Method and system for obtaining short-circuit ratio of new energy power station

Abstract

This invention relates to the field of power system stability analysis technology, and provides a method and system for obtaining the short-circuit ratio of multiple power plants in a new energy power station. The method includes: collecting power grid data and power plant equipment parameters; establishing simulation models of the power grid and the new energy power plant; and performing short-circuit simulation based on the simulation models to obtain the short-circuit capacity S. di Based on the simulation model, steady-state power flow simulation was performed to obtain the low-voltage side voltage value U of the equivalent power generation unit transformer. i0 And the low-voltage side voltage value U of the equivalent power generation unit transformer. i‑j ; Calculate the voltage fluctuation ΔU on the low-voltage side of the equivalent power generation unit transformer. i‑j Based on voltage fluctuation ΔU i‑j Calculate the relative voltage fluctuation coefficient K ij Based on short-circuit capacity S di Relative voltage fluctuation coefficient K ij The short-circuit ratio (MRSCR) of multiple new energy power plants is calculated based on the installed capacity of each new energy power plant. According to the scheme of this invention, the calculation of the self-impedance and complex impedance of nodes is unnecessary, thus simplifying the short-circuit ratio calculation.

Description

Technical Field

[0001] This invention relates to the field of power system stability analysis technology, and in particular to a method and system for obtaining the short-circuit ratio of multiple power plants in a new energy power station. Background Technology

[0002] As the proportion of renewable energy consumption continues to increase, the proportion of synchronous generators is gradually decreasing. Renewable energy power generation, which is mainly based on power electronic interfaces, is characterized by strong volatility and weak support. This leads to a decrease in the rotational inertia, voltage support strength, and stability margin of the AC power grid, resulting in weak grid resistance to disturbances and susceptibility to problems such as frequency deviation, overvoltage, and wideband oscillations. Consequently, operational risks and control difficulties increase. In recent years, several power grid safety and stability incidents caused by insufficient system strength have occurred both domestically and internationally.

[0003] Low system strength is a core bottleneck restricting the grid connection and consumption of new energy sources such as wind and solar power. New energy consumption must be matched with system strength appropriate to its capacity. The short-circuit ratio (SCR) of a converter is an important indicator for measuring the impact of a converter on grid stability when connected to the grid. It is frequently used to analyze grid strength and system dynamic stability after power electronic equipment is connected to an AC system, and is also commonly used to evaluate the operating performance of converters under weak grid conditions. High SCR (>3): indicates a relatively robust grid at the converter connection point, with a strong ability to withstand converter fluctuations. Low SCR (<1.5): indicates a weak grid at the converter connection point, which may lead to voltage instability and resonance problems. The converter requires more stringent control strategies to ensure system stability.

[0004] The relevant definitions of the short-circuit ratio for new energy power plants are described below.

[0005] Short circuit ratio (SCR): The ratio of the short circuit capacity on the low-voltage side of the equivalent power generation unit of a new energy power station to the rated capacity of the equivalent power generation unit of the new energy power station.

[0006] Multi-renewable energy station short circuit ratio (MRSCR): The ratio of the short-circuit capacity of the low-voltage side of the equivalent power generation unit of a new energy station to the equivalent apparent power of the new energy after considering the influence of other new energy stations.

[0007] The short-circuit ratio (MRSCR) of multiple renewable energy power plants effectively takes into account the interactions between them and can quantitatively assess the voltage support strength of renewable energy power plants. Therefore, in regions with a high proportion of renewable energy grid-connected power generation, the MRSCR calculation of multiple renewable energy power plants should be carried out to assess the strength of renewable energy power plant grid connection and guide the planning, design, and operation of renewable energy power generation. The calculation of the MRSCR of multiple renewable energy power plants should comprehensively consider factors such as grid structure, power generation capacity, load distribution, and the impact of renewable energy output changes. Currently, the calculation of the MRSCR of multiple renewable energy power plants generally includes three stages: data preparation, operation mode arrangement, calculation, and evaluation. After the calculation of the MRSCR of multiple renewable energy power plants is completed, it is necessary to conduct research on measures to improve the MRSCR of multiple renewable energy power plants based on the evaluation results. Currently, in areas with a large number of renewable energy power plants and in areas with weak grid structures, the problem of low MRSCR at the generator terminals and grid connection points of renewable energy power plants is particularly prominent. Therefore, researching a simple and accurate method for calculating the MRSCR of renewable energy power plants and proposing effective solutions to improve the MRSCR of renewable energy power plants is of great significance to the stable development of the power system and the safe access of renewable energy power plants.

[0008] Current methods for calculating the short-circuit ratio (MRSCR) of multiple renewable energy power plants require accurate calculation of the self-impedance of the low-voltage side of the equivalent power generation unit of each renewable energy power plant within the synchronous grid, as well as the mutual impedance between the low-voltage sides of the equivalent power generation units of renewable energy power plants. The physical concepts corresponding to these impedance parameters are not clear, making it difficult to obtain them accurately through theoretical calculation methods. In particular, when the network structure is complex, the difficulty of directly calculating the self-impedance and mutual impedance is further increased.

[0009] In addition, the current short-circuit ratio calculation method does not consider the impact of reactive power compensation equipment inside the power station such as SVC and SVG, and also ignores the impact of equipment such as synchronous condensers, series compensation, and DC transmission on the short-circuit ratio of the target node of the new energy power station. Therefore, the current short-circuit ratio calculation method still has the problems of ignoring many factors and inaccurate calculation results.

[0010] The invention patent "A Method and System for Calculating the Equivalent Short-Circuit Ratio of a New Energy Cluster (Application Publication No.: CN112260326A)" provides a method and apparatus for calculating the equivalent short-circuit ratio of a new energy cluster, aiming to solve the technical problem of assessing the grid strength at the grid connection point in the development mode of new energy clusters. The invention includes: determining the equivalent apparent power of each current source in the new energy cluster based on the self-impedance or mutual impedance between current sources; determining the equivalent short-circuit ratio of each current source in the new energy cluster based on the equivalent apparent power and the short-circuit capacity at the grid connection point of each current source; and determining the equivalent short-circuit ratio of the new energy cluster based on the equivalent short-circuit ratio of each current source. This solution, targeting areas where new energy clusters are connected, provides an equivalent short-circuit ratio index for evaluating the overall grid connection strength of new energy clusters, compared to conventional short-circuit ratio calculation methods, and can provide a scientific evaluation method for the development planning and scheduling operation of new energy bases.

