A method and system for optimizing the configuration of a synchronous condenser to improve the voltage strength of a power grid

Abstract

The present invention discloses a method and system for optimizing the configuration of synchronous condensers to enhance the voltage strength of the power grid. The method includes: determining the short-circuit ratio critical values of multiple target new energy power stations when they are connected to an AC-DC hybrid power grid to ensure the stable operation of the power grid system; calculating the short-circuit ratio of each new energy power station among the multiple target new energy power stations; sequentially comparing the short-circuit ratio of each new energy power station with the short-circuit ratio critical value; when there is a new energy power station with a short-circuit ratio less than the short-circuit ratio critical value, determining the configuration quantity of the synchronous condenser based on a pre-determined target for optimizing the configuration of the synchronous condenser, so that the short-circuit ratio of each new energy power station among the multiple target new energy power stations is greater than the short-circuit ratio critical value.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-new energy power station access to AC / DC hybrid power grid planning and operation control, and more specifically, to a method and system for optimizing the configuration of synchronous condensers to enhance the voltage strength of the power grid. Background Art

[0002] Large-capacity UHV AC / DC long-distance power transmission is an important measure to solve the problem of large-scale new energy base power transmission and prevent air pollution. However, the vulnerability and weak support characteristics of new energy power generation equipment itself also bring a series of challenges to the safe and stable operation of the power grid, such as the self-oscillation and overvoltage problems of new energy generating units caused by large-scale access to weak power grids, which seriously restrict the safety of the power grid and the transmission of new energy.

[0003] As traditional synchronous machines in the power grid are gradually replaced by large-scale new energy, the power grid strength gradually weakens, and the acceptance capacity for new energy also gradually decreases. Specifically, during steady-state operation, it is difficult to adjust the reactive power balance; when the power grid is disturbed, the voltage fluctuation range at the terminals of new energy machines is large, easily triggering the control switching of high and low voltage ride-through faults and causing cascading faults; when the grid framework strength is weak, due to large fluctuations in the power grid voltage, the new energy phase-locked loop is difficult to follow the power grid frequency and phase, resulting in oscillations, all of which pose great challenges to the safe and stable operation of the power grid.

[0004] As a type of synchronous machine, a synchronous condenser can effectively increase the short-circuit capacity of the system, enhance the power grid strength, and improve the voltage support ability during power grid disturbances. Since a synchronous condenser is a rotating element, limited by factors such as primary investment, maintenance cost, and site selection, a detailed configuration plan for synchronous condensers needs to be considered during the planning stage; during the operation stage, to ensure the safe and stable operation of the system, it is also necessary to consider installing synchronous condensers as an effective measure to enhance the system strength.

[0005] In an AC / DC hybrid power grid, synchronous condensers generally adopt a configuration method of centralized access to the DC converter bus to provide necessary reactive power and voltage support for the safe and stable operation of the power grid after faults and disturbances. With the access of multiple new energy power stations in the AC / DC hybrid power grid, in order to enhance the strength of the system with multiple new energy power stations access, in addition to configuring centralized synchronous condensers at the converter station, distributed synchronous condensers also need to be correspondingly configured at the connection points of different voltage levels of new energy power stations or at the busbars of the collection stations. However, there is currently no engineering practical configuration process for synchronous condensers, and it is urgent to carry out research on the optimal configuration of synchronous condensers in new energy power stations.

[0006] Therefore, a technology is needed to implement an optimal configuration scheme for synchronous condensers to enhance the voltage strength of the power grid. Summary of the Invention

[0007] The technical solution of the present invention provides a method and system for optimizing the configuration of synchronous condensers to enhance the voltage strength of the power grid, so as to solve the problem of how to optimize the configuration of synchronous condensers for enhancing the voltage strength of the power grid.

[0008] To solve the above problems, the present invention provides a method for optimizing the configuration of synchronous condensers to enhance the voltage strength of the power grid, and the method includes:

[0009] Determine the short-circuit ratio critical values of multiple target new energy power stations when accessing the AC / DC hybrid power grid, so that the power grid system operates stably;

[0010] Calculate the short-circuit ratio of each new energy power station among the multiple target new energy power stations;

[0011] Compare the short-circuit ratio of each new energy power station with the short-circuit ratio critical value in turn;

[0012] When there is a new energy power station with a short-circuit ratio less than the short-circuit ratio critical value, determine the configuration quantity of the synchronous condenser based on the pre-determined optimization configuration target of the synchronous condenser, so that the short-circuit ratio of each new energy power station among the multiple target new energy power stations is greater than the short-circuit ratio critical value.

[0013] Preferably, the short-circuit ratio critical values of the multiple target new energy power stations include: the machine-side short-circuit ratio critical values of the multiple target new energy power stations and the grid connection point short-circuit ratio critical values of the multiple target new energy power stations;

[0014] The short-circuit ratio of each new energy power station among the multiple target new energy power stations includes: the machine-side short-circuit ratio of each new energy power station among the multiple target new energy power stations and the grid connection point short-circuit ratio of each new energy power station.

[0015] Preferably, the method includes:

[0016] Compare the machine-side short-circuit ratio of each new energy power station with the machine-side short-circuit ratio critical value in turn, and compare the grid connection point short-circuit ratio of each new energy power station with the grid connection point short-circuit ratio critical value in turn;

[0017] When there is a machine-side short-circuit ratio less than the machine-side short-circuit ratio critical value, and / or, a grid connection point short-circuit ratio less than the grid connection point short-circuit ratio critical value, determine the configuration quantity of the synchronous condenser based on the pre-determined optimization configuration target of the synchronous condenser, so that the machine-side short-circuit ratio of each new energy power station among the multiple target new energy power stations is greater than the machine-side short-circuit ratio critical value, and the grid connection point short-circuit ratio of each new energy power station is greater than the grid connection point short-circuit ratio critical value.

[0018] Preferably, for the machine-side short-circuit ratio of each new energy power station and the grid connection point short-circuit ratio of each new energy power station among the multiple target new energy power stations, the calculation formula is:

[0019]

[0020] Wherein:

[0021] MRSCR m is the short - circuit ratio at the machine terminal of the m - th new - energy power station and the short - circuit ratio at the grid - connection point of the m - th new - energy power station; n refers to the total number of new - energy power generation units;

[0022] is the voltage at the grid - connection point between the new - energy power station and the i - th power generation unit;

[0023] is the nominal voltage at the grid - connection point between the new - energy power station and the i - th power generation unit;

[0024] are the currents injected into the power grid from the grid - connection point of the j - th power generation unit of the new - energy power station respectively;

[0025] is the current injected into the power grid from the grid - connection point between the new - energy power station and the i - th power generation unit;

[0026] is the element in the a - th row and a - th column of the equivalent impedance matrix Z of the AC power grid of the busbar at the new - energy grid - connection point eq ;

[0027] is the element in the a - th row and b - th column of the equivalent impedance matrix Z of the AC power grid of the busbar at the new - energy grid - connection point eq .

[0028] Preferably, determining the configuration quantity of the synchronous condenser based on the pre - determined optimization configuration target of the synchronous condenser includes:

[0029] Determining the minimum centralized configuration quantity of the synchronous condensers configured only on the AC busbar of the converter station;

[0030] Respectively configuring different quantities of synchronous condensers within the range of the minimum centralized configuration quantity on the AC busbar of the converter station, and determining the configuration quantity of the distributed synchronous condensers based on the pre - determined optimization configuration target of the synchronous condenser, so that the short - circuit ratio of each new - energy power station in multiple target new - energy power stations is greater than the short - circuit ratio critical value.

[0031] Preferably, the optimization configuration target of the synchronous condenser is: when the short - circuit ratio at the machine terminal of each new - energy power station in multiple target new - energy power stations is greater than the machine - terminal short - circuit ratio critical value, and the short - circuit ratio at the grid - connection point of each new - energy power station is greater than the grid - connection - point short - circuit ratio critical value, determining the optimization configuration scheme of the synchronous condenser based on the synchronous - condenser optimization objective function; the synchronous - condenser optimization objective function is:

[0032] minS = min(S C + S G + S S )

[0033] Among them, S is the total configured quantity of synchronous condensers, S C is the quantity of synchronous condensers centrally configured on the AC bus of the converter station, S G is the configured quantity of distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point, S S is the configured quantity of distributed synchronous condensers on the AC bus of the new energy station.

