steps of collecting real-time data, dividing the real-time data into a plurality of segments according to frequency, and calculating harmonic compensation capacity of each frequency band according to the real-time data; according to the harmonic compensation capacity obtained through calculation, priority distribution is carried out on the compensation sequence of the polluted nodes in the micro-grid; the virtual impedance and the injection damping resistance of the inverter are adjusted, and the harmonic current and the resonance phenomenon in the micro-grid are suppressed in different frequency bands; and according to the adjusted virtual impedance and damping resistance, updating a node admittance matrix, monitoring the compensation capacity of the inverter in real time, comparing real-time monitoring data with a threshold value, if the real-time monitoring data exceed the threshold value, correcting the inverter, otherwise, not changing. Through frequency-band-divided control, pertinence and effect of harmonic suppression are improved, frequency-band-divided suppression of micro-grid harmonic and high-frequency resonance is realized, residual capacity of an inverter and harmonic compensation requirements are dynamically matched, and safe and stable operation of a system is ensured.

The invention relates to the technical field of power system testing, in particular to a transformer simulation test current optimization method based on dynamic impedance matching, which comprises the following steps: performing low-power scanning on a tested transformer to establish a nonlinear model capable of predicting harmonic waves; actively synthesizing the virtual impedance of the target power grid; and a feed-forward compensation current is generated by using a harmonic prediction model and is injected into the transformer after being superposed with a fundamental wave instruction. According to the method, accurate identification modeling is carried out on nonlinear characteristics of a tested unit, active synthesis of virtual impedance of a target power grid is combined, and harmonic compensation current is generated in real time by utilizing a feedforward control thought so as to optimize finally injected test current. According to the method, the problems of inaccurate power grid simulation and insufficient nonlinear response coupling of the transformer in a traditional test are solved, high-fidelity current injection is realized, real electrical behaviors of the transformer under various complex power grid working conditions can be accurately simulated, and the flexibility, accuracy and safety of the test are remarkably improved.

The invention belongs to the field of router protection, and particularly provides an energy router protection system and method based on deep reinforcement learning and virtual impedance collaboration, and the method comprises the steps that a high-speed sensing and monitoring unit collects and preprocesses the data of each power branch; the main control unit operates deep Q network fault reasoning, and a fault criterion threshold value is finely adjusted in combination with online Q-learning; calling a virtual impedance injection module, and superposing compensation voltage on the PWM reference signal to realize injection; a topology self-reconfiguration module is triggered synchronously, a fault branch is isolated, and a standby branch is switched to maintain power supply of a key load; the thermal management regulation and control module deploys load shedding through PID load shedding control and a temperature-current permission curve based on the thermal RC equivalent model and the real-time temperature; and synchronously issuing a related instruction by means of the CAN-FD bus. According to the method, the deep reinforcement learning algorithm and the virtual impedance technology are combined, so that adaptive protection and topological optimization of the energy router under complex working conditions are realized.

A low voltage ride through control method for a grid-forming inverter based on dynamic internal potential adjustment comprises the following steps: detecting a voltage per unit value of a grid-connected point in real time, and comparing the voltage per unit value with a threshold value to judge a voltage drop event and trigger low voltage ride through control; dynamically calculating active and reactive power reference values through a reactive compensation equation and an active current limiting equation according to the voltage amplitude and the power reference value before falling during the ride-through period; inputting the active reference value into a virtual rotor motion equation to generate a reference phase, and outputting a phase reference signal in combination with a dual-mode phase compensation controller; superposing the reactive reference value with the reference voltage through a reactive voltage regulating ring to generate a voltage amplitude reference signal; synthesizing an internal potential according to the phase and the amplitude reference signal, and obtaining an inductive current reference value through virtual impedance control and current amplitude limiting; and finally, a driving signal is generated through the current inner loop controller and the modulation module. According to the invention, overcurrent can be effectively inhibited, rapid reactive power support is provided, and synchronous stability and smooth transition in a fault period and a recovery process are ensured.