[0011] The invention patent "A Method, System, Device, and Storage Medium for Calculating Generalized Short-Circuit Ratio (Authorization Announcement No.: CN114899826B)" provides a method, system, device, and storage medium for calculating generalized short-circuit ratio. The method includes: calculating power flow data of the target receiving-end power grid under a first preset operating state based on a set of system parameters; obtaining measurement data sets of each target feeder node in the target feeder node group under a second preset operating state based on the power flow data and the target feeder node group; obtaining a set of calculated current equations and actual feeder current equations matching each target feeder node based on the measurement data sets corresponding to each target feeder node; obtaining a multi-feed Thevenin equivalent model of the target receiving-end power grid based on a preset least squares algorithm and the calculated current equations and actual feeder current equations matching each target feeder node; and obtaining the generalized short-circuit ratio of the target receiving-end power grid based on the multi-feed Thevenin equivalent model and the feeder DC power set. This invention improves the accuracy of generalized short-circuit ratio calculation.

[0012] As can be seen from the above traditional solutions, all of them require complex calculations and processing of power grid impedance and current equations, which are cumbersome and difficult to promote and apply in engineering. Summary of the Invention

[0013] The purpose of this invention is to solve at least one technical problem in the background art and to provide a method and system for obtaining the short-circuit ratio of multiple power plants in a new energy power station.

[0014] To achieve the above objectives, the present invention provides a method for obtaining the short-circuit ratio of multiple power plants in a new energy power station, comprising:

[0015] Collect power grid data and station equipment parameters;

[0016] Establish simulation models of power grid and new energy power stations based on power grid data and power station equipment parameters;

[0017] Short-circuit capacity S is obtained by performing short-circuit simulation based on the simulation model. di ;

[0018] Based on the simulation model, steady-state power flow simulation was performed to obtain the low-voltage side voltage value U of the equivalent power generation unit transformer of new energy power station i when each new energy power station operates at a predetermined power. i0 When the power output of the equivalent power generation unit at renewable energy power station j decreases by ΔP, the low-voltage side voltage U of the equivalent power generation unit transformer at renewable energy power station i is... i-j ;

[0019] Based on the power decrease ΔP of the equivalent power generation unit j at the new energy power station, the low-voltage side voltage U of the equivalent power generation unit transformer of the i-th new energy power station is calculated. i-j The voltage U of the low-voltage side of the equivalent power generation unit transformer of station i when each new energy power station is operating at the predetermined power level. i0 Calculate the voltage fluctuation ΔU on the low-voltage side of the equivalent power generation unit transformer. i-j ;

[0020] Based on the voltage fluctuation ΔU i-j Calculate the relative voltage fluctuation coefficient K on the low-voltage side of the equivalent power generation unit transformer in a new energy power station. ij ;

[0021] Based on the short-circuit capacity S di The relative voltage fluctuation coefficient K ij The short-circuit ratio (MRSCR) of multiple new energy power plants was calculated based on the installed capacity of each new energy power plant.

[0022] According to one aspect of the present invention, the power grid data and station equipment parameters include: power grid network and transformer parameters, conventional power source distribution and installed capacity, new energy power station distribution and installed capacity, load distribution data, and equivalent models of new energy power stations;

[0023] The equivalent model of the new energy power station includes: equivalent power generation unit, equivalent transformer substation, equivalent busbar, and main transformer parameters.

[0024] According to one aspect of the present invention, steady-state power flow simulation is performed based on the simulation model to obtain the low-voltage side voltage U of the equivalent power generation unit transformer of the new energy power station i when the power of the equivalent power generation unit of the new energy power station j decreases by ΔP. i-j ,include:

[0025] Adjust the output power of the first equivalent power generation unit of the new energy power station to reduce its active power by ΔP, perform power flow simulation, and record the voltage values ​​on the low-voltage side of the transformer box of each equivalent power generation unit of the new energy power station.

[0026] The output power of the first equivalent power generation unit of the new energy power station is restored to its maximum value. Then the output power of the second equivalent power generation unit of the new energy power station is adjusted so that its active power decreases by ΔP. Power flow simulation is performed, and the voltage values ​​on the low-voltage side of the transformer box of each equivalent power generation unit of the new energy power station are recorded.

[0027] This process continues until all new energy power plants within the target power grid have completed the power flow simulation corresponding to the same capacity active power decrease ΔP, and the voltage values ​​of the low-voltage side of the equivalent power generation unit transformer of each new energy power plant have been recorded.

[0028] According to one aspect of the present invention, the active power reduction value ΔP of each new energy power station is the same, and ΔP ≤ 5% of the rated capacity of any one of the new energy power stations:

[0029] ;

[0030] In the formula, P1, P2...P n These represent the rated active power of each new energy power station within the target power grid.

[0031] According to one aspect of the invention, the voltage fluctuation ΔU i-j For: △U i-j =U i-j -U i0 .

[0032] According to one aspect of the invention, the relative voltage fluctuation coefficient K ij for:

[0033] K ij =△U i-j / △U i-i ;

[0034] Among them, △U i-i =U i-i -U i0 U i-i This represents the change in voltage on the low-voltage side of the transformer of the equivalent power generation unit at the i-th station of the new energy power station when the power change ΔP occurs.

[0035] According to one aspect of the present invention, the short-circuit ratio (MRSCR) of the multiple power plants in the new energy power station is:

[0036] ;

[0037] Among them, P j The power of each new energy power station j.

[0038] To achieve the above objectives, the present invention also provides a system for obtaining the short-circuit ratio of multiple power plants in a new energy power station, comprising:

[0039] The data parameter acquisition module collects power grid data and station equipment parameters;

[0040] The simulation model building module establishes simulation models of power grids and new energy power stations based on power grid data and station equipment parameters.