[0034] Preferably, determining the optimal configuration scheme of synchronous condensers based on the optimization objective function of synchronous condensers further includes determining a short-circuit ratio judgment formula:

[0035]

[0036] Among them, MRSCR G is the short-circuit ratio at the machine terminal, MRSCR Gmin is the critical value of the short-circuit ratio at the machine terminal, MRSCR S is the short-circuit ratio at the grid connection point, MRSCR Smin is the critical value of the short-circuit ratio at the grid connection point;

[0037] When the short-circuit ratio at the machine terminal or the short-circuit ratio at the grid connection point of the new energy multi-station does not satisfy the short-circuit ratio judgment formula, based on the critical value of the short-circuit ratio at the machine terminal and the critical value of the short-circuit ratio at the grid connection point, determine the quantity of synchronous condensers centrally configured only on the AC bus of the converter station; recalculate the short-circuit ratio at the machine terminal and the short-circuit ratio at the grid connection point of the new energy multi-station after centrally configuring synchronous condensers on the AC bus of the converter station, and judge whether the calculated short-circuit ratio at the machine terminal or the short-circuit ratio at the grid connection point of the new energy multi-station satisfies the short-circuit ratio judgment formula; when the calculated short-circuit ratio at the machine terminal and the short-circuit ratio at the grid connection point of the new energy multi-station after centrally configuring synchronous condensers on the AC bus of the converter station satisfy the short-circuit ratio judgment formula, the quantity of synchronous condensers centrally configured on the AC bus of the converter station is the minimum configured quantity of centralized synchronous condensers;

[0038] After centrally configuring different quantities of synchronous condensers within the range of the minimum centralized configuration quantity on the AC bus of the converter station respectively, when the short-circuit ratio at the grid connection point of the new energy multi-station after centrally configuring synchronous condensers on the AC bus of the converter station is greater than the critical value of the short-circuit ratio at the grid connection point and the short-circuit ratio at the machine terminal is not greater than the critical value of the short-circuit ratio at the machine terminal, configure distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point with the lowest calculated short-circuit ratio at the machine terminal until the calculated short-circuit ratio at the machine terminal of the new energy multi-station after configuring distributed synchronous condensers is greater than the critical value of the short-circuit ratio at the machine terminal, then stop configuring distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point; or

[0039] After separately configuring different numbers of synchronous condensers within the range of the minimum centralized configuration quantity on the AC busbars of the converter station, when the short-circuit ratio of the point of common coupling of the new energy multi-station on the AC busbars of the converter station after configuring the synchronous condensers is calculated to be not greater than the critical value of the short-circuit ratio of the point of common coupling, and the short-circuit ratio at the machine terminal is greater than the critical value of the short-circuit ratio at the machine terminal, a distributed synchronous condenser is configured on the collecting busbar with the lowest calculated short-circuit ratio of the point of common coupling until the short-circuit ratio of the point of common coupling of the new energy multi-station recalculated is greater than the critical value of the short-circuit ratio of the point of common coupling, and then stop configuring the distributed synchronous condenser on the collecting busbar with the lowest calculated short-circuit ratio of the point of common coupling; or

[0040] After separately configuring different numbers of synchronous condensers within the range of the minimum centralized configuration quantity on the AC busbars of the converter station, when the short-circuit ratio of the point of common coupling of the new energy multi-station on the AC busbars of the converter station after configuring the synchronous condensers is calculated to be not greater than the critical value of the short-circuit ratio of the point of common coupling, and the short-circuit ratio at the machine terminal is not greater than the critical value of the short-circuit ratio at the machine terminal, a distributed synchronous condenser is configured on the low-voltage side busbar of the new energy point of common coupling with the lowest calculated short-circuit ratio at the machine terminal until the short-circuit ratio at the machine terminal of the new energy multi-station after recalculating with the distributed synchronous condenser configured is greater than the critical value of the short-circuit ratio at the machine terminal, and then stop configuring the distributed synchronous condenser at the node with the lowest calculated short-circuit ratio at the machine terminal; recalculate the short-circuit ratio of the point of common coupling of the new energy multi-station after configuring the distributed synchronous condenser, and determine whether the calculated short-circuit ratio of the point of common coupling of the new energy multi-station after configuring the distributed synchronous condenser is greater than the critical value of the short-circuit ratio of the point of common coupling;

[0041] When the short-circuit ratio of the point of common coupling of the new energy multi-station after configuring the distributed synchronous condenser is calculated to be not greater than the critical value of the short-circuit ratio of the point of common coupling, a distributed synchronous condenser is configured on the collecting busbar with the lowest calculated short-circuit ratio of the point of common coupling until the short-circuit ratio of the point of common coupling of the new energy multi-station recalculated is greater than the critical value of the short-circuit ratio of the point of common coupling, and then stop configuring the distributed synchronous condenser on the collecting busbar with the lowest calculated short-circuit ratio of the point of common coupling.

[0042] Based on another aspect of the present invention, the present invention provides a synchronous condenser optimal configuration system for enhancing the voltage strength of the power grid, and the system includes:

[0043] An initial unit, configured to determine the critical values of the short-circuit ratios of multiple target new energy stations when multiple target new energy stations are connected to an AC / DC hybrid power grid to ensure the stable operation of the power grid system;

[0044] A calculation unit, configured to calculate the short-circuit ratio of each new energy station among multiple target new energy stations;

[0045] A comparison unit, configured to sequentially compare the short-circuit ratio of each new energy station with the critical value of the short-circuit ratio;

[0046] A result unit, configured to determine the number of synchronous condensers to be configured based on a pre-determined optimization configuration target of synchronous condensers when the short-circuit ratio of a new energy power station is less than the critical short-circuit ratio, so that the short-circuit ratio of each new energy power station in a plurality of target new energy power stations is greater than the critical short-circuit ratio.

[0047] Preferably, the critical short-circuit ratios of the plurality of target new energy power stations include: the critical short-circuit ratio of the machine terminal of the plurality of target new energy power stations and the critical short-circuit ratio of the grid connection point of the plurality of target new energy power stations;

[0048] The short-circuit ratio of each new energy power station in the plurality of target new energy power stations includes: the short-circuit ratio of the machine terminal of each new energy power station in the plurality of target new energy power stations and the short-circuit ratio of the grid connection point of each new energy power station.

[0049] Preferably, the comparison unit is further configured to sequentially compare the short-circuit ratio of the machine terminal of each new energy power station with the critical short-circuit ratio of the machine terminal, and sequentially compare the short-circuit ratio of the grid connection point of each new energy power station with the critical short-circuit ratio of the grid connection point;

[0050] The result unit is further configured to, when there is a short-circuit ratio of the machine terminal less than the critical short-circuit ratio of the machine terminal, and / or a short-circuit ratio of the grid connection point less than the critical short-circuit ratio of the grid connection point, determine the number of synchronous condensers to be configured based on a pre-determined optimization configuration target of synchronous condensers, so that the short-circuit ratio of the machine terminal of each new energy power station in the plurality of target new energy power stations is greater than the critical short-circuit ratio of the machine terminal, and the short-circuit ratio of the grid connection point of each new energy power station is greater than the critical short-circuit ratio of the grid connection point.

[0051] Preferably, the short-circuit ratio of the machine terminal of each new energy power station and the short-circuit ratio of the grid connection point of each new energy power station in the plurality of target new energy power stations are calculated by the following formula:

[0052]

[0053] Where:

[0054] MRSCR m is the short-circuit ratio of the machine terminal of the m-th new energy power station and the short-circuit ratio of the grid connection point of the m-th new energy power station; n refers to the total number of new energy generation units;

[0055] is the grid connection point voltage of the new energy power station and the power generation unit i;

[0056] is the nominal grid connection point voltage of the new energy power station and the power generation unit i;

[0057] are the currents injected from the new energy power station generation unit j into the power grid at the grid connection point respectively;

[0058] The current injected into the power grid at the self - connection point of the new - energy power station and the generating unit i;

[0059] The element at the a - th row and a - th column of the equivalent impedance matrix Z of the AC power grid at the new - energy grid - connection bus point eq ;

[0060] The element at the a - th row and b - th column of the equivalent impedance matrix Z of the AC power grid at the new - energy grid - connection bus point eq .

[0061] Preferably, the result unit is used to determine the configuration quantity of the synchronous condenser based on a pre - determined optimization configuration target of the synchronous condenser, and is also used to:

[0062] Determine the minimum centralized configuration quantity of the synchronous condensers configured only on the AC bus of the converter station;

[0063] Respectively configure different quantities of synchronous condensers within the range of the minimum centralized configuration quantity on the AC bus of the converter station, and determine the configuration quantity of the distributed synchronous condensers based on the pre - determined optimization configuration target of the synchronous condenser, so that the short - circuit ratio of each new - energy power station among multiple target new - energy power stations is greater than the short - circuit ratio critical value.

[0064] Preferably, the optimization configuration target of the synchronous condenser is: when the terminal short - circuit ratio of each new - energy power station among multiple target new - energy power stations is greater than the terminal short - circuit ratio critical value, and the short - circuit ratio at the grid - connection point of each new - energy power station is greater than the grid - connection point short - circuit ratio critical value, determine the optimization configuration scheme of the synchronous condenser based on the optimization objective function of the synchronous condenser; the optimization objective function of the synchronous condenser is:

[0065] minS = min(S C + S G + S S )

[0066] where S is the total configuration quantity of the synchronous condensers, S C is the quantity of the synchronous condensers configured centrally on the AC bus of the converter station, S G is the configuration quantity of the distributed synchronous condensers on the low - voltage - side bus of the new - energy grid - connection point, and S S is the configuration quantity of the distributed synchronous condensers on the AC bus of the new - energy power station.