The invention provides a self-adaptive low-voltage ride-through control method for a network-building type converter considering virtual impedance, and the method comprises the steps: defining a reactive power adjustment coefficient and an active power adjustment coefficient, obtaining a power parameter, building an active-reactive power self-adaptive low-voltage ride-through control strategy formula when the influence of the virtual impedance is not considered, and carrying out the self-adaptive low-voltage ride-through control of the network-building type converter. The relation between the virtual impedance and the output reactive power is analyzed through the reactive power of the network-forming converter control system after the virtual impedance link is switched in, so that the enlightenment that the virtual impedance needs to be introduced to carry out linear correction on the reactive power regulation coefficient is obtained; a corrected value function can be obtained after linear correction is carried out on reactive adjustment parameters through virtual impedance, the corrected value function is finally substituted into a strategy formula, an active-reactive self-adaptive low-voltage ride-through control strategy formula considering the influence of the virtual impedance is obtained, the transient power angle stability of a grid-forming type converter system can be enhanced, and the stability of the grid-forming type converter system is improved. And meanwhile, the problem of over-current of the converter under large disturbance is solved.

The invention discloses a converter collaborative current limiting method based on adaptive virtual impedance and a power loop, and the method comprises the steps: firstly building an equivalent impedance model of a converter and a power grid, analyzing the steady-state and transient characteristics of fault current, and extracting key parameters for current limiting design; when it is detected that the voltage drop of the grid-connected point exceeds a threshold value, a self-adaptive virtual impedance link is automatically put into use, and virtual resistance and reactance values are dynamically calculated according to the variation amplitude of voltage or current, so that the virtual resistance and reactance values are proportionally adjusted along with the fault degree; and when the system voltage returns to normal, the virtual impedance automatically quits, and the control continuity is ensured. Then, the active and reactive power reference values are dynamically corrected according to the voltage drop depth, a power reference signal matched with the voltage amplitude is generated, it is guaranteed that power output does not exceed the limit, and the voltage supporting capacity is improved. Finally, real-time current-limiting control of the converter and stable operation of the system are realized on the premise of not switching the control mode through the synergistic effect of the virtual impedance ring and the power ring. The method has the advantages of being high in response speed, excellent in current limiting effect, good in control continuity and the like, and is suitable for fault current limiting and voltage support control of the grid-forming converter.

The invention relates to the technical field of on-load voltage regulation, in particular to a transformer on-load voltage regulation control method. According to the technical scheme, the transformer on-load voltage regulation control method comprises the following steps that S1, a transformer cluster running in parallel is decomposed into distributed intelligent nodes, and each node executes local voltage prediction and constraint condition management; s2, adopting a distributed model prediction control framework, and cooperatively solving a voltage regulation optimization target through an edge calculation unit; s3, a harmonic disturbance signal with a preset amplitude is injected into the transformer, equivalent impedance is dynamically identified based on response data, and virtual impedance compensation is triggered; and S4, establishing a hierarchical cooperative control architecture, and realizing clock synchronization, dynamic weight distribution and multi-objective optimization decision among nodes. Through a cooperative mechanism of distributed predictive control and dynamic impedance compensation, the response speed and the regulation precision of the on-load voltage regulation system to the power grid voltage fluctuation are remarkably improved, and the voltage out-of-limit problem under the complex working conditions of new energy grid connection, load sudden change and the like is effectively solved.

The invention provides a grid-connected and off-grid seamless switching method and system for a network-constructed energy storage micro-grid, belongs to the technical field of grid-connected and off-grid switching, and realizes rapidity and stability of micro-grid mode switching through multi-stage cooperative control. The method comprises the following steps: a power grid state real-time monitoring stage: acquiring power grid short-circuit capacity, impedance angle, voltage amplitude, frequency and phase parameters through impedance spectrum analysis and phase-locked loop cooperative detection; a pre-synchronization-hybrid control-dynamic damping three-stage switching stage; a steady state maintaining stage: maintaining a system damping ratio gt through a multi-target cooperative controller; and in the whole switching process, the bus voltage fluctuation is less than or equal to 2%, and the frequency deviation is less than or equal to 0.1 Hz. According to the method, MPC pre-synchronization, hybrid control of dynamic weight, virtual impedance adaptive compensation and multi-target collaborative optimization are controlled through model prediction, so that the problems are solved, seamless switching is realized, and the quality of electric energy is improved.