[0041] The short-circuit capacity acquisition module obtains the short-circuit capacity S by performing short-circuit simulation based on the simulation model. di ;

[0042] The module for obtaining the low-voltage side voltage value of the equivalent generation unit transformer substation performs steady-state power flow simulation based on the simulation model to obtain the low-voltage side voltage value U of the equivalent generation unit transformer substation of new energy power station i when each new energy power station is running at a predetermined power. i0 When the power output of the equivalent power generation unit at renewable energy power station j decreases by ΔP, the low-voltage side voltage U of the equivalent power generation unit transformer at renewable energy power station i is... i-j ;

[0043] The voltage fluctuation calculation module is based on the low-voltage side voltage U of the equivalent power generation unit transformer of the new energy power station i when the power of the equivalent power generation unit j decreases by ΔP. i-j The voltage U of the low-voltage side of the equivalent power generation unit transformer of station i when each new energy power station is operating at the predetermined power level. i0 Calculate the voltage fluctuation ΔU on the low-voltage side of the equivalent power generation unit transformer. i-j ;

[0044] The relative voltage fluctuation coefficient calculation module is based on the voltage fluctuation ΔU i-j Calculate the relative voltage fluctuation coefficient K on the low-voltage side of the equivalent power generation unit transformer in a new energy power station. ij ;

[0045] The short-circuit ratio calculation module for multiple power plants in the new energy power generation system is based on the short-circuit capacity S. di The relative voltage fluctuation coefficient K ij The short-circuit ratio (MRSCR) of multiple new energy power plants was calculated based on the installed capacity of each new energy power plant.

[0046] To achieve the above objectives, the present invention also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the method for obtaining the short-circuit ratio of multiple power plants in a new energy power plant as described above.

[0047] To achieve the above objectives, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for obtaining the short-circuit ratio of multiple power plants in a new energy power plant as described above.

[0048] According to the solution of the present invention, the present invention does not require calculation of the self-impedance and complex impedance of the node, thus simplifying the calculation of the short-circuit ratio;

[0049] The short-circuit ratio calculation of this invention can take into account the influence of various equipment such as SVG, synchronous condenser, series compensation and other FACTS devices and DC power transmission on the short-circuit ratio;

[0050] This invention has low software requirements; any software that can perform power flow and short-circuit simulations simultaneously can meet the requirements. Currently, common software such as BPA, ETAP, and Digsilent / powerfactory can all achieve this.

[0051] The model used in this invention is a general model that can be used not only for short-circuit ratio calculation, but also for power flow, short circuit, stability, and power quality analysis. The calculations in this invention are also necessary in the analysis of new energy power grids. Therefore, it can unify modeling and improve the efficiency of engineering research. Attached Figure Description

[0052] Figure 1 This schematic diagram illustrates a flowchart of a method for obtaining the short-circuit ratio of multiple power plants in a new energy power plant according to an embodiment of the present invention.

[0053] Figure 2 A schematic diagram illustrating a simulation model according to Embodiment 1 of the present invention;

[0054] Figure 3 This diagram schematically illustrates the full-capacity power flow simulation results according to Embodiment 1 of the present invention.

[0055] Figure 4 This diagram schematically illustrates the power flow simulation results after adjusting the output power of the equivalent power generation unit at station A according to Embodiment 1 of the present invention.

[0056] Figure 5 The diagram illustrates the power flow simulation results after restoring the output power of the equivalent power generation unit at station A and adjusting the output power of the equivalent power generation unit at station B according to Embodiment 1 of the present invention.

[0057] Figure 6 The diagram illustrates the power flow simulation results after restoring the output power of the equivalent power generation unit at station B and adjusting the output power of the equivalent power generation unit at station C according to Embodiment 1 of the present invention.

[0058] Figure 7 The diagram illustrates the power flow simulation results after restoring the output power of the equivalent power generation unit at station C and adjusting the output power of the equivalent power generation unit at station D according to Embodiment 1 of the present invention.

[0059] Figure 8The diagram schematically illustrates the power flow simulation results after restoring the output power of the equivalent power generation unit at station D and adjusting the output power of the equivalent power generation unit at station E according to Embodiment 1 of the present invention. Detailed Implementation

[0060] The invention will now be discussed with reference to exemplary embodiments. It should be understood that the described embodiments are merely intended to enable those skilled in the art to better understand and thus implement the invention, and are not intended to imply any limitation on the scope of the invention.

[0061] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment".

[0062] Figure 1 The flowchart illustrates a method for obtaining the short-circuit ratio of multiple power plants in a new energy power plant according to an embodiment of the present invention. Figure 1 As shown in this embodiment, the method for obtaining the short-circuit ratio of multiple power plants in a new energy power station includes:

[0063] Collect power grid data and station equipment parameters;

[0064] Establish simulation models of power grid and new energy power stations based on power grid data and power station equipment parameters;

[0065] Short-circuit capacity S is obtained by performing short-circuit simulation based on the simulation model. di ;

[0066] Based on the simulation model, steady-state power flow simulation was performed to obtain the low-voltage side voltage value U of the equivalent power generation unit transformer of new energy power station i when each new energy power station operates at a predetermined power. i0 When the power output of the equivalent power generation unit at renewable energy power station j decreases by ΔP, the low-voltage side voltage U of the equivalent power generation unit transformer at renewable energy power station i is... i-j ;

[0067] Based on the power decrease ΔP of the equivalent power generation unit j at the new energy power station, the low-voltage side voltage U of the equivalent power generation unit transformer of the i-th new energy power station is calculated. i-j The voltage U of the low-voltage side of the equivalent power generation unit transformer of station i when each new energy power station is operating at the predetermined power level. i0 Calculate the voltage fluctuation ΔU on the low-voltage side of the equivalent power generation unit transformer. i-j ;

[0068] Based on the voltage fluctuation ΔU i-j Calculate the relative voltage fluctuation coefficient K on the low-voltage side of the equivalent power generation unit transformer in a new energy power station. ij ;

[0069] Based on the short-circuit capacity S di The relative voltage fluctuation coefficient K ij The short-circuit ratio (MRSCR) of multiple new energy power plants is calculated based on the installed capacity of each new energy power plant (the rated active power of each new energy power plant in the following text).

[0070] Furthermore, according to one embodiment of the present invention, the power grid data and station equipment parameters include: power grid network and transformer parameters, conventional power source distribution and installed capacity, new energy power station distribution and installed capacity, load distribution data, and equivalent models of new energy power stations;

[0071] The equivalent model of the new energy power station includes: equivalent power generation unit, equivalent transformer substation, equivalent busbar, and main transformer parameters.

