328 results about "Short circuit ratio" patented technology

The invention relates to a follow-up network type control smooth switching method based on a generalized operation short-circuit ratio index. The follow-up network type control smooth switching method comprises the following steps of 1, introducing a generalized operation short-circuit ratio (GOSCR) as a switching index, and proposing a GOSCR-based hysteresis control mode switching judgment index under different power grid strength and power output working conditions; step 2, establishing a unified new energy grid-connected control unit model: constructing a unified grid-connected control model in two modes of network following control and network construction control, systematically analyzing oscillation characteristics of a grid-connected unit in the two modes, and defining boundary conditions of mode switching; 3, proposing an LADRC-based undisturbed switching control strategy: observing and estimating system current disturbance parameters online by utilizing LESO, realizing real-time compensation of disturbance quantity, and reducing dynamic sudden change in the switching process; the method has the advantages that GOSCR switching indexes are introduced to comprehensively evaluate the strength, a unified grid-connected control model is established, and an undisturbed switching control strategy is provided.

The invention relates to a quantitative evaluation method for robust stability of a hybrid multi-infeed system constructed with a network. The quantitative evaluation method comprises the following steps: S1, constructing a hybrid multi-infeed system model; s2, enabling the series-parallel multi-infeed system to be equivalent to an equivalent network construction subsystem and an equivalent network following subsystem, and respectively calculating a generalized short-circuit ratio as a power grid strength quantitative index; s3, selecting a nominal system model, and determining a critical value of small interference stability of a nominal system through the dominant feature root locus; s4, drawing a frequency domain characteristic curve of the uncertainty perturbation singular value, and determining an uncertainty perturbation upper bound; and S5, drawing a complementary sensitivity peak curve when the decoupled nominal system is connected to alternating current networks with different power grid intensities, and quantifying a critical value and a margin of robust stability under a power grid intensity perspective by combining an uncertainty perturbation upper bound. Compared with the prior art, the robust small-interference stability quantitative evaluation method is creatively provided, and technical support can be provided for coordinated optimization configuration and safe and stable operation of the high-proportion new energy grid-connected system.

The invention discloses a power coupling-considered capacity ratio estimation method for a network-constructing / network-following multi-machine hybrid system, and the method comprises the steps: building a GFL-GFM hybrid system model, combining VSG power coupling small signal modeling and a dynamic relative gain matrix (DRGA), and quantifying the coupling strength of active / reactive power to output voltage; the frequency domain impedance characteristic of the GFM converter is simplified, and an ideal voltage source series equivalent reactance equivalent model is constructed; deriving an analytical relationship between a generalized short-circuit ratio (gSCR) and a capacity ratio based on the model, and generating a ratio formula in combination with engineering boundary sub-scenes to form a ratio range suitable for multiple scenes; for coupling time-varying characteristics, a closed-loop mechanism of'mixed mode-coupling sensing-correction calculation-execution feedback 'is constructed, and the ratio is dynamically adjusted. According to the method, coupling quantization and multi-machine coordination control are deeply fused, the problem that the external characteristic model precision and the multi-working-condition adaptability are difficult to consider under complex environment coupling is effectively solved, and the engineering applicability of the hybrid fan system is enhanced.

The invention discloses a stability evaluation and optimization method for a multi-infeed series-parallel new energy station based on equivalent external characteristics of a network construction type converter, and belongs to the technical field of electric power automation. Comprising the following steps: constructing a new energy multi-infeed hybrid system stability analysis closed-loop dynamic model, and simplifying a network construction type admittance transfer function; based on a stability analysis closed-loop dynamic model of the new energy multi-infeed series-parallel system, simplifying the new energy multi-infeed series-parallel system into an equivalent single-infeed system, and evaluating the stability of the equivalent single-infeed system through a generalized operation short-circuit ratio and a critical generalized operation short-circuit ratio; analyzing and quantifying the influence of key parameters of the network construction type equipment on the stability of the system through a parameter sensitivity analysis method; a node participation factor is used as an evaluation index, and control parameters are optimized based on a stability optimization method of key parameters of network construction type equipment of system weak nodes. The method provided by the invention has good effectiveness and reliability, and can realize gradual improvement and refined regulation and control of the system stability.