The invention discloses a virtual synchronous machine control-based impedance modeling and virtual impedance design method for a network construction type MMC (Modular Multilevel Converter). The method comprises the following steps: firstly, establishing a mathematical model of a network construction type MMC converter based on virtual synchronous machine control through a control strategy, and establishing a sequence impedance model of the MMC by adopting a harmonic linearization method; secondly, designing virtual impedance control to optimize traditional VSG control, and proposing a sequence impedance model after introduction of the virtual impedance control; and finally, analyzing impedance characteristics and grid-connected stability of the MMC converter after virtual impedance control is introduced. According to the method, the MMC sequence impedance model based on virtual impedance control can be effectively established, the grid-connected stability of the MMC sequence impedance model is analyzed, and the method has economical and practical values.

The invention relates to the technical field of new energy power system control, and relates to a power decoupling method for cooperative control of voltage feed-forward compensation and adaptive virtual impedance. The method comprises the following steps: acquiring a power grid current and a power grid voltage, and calculating a reactive power measured value and an active power measured value of a power grid; virtual synchronous machine control is carried out, and a voltage feed-forward pre-compensation item is introduced into a reactive power control loop; calculating a reactive power control loop after VSG compensation, and obtaining VSG output side voltage and instantaneous angular frequency; self-adaptive virtual impedance control is adopted, a self-adaptive virtual impedance reference value is calculated, line impedance is dynamically adjusted, and a voltage loop input instruction voltage is calculated according to the line impedance; and adjusting the output performance of the inverter according to the instruction voltage. According to the invention, the problem of power fluctuation caused by VSG output voltage amplitude variation is effectively solved, and the dynamic influence of a power coupling item is weakened.

The invention relates to the technical field of converter power averaging and circulating current suppression, in particular to a power averaging and circulating current suppression method for parallel operation of a plurality of grid-forming type energy storage converters, which averages power through communication interaction and generates frequency and voltage compensation quantity by adopting a first regulator and a second regulator to realize accurate power averaging; meanwhile, the total current is measured locally, and virtual impedance feedforward control is adopted, so that rapid suppression of the high-frequency circulating current is realized. According to the invention, high-precision active power and reactive power equalization is realized, the capacity utilization rate is improved, high-frequency circulating current is effectively suppressed, loss and thermal stress are reduced, dynamic performance and system reliability are considered, a cooperative control architecture with complementary advantages is formed, adaptability to complex working conditions and system stability are enhanced, and engineering applicability is improved.

The invention discloses a grid-connected and off-grid control system and method for a hybrid energy storage inverter, and relates to the technical field of grid-connected and off-grid control. The grid-connected and off-grid control method for the hybrid energy storage inverter comprises the following steps: S1, system initialization and data acquisition; s2, off-network dynamic load adaptability optimization; s3, power grid fault judgment and mode switching preparation; s4, grid-connected and off-grid mode switching control is carried out; the droop coefficient is adaptively adjusted according to the power change rate, response speed and stability are considered, virtual impedance is introduced to compensate line impedance difference, reactive power equalization is realized in combination with a distributed consistency algorithm, and the problem of multi-machine parallel circulating current suppression is solved. A fuzzy logic rule base is adopted to analyze the data output fault probability, the threshold value is dynamically adjusted, and the misjudgment risk is reduced. Hardware auxiliary synchronization and software pre-synchronization compensation are combined, a phase error feedback loop is introduced, and pre-synchronization robustness is enhanced. The output power is accurately switched and adjusted according to different scenes, and energy storage balance is maintained.

The invention relates to the technical field of network construction type converter control, in particular to a network construction type converter fault ride-through method and system based on dynamic virtual resistance control, and the method comprises the steps: adding a control link based on virtual impedance in a network construction type converter control system; detecting the actual value of the power grid voltage, and judging whether the power grid voltage drops or not; detecting the current amplitude output by the grid-forming converter in real time, and judging whether the current amplitude exceeds a set value or not; if one of the two conditions is met, a virtual impedance control link is started: stage-type current limiting control is performed on the virtual resistor, and the size of the virtual resistor provided by the network-forming converter to the power system is adjusted in real time along with the amplitude of the fault current; and when the power grid voltage recovers and the current amplitude is smaller than the set value, the virtual resistor staged current-limiting control exits. According to the invention, the amplitude limiting of the fault current in the fault ride-through of the network-constructed converter can be realized, so that the fault ride-through capability and transient stability of the network-constructed converter are improved.