[0072] Furthermore, according to one embodiment of the present invention, simulation software capable of simultaneously performing power flow and short-circuit simulations is used, such as the commonly used BPA, ETAP, and Digsilent / PowerFactory, all of which meet the requirements. Simulation models of the power grid and renewable energy power plants are established within the software. The modeling scope includes power grid substations, power plants, user substations, renewable energy power plants (renewable energy power stations), DC transmission (if any), series compensation, etc. (if any). Substations include main transformers, high and low voltage buses, equivalent loads, and reactive power compensation equipment; power plants include generator sets, step-up transformers, buses of various voltage levels, and plant auxiliary power loads; user substations include main transformers, high and low voltage buses, equivalent loads, and reactive power compensation equipment; renewable energy power plants refer to wind farms, photovoltaic power plants, energy storage power plants, etc., and the model should cover power generation equipment (photovoltaic inverters, energy storage PCS, wind turbines), collector lines, box-type substations, and main transformers. The power generation equipment, collector lines, and box-type substations all use aggregated equivalent models. Power plants are connected via overhead lines and cables, with the line type, length, and parameters consistent with actual conditions.

[0073] Specifically, in this embodiment, establishing simulation models for the power grid and new energy power plants includes:

[0074] (1) Establish an external power grid simulation model

[0075] The external power grid is equivalently represented at the highest voltage level bus of the regional power grid. The external power grid is modeled using the single-port Thevenin equivalent method, and the external power grid is modeled according to the principle of consistency between short-circuit capacity, operating voltage and power flow data. The external power grid is set as a slack node, and its impedance is the series impedance (K=X / R, where X is the series inductive reactance of the equivalent power grid in Ω; R is the series resistance of the equivalent power grid in Ω).

[0076] PCC external power grid equivalent voltage Calculate using the following formula:

[0077] ;

[0078] In the formula: U AV The average operating line voltage of the equivalent bus is given in kV.

[0079] The series impedance of the external power grid for the PCC is calculated using the following formula:

[0080]

[0081]

[0082] In the formula: The short-circuit capacity at the equivalent busbar is in MVA; K is the equivalent grid impedance ratio, K=X / R, where X is the series inductive reactance of the equivalent grid in Ω; and R is the series resistance of the equivalent grid in Ω.

[0083] (2) Establish a simulation model for new energy power stations

[0084] The new energy power station model is divided into two parts: the booster station and the new energy power station equipment. The booster station includes equipment such as busbars, main transformers, SVCs, SVGs, and synchronous condensers, which can be modeled according to actual parameters and generally do not require equivalent modeling. The new energy power station equipment includes collection lines, box-type substations, and power generation equipment (photovoltaic inverters, wind turbines, and energy storage converters PCS), which are modeled using the following method.

[0085] Equivalent modeling method for prefabricated substations: One equivalent prefabricated substation is set up for each station. The voltage transformation ratio of the equivalent prefabricated substation is taken as the actual transformation ratio of the prefabricated substations in the station. The capacity is set according to the sum of the capacities of all prefabricated substations in the station. The short-circuit impedance and no-load current percentage of the equivalent prefabricated substation are determined according to the principle of equal reactive power loss of the prefabricated substation. The equivalent method is as follows:

[0086] ;

[0087] In the formula: S represents the percentage of the equivalent short-circuit impedance of the transformer. i视在功率 The apparent power of a single transformer substation; For the total apparent power of new energy power stations, S i箱变 The rated capacity of a single transformer substation in a new energy power station. For the equivalent box variable capacity, U ki The percentage represents the short-circuit impedance of a single transformer substation. 0等值 % represents the equivalent no-load current percentage of the transformer substation, I 0i The percentage represents the no-load current of a single transformer substation.

[0088] Equivalent modeling method for power generation equipment (photovoltaic inverters, wind turbines, energy storage converters PCS): All power generation equipment in the power generation units of the new energy power station are aggregated into one equivalent power generation equipment according to the total capacity, and the rated voltage is the same as that of a single equipment.

[0089] Equivalent modeling method for collector lines: Collector lines are equivalent according to the principle that inductive reactive power loss and capacitive reactive power loss (charging power) are equal respectively, as follows.

[0090] ;

[0091] In the formula: L 等值 C is the equivalent reactance of the collector line. 等值 Q is the equivalent capacitance of the collector circuit. 总感性无功损耗 Q represents the total inductive reactive power loss of all collector lines at this station. 总容性无功损耗 I represents the total capacitive reactive power loss of all collector lines in this station. 等值 U is the equivalent unit operating current. AV ω is the average operating voltage at the power generation unit port, ω is the grid angular frequency, ω=2πf, f is the grid frequency, 50Hz.

[0092] Furthermore, according to one embodiment of the present invention, short-circuit simulation is performed using the short-circuit simulation function of software to obtain the short-circuit capacity S on the low-voltage side of the equivalent power generation unit transformer of each new energy power station. di (Unit: MVA) Short-circuit simulation should not include the short-circuit current of new energy power generation equipment.

[0093] The statistical table of short-circuit simulation results is shown in Table 1 below:

[0094] Table 1. Short-circuit capacity S of the low-voltage side of the transformer substation for each new energy power station's equivalent power generation unit. di Statistical table

[0095]

[0096] In this embodiment, S di This refers to the simulated short-circuit capacity of the low-voltage side of the equivalent generation unit transformer at station i, such as S. dA This refers to the simulated short-circuit capacity of the low-voltage side of the equivalent power generation unit transformer at station A, where i is the number of the new energy power station.

[0097] Furthermore, according to one embodiment of the present invention, since the short-circuit ratio of multiple stations in a new energy power station reaches its lowest value in the range of high output, and the output of the new energy power station is synchronous, the working capacity of the equivalent power generation unit of each station is set to the maximum value, and the user station and power station can be set according to the normal operation mode.

[0098] Power flow simulation was conducted to obtain the voltage values ​​on the low-voltage side of the equivalent generation unit transformer of each new energy power station. To facilitate accurate calculation, the voltage values ​​were made as precise as possible, such as retaining several decimal places. After the full-capacity power flow simulation was completed, the voltage values ​​on the low-voltage side of the equivalent generation unit transformer of each new energy power station were recorded.

[0099] In the implementation method, steady-state power flow simulation based on the simulation model is used to obtain the low-voltage side voltage U of the equivalent power generation unit transformer of the new energy power station i when the power of the equivalent power generation unit of the j-th power station decreases by ΔP. i-j ,include:

[0100] Adjust the output power of the first equivalent power generation unit of the new energy power station to reduce its active power by ΔP, perform power flow simulation, and record the voltage values ​​on the low-voltage side of the transformer box of each equivalent power generation unit of the new energy power station.