The invention relates to an optimization configuration method, equipment and medium for a network-following construction type series-parallel system considering uncertainty, and the method comprises the steps: constructing a converter optimization configuration model by taking the minimum number of reconstruction times as an optimization target and taking the robust stability of the series-parallel system as a constraint condition; the optimized configuration process of the series-parallel system comprises the following steps: S1, segmenting the current series-parallel system into equivalent network following / network constructing subsystems, respectively calculating a generalized short-circuit ratio, determining a critical value of small interference stability of a corresponding nominal system, and solving a generalized short-circuit ratio and a robust stability margin of critical robustness of a subsynchronous frequency band based on a small gain theorem; s2, judging whether constraint conditions are met or not, if yes, ending the current optimization process, and otherwise, turning to S3; and S3, identifying the weakest feed-in point in the current series-parallel system by adopting a participation factor method, transforming the station corresponding to the weakest feed-in point into network construction type control, and turning to S1. Compared with the prior art, the input cost in the system transformation process is reduced on the basis of ensuring the robust stability of the system.

The invention discloses a partition new energy consumption rate calculation method considering short circuit ratio and grid constraint. The method comprises the following steps: 1, collecting system data of each regional power grid; 2, establishing an electrical simulation model of a regional power grid, and calculating a new energy multi-station short-circuit ratio level of each region and inter-region main section power transmission capacity; 3, calculating a new energy output upper limit of each region; 4, correcting the wind and light output characteristic curve of each region according to the new energy output upper limit of each region, and calculating the photovoltaic abandoned electric quantity and the wind power abandoned electric quantity generated by insufficient new energy multi-station short-circuit ratio; 5, calculating a year-round 8760 profit and loss result of each region through a time sequence simulation program by using the corrected wind and light output characteristic curve of each region; and 6, calculating the new energy consumption rates of the whole area and each subarea. The invention provides a partition new energy consumption rate calculation scheme considering the net rack constraint, is used for practically reflecting the profit and loss conditions of the whole and each partition, and provides a scientific basis for promoting the efficient consumption of new energy.

The invention relates to the technical field of electric energy storage systems, in particular to an offshore wind-solar hydrogen storage ammonia-alcohol-based constructed network control system and a broadband oscillation prevention and control method. Comprising an offshore hydrogen-ammonia-alcohol base, an offshore wind power base, an offshore photovoltaic base, an inverter station, an offshore wind-light base energy storage power station, a booster station, a network-forming type energy storage phase modulation power station and a broadband oscillation control and prevention device, so that the network-forming type energy storage control research of the offshore wind-light hydrogen-ammonia-alcohol multi-energy complementary base can be carried out under low-short-circuit-ratio access and isolated network operation. Voltage, frequency and short-circuit capacity adjustment and inertia supporting are achieved, oscillation prevention and control can be carried out, and the purposes of power grid supporting optimization adjustment and oscillation treatment are achieved; meanwhile, multi-energy complementation is achieved, the energy utilization rate is increased, hydrogen ammonia alcohol can be prepared through green energy, and carbon emission is reduced. Therefore, the problems of poor frequency stability, weak voltage supporting capability, serious weak power grid oscillation and the like in the prior art are solved.

The invention provides a network construction type converter proportion configuration method and system suitable for a hundred percent new energy independent power supply system. The method comprises the following steps: carrying out information sampling before configuration of a network construction type converter of the hundred percent new energy independent power supply system; according to the number of the sampled network construction converters and the internal impedance of the network construction converters, performing network construction type new energy field station internal impedance equivalence to obtain the network construction type new energy field station internal impedance; calculating the short-circuit ratio of the low-voltage side of the step-up transformer of the following network type new energy station, comparing the calculated short-circuit ratio with a critical short-circuit ratio SCR0, and setting the short-circuit ratio of the low-voltage side of the step-up transformer of the following network type new energy station not to be less than the critical short-circuit ratio SCR0 according to the stable operation requirement of the system; and calculating to obtain the proportion configuration of the networking converter in the hundred percent new energy independent power supply system. According to the invention, an effective basis can be provided for the proportion configuration of the networking converter in the hundred-percent new energy independent power supply system, and the safe and stable operation capability of the hundred-percent new energy independent operation system is improved.