[0067] Preferably, determining the optimization configuration scheme of the synchronous condenser based on the optimization objective function of the synchronous condenser further includes determining the short - circuit ratio judgment formula:

[0068]

[0069] where MRSCR G is the terminal short - circuit ratio, and MRSCR Gminis the critical value of the short-circuit ratio at the generator terminal, MRSCR S is the short-circuit ratio at the point of common coupling, MRSCR Smin is the critical value of the short-circuit ratio at the point of common coupling;

[0070] When the short-circuit ratio at the generator terminal or the short-circuit ratio at the point of common coupling of the new energy multi-station does not satisfy the short-circuit ratio judgment formula, based on the critical value of the short-circuit ratio at the generator terminal and the critical value of the short-circuit ratio at the point of common coupling, determine the number of synchronous condensers concentratedly configured only on the AC bus of the converter station; recalculate the short-circuit ratio at the generator terminal and the short-circuit ratio at the point of common coupling of the new energy multi-station after the synchronous condensers are concentratedly configured on the AC bus of the converter station, and judge whether the calculated short-circuit ratio at the generator terminal or the short-circuit ratio at the point of common coupling of the new energy multi-station satisfies the short-circuit ratio judgment formula; when the calculated short-circuit ratio at the generator terminal and the short-circuit ratio at the point of common coupling of the new energy multi-station after the synchronous condensers are concentratedly configured on the AC bus of the converter station satisfy the short-circuit ratio judgment formula, the number of synchronous condensers concentratedly configured on the AC bus of the converter station is the minimum configuration number of the centralized synchronous condenser;

[0071] After respectively configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station, when the short-circuit ratio at the point of common coupling of the new energy multi-station after the synchronous condensers are concentratedly configured on the AC bus of the converter station is greater than the critical value of the short-circuit ratio at the point of common coupling and the short-circuit ratio at the generator terminal is not greater than the critical value of the short-circuit ratio at the generator terminal, configure a distributed synchronous condenser on the low-voltage side bus of the new energy point of common coupling with the lowest calculated short-circuit ratio at the generator terminal until the calculated short-circuit ratio at the generator terminal of the new energy multi-station after configuring the distributed synchronous condenser is greater than the critical value of the short-circuit ratio at the generator terminal, then stop configuring the distributed synchronous condenser on the low-voltage side bus of the new energy point of common coupling; or

[0072] After respectively configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station, when the short-circuit ratio at the point of common coupling of the new energy multi-station after the synchronous condensers are concentratedly configured on the AC bus of the converter station is not greater than the critical value of the short-circuit ratio at the point of common coupling and the short-circuit ratio at the generator terminal is greater than the critical value of the short-circuit ratio at the generator terminal, configure a distributed synchronous condenser on the collecting bus with the lowest calculated short-circuit ratio at the point of common coupling until the calculated short-circuit ratio at the point of common coupling of the new energy multi-station is greater than the critical value of the short-circuit ratio at the point of common coupling, then stop configuring the distributed synchronous condenser on the collecting bus with the lowest calculated short-circuit ratio at the point of common coupling; or

[0073] After different numbers of synchronous condensers within the range of the minimum centralized configuration quantity are centrally configured on the AC busbars of the converter station respectively, when the short-circuit ratio of the grid connection point of the new energy multi-station after the synchronous condensers are centrally configured on the AC busbars of the converter station is calculated and is not greater than the critical value of the short-circuit ratio of the grid connection point, and the short-circuit ratio at the machine terminal is not greater than the critical value of the short-circuit ratio at the machine terminal, a distributed synchronous condenser is configured on the low-voltage side busbar of the new energy grid connection point with the lowest calculated short-circuit ratio at the machine terminal until the short-circuit ratio at the machine terminal of the new energy multi-station after the distributed synchronous condenser is re-calculated is greater than the critical value of the short-circuit ratio at the machine terminal, and then stop configuring the distributed synchronous condenser at the node with the lowest calculated short-circuit ratio at the machine terminal; re-calculate the short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured, and judge whether the calculated short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured is greater than the critical value of the short-circuit ratio of the grid connection point.

[0074] When the calculated short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured is not greater than the critical value of the short-circuit ratio of the grid connection point, a distributed synchronous condenser is configured on the collecting busbar with the lowest calculated short-circuit ratio of the grid connection point until the short-circuit ratio of the new energy multi-station re-calculated is greater than the critical value of the short-circuit ratio of the grid connection point, and then stop configuring the distributed synchronous condenser on the collecting busbar with the lowest calculated short-circuit ratio of the grid connection point.

[0075] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium, characterized in that the storage medium stores a computer program, and the computer program is used to execute the above-mentioned synchronous condenser optimal configuration method for enhancing the grid voltage strength.

[0076] Based on another aspect of the present invention, the present invention provides an electronic device, characterized in that the electronic device includes:

[0077] a processor;

[0078] a memory for storing executable instructions of the processor;

[0079] The processor is used to read the executable instructions from the memory and execute the above-mentioned synchronous condenser optimal configuration method for enhancing the grid voltage strength.

[0080] The technical solution of the present invention provides a method and system for optimizing the configuration of synchronous condensers to enhance the voltage strength of the power grid. The method includes: determining the critical short-circuit ratio values of multiple target new energy power stations when accessing the AC-DC hybrid power grid to ensure the stable operation of the power grid system; calculating the short-circuit ratio of each new energy power station among the multiple target new energy power stations; comparing the short-circuit ratio of each new energy power station with the critical short-circuit ratio value in turn; when there is a new energy power station with a short-circuit ratio less than the critical short-circuit ratio value, determining the configuration quantity of the synchronous condenser based on the pre-determined optimization configuration target of the synchronous condenser, so that the short-circuit ratio of each new energy power station among the multiple target new energy power stations is greater than the critical short-circuit ratio value.

[0081] The technical solution of the present invention proposes a method and system for optimizing the configuration of synchronous condensers to enhance the voltage strength of the power grid. Based on the calculation results of the short-circuit ratios of multiple new energy power stations, the weak points of the large-scale new energy access to the AC-DC hybrid power grid are obtained. Appropriate-capacity centralized or distributed synchronous condensers are configured at the weak points of the system, maximizing the configuration effect of the synchronous condensers while minimizing the configuration capacity of the synchronous condensers, that is, obtaining better economy, ensuring the safe grid connection of new energy, enhancing the voltage strength of the power grid, and preventing large-area disconnection of new energy power stations caused by the oscillation of new energy power generation equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] The exemplary embodiments of the present invention can be more fully understood by referring to the following drawings:

[0083] Figure 1 It is a flowchart of a method for optimizing the configuration of synchronous condensers to enhance the voltage strength of the power grid according to a preferred embodiment of the present invention;

[0084] Figure 2 It is a simplified schematic diagram of a multi-new energy power station access system including n new energy power stations according to a preferred embodiment of the present invention;

[0085] Figure 3 It is a flowchart of the synchronous condenser configuration based on the calculation results of the short-circuit ratio according to a preferred embodiment of the present invention;

[0086] Figure 4 It is a flowchart of the specific configuration method of the distributed synchronous condenser according to a preferred embodiment of the present invention;

[0087] Figure 5 It is a structural diagram of the test power grid for synchronous condenser configuration according to a preferred embodiment of the present invention;

[0088] Figure 6 It is a simulation waveform diagram after a three-phase short-circuit fault occurs under the condition of large new energy generation in the system selected according to a preferred embodiment of the present invention;

[0089] Figure 7The simulation waveform diagram after a three-phase short-circuit fault occurs under the condition of large-scale new energy generation in the system selected for the numerical example according to the preferred embodiment of the present invention, after configuring a synchronous condenser; and

[0090] Figure 8 The structural diagram of a synchronous condenser optimization configuration system for enhancing the voltage strength of the power grid according to the preferred embodiment of the present invention. Specific embodiments

[0091] Now, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely, and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the drawings are not limitations on the present invention. In the drawings, the same units / components are denoted by the same reference numerals.

[0092] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. In addition, it can be understood that the terms defined in the commonly used dictionary should be understood as having a meaning consistent with the context of their related fields, and should not be understood as idealized or overly formal meanings.

[0093] Figure 1 The flowchart of a synchronous condenser optimization configuration method for enhancing the voltage strength of the power grid according to the preferred embodiment of the present invention. The present invention is based on the calculation results of the short-circuit ratios of multiple new energy power stations, obtains the weak points of a large-scale new energy-connected AC / DC hybrid power grid, configures centralized or distributed synchronous condensers with appropriate capacities at the weak points of the system, and minimizes the configuration capacity of the synchronous condensers while maximizing the configuration effect of the synchronous condensers.