[0101] The output power of the first equivalent power generation unit of the new energy power station is restored to its maximum value. Then the output power of the second equivalent power generation unit of the new energy power station is adjusted so that its active power decreases by ΔP. Power flow simulation is performed, and the voltage values ​​on the low-voltage side of the transformer box of each equivalent power generation unit of the new energy power station are recorded.

[0102] This process continues until all new energy power plants within the target power grid have completed the power flow simulation corresponding to the same capacity active power decrease ΔP, and the voltage values ​​of the low-voltage side of the equivalent power generation unit transformer of each new energy power plant have been recorded.

[0103] Furthermore, according to one embodiment of the present invention, the active power reduction value ΔP of each new energy power station is the same, and ΔP ≤ 5% of the rated capacity of any one new energy power station:

[0104] ;

[0105] In the formula, P1, P2...P n These represent the rated active power of each new energy power station within the target power grid.

[0106] In this embodiment, after the power flow simulation is completed, the simulation results are summarized in Table 2 below:

[0107] Table 2. Voltage Statistics of Low-Voltage Side of Equivalent Generation Unit Substations for Each New Energy Power Station

[0108]

[0109] In this embodiment, the above-mentioned U i0 This refers to the low-voltage side voltage value of the equivalent power generation unit transformer of the i-th station when all new energy power plants are operating at their predetermined power output, where i is the new energy power plant number, such as U. B0This refers to the low-voltage side voltage value of the equivalent power generation unit transformer box of Station B when all new energy power plants are operating at their predetermined power.

[0110] The above U i-j This refers to the low-voltage side voltage value of the equivalent power generation unit transformer at the i-th station of the new energy power station when the power of the j-th station decreases by ΔP. i and j are the station numbers, such as U. C-B This refers to the low-voltage side voltage value of the equivalent power generation unit transformer at the new energy power station C when the power of the equivalent power generation unit at station B decreases by ΔP.

[0111] Furthermore, according to one embodiment of the present invention, the voltage fluctuation ΔU i-j For: △U i-j =U i-j -U i0 In this embodiment, the voltage fluctuation ΔU on the low-voltage side of the equivalent power generation unit transformer of each new energy power station is... i-j This refers to the voltage value on the low-voltage side of the equivalent power generation unit transformer of the i-th station of the new energy power station when the power of the j-th equivalent power generation unit decreases by ΔP, minus the voltage value on the low-voltage side of the equivalent power generation unit transformer of the i-th station when all new energy power stations are running at the predetermined power.

[0112] In this embodiment, the voltage statistics table (U) of the low-voltage side of the equivalent power generation unit transformer of each new energy power station obtained from the power flow simulation of each operating condition in Table 2 is used. i0 and U i-j ), calculate the voltage fluctuation value ΔU using the method above. i-j The statistical results are shown in Table 3 below.

[0113] Table 3 Voltage fluctuations (ΔU) on the low-voltage side of the transformer substation of each new energy power station's equivalent power generation unit. i-j Statistical table

[0114]

[0115] Furthermore, according to one embodiment of the present invention, the relative voltage fluctuation coefficient K ij for:

[0116] K ij =△U i-j / △U i-i ;

[0117] Among them, △U i-i =U i-i -U i0 U i-i Let K be the voltage change on the low-voltage side of the equivalent power generation unit transformer at the i-th station of the new energy power station when the power change ΔP occurs. In the above formula, when i=j, K... ij =1.

[0118] In this embodiment, the relative voltage fluctuation coefficient Kij of the low-voltage side of the equivalent power generation unit transformer of each new energy power station is calculated based on the voltage fluctuation statistics of the transformer. The results are shown in Table 4 below.

[0119] Table 4 Voltage fluctuation coefficient K between various new energy power plants ij Statistical table

[0120]

[0121] Furthermore, according to one embodiment of the present invention, for n new energy power stations, based on the short-circuit capacity S of the low-voltage side of the equivalent power generation unit transformer of each new energy power station... di (Table 1 Simulation Data) Relative Voltage Fluctuation Coefficient K of the Low-Voltage Side of the Equivalent Generation Unit Transformer for Each New Energy Power Station ij (Table 4 Calculation Data) The installed capacity of each new energy power station is calculated according to the following formula for the short-circuit ratio (MRSCR) of multiple new energy power stations:

[0122] ;

[0123] Among them, P j The power of each new energy power station j.

[0124] According to the above-described scheme of the present invention, the present invention does not require calculation of the self-impedance and complex impedance of the node, thus simplifying the calculation of the short-circuit ratio;

[0125] The short-circuit ratio calculation of this invention can take into account the influence of various equipment such as SVG, synchronous condenser, series compensation and other FACTS devices and DC power transmission on the short-circuit ratio;

[0126] This invention has low software requirements; any software that can perform power flow and short-circuit simulations simultaneously can meet the requirements. Currently, common software such as BPA, ETAP, and Digsilent / powerfactory can all achieve this.

[0127] The model used in this invention is a general model that can be used not only for short-circuit ratio calculation, but also for power flow, short circuit, stability, and power quality analysis. The calculations in this invention are also necessary in the analysis of new energy power grids. Therefore, it can unify modeling and improve the efficiency of engineering research.

[0128] Furthermore, to achieve the above objectives, the present invention also provides a system for obtaining the short-circuit ratio of multiple power plants in a new energy power station, comprising:

[0129] The data parameter acquisition module collects power grid data and station equipment parameters;

[0130] The simulation model building module establishes simulation models of power grids and new energy power stations based on power grid data and station equipment parameters.

[0131] The short-circuit capacity acquisition module obtains the short-circuit capacity S by performing short-circuit simulation based on the simulation model. di ;

[0132] The module for obtaining the low-voltage side voltage value of the equivalent generation unit transformer substation performs steady-state power flow simulation based on the simulation model to obtain the low-voltage side voltage value U of the equivalent generation unit transformer substation of new energy power station i when each new energy power station is running at a predetermined power. i0 When the power output of the equivalent power generation unit at renewable energy power station j decreases by ΔP, the low-voltage side voltage U of the equivalent power generation unit transformer at renewable energy power station i is... i-j ;

[0133] The voltage fluctuation calculation module is based on the low-voltage side voltage U of the equivalent power generation unit transformer of the new energy power station i when the power of the equivalent power generation unit j decreases by ΔP. i-j The voltage U of the low-voltage side of the equivalent power generation unit transformer of station i when each new energy power station is operating at the predetermined power level. i0 Calculate the voltage fluctuation ΔU on the low-voltage side of the equivalent power generation unit transformer. i-j ;

[0134] The relative voltage fluctuation coefficient calculation module is based on the voltage fluctuation ΔU i-j Calculate the relative voltage fluctuation coefficient K on the low-voltage side of the equivalent power generation unit transformer in a new energy power station. ij ;

[0135] The short-circuit ratio calculation module for multiple power plants in the new energy power generation system is based on the short-circuit capacity S. di The relative voltage fluctuation coefficient K ij The short-circuit ratio (MRSCR) of multiple new energy power plants was calculated based on the installed capacity of each new energy power plant.

