435 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 discloses an active support control method and system for a follow-up network hybrid new energy station, and the method comprises the steps: collecting the operation state data of a high-voltage side of a grid-connected point of the new energy station, and calculating the short-circuit ratio of the new energy station; according to the station short-circuit ratio, switching an operation mode of a unit with a network following / constructing power generation mode; obtaining the active margin of each unit, calculating the active increment of the primary frequency modulation of the whole field, and carrying out the distribution according to the obtained active margin of the network tracking / constructing unit; calculating a full-field inertia frequency modulation active increment, judging an autonomous inertia supporting effect of the network-building type unit according to an active margin of the network-building type unit, and coordinating with the network-building type unit to jointly complete inertia frequency modulation; the reactive power margin of each unit is obtained, the autonomous voltage regulation supporting effect of the network-building type unit is judged according to the reactive power margin of the network-building type unit, and the network-building type unit is coordinated to carry out residual reactive power distribution according to the reactive power margin, so that economical and efficient cooperative operation of the hybrid new energy station and friendly power grid is realized.

The invention discloses a network-following flexible switching prediction control method and system for a grid-connected converter, and the method comprises the steps: calculating a short-circuit ratio according to obtained power grid impedance data, and if the short-circuit ratio is smaller than a switching threshold value, indicating that the power grid strength is reduced, and otherwise, indicating that the power grid strength is not reduced. At the moment, a prediction control reference current in the switching process is calculated through an adaptive switching function in a first switching function form and a current reference value in a grid following mode and a grid construction mode, and the grid-connected converter is switched from the grid following mode to the grid construction mode; and otherwise, indicating that the power grid intensity is increased, calculating a prediction control reference current in a switching process through an adaptive switching function in a second switching function form and a current reference value in a grid following mode and a grid construction mode, and switching the grid-connected converter from the grid construction mode to the grid following mode. Therefore, according to the adaptive switching function-based network-following flexible switching prediction control method, rapid and flexible switching of the grid-connected converter module is ensured, and the stability and the grid-connected output efficiency of the converter in the new energy grid-connected power generation system can be effectively improved.

The invention discloses a new energy bearing capacity evaluation method considering transient overvoltage constraint, and belongs to the technical field of energy safety. The invention discloses a new energy bearing capacity evaluation method considering transient overvoltage constraint. The method comprises the following steps: S1, calculating a short-circuit ratio of a multi-new energy station sending end system; s2, calculating the transient overvoltage of a new energy station node in the sending end system; and S3, constructing a power grid new energy bearing capacity evaluation model considering the transient overvoltage constraint. According to the new energy bearing capacity evaluation method considering the transient overvoltage constraint, the mathematical relation among the transient overvoltage amplitude, the system short-circuit ratio and the active power of the new energy station is used as a main line, and the system short-circuit ratio is used as an intermediate quantity; a mathematical expression of a new energy station node transient overvoltage amplitude and new energy station active power is established, and a power grid new energy bearing capacity evaluation model considering multiple new energy station transient overvoltage constraints is constructed, so that it is ensured that an optimal new energy station output value can be obtained, and safe operation of a power grid is ensured.

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 an autonomous voltage support method and device for a network-constructed converter and a medium, and the method comprises the steps: constructing a converter network-constructed control topological structure, determining a droop control output frequency and a droop control output voltage amplitude according to the topological structure, obtaining the resistance and inductance of a power grid, and the voltage and current of a PCC point, and carrying out the control of the droop control output frequency and the droop control output voltage amplitude. The droop control output frequency and the droop control output voltage amplitude are combined to obtain droop control positive and negative sequence active / reactive reference power, so that an autonomous voltage support strategy is generated to carry out coordinated adjustment of a voltage outer loop / current inner loop, and the real-time impedance measurement is combined with reference power calculation based on autonomous voltage support to obtain the real-time impedance of the droop control output frequency and the droop control output voltage amplitude. According to the invention, accurate voltage support and power adjustment of the grid-forming converter in the weak power grid can be realized, the correctness of the support method is improved, the support capability of the grid-forming converter can be obviously improved, and the power quality and the power supply reliability of the grid-forming converter in the weak power grid with low short circuit ratio and high impedance can be improved.

