251 results about "Short circuit ratio" patented technology

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 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 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 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 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 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 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 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 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 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.

The invention discloses a low-voltage-crossing adaptive control method and device of a wind turbine generator, electronic equipment and a medium, and aims to solve the problems of slow system recovery, voltage overshoot and current out-of-limit in the current low-voltage-crossing control technology. The method comprises the following steps: acquiring running state data of a wind turbine generator at a grid-connected point in a low-voltage period in real time, and calculating a system short-circuit ratio according to the running state data; considering a power adjustment coefficient, and constructing a current feedback controller based on the operation state data; introducing an adaptive weighting strategy of a system short-circuit ratio, and combining a power adjustment coefficient to construct a multi-objective optimization function; the multi-objective optimization function is subjected to parameter optimization solution combined with system short-circuit ratio self-adaptive correction, and an optimized power adjustment coefficient is obtained; and substituting the optimized power adjustment coefficient into a current feedback controller, solving a control current value, and performing current control on the wind turbine generator based on the control current value.

The invention relates to a fault ride-through method based on hybrid synchronous control voltage / current source mode switching, aiming at fault ride-through (FRT) challenge in a novel power system, and breaking through the limitation of the existing solution from three key dimensions of overcurrent limitation, fault synchronization and reactive power support. On the basis of a hybrid synchronous control strategy, the damping characteristic of the system is remarkably improved, and the synchronous stability of the inverter during the fault period is effectively guaranteed; meanwhile, the intelligent control of smooth mode switching can be completed without complex switching logic or power grid information by utilizing simple detection of a saturation signal of a current limiter and combining with a mixed voltage / current source control architecture. Besides, the method has excellent short-circuit ratio (SCR) adaptive capacity, stable operation can be kept under different power grid strength conditions, and an innovative solution is provided for friendly improvement of new energy grid connection and transient performance optimization of a power system.

The invention discloses a direct-current transmission power evaluation method and device of a water-wind-light integrated base and a medium. The method comprises the steps that a direct-current transmission power evaluation model of the water-wind-light integrated base is established; the DC delivery power evaluation model takes DC power delivery maximization as an objective function and takes DC delivery power of each operation time period as a decision variable; according to the frequency response capability of the water-wind-light integrated base and the new energy multi-station short-circuit ratio, multiple safety constraints are constructed; the multiple security constraints comprise a frequency change rate security constraint, a maximum frequency deviation security constraint and a new energy multi-station short circuit ratio security constraint; adding multiple security constraints and multiple conventional constraints to the target function; and solving the target function to obtain the direct-current transmission power of the water-wind-light integrated base in each operation period. According to the invention, the problem of how to accurately evaluate the direct-current transmission power of the water-wind-light integrated base is solved.

The invention belongs to the technical field of power systems, and particularly relates to a power grid impedance simulation device, a design method and a use method.The design of the device comprises the steps that the types of needed components are determined, and the number of the components and electrical parameter values are obtained according to the actual national standard in combination with the minimum component number criterion; all components are connected according to needs, and a controller is adopted to realize corresponding control so as to support working condition simulation and switching of different short circuit ratios and series compensation degrees; a switch logic control program is set in the controller, so that when the controller receives a power grid working condition switching instruction, switching of working conditions corresponding to the power grid short-circuit ratio and the series compensation degree is achieved by executing the preset switch logic control program. According to the technical scheme, through the integrated design of parameter calculation, hardware topology and logic control, the problems of low test efficiency, poor simulation precision and high cost in the prior art are solved, and an efficient, accurate and economical solution is provided for the adaptability test of the new energy converter under a double-high power system.

The invention provides an optimal configuration method of a network construction type wind storage machine, a medium and computer equipment. The optimal configuration method comprises the steps that the machine end short-circuit ratio MRSCRG of each wind generating set connected to a power grid is calculated; calculating the grid-connected point short-circuit ratio MRSCRS of each wind power station accessed to the power grid; and according to the machine end short-circuit ratio MRSCRG of each wind generating set and the grid-connected point short-circuit ratio MRSCRS of each wind power plant station, determining the configuration mode of the grid-forming type wind storage machine.

The multi-inverter control mode self-adaptive switching method based on the operation short circuit ratio comprises the steps that an optical storage station grid-connected model is built, and inverter control modes are set to be a GFL mode and a GFM mode; acquiring operation data of a grid-connected point of the optical storage station, and calculating a numerical value of an operation short-circuit ratio (OSCR); when the operation short circuit ratio OSCR is smaller than C1 or larger than C2, the multi-inverter control mode switching optimization requirement is triggered; meanwhile, initializing a to-be-optimized variable; an MATD3 algorithm is adopted to determine an optimal switching combination of a multi-inverter control mode; issuing the output execution scheme of the optimal switching combination in the control period to a station inverter; when the operation short circuit ratio OSCR is between (C1 and C2), triggering the multi-inverter control mode switching optimization requirement again, outputting an optimal switching combination scheme by the MATD3 algorithm, and issuing the optimal switching combination scheme to the station inverter; wherein a part of the inverters are switched to GFL operation according to an optimization result, and the other part of the inverters are kept to control GFM operation in a network construction mode. According to the method, the collaborative minimization of dynamic voltage support and operation loss is realized.