[0094] As Figure 1 shown, the present invention provides a synchronous condenser optimization configuration method for enhancing the voltage strength of the power grid. The method includes:

[0095] Step 101: Determine the critical short-circuit ratio values of multiple target new energy power stations when they are connected to an AC / DC hybrid power grid to ensure the stable operation of the power grid system. Preferably, it includes determining the critical short-circuit ratio values at the machine terminals of multiple target new energy power stations and the critical short-circuit ratio values at the grid connection points of multiple target new energy power stations when they are connected to an AC / DC hybrid power grid to ensure the stable operation of the power grid system.

[0096] Step 102: Calculate the short-circuit ratio of each new energy power station among multiple target new energy power stations. Preferably, it includes calculating the short-circuit ratio at the machine terminal of each new energy power station among multiple target new energy power stations and the short-circuit ratio at the grid connection point of each new energy power station. The short-circuit ratio of each new energy power station among multiple target new energy power stations includes: the short-circuit ratio at the machine terminal of each new energy power station among multiple target new energy power stations and the short-circuit ratio at the grid connection point of each new energy power station.

[0097] Step 103: Compare the short-circuit ratio of each new energy power station with the short-circuit ratio threshold value in sequence. Preferably, it includes comparing the short-circuit ratio at the machine terminal of each new energy power station with the short-circuit ratio threshold value at the machine terminal in sequence, and comparing the short-circuit ratio at the grid connection point of each new energy power station with the short-circuit ratio threshold value at the grid connection point in sequence. Preferably, for the short-circuit ratio at the machine terminal of each new energy power station and the short-circuit ratio at the grid connection point of each new energy power station among multiple target new energy power stations, the calculation formula is:

[0098]

[0099] Where:

[0100] MRSCR m is the short-circuit ratio at the machine terminal of the m-th new energy power station and the short-circuit ratio at the grid connection point of the m-th new energy power station; n refers to the total number of new energy power generation units;

[0101] is the grid connection point voltage between the new energy power station and the i-th power generation unit;

[0102] is the nominal voltage of the grid connection point between the new energy power station and the i-th power generation unit;

[0103] are the currents injected into the power grid by the j-th power generation unit of the new energy power station from the grid connection point respectively;

[0104] is the current injected into the power grid by the new energy power station and the i-th power generation unit from the grid connection point;

[0105] is the element in the a-th row and a-th column of the AC power grid equivalent impedance matrix Z eq of the new energy grid connection point bus;

[0106] is the element in the a-th row and b-th column of the AC power grid equivalent impedance matrix Z eq of the new energy grid connection point bus. The present invention first determines the configuration requirements of synchronous condensers in the power grid. The present invention selects multiple new energy power stations accessing the AC / DC hybrid power grid as the target power grid according to needs. For Figure 2 the multi-new energy power station access system shown including n new energy power stations, the definition of the multi-new energy power station short-circuit ratio (MRSCR) conforms to formula (1).

[0107] Figure 2 Simplified schematic diagram of a multi-new energy power station access system including n new energy power stations according to a preferred embodiment of the present invention. As Figure 2 shown, n new energy power stations are simultaneously connected to the power grid, and there is impedance interconnection between each power station.

[0108] The present invention respectively determines the critical values MRSCR of the machine-side short-circuit ratio of the new energy multi-power stations and the short-circuit ratio at the grid connection point of the new energy multi-power stations in the multi-new energy power station access to the AC / DC hybrid power grid that can ensure the stability of the system Gmin and MRSCR Smin .

[0109] In the multi-new energy power station access to the AC / DC hybrid power grid selected by the present invention, the machine-side short-circuit ratio MRSCR of the new energy power station is calculated respectively by formula (1) G and the short-circuit ratio MRSCR at the grid connection point of the new energy power station S . If MRSCR G and MRSCR S satisfy formula (2), then no synchronous condenser needs to be configured in this power grid; if MRSCR G and MRSCR S do not satisfy formula (2), then a synchronous condenser needs to be configured in this system to improve the short-circuit ratio.

[0110]

[0111] Among them, MRSCR G and MRSCR S are the calculation results of the short-circuit ratio of the new energy multi-power stations for each new energy unit or power station.

[0112] Step 104: When the short-circuit ratio of a new energy power station is less than the critical short-circuit ratio, determine the number of synchronous condensers configured based on the pre-determined optimization configuration target of the synchronous condenser, so that the short-circuit ratio of each new energy power station in multiple target new energy power stations is greater than the critical short-circuit ratio.

[0113] Preferably, the machine-side short-circuit ratio of each new energy power station is compared with the critical machine-side short-circuit ratio in turn, and the short-circuit ratio at the grid connection point of each new energy power station is compared with the critical short-circuit ratio at the grid connection point in turn;

[0114] When there is a situation where the machine-side short-circuit ratio is less than the critical machine-side short-circuit ratio, and / or the short-circuit ratio at the grid connection point is less than the critical short-circuit ratio at the grid connection point, determine the number of synchronous condensers configured based on the pre-determined optimization configuration target of the synchronous condenser, so that the machine-side short-circuit ratio of each in multiple target new energy power stations is greater than the critical machine-side short-circuit ratio, and the short-circuit ratio at the grid connection point of each is greater than the critical short-circuit ratio at the grid connection point.

[0115] Preferably, determining the configuration quantity of the synchronous condenser based on a pre-determined optimization configuration target of the synchronous condenser includes:

[0116] Determining the minimum centralized configuration quantity of the synchronous condenser configured only on the AC bus of the converter station;

[0117] Respectively configuring different quantities of synchronous condensers within the range of the minimum centralized configuration quantity on the AC bus of the converter station, and determining the configuration quantity of the distributed synchronous condenser based on the pre-determined optimization configuration target of the synchronous condenser, such that the short-circuit ratio of each new energy power station among multiple target new energy power stations is greater than the short-circuit ratio critical value.

[0118] The new energy grid connection point bus refers to the high-voltage side node of the main transformer in the new energy power station, usually adopting the highest voltage level of the distribution network in the local power grid. For the 750kV / 330kV system in the northwest power grid, the grid connection point here refers to the 330kV bus; for the 500kV / 220kV system in the eastern region, the grid connection point here refers to the 220kV bus; the AC bus of the converter station refers to the AC side bus of the converter valve in the UHV DC converter station, usually consistent with the main grid voltage level, that is, 750kV or 500kV. It is considered here that the synchronous condensers on the AC bus of the converter station are centrally connected, and the synchronous condensers at the grid connection point and machine terminal of the new energy power station are distributedly connected. Preferably, the optimization configuration target of the synchronous condenser is: when the machine terminal short-circuit ratio of each new energy power station among multiple target new energy power stations is greater than the machine terminal short-circuit ratio critical value, and the short-circuit ratio of the grid connection point of each new energy power station is greater than the grid connection point short-circuit ratio critical value, determining the optimization configuration scheme of the synchronous condenser based on the synchronous condenser optimization objective function; the synchronous condenser optimization objective function is:

[0119] minS = min(S C + S G + S S )

[0120] wherein, S is the total configuration quantity of the synchronous condenser, S C is the quantity of the synchronous condenser configured centrally on the AC bus of the converter station, S G is the configuration quantity of the distributed synchronous condenser on the low-voltage side bus of the new energy grid connection point, S S is the configuration quantity of the distributed synchronous condenser on the AC bus of the new energy power station.

[0121] The present invention determines the optimization target of the synchronous condenser. Similar to other synchronous motors, the synchronous condenser utilizes the electromagnetic coupling relationship between the stator and rotor of the synchronous motor to provide short-circuit current when a grid fault occurs, thereby increasing the short-circuit capacity. By configuring the synchronous condenser and increasing the quantity of synchronous motors, the short-circuit ratio of the new energy grid connection node can be effectively improved. The goal of optimizing the configuration of the synchronous condenser is to maximize the configuration effect of the synchronous condenser while minimizing the configuration capacity of the synchronous condenser, that is, to obtain better economy.