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 power grid node frequency intensity and voltage intensity-oriented quantification method. The method comprises the following steps of: 1) respectively considering an inertia evaluation strategy of equivalent inertia of a synchronous machine, equivalent inertia of a new energy converter station and equivalent inertia of a load to be used for analyzing node-level inertia support intensity of a system; 2) proposing a power grid node level frequency intensity quantification strategy based on power grid node frequency deviation, frequency change rate and node inertia intensity; and 3) a system node voltage support strength quantification method considering node short-circuit capacity influence caused by voltage drop. And 4) proposing a power grid node-level voltage intensity quantification strategy considering the system node voltage deviation, the voltage change rate and the operation short-circuit ratio. According to the invention, through frequency voltage disturbance quantity information, inertia intensity and a short-circuit ratio, influences of different response characteristics of different inertia sources and system operation state changes on the short-circuit ratio are considered, and frequency support intensity and voltage support intensity are respectively subjected to quantitative analysis; the accuracy and reliability of frequency support strength and voltage support strength quantification are improved.

The invention discloses a switchable converter capacity configuration and switching boundary setting method and device and a medium, and the method comprises the steps: enabling a switchable converter to be switched into a network construction control mode, and obtaining the mode switchable converter capacity in the network construction control mode; the method comprises the following steps: establishing a small signal model of a grid following converter and a grid following / constructing mode switchable converter series-parallel field station according to working conditions, calculating whether a current dominant characteristic root damping ratio of the small signal model meets a stability margin requirement or not, and if the requirement is met, constructing a switching boundary of a hysteresis control strategy setting mode switchable converter by taking an operation short circuit ratio as an index. According to the method, the capacity required by the mode switchable converter is determined under the specified working condition, the switchable converter is converted comprehensively based on the change of the short-circuit ratio and the active power output, the sufficient stability margin is ensured, the operating short-circuit ratio index is introduced, the stability of the active power non-full-power working condition can be reflected, and the stability of the mode switchable converter is improved. The set switching boundary is more reasonable and accurate compared with the short circuit ratio.

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 discloses a network construction power supply capacity configuration optimization method and system, and belongs to the technical field of power system planning. The method comprises the following steps: on the basis of constraint conditions of new energy grid-connected stability, associating technical indexes corresponding to a network construction power supply, and estimating and giving an initial configuration capacity of the network construction power supply; selecting a high-voltage side and a low-voltage side of a step-up transformer of the new energy station as a network construction power supply access position; according to the new energy machine end and grid-connected point multi-station short-circuit ratio constraint, static security constraint and transient stability constraint conditions, verifying whether the network construction power supply meets the constraint requirements, and if not, adjusting the access capacity; if yes, calculating the cost required by the current capacity according to the comprehensive unit price; and comparing the total costs of the corresponding capacities of the two access positions, and selecting the economic optimal capacity as the final configuration capacity. According to the method, the optimal stability and economical efficiency of the new energy station are taken as the target, the optimal access position and capacity of a network construction power supply during grid connection of the new energy single station are determined, and the stability of a power grid in a new energy grid connection scene is improved.

The invention provides a hardware-in-the-loop simulation test method and system for a network construction type wind turbine generator. The method comprises the following steps: establishing a pneumatic model, a mechanical model and a control model of the wind turbine generator in Bladed software; building a wind turbine generator electrical part, a power grid short-circuit ratio adjustable device, a load simulation device, an energy storage device and a power grid simulator model in the RT-LAB simulation platform; and secondly, carrying out simulation test on the low-short-circuit-ratio operation characteristics of the network construction type wind turbine generator through the constructed hardware-in-the-loop platform. According to the method, simulation verification can be carried out on the low-short-circuit-ratio operation characteristic control parameters of the grid-forming type wind turbine generator set, and then the optimal control logic is determined.

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 relay protection, in particular to a new energy grid-connected line phase-to-phase distance protection adaptability quantitative evaluation method and a new energy grid-connected line phase-to-phase distance protection adaptability quantitative evaluation system. Calculating conventional power supply and new energy short-circuit current data of the bus at the side when the three-phase fault of the bus at the receiving end occurs, and preprocessing the short-circuit current data; calculating a short-circuit ratio of a conventional power supply to new energy based on the preprocessed short-circuit current data; and judging the distance protection adaptability of the output grid-connected line according to the short-circuit comparison. According to the method, the ratio of the conventional power supply to the new energy short-circuit current is calculated, and the short-circuit ratio threshold value 1.73 is introduced as a criterion, so that quantitative evaluation of the new energy grid-connected line distance protection adaptability is realized. According to the method, the defect that a traditional evaluation method depends on complex transient simulation is overcome, the evaluation efficiency is remarkably improved, and meanwhile the accuracy of an evaluation result is guaranteed. The invention provides a quantitative criterion of new energy grid-connected line distance protection adaptability for the first time.