The invention provides a network construction type energy storage wide short circuit ratio adaptive stability control method and system, and the method comprises the steps: carrying out the calculation based on a power grid energy storage parameter, power grid impedance and energy storage impedance, and obtaining a dynamic short circuit ratio; according to the dynamic short-circuit ratio, switching the power grid operation condition mode to a power grid operation condition mode corresponding to the dynamic short-circuit ratio; in a power grid operation working condition mode, obtaining optimized virtual inductance resistance parameters or frequency-variable admittance regulator parameters; a corresponding control instruction is generated according to the virtual inductance resistance parameters or the frequency-variable admittance regulator parameters, and self-adaptive stability control is completed; real-time identification and dynamic adjustment of the power grid impedance and the energy storage impedance are achieved, traditional fixed parameter control limitation is broken through, the dynamic short-circuit ratio is obtained through calculation, the problem of power angle instability under the wide short-circuit ratio is solved, corresponding switching of power grid operation working condition modes can be conducted based on the dynamic short-circuit ratio, differential control requirements of a weak power grid and a strong power grid are considered, and the method is suitable for large-scale popularization and application. And the full-working-condition adaptive capacity is improved.

The invention relates to the technical field of stability analysis of a new energy grid-connected system, in particular to a new energy real-time short-circuit ratio margin evaluation method, system equipment and a medium, and the method comprises the steps: building an equivalent model based on power grid parameters, calculating equivalent capacity, and carrying out online correction in combination with multi-source data; calculating a new energy grid-connected short-circuit ratio according to the equivalent capacity ratio, calculating a short-circuit ratio index based on a constraint equation, refreshing a real-time index through measurement data of local voltage and current, and outputting a real-time short-circuit ratio; calculating the short-circuit ratio margin of the new energy station based on the short-circuit ratio difference value, quantitatively evaluating the stability, judging a stable state according to a positive value and a negative value of the margin, quantifying an instability risk level according to an absolute value of the margin, and generating a graded early warning signal and a control instruction; through dynamic fusion of multi-source data correction capacity, local measurement of millisecond-level refreshing indexes and margin positive and negative values, a control instruction is triggered, stable monitoring and active defense are realized, and the anti-disturbance capability and the safety level of a high-proportion new energy power grid are remarkably improved.

The invention discloses a method and a system for measuring the real-time short-circuit ratio of a new energy station based on Kalman filtering. The method comprises the following steps: constructing a Thevenin equivalent circuit of a new energy station connected to an alternating current system; inputting a reference voltage into the Thevenin equivalent circuit, and measuring two groups of voltages and currents of the grid-connected point at different moments; filtering the measured voltage and current values by using Kalman filtering; calculating system parameters of the Thevenin equivalent circuit by using the filtered voltage and current values; and calculating the real-time short-circuit ratio of the new energy station according to the system parameters of the Thevenin equivalent circuit. The problem that the real-time short-circuit ratio of the system is difficult to accurately measure due to the fact that large-scale new energy is connected to the power system at present can be solved.

The invention relates to the technical field of power system planning, and discloses a new energy grid-connectable capacity margin evaluation method based on spatio-temporal distribution characteristics, which comprises the following steps: constructing a joint probability distribution model based on nonparametric kernel density estimation and a Copula function by using historical and meteorological data of a wind and light station, and generating a random output scene reflecting the spatio-temporal complementarity of wind and light resources; constructing a multi-dimensional stability constraint set containing a generalized short circuit ratio and broadband oscillation as a safety boundary of a random output scene; establishing a grid source interaction control strategy considering energy storage adjustment and direct current power modulation by taking grid-connected capacity maximization as a target, solving an optimal installed capacity scheme, and activating the grid source interaction control strategy to perform dynamic correction when a scene is out of limit; the maximum grid-connected capacity distribution meeting the constraint is counted, and the shadow price of the constraint is calculated to identify the bottleneck. According to the method, the wind and light resource complementary benefit and the system regulation potential can be quantified, and the new energy grid-connected capacity evaluation margin is improved on the premise of guaranteeing the safety.