[0122] Determining the optimized configuration scheme of the synchronous condenser based on the optimization objective function of the synchronous condenser further includes determining the short-circuit ratio judgment formula:

[0123]

[0124] wherein, MRSCR G is the short-circuit ratio at the machine terminal, MRSCR Gmin is the critical value of the short-circuit ratio at the machine terminal, MRSCR S is the short-circuit ratio at the grid connection point, MRSCR Smin is the critical value of the short-circuit ratio at the grid connection point;

[0125] When the short-circuit ratio at the machine terminal or the short-circuit ratio at the grid connection point of the multi-station new energy does not satisfy the short-circuit ratio judgment formula, based on the critical value of the short-circuit ratio at the machine terminal and the critical value of the short-circuit ratio at the grid connection point, determine the number of synchronous condensers configured only on the AC bus of the converter station; recalculate the short-circuit ratio at the machine terminal and the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers on the AC bus of the converter station, and judge whether the calculated short-circuit ratio at the machine terminal or the short-circuit ratio at the grid connection point of the multi-station new energy satisfies the short-circuit ratio judgment formula; when the calculated short-circuit ratio at the machine terminal and the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers on the AC bus of the converter station satisfy the short-circuit ratio judgment formula, the number of synchronous condensers configured on the AC bus of the converter station is the minimum configuration number of the centralized synchronous condenser;

[0126] After respectively configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station, when the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers on the AC bus of the converter station is greater than the critical value of the short-circuit ratio at the grid connection point and the short-circuit ratio at the machine terminal is not greater than the critical value of the short-circuit ratio at the machine terminal, configure distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point with the lowest calculated short-circuit ratio at the machine terminal until the recalculated short-circuit ratio at the machine terminal of the multi-station new energy after configuring the distributed synchronous condensers is greater than the critical value of the short-circuit ratio at the machine terminal, then stop configuring distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point; or

[0127] After respectively configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station, when the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers on the AC bus of the converter station is not greater than the critical value of the short-circuit ratio at the grid connection point and the short-circuit ratio at the machine terminal is greater than the critical value of the short-circuit ratio at the machine terminal, configure distributed synchronous condensers on the collection bus with the lowest calculated short-circuit ratio at the grid connection point until the recalculated short-circuit ratio at the grid connection point of the multi-station new energy is greater than the critical value of the short-circuit ratio at the grid connection point, then stop configuring distributed synchronous condensers on the collection bus with the lowest calculated short-circuit ratio at the grid connection point; or

[0128] After different numbers of synchronous condensers within the range of the minimum centralized configuration quantity are centrally configured on the AC buses of the converter station respectively, when the short-circuit ratio of the grid connection point of the new energy multi-station after the synchronous condensers are centrally configured on the AC buses of the converter station is calculated to be not greater than the critical value of the short-circuit ratio of the grid connection point, and the short-circuit ratio at the machine terminal is not greater than the critical value of the short-circuit ratio at the machine terminal, a distributed synchronous condenser is configured on the low-voltage side bus of the new energy grid connection point with the lowest calculated short-circuit ratio at the machine terminal until the short-circuit ratio at the machine terminal of the new energy multi-station after the distributed synchronous condenser is re-calculated is greater than the critical value of the short-circuit ratio at the machine terminal, and then stop configuring the distributed synchronous condenser at the node with the lowest calculated short-circuit ratio at the machine terminal; re-calculate the short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured, and judge whether the calculated short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured is greater than the critical value of the short-circuit ratio of the grid connection point.

[0129] When the short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured is calculated to be not greater than the critical value of the short-circuit ratio of the grid connection point, a distributed synchronous condenser is configured on the collecting bus with the lowest calculated short-circuit ratio of the grid connection point until the short-circuit ratio of the grid connection point of the new energy multi-station re-calculated is greater than the critical value of the short-circuit ratio of the grid connection point, and then stop configuring the distributed synchronous condenser on the collecting bus with the lowest calculated short-circuit ratio of the grid connection point.

[0130] The configuration of the synchronous condenser needs to be optimized with minS as the objective on the premise of satisfying the constraint condition formula (2).

[0131] The present invention determines the synchronous condenser configuration process, including determining the centralized synchronous condenser configuration scheme:

[0132] If the selected multiple new energy stations are connected to the AC / DC hybrid power grid and the calculated short-circuit ratio of the new energy multi-station does not satisfy formula (2), and there are nodes with the short-circuit ratio of the new energy multi-station lower than the lowest index, then it is necessary to select to centrally configure centralized synchronous condensers on the AC side of the DC converter station. The specific configuration quantity can be selected according to the lowest index requirement of the short-circuit ratio in formula (2), and the centralized synchronous condensers are usually configured in pairs, that is, the number of units is a multiple of 2. Through short-circuit ratio calculation, compare MRSCR G and MRSCR S , if formula (2) can be satisfied only by configuring centralized synchronous condensers, then the number of groups N cmin of the centralized synchronous condensers at this time cmin is the minimum value of the number of groups of the centralized synchronous condensers, indicating that 2N cmin units of centralized synchronous condensers need to be connected to the system to satisfy formula (2). From this, N Ci configuration schemes of the centralized synchronous condensers can be obtained, where N Ci (N cmin =1, 2,..., N

[0133] Under each centralized synchronous condenser configuration scheme, calculate MRSCR respectively G and MRSCR S . If the calculation results of the short-circuit ratios of all nodes in the AC / DC hybrid power grid connected by the selected multiple new energy power stations all satisfy Equation (2), then the system does not need to configure a synchronous condenser; if it does not satisfy Equation (2), then a comprehensive configuration scheme of configuring distributed synchronous condensers at the new energy power stations needs to be considered in addition to the centralized synchronous condenser. Compare the total capacity of the synchronous condenser configuration in each comprehensive configuration scheme, and conduct an overall comparison to obtain the final scheme.

[0134] The present invention selects a comprehensive configuration scheme and optimally configures distributed synchronous condensers under different centralized synchronous condenser configuration conditions. First, it is necessary to determine the node with the lowest short-circuit ratio of multiple new energy power stations in the system connected by the selected multiple new energy power stations;

[0135] a) If MRSCR G does not satisfy Equation (2), while MRSCR S satisfies Equation (2):

[0136] Configure 1 distributed synchronous condenser at the node with the lowest MRSCR G ;

[0137] Recalculate MRSCR G , determine the minimum value of MRSCR G at this time. If the node with the lowest MRSCR G has satisfied Equation (2), then stop configuring the synchronous condenser; if the node with the lowest MRSCR G still does not satisfy Equation (2), then continue to configure 1 distributed synchronous condenser at the node with the lowest MRSCR G until all MRSCR G in the AC / DC hybrid power grid connected by the selected multiple new energy power stations all satisfy Equation (2).

[0138] The synchronous condenser configuration scheme obtained at this time is the distributed synchronous condenser configuration scheme that can improve the grid voltage strength under this centralized synchronous condenser configuration scheme;

[0139] b) If MRSCR G satisfies Equation (2), while MRSCR S does not satisfy Equation (2):

[0140] Configure 1 distributed synchronous condenser at the node with the lowest MRSCR S ;

[0141] Recalculate MRSCR S , determine the minimum value of MRSCR S at this time. If MRSCR SIf the minimum value of MRSCR has satisfied Equation (2), the configuration of the synchronous condenser is stopped; if the lowest node of MRSCR S still does not satisfy Equation (2), continue to configure 1 distributed synchronous condenser at the lowest node of MRSCR S until all MRSCRs S in the selected multi-new energy power stations connected to the system satisfy Equation (2).

[0142] At this time, the obtained synchronous condenser configuration plan is the distributed synchronous condenser configuration plan that can improve the grid voltage strength under this centralized synchronous condenser configuration plan;

[0143] c) If both MRSCR G and MRSCR S do not satisfy Equation (2):

[0144] Configure 1 distributed synchronous condenser at the lowest node of MRSCR G ;

[0145] Recalculate MRSCR G to determine the minimum value of MRSCR G at this time. If the minimum value of MRSCR G has satisfied Equation (2), the configuration of the synchronous condenser is stopped; if the lowest node of MRSCR G still does not satisfy Equation (2), continue to configure 1 distributed synchronous condenser at the lowest node of MRSCR G until all MRSCRs G in the selected multi-new energy power stations connected to the system satisfy Equation (2).

[0146] Calculate MRSCR S at this time:

[0147] If all MRSCRs S in the selected multi-new energy power stations connected to the system satisfy Equation (2) at this time, the obtained synchronous condenser configuration plan is the distributed synchronous condenser configuration plan that can improve the grid voltage strength under this centralized synchronous condenser configuration plan;

[0148] If there is an MRSCR S in the selected multi-new energy power stations connected to the system SPS that does not satisfy Equation (2), configure 1 distributed synchronous condenser at the lowest node of MRSCR S ;

[0149] Recalculate MRSCR S to determine the minimum value of MRSCR S at this time. If the lowest node of MRSCR S has satisfied Equation (2), the configuration of the synchronous condenser is stopped; if MRSCR SIf the lowest node still does not satisfy Equation (2), continue with MRSCR S Configure 1 distributed synchronous condenser for the lowest node until all MRSCRs in the selected multi-new energy power stations connected to the system S all satisfy Equation (2).

[0150] The synchronous condenser configuration plan obtained at this time is the distributed synchronous condenser configuration plan that can improve the grid voltage strength under the selected centralized synchronous condenser configuration plan.

[0151] The present invention makes a comparative selection of the optimal configuration plans. Through the above calculations, for different centralized synchronous condenser configuration plans N Ci (N Ci = 1, 2, …, N cmin ), the required distributed synchronous condenser configuration plans are obtained. By comparing the sum of the configuration capacities of all synchronous condensers in each plan, based on the synchronous condenser optimization objective function minS = min(S C + S G + S S ), select the plan with the least configuration capacity of synchronous condensers, which is the optimal configuration plan of synchronous condensers.