The invention discloses an energy storage optimal configuration method and system for improving the short-circuit ratio of multiple new energy stations, and the method comprises the steps: building a power grid simulation digital model comprising a plurality of new energy stations, and determining the selected range of the new energy stations; calculating the short-circuit ratio of each new energy station in the selected range; determining the capacity configuration and access position scheme of energy storage which can be accessed by each new energy station; based on the short-circuit ratio, the energy storage capacity configuration and the access position scheme of each new energy station, determining an energy storage configuration scheme of each new energy station meeting the short-circuit ratio requirement; based on the power grid security constraint, determining an energy storage configuration scheme meeting the power grid security constraint; and determining an energy storage configuration scheme meeting the economical efficiency requirement based on the economical efficiency requirement objective function.

The invention discloses an optimization algorithm for capacity configuration of a phase modifier of an offshore wind power plant, and the optimization process is divided into two stages, the first stage aims at improving the short-circuit ratio of the offshore wind power plant, and the second stage aims at suppressing overvoltage. The method comprises the following steps: firstly, establishing objective functions and constraint conditions of two stage targets; and solving the target function by adopting an eagle group intelligent optimization algorithm to obtain the capacity of the phase modifier which should be configured for each sub-wind power plant in the offshore wind power plant.

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 parallel inverter system hybrid synchronous control method and a related device, and the method comprises the steps: calculating the reactive output power and the active output power of an inverter according to the output voltage and the output current of the inverter, and then calculating a current reference value of voltage loop PI control and a current reference value of current loop PI control; and finally, the PWM module generates a modulation signal to control the operation of the inverter. The hybrid synchronous control method for the parallel inverter system provided by the invention breaks through the bottleneck that the existing hybrid synchronous control method is only suitable for a grid-connected inverter system, has higher stability margin on a wide-range short-circuit ratio system, and can achieve positive response to system frequency and voltage support requirements at the same time; a new way is provided for friendly grid connection and efficient consumption of new energy, and the technical problems that an existing hybrid synchronous control strategy is only suitable for a grid-connected inverter system under the rated frequency, and the application scene is limited are solved.

The invention discloses a power grid transient voltage coordination control method under a distributed photovoltaic storage high permeability working condition, and the method comprises the steps: detecting the voltage change condition of a grid-connected point where a distributed photovoltaic power station is located, and combining the short-circuit ratio of the grid-connected point where the distributed photovoltaic power station is located to a collection point; carrying out pre-estimation calculation on the reactive compensation amount required near the grid-connected point where the key point is located; and through optical storage cooperative control and consideration of different photovoltaic reactive power margin conditions, the reactive power compensation capability of the photovoltaic inverter is developed, smooth processing of the output power of the photovoltaic inverter is realized, and the transient voltage stability of a grid-connected point is improved.

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 stable operation limit evaluation method, system and device for power electronic equipment under a weak power grid condition and a storage medium. The method comprises the steps that the limit short-circuit ratio of the power electronic equipment under different control parameter initial values is calculated; calculating the sensitivity of the limit short-circuit ratio to each control parameter of the power electronic equipment, and screening key control parameters of the power electronic equipment which influence the limit short-circuit ratio; calculating a system short-circuit ratio of the power electronic equipment multi-infeed system and calculating a comparison coefficient between the system short-circuit ratio and the limit short-circuit ratio; and acquiring limit values of all key control parameters of the power electronic equipment when the power electronic equipment is in a critical stable operation state after grid connection, and forming a stable operation limit space of the power electronic equipment under a weak power grid condition. According to the method, the comparison coefficient can be used for judging the adaptability of the power electronic equipment to the weak power grid connected with the power electronic equipment, and the obtained stable operation limit space of the power electronic equipment can provide guidance for parameter design and site selection planning of the power electronic equipment.

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.