[0136] The above-mentioned short-circuit ratio acquisition system for multiple new energy power plants according to the present invention can realize the above-mentioned method for acquiring the short-circuit ratio for multiple new energy power plants. The specific process steps are as described above and will not be repeated here.

[0137] Furthermore, to achieve the above objectives, the present invention also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the method for obtaining the short-circuit ratio of multiple power plants in a new energy power plant as described above.

[0138] Furthermore, to achieve the above objectives, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for obtaining the short-circuit ratio of multiple stations in a new energy power plant as described above.

[0139] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely one preferred embodiment of the invention and are only used to explain the invention. They do not limit the scope of protection of the invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0140] Example 1

[0141] A method for obtaining the short-circuit ratio of multiple power plants in a new energy power plant includes the following steps:

[0142] Step 1: Prepare power grid and substation equipment parameters

[0143] (1) Network structure

[0144] This embodiment consists of five new energy power stations (all wind farms) A, B, C, D, and E, and a power grid. The grid bus voltage level is 220kV, and the external power grid is equivalent to the 220kV bus of the power grid. The voltage levels of the booster stations A, B, C, D, and E of the new energy power stations are all 220 / 35kV, and the voltage levels of the equivalent transformer substations are 35 / 1.14kV. Wind farm A has a capacity of 200MW, a main transformer capacity of 200MVA, an equivalent transformer substation capacity of 200MVA, and an equivalent wind turbine capacity of 200MW; wind farm B has a capacity of 100MW, a main transformer capacity of 100MVA, an equivalent transformer substation capacity of 100MVA, and an equivalent wind turbine capacity of 100MW; wind farm C has a capacity of 150MW, a main transformer capacity of 150MVA, an equivalent transformer substation capacity of 150MVA, and an equivalent wind turbine capacity of 150MW; wind farm D has a capacity of 200MW, a main transformer capacity of 200MVA, an equivalent transformer substation capacity of 200MVA, and an equivalent wind turbine capacity of 200MW; wind farm E has a capacity of 200MW, a main transformer capacity of 200MVA, an equivalent transformer substation capacity of 200MVA, and an equivalent wind turbine capacity of 200MW.

[0145] Station A is connected to the 220kV busbar of Station B via 220kV interconnection line 3. Station B is connected to the 220kV busbar of the power station via 220kV interconnection line 1. Station C is connected to the 220kV busbar of Station D via 220kV interconnection line 4. Station E is connected to the 220kV busbar of Station D via 220kV interconnection line 5. Station D is connected to the 220kV busbar of the power station via 220kV interconnection line 2.

[0146] (2) External power grid equivalent

[0147] The short-circuit capacity of the 220kV busbar of the power station is 8000MVA, K=10. The equivalent algorithm proposed in this invention is used for the external power grid, and the equivalent results are as follows:

[0148] ;

[0149] = ;

[0150] = ;

[0151] (3) Transformer parameters

[0152] The main transformer parameters are as follows:

[0153] The main transformer at station A has a capacity of 200MVA, a voltage level of 230 / 37kV, a short-circuit impedance of 14%, and a no-load current of 0.05%.

[0154] Station B's main transformer has a capacity of 100MVA, a voltage level of 230 / 37kV, a short-circuit impedance of 10%, and a no-load current of 0.05%.

[0155] The main transformer at station C has a capacity of 150MVA, a voltage level of 230 / 37kV, a short-circuit impedance of 12%, and a no-load current of 0.05%.

[0156] The main transformer at station D has a capacity of 200MVA, a voltage level of 230 / 37kV, a short-circuit impedance of 14%, and a no-load current of 0.05%.

[0157] The main transformer at station E has a capacity of 200MVA, a voltage level of 230 / 37kV, a short-circuit impedance of 14%, and a no-load current of 0.05%.

[0158] The equivalent box transformer parameters are as follows:

[0159] The transformer substation A has a capacity of 200MVA, a voltage transformation ratio of 37 / 1.14kV, a short-circuit impedance of 7%, and a no-load current of 0.1%.

[0160] Bilibili's transformer substation has a capacity of 100MVA, a voltage transformation ratio of 37 / 1.14kV, a short-circuit impedance of 7%, and a no-load current of 0.1%.

[0161] The C-station transformer has a capacity of 150MVA, a voltage transformation ratio of 37 / 1.14kV, a short-circuit impedance of 7%, and a no-load current of 0.1%.

[0162] The D-station transformer has a capacity of 200MVA, a voltage transformation ratio of 37 / 1.14kV, a short-circuit impedance of 7%, and a no-load current of 0.1%.

[0163] The E-station transformer has a capacity of 200MVA, a voltage transformation ratio of 37 / 1.14kV, a short-circuit impedance of 7%, and an no-load current of 0.1%.

[0164] (4) 220kV line parameters

[0165] Connection line 1 model: LGJ-400×2, length 35km, resistance per unit length R=0.1Ω / km, reactance per unit length X=0.3Ω / km;

[0166] Connection line 2 model: LGJ-400×2, length 40km, resistance per unit length R=0.1Ω / km, reactance per unit length X=0.3Ω / km;

[0167] Connection line 3, model: LGJ-400, length 20km, resistance per unit length R=0.12Ω / km, reactance per unit length X=0.33Ω / km;

[0168] Connection line 4, model: LGJ-400, length 20km, resistance per unit length R=0.12Ω / km, reactance per unit length X=0.33Ω / km;

[0169] Connection line 5, model: LGJ-400, length 35km, resistance per unit length R=0.12Ω / km, reactance per unit length X=0.33Ω / km.

[0170] In this embodiment, the collector line is relatively short and is a low-impedance cable, so it has little impact on the short-circuit ratio calculation and therefore the collector line parameters are ignored.