[0152] Specific precautions are as follows:

[0153] (1) For a power grid with a strong AC grid framework, new energy access will not cause major stability problems, so there is no need to configure synchronous condensers in new energy power stations;

[0154] (2) For a power grid with a weak AC grid framework, after configuring synchronous condensers based on the short-circuit ratio results of multiple new energy power stations obtained from electromechanical transient simulation results, it is necessary to conduct full electromagnetic simulation verification on the system to ensure that the synchronous condensers can keep the system stable;

[0155] The present invention aims at the problem of oscillation and disconnection of new energy power generation equipment or clusters caused by large-scale new energy access to AC / DC hybrid power grids. Under the condition of ensuring a certain new energy access scale, the configuration plan with the least total capacity of synchronous condensers to be installed can prevent large-area oscillation and disconnection of new energy while greatly improving the grid voltage strength of the power grid; it can be applied to various new energy power stations such as wind farms and photovoltaic power stations, with a wide coverage range, convenient implementation and remarkable effects.

[0156] Figure 3Flow chart of the configuration of synchronous condensers based on the short - circuit ratio calculation results according to the preferred embodiment of the present invention. The present invention first determines the critical values of the machine - side short - circuit ratio and the critical values of the short - circuit ratio at the grid connection points of multiple target new - energy power stations when multiple new - energy power stations are connected to an AC - DC hybrid power grid to ensure the stable operation of the power grid system. The present invention calculates the machine - side short - circuit ratio and the short - circuit ratio at the grid connection point of each new - energy power station respectively. The present invention compares the machine - side short - circuit ratio of each new - energy power station with the critical value of the machine - side short - circuit ratio in turn, and compares the short - circuit ratio at the grid connection point of each new - energy power station with the critical value of the short - circuit ratio at the grid connection point in turn. When there is a new - energy power station with a short - circuit ratio less than the critical value of the short - circuit ratio, the minimum centralized configuration quantity of synchronous condensers configured only on the AC bus of the converter station is determined, and there are N cmin configuration schemes of centralized synchronous condensers, where N Ci (N Ci = 1, 2, …, N cmin ) is the number of groups of synchronous condensers put into operation centrally. When there are still nodes with a short - circuit ratio lower than the minimum index after the centralized configuration of synchronous condensers, synchronous condensers are configured through a distributed synchronous condenser configuration scheme. When there is no new - energy power station with a short - circuit ratio less than the critical value of the short - circuit ratio, the system does not need to newly configure synchronous condensers.

[0157] Figure 4 Flow chart of the specific configuration method of distributed synchronous condensers according to the preferred embodiment of the present invention. As Figure 4 shown, when there are still nodes with a short - circuit ratio lower than the minimum index after the centralized configuration of synchronous condensers, when only MRSCR - I, that is, MRSCR S is lower than the minimum index, one distributed synchronous condenser is configured at the node with the lowest MRSCR S ; MRSCR S is recalculated to determine the minimum value of MRSCR S at this time. If the minimum value of MRSCR S satisfies formula (2), the configuration of synchronous condensers is stopped; if the node with the lowest MRSCR S still does not satisfy formula (2), then continue to configure one distributed synchronous condenser at the node with the lowest MRSCR S until all MRSCR S in the system of multiple new - energy power stations selected satisfy formula (2). The obtained configuration scheme of synchronous condensers is the configuration scheme of distributed synchronous condensers that can improve the voltage strength of the power grid under this centralized synchronous condenser configuration scheme.

[0158] When only MRSCR - P, that is, MRSCR G is lower than the minimum index, one distributed synchronous condenser is configured at the node with the lowest MRSCR G ; MRSCR G is recalculated to determine MRSCRG The minimum value, if MRSCR G The lowest node has satisfied Equation (2), then stop configuring the synchronous condenser; if MRSCR G The lowest node still does not satisfy Equation (2), then continue to configure 1 distributed synchronous condenser at the MRSCR G lowest node until all MRSCRs in the multi-new energy power stations selected for connection to the AC / DC hybrid power grid G all satisfy Equation (2). The synchronous condenser configuration plan obtained at this time is the distributed synchronous condenser configuration plan that can improve the grid voltage strength under this centralized synchronous condenser configuration plan.

[0159] When both MRSCR-P and MRSCR-I are lower than the lowest index, configure 1 distributed synchronous condenser at the MRSCR G lowest node;

[0160] Recalculate MRSCR G and determine the minimum value of MRSCR at this time. If MRSCR G the minimum value has satisfied Equation (2), then stop configuring the synchronous condenser; if MRSCR G the lowest node still does not satisfy Equation (2), then continue to configure 1 distributed synchronous condenser at the MRSCR G lowest node until all MRSCRs in the multi-new energy power stations selected for connection to the system G all satisfy Equation (2). Calculate MRSCR at this time G : S :

[0161] If all MRSCRs in the multi-new energy power stations selected for connection to the system S all satisfy Equation (2), then the synchronous condenser configuration plan obtained at this time is the distributed synchronous condenser configuration plan that can improve the grid voltage strength under this centralized synchronous condenser configuration plan;

[0162] If there is an MRSCR in the multi-new energy power stations selected for connection to the system SPS S that does not satisfy Equation (2), configure 1 distributed synchronous condenser at the MRSCR S lowest node;

[0163] Recalculate MRSCR S and determine the minimum value of MRSCR at this time. If MRSCR S the lowest node has satisfied Equation (2), then stop configuring the synchronous condenser; if MRSCR S the lowest node still does not satisfy Equation (2), then continue to configure 1 distributed synchronous condenser at the MRSCR S lowest node; if MRSCR SConfigure 1 distributed synchronous condenser with the lowest node configuration until all MRSCRs in the selected multiple new energy power stations connected to the system S all satisfy Equation (2). The synchronous condenser configuration plan obtained at this time is the distributed synchronous condenser configuration plan that can improve the grid voltage strength under the selected centralized synchronous condenser configuration plan.

[0164] Figure 5 is the synchronous condenser configuration test power grid structure diagram according to the embodiment of the present invention. As Figure 5 shown, this system is a provincial power grid in the western region of China, with a main grid voltage level of 750 kV, including 2 main new energy bases, namely the new energy base within the province and the new energy base in the DC near area; this power grid is connected to the main grid through 2 AC channels; this provincial power grid is connected to other regional power grids through a UHV DC channel. The main conventional units in this power grid are far from the new energy bases, more than 300 kilometers. Figure 5 In the system shown, under the condition of large new energy generation, the lowest short-circuit ratio at the machine terminals of the whole network is 1.117, and the lowest short-circuit ratio at the connection points is 1.392. The lowest index of the short-circuit ratio at the machine terminals of this system is 1.5, and the lowest index of the short-circuit ratio at the connection points is 2.5. Obviously, both the short-circuit ratio at the machine terminals and the short-circuit ratio at the connection points of this system are lower than the lowest index. It is necessary to configure synchronous condensers.

[0165] Figure 6 is the simulation waveform diagram after a three-phase short-circuit fault occurs under the condition of large new energy generation in the system selected for the example. It can be seen from the simulation results that although this system can operate stably without disturbance, after a disturbance occurs, the system will oscillate. Therefore, there are relatively large stability problems in this system and it is necessary to configure synchronous condensers.

[0166] Figure 7 is the simulation waveform diagram after a three-phase short-circuit fault occurs under the condition of large new energy generation in the system selected for the example after configuring synchronous condensers. For the system selected for the example, based on Figure 3 and Figure 4 the synchronous condenser configuration process shown, after configuring synchronous condensers, a total of 10 300 Mvar synchronous condensers are configured at 2 new energy bases (6 are configured at the 330 kV bus of the new energy power station under Substation A, 2 are configured at the 330 kV bus of the new energy power station under Substation B, and 2 are centrally configured at the 750 kV bus of the converter station),) and 25 50 Mvar synchronous condensers, the lowest short-circuit ratio at the machine terminals can be 1.561, and the lowest short-circuit ratio at the connection points is 2.669, both higher than the lowest index. At this time, after a three-phase short-circuit fault occurs under the condition of large new energy generation in the system selected for the example, the system can restore stability, proving the practicability of the synchronous condenser configuration method based on the short-circuit ratio.

[0167] Figure 8A structure diagram for optimizing the configuration of a synchronous condenser for enhancing the voltage strength of a power grid according to a preferred embodiment of the present invention. The system includes:

[0168] An initial unit 801, configured to determine the critical short-circuit ratio values of multiple target new energy power stations when they are connected to an AC-DC hybrid power grid to ensure the stable operation of the power grid system. Preferably, it is configured to determine the critical short-circuit ratio values at the machine terminals and the critical short-circuit ratio values at the grid connection points of multiple target new energy power stations when they are connected to an AC-DC hybrid power grid.