The invention discloses a network construction type and network type energy storage combined control method, electronic equipment and a storage medium, and the method comprises the steps: firstly obtaining the inertia of a power grid and the short-circuit capacity of a grid-connected point of an energy storage power station, and calculating the short-circuit ratio of the grid-connected point of the power station; dynamically adjusting the basic operation proportion of the two types of energy storage according to the inertia and short-circuit ratio of the power grid; then determining the frequency deviation and the frequency change rate of the power grid, calculating the initial output of two types of energy storage in combination with the basic operation proportion, and executing hierarchical control: constructing network type energy storage dominated virtual inertia control based on the frequency change rate, and preferentially responding to the network type energy storage to primary frequency modulation control based on the frequency deviation of the power grid; and finally, dynamically distributing a real-time output weight by combining the power grid frequency deviation, the frequency change rate and the short-circuit ratio through the coordination controller, and carrying out weighted optimization on the initial output to realize collaborative adaptation of primary frequency modulation and virtual inertia control. According to the scheme, weak power grid stability improvement and fast frequency modulation active supporting capability are effectively considered, and the operation requirements of a high-proportion new energy power grid are met.

The invention discloses a flexible DC power transmission system grid following-grid construction hybrid control method, and the method comprises the following steps: obtaining the voltage and current of a receiving end MMC grid connection point, and carrying out the dq decomposition, thereby obtaining a d-axis component and a q-axis component under a dq rotating coordinate system; acquiring actual values and related reference values of direct-current voltage output by the receiving-end MMC, alternating-current voltage and frequency of a grid-connected point of the receiving-end MMC and average capacitance voltage of a sub-module; sequentially calculating a phase reference value of the receiving end MMC, a d-axis current reference value and a q-axis current reference value of the grid connection point, a d-axis voltage reference value and a q-axis voltage reference value of the differential mode voltage, a direct current reference value and a direct current modulation ratio reference value; and calculating the reference value of the modulation voltage of the receiving end MMC under the abc static coordinate system. The control method has the advantages of adapting to wide-range short-circuit ratio change of the receiving-end power grid, guaranteeing reliable transmission of power under the condition of wind speed change, and still maintaining synchronous operation when the receiving-end alternating-current power grid seriously breaks down.

The invention provides a new energy transmission system new energy-storage cooperative support control method under multiple constraints of a voltage stability domain, and relates to the technical field of power system voltage stabilization. According to the method, a model of reactive power, grid-connected voltage, active power and system parameters is established based on a power flow equation, and a required reactive reference is calculated by combining a set voltage expected value and real-time output power; and under the constraints of the voltage ride-through threshold, the converter capacity, the short-circuit ratio and the power margin, executing a new-storage cooperative voltage support strategy. Under the working conditions of new energy fault ride-through, output power out-of-limit and the like, the voltage stability can be remarkably improved, the output capacity of a new energy station is enhanced, and safe and stable operation of the system is ensured.

The invention is suitable for the technical field of converter configuration, and provides a capacity configuration optimization method and related equipment for a network tracking / constructing hybrid energy storage power station, and the method comprises the steps: constructing a capacity optimization objective function based on a short-circuit ratio; constructing a number constraint condition, an alternating current power flow constraint condition and a system stability constraint condition of the network tracking / constructing hybrid energy storage power station; and taking the capacity optimization objective function as a fitness function of a particle swarm optimization algorithm, and optimizing the capacity ratio of the tracking / networking hybrid energy storage power station by using the particle swarm optimization algorithm to obtain an optimal capacity ratio which has the minimum fitness function and meets a quantity constraint condition, an alternating current power flow constraint condition and a system stability constraint condition. According to the invention, an operable capacity ratio can be provided for the following / networking hybrid energy storage power station, so that the power station can meet engineering requirements.

The invention provides a new energy station voltage supporting capability evaluation method based on equivalent impedance. The method is suitable for a new energy power system with hybrid access of a constructed network type converter and a following network type converter. The method comprises the following steps: deducing an equivalent impedance model based on control parameters of the network-forming converter; constructing a new energy multi-station short-circuit ratio index considering the equivalent impedance characteristic; a hybrid new energy station model is constructed in a power system modeling platform, a voltage disturbance working condition is set, system dynamic response is simulated and analyzed, and the voltage supporting capacity is evaluated based on a short-circuit ratio index. The method can quantify the influence of the parameters of the network construction type converter on the system voltage support capability, supports the comparative analysis of the voltage support performance and the optimization of the control parameters, and provides a theoretical basis for the formulation of a multi-station coordination control strategy.

The invention relates to a fault chain searching method and device for a power grid containing a flexible direct access receiving end and a medium, and relates to the field of power grid safety, and the method comprises the steps: S1, constructing an electromagnetic electromechanical joint simulation model; s2, simulation is carried out based on the electromagnetic electromechanical joint simulation model, and comprehensive vulnerability indexes of all alternating-current lines in the receiving-end power grid are obtained through calculation based on simulation data, the comprehensive vulnerability index is obtained by a hybrid multi-infeed short-circuit ratio variable quantity, a DC commutation failure voltage recovery capability metric value, a node voltage offset and a power flow transfer entropy; and S3, sorting all the alternating-current lines according to the comprehensive vulnerability indexes from large to small, selecting the first alternating-current line as a starting point of a fault chain, and searching in combination with an electromagnetic-electromechanical joint simulation model to obtain the fault chain. Compared with the prior art, the method has the advantages of reflecting the response process of the conventional DC control system and the flexible DC control system, improving the fault chain search accuracy and the like.