[0171] Step 2: Establish a simulation model

[0172] The Digsilent / powerfactory software was used to establish simulation models of the power grid and new energy power plants. This software has power flow simulation and short circuit simulation functions, which meet the requirements of this embodiment.

[0173] The simulation model is attached. Figure 2 As shown.

[0174] Step 3: Conduct short-circuit simulation to obtain the short-circuit capacity S di

[0175] Using the software's short-circuit simulation function, short-circuit simulations were conducted to obtain the short-circuit capacity S on the low-voltage side of each equivalent power generation unit transformer in each new energy power station. di The short-circuit simulation does not include the short-circuit current of new energy power generation equipment.

[0176] The statistical table of short-circuit simulation results in this embodiment is shown in Table 5 below.

[0177] Table 5. Short-circuit capacity S of the low-voltage side of the transformer substation in the equivalent power generation unit of each new energy power station di Statistical table

[0178]

[0179] Step 4: Conduct steady-state power flow simulation to obtain voltage Ui0 and U i-j

[0180] Since the short-circuit ratio of the new energy power station in this embodiment reaches the lowest value in the range of high output, and the output of the new energy power station is synchronous, the capacity of the power generation unit of each station is set to the maximum value.

[0181] Power flow simulation was conducted to obtain the voltage values ​​on the low-voltage side of the equivalent generation unit transformer of each new energy power station in this embodiment. To facilitate accurate calculation, the voltage values ​​were taken as precisely as possible. The voltage simulation results are per-unit values, and all values ​​are retained to 6 decimal places. After the full-capacity power flow simulation was completed, the voltage values ​​on the low-voltage side of the equivalent generation unit transformer of each new energy power station were recorded. A screenshot of the simulation results under this condition is attached. Figure 3 As shown.

[0182] Adjust the output power of the equivalent generation unit at station A, reducing its active power by 5MW. Perform power flow simulation and record the voltage values ​​on the low-voltage side of the transformer substation for each equivalent generation unit at the new energy power station. A screenshot of the simulation results is attached. Figure 4 As shown.

[0183] The output power of the equivalent generating unit at station A was restored to its initial and maximum values. Then, the output power of the equivalent generating unit at station B was adjusted to reduce its active power by 5MW. Power flow simulation was performed, and the voltage values ​​on the low-voltage side of the transformer substation of each equivalent generating unit at the new energy power station were recorded. A screenshot of the simulation results is attached. Figure 5 As shown.

[0184] The output power of the equivalent generation unit at station B was restored to its initial and maximum values. Then, the output power of the equivalent generation unit at station C was adjusted to reduce its active power by 5MW. Power flow simulation was performed, and the voltage values ​​on the low-voltage side of the transformer substation of each equivalent generation unit at the new energy power station were recorded. A screenshot of the simulation results is attached. Figure 6 As shown.

[0185] The output power of the equivalent generating unit at station C was restored to its initial and maximum values. Then, the output power of the equivalent generating unit at station D was adjusted to reduce its active power by 5MW. Power flow simulation was performed, and the voltage values ​​on the low-voltage side of the transformer substation of each equivalent generating unit at the new energy power station were recorded. A screenshot of the simulation results is attached. Figure 7 As shown.

[0186] The output power of the equivalent generating unit at station D was restored to its initial and maximum values. Then, the output power of the equivalent generating unit at station E was adjusted to reduce its active power by 5MW. Power flow simulation was performed, and the voltage values ​​on the low-voltage side of the transformer substation of each equivalent generating unit at the new energy power station were recorded. A screenshot of the simulation results is attached. Figure 8 As shown.

[0187] The output power of the equivalent power generation unit at station E is restored to its initial and maximum values, and the power flow simulation ends.

[0188] After the power flow simulation was completed, the simulation results were summarized in Table 6 below.

[0189] Table 6. Low-voltage side voltage (U) of the equivalent power generation unit transformer for each new energy power station i0 and U i-j Statistical table

[0190]

[0191] Step 5: Calculate the voltage fluctuation (ΔU) on the low-voltage side of the equivalent power generation unit transformer. i-j )

[0192] Based on the voltage statistics of the low-voltage side of the equivalent power generation unit transformer of each new energy power station obtained from the power flow simulation under various operating conditions (U... i0 and U i-j ), calculate the voltage fluctuation value ΔU in this embodiment. i-j The statistical results are shown in Table 7 below.

[0193] Table 7 Voltage fluctuations (ΔU) on the low-voltage side of the transformer substation of each new energy power station's equivalent power generation unit. i-j Statistical table

[0194]

[0195] Step 6: Calculate the relative voltage fluctuation coefficient K on the low-voltage side of the equivalent power generation unit transformer at the new energy power station. ij

[0196] Based on the voltage fluctuation statistics table (Table 7) of the equivalent power generation unit transformers of each new energy power station in this embodiment, the relative voltage fluctuation coefficient K of the low-voltage side of the transformers of the equivalent power generation unit of the new energy power station is calculated. ij The calculation method and results are shown in Table 8 below.

[0197] Table 8. Statistics of Kij Transmission Coefficients among New Energy Power Stations

[0198]

[0199] Step 7: Calculate the short-circuit ratio (MRSCR) of the new energy power station

[0200] For the five new energy power stations in this embodiment, based on the short-circuit capacity S of the low-voltage side of each equivalent power generation unit transformer in each new energy power station... di The relative voltage fluctuation coefficient K on the low-voltage side of each equivalent power generation unit transformer. ij The installed capacity of each new energy power station is calculated using the following formula to determine the short-circuit ratio (MRSCR) of multiple new energy power stations:

[0201] ;

[0202] in, The equivalent apparent power of new energy sources after taking into account the impact of other new energy power plants.

[0203] The calculation results are shown in Table 9 below.

[0204] Table 9 Calculation results of short-circuit ratio (MRSCR) for multiple new energy power plants

[0205]

[0206] As can be seen from the calculation results in the table above, the short-circuit ratio of station E in this embodiment is the lowest. Based on the main electrical wiring diagram, it can be seen that station E has a longer power supply line and a larger installed capacity, hence its lowest short-circuit ratio. Therefore, the short-circuit ratio calculation results in this embodiment are reasonable.

[0207] Those skilled in the art will recognize that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0208] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and equipment can be referred to the corresponding process in the foregoing method implementation, and will not be repeated here.

[0209] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0210] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the objectives of the embodiments of the present invention, depending on actual needs.