[0169] A calculation unit 802, configured to calculate the short-circuit ratio of each new energy power station among multiple target new energy power stations. Preferably, it is configured to calculate the short-circuit ratio at the machine terminal of each new energy power station and the short-circuit ratio at the grid connection point of each new energy power station among multiple target new energy power stations. Preferably, for the short-circuit ratio at the machine terminal of each new energy power station and the short-circuit ratio at the grid connection point of each new energy power station among multiple target new energy power stations, the calculation formula is:

[0170]

[0171] Where:

[0172] MRSCR m Is the short-circuit ratio at the machine terminal of the m-th new energy power station and the short-circuit ratio at the grid connection point of the m-th new energy power station; n refers to the total number of new energy generation units;

[0173] Is the grid connection point voltage between the new energy power station and the i-th power generation unit;

[0174] Is the nominal grid connection point voltage between the new energy power station and the i-th power generation unit;

[0175] Are respectively the currents injected by the j-th power generation unit of the new energy power station into the power grid from the grid connection point;

[0176] Is the current injected by the new energy power station and the i-th power generation unit into the power grid from the grid connection point;

[0177] Is the element in the a-th row and a-th column of the equivalent impedance matrix Z of the AC power grid at the new energy grid connection bus point eq ;

[0178] Is the element in the a-th row and b-th column of the equivalent impedance matrix Z of the AC power grid at the new energy grid connection bus point eq ;

[0179] A comparison unit 803 for sequentially comparing the short - circuit ratio of each new - energy power station with a short - circuit ratio critical value. Preferably, for sequentially comparing the terminal short - circuit ratio of each new - energy power station with a terminal short - circuit ratio critical value, and sequentially comparing the short - circuit ratio at the grid - connection point of each new - energy power station with a short - circuit ratio critical value at the grid - connection point.

[0180] A result unit 804 for, when there is a new - energy power station with a short - circuit ratio less than the short - circuit ratio critical value, determining the configuration quantity of the synchronous condenser based on a pre - determined synchronous condenser optimization configuration target, such that the short - circuit ratio of each new - energy power station among multiple target new - energy power stations is greater than the short - circuit ratio critical value. Preferably, for when there is a new - energy power station with a terminal short - circuit ratio less than the terminal short - circuit ratio critical value, and / or a new - energy power station with a short - circuit ratio at the grid - connection point less than the short - circuit ratio critical value at the grid - connection point, determining the configuration quantity of the synchronous condenser based on a pre - determined synchronous condenser optimization configuration target, such that the terminal short - circuit ratio of each new - energy power station among multiple target new - energy power stations is greater than the terminal short - circuit ratio critical value, and the short - circuit ratio at the grid - connection point of each new - energy power station is greater than the short - circuit ratio critical value at the grid - connection point.

[0181] Preferably, the result unit 604 is used to determine the configuration quantity of the synchronous condenser based on a pre - determined synchronous condenser optimization configuration target, and is further used to: determine the minimum centralized configuration quantity of the synchronous condensers configured only on the AC bus of the converter station; respectively configure different quantities of synchronous condensers within the range of the minimum centralized configuration quantity on the AC bus of the converter station, and determine the configuration quantity of the distributed synchronous condensers based on a pre - determined synchronous condenser optimization configuration target, such that the short - circuit ratio of each new - energy power station among multiple target new - energy power stations is greater than the short - circuit ratio critical value.

[0182] Preferably,

[0183] The synchronous condenser optimization configuration target is: when the terminal short - circuit ratio of each new - energy power station among multiple target new - energy power stations is greater than the terminal short - circuit ratio critical value, and the short - circuit ratio at the grid - connection point of each new - energy power station is greater than the short - circuit ratio critical value at the grid - connection point, determining a synchronous condenser optimization configuration scheme based on a synchronous condenser optimization objective function; the synchronous condenser optimization objective function is:

[0184] minS = min(S C + S G + S S )

[0185] Wherein, S is the total configuration quantity of the synchronous condensers, S C is the quantity of the synchronous condensers configured centrally on the AC bus of the converter station, S G is the configuration quantity of the distributed synchronous condensers on the low - voltage side bus at the new - energy grid - connection point, S S is the configuration quantity of the distributed synchronous condensers on the AC bus of the new - energy station.

[0186] Preferably, determining the optimized configuration scheme of the synchronous condenser based on the optimization objective function of the synchronous condenser further includes determining the short-circuit ratio judgment formula:

[0187]

[0188] wherein, MRSCR G is the short-circuit ratio at the generator terminal, MRSCR Gmin is the critical value of the short-circuit ratio at the generator terminal, MRSCR S is the short-circuit ratio at the grid connection point, MRSCR Smin is the critical value of the short-circuit ratio at the grid connection point;

[0189] When the short-circuit ratio at the generator terminal or the short-circuit ratio at the grid connection point of the multi-station new energy does not satisfy the short-circuit ratio judgment formula, based on the critical value of the short-circuit ratio at the generator terminal and the critical value of the short-circuit ratio at the grid connection point, determine the number of synchronous condensers configured only on the AC bus of the converter station; recalculate the short-circuit ratio at the generator terminal and the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers on the AC bus of the converter station, and judge whether the calculated short-circuit ratio at the generator terminal or the short-circuit ratio at the grid connection point of the multi-station new energy satisfies the short-circuit ratio judgment formula; when the calculated short-circuit ratio at the generator terminal and the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers on the AC bus of the converter station satisfy the short-circuit ratio judgment formula, the number of synchronous condensers configured on the AC bus of the converter station is the minimum configuration number of the centralized synchronous condenser;

[0190] After respectively configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station, when the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers on the AC bus of the converter station is greater than the critical value of the short-circuit ratio at the grid connection point and the short-circuit ratio at the generator terminal is not greater than the critical value of the short-circuit ratio at the generator terminal, configure distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point with the lowest calculated short-circuit ratio at the generator terminal until the recalculated short-circuit ratio at the generator terminal of the multi-station new energy after configuring the distributed synchronous condensers is greater than the critical value of the short-circuit ratio at the generator terminal, then stop configuring distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point; or

[0191] After respectively configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station, when the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers on the AC bus of the converter station is not greater than the critical value of the short-circuit ratio at the grid connection point and the short-circuit ratio at the generator terminal is greater than the critical value of the short-circuit ratio at the generator terminal, configure distributed synchronous condensers on the collection bus with the lowest calculated short-circuit ratio at the grid connection point until the recalculated short-circuit ratio at the grid connection point of the multi-station new energy is greater than the critical value of the short-circuit ratio at the grid connection point, then stop configuring distributed synchronous condensers on the collection bus with the lowest calculated short-circuit ratio at the grid connection point; or

[0192] After different numbers of synchronous condensers within the range of the minimum centralized configuration quantity are centrally configured on the AC busbars of the converter station respectively, when the short-circuit ratio of the grid connection point of the new energy multi-station after the synchronous condensers centrally configured on the AC busbars of the converter station is calculated to be not greater than the critical value of the short-circuit ratio of the grid connection point and the short-circuit ratio at the machine terminal is not greater than the critical value of the short-circuit ratio at the machine terminal, a distributed synchronous condenser is configured on the low-voltage side busbar of the new energy grid connection point with the lowest calculated short-circuit ratio at the machine terminal until the short-circuit ratio at the machine terminal of the new energy multi-station after the distributed synchronous condenser is re-calculated is greater than the critical value of the short-circuit ratio at the machine terminal, and then stop configuring the distributed synchronous condenser at the node with the lowest calculated short-circuit ratio at the machine terminal; re-calculate the short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured, and judge whether the calculated short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured is greater than the critical value of the short-circuit ratio of the grid connection point.

[0193] When the short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is calculated to be not greater than the critical value of the short-circuit ratio of the grid connection point, a distributed synchronous condenser is configured on the collecting busbar with the lowest calculated short-circuit ratio of the grid connection point until the short-circuit ratio of the grid connection point of the new energy multi-station re-calculated is greater than the critical value of the short-circuit ratio of the grid connection point, and then stop configuring the distributed synchronous condenser on the collecting busbar with the lowest calculated short-circuit ratio of the grid connection point.

[0194] A synchronous condenser optimization configuration system 800 for enhancing the grid voltage strength in a preferred embodiment of the present invention corresponds to a synchronous condenser optimization configuration method 100 for enhancing the grid voltage strength in a preferred embodiment of the present invention, and will not be elaborated herein.

[0195] An embodiment of the present invention provides a computer-readable storage medium, and the storage medium stores a computer program, and the computer program is used to execute the above-mentioned synchronous condenser optimization configuration method for enhancing the grid voltage strength.

[0196] An embodiment of the present invention provides an electronic device, and the electronic device includes: a processor; a memory for storing executable instructions executable by the processor; the processor is used to read the executable instructions from the memory and execute the instructions to implement the above-mentioned synchronous condenser optimization configuration method for enhancing the grid voltage strength. Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0197] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and combinations of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device generate means for implementing the functions specified in the flow Figure 1 one or more flows and / or blocks Figure 1 or means for implementing the functions specified in one or more blocks.