The invention discloses a network construction type energy storage locating and sizing optimization method considering new energy multi-station short circuit ratio improvement, and relates to the technical field of power system and energy storage system planning. Proposing an accurate modeling method of the new energy multi-station short-circuit ratio considering the resistance influence; based on the characteristics of a network construction type energy storage independent voltage source and the characteristics of short-time high-rate overload capacity, a relation model between new energy multi-station short-circuit ratio improvement and network construction type energy storage site selection capacity is provided; based on a convex optimization theory and a mixed integer quadratic programming method, a network construction type energy storage locating and sizing optimization model considering new energy multi-station short-circuit ratio improvement is constructed. The new energy multi-station short-circuit ratio under the weak power grid is improved, the addressing and sizing scheme optimization of network-building type energy storage is realized, and the operation safety of a new energy unit and the reliability of new energy power transmission under the weak power grid area are improved.

The invention discloses a performance detection device for a network construction type converter suitable for new energy and energy storage, and relates to the field of power conversion equipment testing. The automatic test unit comprises a frequency adjustment test module, a phase jump test module, a short circuit ratio adjustment test module, a broadband harmonic injection test module, an island simulation test module, a source load switching test module and a damping test module. Compared with an existing test platform, the precision in the aspects of frequency, phase, short-circuit ratio adjustment and the like is improved, and the precision of a test result is ensured; testing of various complex working conditions such as isolated island operation, source load switching and broadband harmonic injection is supported, and all key working conditions possibly encountered by the power conversion system in practical application can be simulated; the system has an automatic testing function, various tests are automatically carried out through preset working conditions, a detailed analysis report is generated, and manual intervention is reduced.

The invention provides a smooth switching method of a converter network construction type control mode and a network following type control mode, and relates to the technical field of grid-connected control, and the method comprises the steps: obtaining a short-circuit ratio of a new energy grid-connected system; determining a current power grid type according to the short-circuit ratio of the new energy grid-connected system; under the condition that the current power grid type is determined to be a strong power grid and the converter operates in a network-building type control mode, a converter phase angle, a converter current reference value, an active power reference instruction value and a reactive power reference instruction value are respectively controlled to be switched into corresponding parameters in the network-building type control mode, and integral zero clearing operation is carried out on a converter current loop PI; and the converter is controlled to be switched to a network following type control mode. By means of the method, smooth switching between the network construction type control mode and the network following type control mode of the converter can be achieved.

The invention discloses an AI feedback system for monitoring opening and closing time of a switch in real time, which relates to the technical field of electrical variable measurement, and comprises a data acquisition module for acquiring three types of data in real time, pre-processing the data, marking the closing time by a central calculation processing module, comprehensively processing the data to obtain a copper scale interference model, and judging whether the copper scale interference model is interfered or not according to the copper scale interference model; the opening speed is adjusted, the opening moment is marked, the opening and closing time is calculated, and the early warning feedback module is called for early warning and AI feedback in case of abnormality. According to the method, multi-dimensional data are collected in real time to construct a copper scale interference model, when interference is detected, capacitor voltage is automatically increased to accelerate opening, compensation opening time is prolonged, equipment short circuit is avoided, the method is more real-time and self-adaptive compared with a traditional scheme, arc light and frequency parameters are comprehensively calculated, historical and real-time data are analyzed in combination with AI, early warning is carried out in the case of abnormity, and an adjustment strategy is optimized. Decision support is provided through a visual chart, whole-process intelligent management is achieved, and the safety and reliability of equipment are improved.

The invention discloses a network following and network construction control switching method, device, equipment, medium and product, and the method comprises the steps: when all buses of a transformer substation of a power grid system are detected not to operate, controlling the power grid system to operate in a network construction control mode; and when it is detected that at least one bus of the transformer substation of the power grid system operates, according to the effective short-circuit ratio corresponding to the bus, it is judged that the power grid system is controlled to operate in a network following / constructing control mode. The control mode can be automatically switched on the basis of a network following and network constructing dual-control framework, the operation requirements of the power grid in various scenes of a strong network, a weak network and an isolated network can be met, and safe and stable operation of a direct current project and a power grid system is ensured.