[0211] In addition, the functional modules in the embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0212] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the sending / receiving methods of various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0213] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

[0214] It should be understood that the sequence number of each step in the invention and its embodiments does not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

Claims

1. A method for obtaining the short-circuit ratio of multiple power plants in a new energy power station, characterized in that, include: Collect power grid data and station equipment parameters; Establish simulation models of power grid and new energy power stations based on power grid data and power station equipment parameters; Short-circuit capacity S is obtained by performing short-circuit simulation based on the simulation model. di ; Based on the simulation model, steady-state power flow simulation was performed to obtain the low-voltage side voltage value U of the equivalent power generation unit transformer of new energy power station i when each new energy power station operates at a predetermined power. i0 When the power output of the equivalent power generation unit at renewable energy power station j decreases by ΔP, the low-voltage side voltage U of the equivalent power generation unit transformer at renewable energy power station i is... i-j ; Based on the power decrease ΔP of the equivalent power generation unit j at the new energy power station, the low-voltage side voltage U of the equivalent power generation unit transformer of the i-th new energy power station is calculated. i-j The voltage U of the low-voltage side of the equivalent power generation unit transformer of station i when each new energy power station is operating at the predetermined power level. i0 Calculate the voltage fluctuation ΔU on the low-voltage side of the equivalent power generation unit transformer. i-j ; Based on the voltage fluctuation ΔU i-j Calculate the relative voltage fluctuation coefficient K on the low-voltage side of the equivalent power generation unit transformer in a new energy power station. ij ; Based on the short-circuit capacity S di The relative voltage fluctuation coefficient K ij The short-circuit ratio (MRSCR) of multiple new energy power plants was calculated based on the installed capacity of each new energy power plant.

2. The method for obtaining the short-circuit ratio of multiple new energy power plants according to claim 1, characterized in that, The power grid data and station equipment parameters include: power grid network and transformer parameters, conventional power source distribution and installed capacity, new energy power station distribution and installed capacity, load distribution data, and equivalent models of new energy power stations; The equivalent model of the new energy power station includes: equivalent power generation unit, equivalent transformer substation, equivalent busbar, and main transformer parameters.

3. The method for obtaining the short-circuit ratio of multiple power plants in a new energy power station according to claim 2, characterized in that, Based on the simulation model, steady-state power flow simulation was performed to obtain the low-voltage side voltage U of the equivalent power generation unit transformer of new energy power station i when the power of the equivalent power generation unit of new energy power station j decreased by ΔP. i-j ,include: Adjust the output power of the first equivalent power generation unit of the new energy power station to reduce its active power by ΔP, perform power flow simulation, and record the voltage values ​​on the low-voltage side of the transformer box of each equivalent power generation unit of the new energy power station. The output power of the first equivalent power generation unit of the new energy power station is restored to its maximum value. Then the output power of the second equivalent power generation unit of the new energy power station is adjusted so that its active power decreases by ΔP. Power flow simulation is performed, and the voltage values ​​of the low-voltage side of the transformer box of each equivalent power generation unit of the new energy power station are recorded. This process continues until all new energy power plants within the target power grid have completed the power flow simulation corresponding to the same capacity active power decrease ΔP, and the voltage values ​​of the low-voltage side of the equivalent power generation unit transformer of each new energy power plant have been recorded.

4. The method for obtaining the short-circuit ratio of multiple power plants in a new energy power station according to claim 3, characterized in that, The active power reduction ΔP of each renewable energy power station is the same, and ΔP ≤ 5% of the rated capacity of any renewable energy power station: ； In the formula, P1, P2...P n These represent the rated active power of each new energy power station within the target power grid.

5. The method for obtaining the short-circuit ratio of multiple power plants in a new energy power station according to claim 4, characterized in that, The voltage fluctuation ΔU i-j For: △U i-j =U i-j -U i0 .

6. The method for obtaining the short-circuit ratio of multiple new energy power plants according to claim 5, characterized in that, The relative voltage fluctuation coefficient K ij for: K ij =△U i-j / △U i-i ; Among them, △U i-i =U i-i -U i0 U i-i This represents the change in voltage on the low-voltage side of the transformer of the equivalent power generation unit at the i-th station of the new energy power station when the power change ΔP occurs.

7. The method for obtaining the short-circuit ratio of multiple new energy power plants according to claim 6, characterized in that, The short-circuit ratio (MRSCR) of the multiple power stations of the new energy power plant is: ； Among them, P j The power of each new energy power station j.

8. A system for obtaining the short-circuit ratio of multiple power plants in a new energy power station, characterized in that: include: The data parameter acquisition module collects power grid data and station equipment parameters; The simulation model building module establishes simulation models of power grids and new energy power stations based on power grid data and station equipment parameters. The short-circuit capacity acquisition module obtains the short-circuit capacity S by performing short-circuit simulation based on the simulation model. di ; The module for obtaining the low-voltage side voltage value of the equivalent generation unit transformer substation performs steady-state power flow simulation based on the simulation model to obtain the low-voltage side voltage value U of the equivalent generation unit transformer substation of new energy power station i when each new energy power station is running at a predetermined power. i0 When the power output of the equivalent power generation unit at renewable energy power station j decreases by ΔP, the low-voltage side voltage U of the equivalent power generation unit transformer at renewable energy power station i is... i-j ; The voltage fluctuation calculation module is based on the low-voltage side voltage U of the equivalent power generation unit transformer of the new energy power station i when the power of the equivalent power generation unit j decreases by ΔP. i-j The voltage U of the low-voltage side of the equivalent power generation unit transformer of station i when each new energy power station is operating at the predetermined power level. i0 Calculate the voltage fluctuation ΔU on the low-voltage side of the equivalent power generation unit transformer. i-j ; The relative voltage fluctuation coefficient calculation module is based on the voltage fluctuation ΔU i-j Calculate the relative voltage fluctuation coefficient K on the low-voltage side of the equivalent power generation unit transformer in a new energy power station. ij ; The short-circuit ratio calculation module for multiple power plants in the new energy power station is based on the short-circuit capacity S. di The relative voltage fluctuation coefficient K ij The short-circuit ratio (MRSCR) of multiple new energy power plants was calculated based on the installed capacity of each new energy power plant.

9. An electronic device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the method for obtaining the short-circuit ratio of multiple power plants in a new energy power plant as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for obtaining the short-circuit ratio of multiple power plants in a new energy power plant as described in any one of claims 1-7.

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