The present application relates to the technical field of wind power generation, and discloses a control method and apparatus for a grid-forming doubly-fed wind turbine generator, a generator, and a medium. In embodiments of the present application, a current reference value of a grid connection point is determined on the basis of measurement parameters of the grid connection point in combination with an internal potential parameter of a grid-forming doubly-fed wind turbine generator and a virtual impedance reference value, a voltage reference value of a grid-side converter is further determined on the basis of the current reference value of the grid connection point, and the grid-side converter is modulated on the basis of the voltage reference value, thereby implementing closed-loop control of the grid-side converter, such that a difference between an output voltage value and the voltage reference value of the grid-side converter is less than a preset threshold.

The invention relates to the technical field of micro-grids, and provides a network construction type energy storage system reconstruction method and system based on dynamic impedance matching, and the method comprises the steps: obtaining the real-time impedance and real-time reactance of an associated power grid through a high-frequency disturbance signal injection decoupling mode; meanwhile, according to the voltage phase angle and the voltage drop depth of the associated power grid, respectively obtaining a phase compensation item and a dynamic adjustment coefficient, so as to dynamically adjust the virtual impedance through the phase compensation item and the dynamic adjustment coefficient; and real-time output of the target energy storage system is regulated and controlled by combining closed-loop control of the impedance outer loop and the voltage inner loop, so that voltage offset and broadband oscillation of the associated power grid are suppressed. According to the invention, the phase compensation item obtained according to the voltage phase angle and the dynamic adjustment coefficient obtained according to the voltage drop depth are added to the calculation of the virtual impedance, and the closed-loop control of the impedance outer loop and the voltage inner loop is combined, so that transient impact suppression and oscillation suppression can be realized at the same time, the limitation of separate triggering is effectively avoided, and the reliability of the system is improved. And the power grid voltage stabilization control effect is improved.

The invention belongs to the field of stability analysis of a grid-connected system of a grid-building converter, and particularly relates to a grid-building converter grid-connected resonance risk analysis method considering virtual impedance, which comprises the following steps: S1, establishing a three-phase time domain differential equation and simplifying the equation into a single-phase equivalent time domain model; converting into a harmonic state space model of the main circuit; s2, constructing a harmonic state space model of a control system comprising an active power control loop and a reactive power control loop; s3, introducing a virtual impedance control link, and correcting the voltage amplitude reference phasor output by the reactive power control loop; deriving an expression of a modulation signal disturbance phasor; s4, obtaining a complete frequency domain admittance model YGSC of the network construction converter considering the influence of the virtual impedance; an open loop gain TGFM of the grid converter grid-connected system is constructed; and S5, drawing a Nyquist curve based on TGFM, and carrying out resonance risk determination. According to the method, the interaction dynamic characteristics of the network building converter and the power grid under the influence of the virtual impedance can be accurately represented, and the resonance risk of the grid-connected system is evaluated.

The invention discloses a transformer area topology identification method and system capable of being deployed in a concentrator, equipment and a medium, and the method comprises the steps: solving an initial virtual impedance matrix based on historical electrical quantity data of a transformer area, and taking the minimum deviation between an optimization result and the initial matrix as an optimization target; and taking symmetry constraint, boundary constraint and collinear constraint as constraint conditions, and performing iterative solution to obtain an optimized virtual impedance matrix, so that the optimized virtual impedance matrix is closest to an original matrix on the basis of conforming to the actual topology, noise interference can be eliminated, the topology identification precision is improved, the method can dynamically adapt to a transformer area change scene, and the method is suitable for being applied to a transformer area. The method has high robustness, the unstructured virtual impedance matrix can be fitted into a unique solution conforming to physical topology, fuzziness of a traditional method is avoided, the whole recognition process only depends on historical electrical quantity data of the transformer area, no initial topology information is needed, and the high-precision transformer area topology can be constructed from zero.

The invention discloses a modular high-voltage SVG circulating current suppression method. The method comprises the steps of obtaining and preprocessing module circulating current, voltage and state data; constructing an enhanced phase space fused with multiple physical quantities, extracting circulating current phase features and generating dynamic trend prediction data; calculating optimal feed-forward and feedback virtual impedance parameters based on phase characteristics and trend prediction; and generating a module control voltage correction value and a PWM control signal by applying a multi-time scale hybrid control strategy. Through hybrid control of phase space reconstruction of topology perception, multi-dimensional entropy analysis and stability guarantee, efficient suppression of the circulating current is realized, and the stability and robustness of the SVG system are improved.