The invention discloses a reactive compensation optimal configuration method and system of a new energy base, equipment and a medium, the method performs steady-state configuration of initial reactive capacity based on load flow calculation, can obtain effective steady-state reactive compensation configuration in a full output range, improves the robustness of steady-state reactive compensation, and improves the optimal configuration of the reactive compensation of the new energy base. A global coupling optimization architecture crossing steady state and transient state is constructed for the first time, closed-loop convergence of three optimization configuration stages is realized, so that global optimal configuration of reactive compensation is realized, and meanwhile, reasonable division and matching between two types of dynamic reactive compensation equipment, namely a phase modifier and an SVG / STATCOM, are realized; therefore, the new energy base not only can solve the transient voltage problem, but also has high power grid support strength, and the total configuration cost is greatly reduced while the requirements of standards, short-circuit ratio and transient voltage stability are met.

The embodiment of the invention provides a small-disturbance stability optimization method and device for a single-network converter grid-connected system. The method comprises the following steps: constructing a small-signal model representing dynamic behaviors of the system based on control parameters and network parameters of the single-network converter grid-connected system; performing preprocessing operation on the small signal model to obtain a small signal model only comprising an active synchronization control link; performing order reduction processing on the small signal model to obtain a corresponding equivalent second-order model; determining the dynamic influence of active outer loop control, voltage inner loop control and short-circuit comparison on the stability of the current system according to the equivalent second-order model; adjusting a current system control parameter according to the dynamic influence to meet a small disturbance stability requirement; according to the method, the control parameters of the single-network converter can be optimized based on the small signal model, so that the small disturbance stability of the system is improved, and an optimization strategy is provided for stable operation of the network converter.

The invention discloses a mode switching method, device and equipment of an energy storage converter and a storage medium, and relates to the technical field of power grid control, and the method comprises the steps: obtaining a multi-mode control grid-connected model of the energy storage converter, and the grid-connected model comprises a grid-following type control model and a grid-constructing type control model; based on the grid-connected model, injecting a high-frequency small signal into a power grid through an energy storage converter, and processing the high-frequency small signal by adopting a discrete Fourier transform algorithm to obtain grid-connected point voltage and current response; obtaining a power grid impedance parameter according to the grid-connected point voltage and current response; calculating an operation short-circuit ratio according to the power grid impedance parameter in combination with the actual output power of the energy storage converter and the power grid voltage amplitude; according to the operation short-circuit ratio and the short-circuit ratio threshold value, mode switching is carried out on the following network type control and the construction network type control, and the method can improve the accuracy of mode switching of the energy storage converter.

The invention provides a control method and device based on a network following proportion and a network construction proportion, equipment and a medium, and relates to the technical field of power systems, and the method comprises the steps: obtaining the system capacity and the device capacity of a power system; wherein the system capacity refers to the sum of rated capacities of various hub substations in the power system, and the device capacity refers to the installation capacity of equipment integrating a network following function and a network construction function in a preset range of the power system; determining a short-circuit ratio according to the system capacity and the device capacity; determining a network following proportion and a network construction proportion according to the short-circuit ratio; acquiring three-phase voltage, three-phase current, direct-current side voltage and direct-current side reference voltage of the power system; and performing pulse width control according to the three-phase voltage, the three-phase current, the direct current side voltage, the direct current side reference voltage, the network following proportion and the network construction proportion. According to the technical scheme, the pulse width of the power system is comprehensively controlled and adjusted based on the network following proportion and the network construction proportion by determining the network following proportion and the network construction proportion.

The invention relates to the technical field of articles for old people, in particular to an adjusting method, system, equipment and medium for improving the short circuit ratio of a new energy station, and the method comprises the steps: calculating a first target index and a second target index of the new energy station, and switching a part of grid-connected converters into a virtual synchronous generator control mode; when the second target index does not meet the short-circuit ratio control requirement, changing the equivalent impedance of the grid-connected point by adjusting the virtual impedance of the virtual synchronous generator so as to reduce the second target index of the new energy station; and when the grid fault causes the voltage drop of the grid-connected point, reactive voltage control is carried out through the virtual exciter of the virtual synchronous generator, and voltage support is provided for the grid-connected point. The method has the beneficial effects that flexible and efficient dynamic adjustment is realized by using the virtual synchronous generator, the system operation efficiency is improved, and the short-circuit ratio of a new energy field station is improved by combining virtual impedance and a reactive power support function, so that the operation capability of the new energy field station in a weak power grid is enhanced.

The invention discloses a cooperative suppression method for transient overvoltage of a hybrid wind power plant by a network-constructing type direct-driven wind turbine, which is suitable for the hybrid wind power plant comprising a network-constructing type permanent magnet direct-driven wind turbine generator and a network-following type permanent magnet direct-driven wind turbine generator. The method comprises the steps of constructing an electrical equivalent model, extracting key parameters, identifying regulation and control factors, formulating a cooperative control strategy, and executing control response and strategy optimization in an abnormal state of a system. Voltage response characteristics are analyzed through indexes such as self-impedance, mutual impedance and short-circuit ratio, and effective suppression of transient overvoltage and improvement of system voltage supporting capability are realized by combining controller parameter setting and reactive power compensation device control.

The invention discloses a voltage dynamic support capability evaluation method suitable for grid-connected equipment of a network construction converter. The method comprises the following steps: firstly, acquiring a port voltage amplitude and a phase angle of the grid-connected equipment of the network construction converter, a voltage amplitude and a phase angle of a grid-connected point and grid-connected impedance of the grid-connected equipment of the network construction converter; and then, according to a reactive outer ring control strategy of the grid-connected equipment of the network construction converter, selecting a corresponding calculation formula for the evaluation index of the dynamic voltage supporting capability of the grid-connected equipment of the network construction converter, and according to the obtained data, calculating the evaluation index of the dynamic voltage supporting capability of the grid-connected equipment of the network construction converter in real time. Compared with the short-circuit ratio index of the traditional evaluation system strength, the voltage dynamic support capability evaluation index can accurately evaluate the voltage support capability of the grid-connected equipment of the network construction converter, and can quantitatively analyze the influence of the reactive power control parameters of the grid-connected equipment of the network construction converter on the voltage support capability; the method is of great significance in improving the voltage supporting capacity of the grid-connected equipment of the grid-forming converter and guaranteeing safe and stable operation of a power system.

The invention discloses a new energy openable capacity evaluation method, system, equipment and medium considering short-circuit ratio constraint, and belongs to the technical field of new energy openable capacity evaluation, and the method comprises the steps: calculating a new energy multi-station short-circuit ratio based on a ratio of an AC system equivalent short-circuit capacity to a new energy equivalent grid-connected capacity; calculating a new energy multi-station short-circuit ratio after the new station is accessed by considering the influence of adding the new energy station, and constructing a short-circuit ratio constraint by considering a critical short-circuit ratio limit value; considering constraint conditions, constructing a new energy openable capacity evaluation objective function, and forming an openable capacity evaluation model; and constructing a planning problem in combination with the constraint condition and the target function, and performing iterative solution on the planning problem based on a Benders decomposition algorithm to obtain a new energy openable capacity value under the corresponding condition. According to the method, starting from the influence of the access of the new energy station on the short-circuit ratio, the evaluation result of the new energy openable capacity of the power grid can be optimized, and an effective reference is provided for evaluation of the new energy openable capacity.

The invention relates to the technical field of new energy parameter optimization, and relates to a method and a system for optimizing low-voltage ride-through parameters of a multi-station new energy unit by considering transient voltage stability. Comprising the following steps: building a researched power grid model; adjusting the starting number and output of the conventional power supply units and the new energy units of the power grid model to obtain operation modes in different states with the new energy permeability smaller than or equal to 70%; calculating the new energy multi-station short-circuit ratio under the operation modes in different states in which the new energy permeability is less than or equal to 70%; fault simulation calculation is carried out near the bus nodes with the new energy multi-station short-circuit ratio smaller than a set threshold value, and a bus voltage curve is output; and judging whether transient voltage stability is met or not, if not, optimizing the low-voltage ride-through parameters of the near-field new energy unit for the weak nodes which do not meet the transient voltage stability, and applying the optimized low-voltage ride-through parameters of the new energy unit to fault simulation. According to the invention, the transient voltage stability of the power grid during the fault period is obviously enhanced.

The invention provides a pure new energy large base network construction type equipment configuration method for direct current delivery through an island, and relates to the field of power grid planning, and the method comprises the steps: obtaining the multi-station short-circuit ratio condition of the boost transformer low-voltage side of a power generation unit of all new energy stations in a pure new energy large base, judging whether the short-circuit ratio condition meets a first preset condition or not, and according to a judgment result, determining whether the short-circuit ratio condition meets the first preset condition; selecting a corresponding new energy station to configure network energy storage, so as to enable the short-circuit ratio of multiple stations at the boost transformer low-voltage side of all power generation units to meet a first preset condition; obtaining an effective short-circuit ratio condition of the isolated island direct current, and configuring a network construction type SVG in the isolated island direct current, so that the effective short-circuit ratio of the isolated island direct current meets a second preset condition; and according to the configured networking type energy storage and the configured networking type SVG, forming a networking type equipment configuration scheme. According to the invention, the reasonable configuration of the network-forming type energy storage and the network-forming type SVG can be realized, and the power grid strength and the voltage supporting capability of the whole system are effectively improved.

The invention relates to the technical field of high-proportion new energy power systems, in particular to a method and system for calculating the short-circuit ratio of a network-following / network-constructing hybrid new energy power system, and the method comprises the steps: determining a network-constructing new energy access node, and deducing an impedance matrix of the network-following / network-constructing hybrid new energy power system; the system equivalent impedance calculation considering the virtual impedance control is used for considering the influence of the network construction type virtual impedance control on impedance characteristics; an improved new energy multi-station short-circuit ratio calculation model is given according to a traditional new energy multi-station short-circuit ratio simplification condition, the multi-station short-circuit ratio of any new energy node is calculated, and the influence rule of the access capacity, the connection reactance and the control characteristic of the network construction type new energy on the new energy multi-station short-circuit ratio of any node can be effectively evaluated; and the method can be further popularized and applied to strength calculation and influence law analysis of the power grid accessed by the converter with the network construction control characteristic.

The invention belongs to the technical field of mathematical modeling of a network construction converter, and discloses a network construction converter model order reduction method, system and equipment based on optimal Hankel norm approximation and a medium, so as to solve the problem of applicability of a network construction converter model under the condition of a high short circuit ratio. The method is based on a full-order model and comprises the steps of S1, current loop order reduction processing, S2, voltage loop Hankel approximation order reduction and S3, construction of a nine-order model. According to the method, through dq decoupling, feedforward offset and optimal Hankel norm approximation, a full-order system is reduced into a nine-order model, and the calculation complexity is greatly reduced while the control precision is ensured. According to the method, active and reactive high-frequency component quantity links filtered by a filter and a line resistance-inductance equation are considered, the nine-order model of the network construction converter is constructed, and the model precision is effectively improved.

The invention belongs to the technical field of grid-connected control of a power system, and discloses a method, equipment and medium for reducing a short-circuit ratio critical value of a new energy station, the method is applied to a grid-connected system, the grid-connected system comprises the new energy station and a grid-connected line for connecting the new energy station into a power grid, and the new energy station comprises a grid-following type converter. The method comprises the following steps: acquiring a rated capacity and a grid-connected voltage grade of a new energy station, and determining a pre-selected capacity of direct-current self-synchronization control networking type equipment; the method comprises the following steps of: deploying network construction type equipment in parallel at a main current collection bus side of a new energy station, configuring a direct current self-synchronization control ring on the network construction type equipment, and introducing equivalent inertia and damping characteristics into a direct current side voltage ring; and setting the parameters of the direct current self-synchronization control loop to reduce the short-circuit ratio critical value of the new energy station. The short-circuit ratio critical value of the new energy station is reduced on the premise of not transforming the infrastructure of the power grid side by introducing the network construction type equipment with the direct-current self-synchronization control function and setting the parameters of the network construction type equipment.