[0198] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including instruction means that implement the functions specified in the flow Figure 1 one or more flows and / or blocks Figure 1 or means for implementing the functions specified in one or more blocks.

[0199] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operational steps are performed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in the flow Figure 1 one or more flows and / or blocks Figure 1 or means for implementing the functions specified in one or more blocks.

[0200] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the scope of its protection. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that after reading the present invention, various changes, modifications, or equivalent replacements can still be made to the specific implementation manners of the invention, but these changes, modifications, or equivalent replacements are all within the scope of the protection of the pending claims of the invention.

[0201] The present invention has been described by reference to a few embodiments. However, as is well known to those skilled in the art, other embodiments equivalent to those disclosed above of the present invention equally fall within the scope of the present invention as defined by the appended patent claims.

[0202] Generally, all terms used in the claims are construed according to their ordinary meaning in the technical field, unless otherwise expressly defined therein. All references to "a / the [device, component, etc.]" are to be construed openly as at least one instance of the device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed, unless expressly stated.

Claims

1. A method for optimizing the configuration of a synchronous condenser to enhance the voltage strength of a power grid, the method comprising: Determine the short-circuit ratio critical values of multiple target new energy power stations when they are connected to an AC / DC hybrid power grid to ensure the stable operation of the power grid system; The short-circuit ratio critical values of the multiple target new energy power stations include: the critical value of the machine-side short-circuit ratio of the multiple target new energy power stations and the critical value of the short-circuit ratio at the grid connection point of the multiple target new energy power stations; The short-circuit ratio of each new energy power station among the multiple target new energy power stations includes: the machine-side short-circuit ratio of each new energy power station among the multiple target new energy power stations and the short-circuit ratio at the grid connection point of each new energy power station; Compare the machine-side short-circuit ratio of each new energy power station with the critical value of the machine-side short-circuit ratio in turn, and compare the short-circuit ratio at the grid connection point of each new energy power station with the critical value of the short-circuit ratio at the grid connection point in turn; When there is a machine-side short-circuit ratio less than the critical value of the machine-side short-circuit ratio, and / or, a short-circuit ratio at the grid connection point less than the critical value of the short-circuit ratio at the grid connection point, determine the configuration quantity of the synchronous condenser based on a pre-determined synchronous condenser optimization configuration target, so that the machine-side short-circuit ratio of each of the multiple target new energy power stations is greater than the critical value of the machine-side short-circuit ratio, and the short-circuit ratio at the grid connection point of each is greater than the critical value of the short-circuit ratio at the grid connection point; Calculate the short-circuit ratio of each new energy power station among the multiple target new energy power stations; Compare the short-circuit ratio of each new energy power station with the critical value of the short-circuit ratio in turn; When there is a new energy power station with a short-circuit ratio less than the critical value of the short-circuit ratio, determine the configuration quantity of the synchronous condenser based on a pre-determined synchronous condenser optimization configuration target, so that the short-circuit ratio of each of the multiple target new energy power stations is greater than the critical value of the short-circuit ratio; The determining the configuration quantity of the synchronous condenser based on a pre-determined synchronous condenser optimization configuration target includes: Determine the minimum centralized configuration quantity of the synchronous condenser configured only on the AC bus of the converter station; Configure different quantities of synchronous condensers within the range of the minimum centralized configuration quantity on the AC bus of the converter station respectively, and determine the configuration quantity of the distributed synchronous condenser based on a pre-determined synchronous condenser optimization configuration target, so that the short-circuit ratio of each of the multiple target new energy power stations is greater than the critical value of the short-circuit ratio; The synchronous condenser optimization configuration target is: when the machine-side short-circuit ratio of each of the multiple target new energy power stations is greater than the critical value of the machine-side short-circuit ratio, and the short-circuit ratio at the grid connection point of each new energy power station is greater than the critical value of the short-circuit ratio at the grid connection point, determine the synchronous condenser optimization configuration scheme based on the synchronous condenser optimization objective function; the synchronous condenser optimization objective function is: minS = min(S C + S G + S S ) Among them, S is the total configured quantity of synchronous condensers, S C is the quantity of synchronous condensers centrally configured on the AC bus of the converter station, S G is the configured quantity of distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point, S S is the configured quantity of distributed synchronous condensers on the AC bus of the new energy station; The determining the synchronous condenser optimization configuration scheme based on the synchronous condenser optimization objective function further includes determining a short-circuit ratio judgment formula: Among them, MRSCR G is the machine-side short-circuit ratio, MRSCR Gmin is the critical value of the machine-side short-circuit ratio, MRSCR S is the short-circuit ratio at the point of common coupling, MRSCR Smin is the critical value of the short-circuit ratio at the point of common coupling; When the short-circuit ratio at the generator terminals or the short-circuit ratio at the grid connection point of the new energy multi-station does not meet the short-circuit ratio judgment formula, based on the critical value of the short-circuit ratio at the generator terminals and the critical value of the short-circuit ratio at the grid connection point, determine the number of synchronous condensers centrally configured only on the AC bus of the converter station; recalculate the short-circuit ratio at the generator terminals and the short-circuit ratio at the grid connection point of the new energy multi-station after centrally configuring the synchronous condensers on the AC bus of the converter station, and judge whether the calculated short-circuit ratio at the generator terminals or the short-circuit ratio at the grid connection point of the new energy multi-station meets the short-circuit ratio judgment formula; when the calculated short-circuit ratio at the generator terminals and the short-circuit ratio at the grid connection point of the new energy multi-station after centrally configuring the synchronous condensers on the AC bus of the converter station meet the short-circuit ratio judgment formula, the number of synchronous condensers centrally configured on the AC bus of the converter station is the minimum configuration number of the centralized synchronous condenser; After centrally configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station respectively, when the short-circuit ratio at the grid connection point of the new energy multi-station after centrally configuring the synchronous condensers on the AC bus of the converter station is greater than the critical value of the short-circuit ratio at the grid connection point and the short-circuit ratio at the generator terminals is not greater than the critical value of the short-circuit ratio at the generator terminals, configure a distributed synchronous condenser on the low-voltage side bus of the new energy grid connection point with the lowest calculated short-circuit ratio at the generator terminals until the calculated short-circuit ratio at the generator terminals of the new energy multi-station after configuring the distributed synchronous condenser is greater than the critical value of the short-circuit ratio at the generator terminals, and then stop configuring the distributed synchronous condenser on the low-voltage side bus of the new energy grid connection point; or After centrally configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station respectively, when the short-circuit ratio at the grid connection point of the new energy multi-station after centrally configuring the synchronous condensers on the AC bus of the converter station is not greater than the critical value of the short-circuit ratio at the grid connection point and the short-circuit ratio at the generator terminals is greater than the critical value of the short-circuit ratio at the generator terminals, configure a distributed synchronous condenser on the collecting bus with the lowest calculated short-circuit ratio at the grid connection point until the calculated short-circuit ratio at the grid connection point of the new energy multi-station is greater than the critical value of the short-circuit ratio at the grid connection point, and then stop configuring the distributed synchronous condenser on the collecting bus with the lowest calculated short-circuit ratio at the grid connection point; or After centrally configuring different numbers of synchronous condensers within the range of the minimum centralized configuration number on the AC bus of the converter station respectively, when the short-circuit ratio at the grid connection point of the new energy multi-station after centrally configuring the synchronous condensers on the AC bus of the converter station is not greater than the critical value of the short-circuit ratio at the grid connection point and the short-circuit ratio at the generator terminals is not greater than the critical value of the short-circuit ratio at the generator terminals, configure a distributed synchronous condenser on the low-voltage side bus of the new energy grid connection point with the lowest calculated short-circuit ratio at the generator terminals until the calculated short-circuit ratio at the generator terminals of the new energy multi-station after configuring the distributed synchronous condenser is greater than the critical value of the short-circuit ratio at the generator terminals, and then stop configuring the distributed synchronous condenser at the node with the lowest calculated short-circuit ratio at the generator terminals; recalculate the short-circuit ratio at the grid connection point of the new energy multi-station after configuring the distributed synchronous condenser, and judge whether the calculated short-circuit ratio at the grid connection point of the new energy multi-station after configuring the distributed synchronous condenser is greater than the critical value of the short-circuit ratio at the grid connection point; When the short-circuit ratio of the grid connection point of the new energy multi-station after configuring the distributed synchronous condenser is calculated to be not greater than the critical value of the short-circuit ratio of the grid connection point, configure the distributed synchronous condenser on the collecting bus with the lowest calculated short-circuit ratio of the grid connection point until the calculated short-circuit ratio of the grid connection point of the new energy multi-station is greater than the critical value of the short-circuit ratio of the grid connection point, and then stop configuring the distributed synchronous condenser on the collecting bus with the lowest calculated short-circuit ratio of the grid connection point.

2. According to the method described in claim 1, the calculation formulas for the terminal short-circuit ratio of each new energy station and the short-circuit ratio of the grid connection point of each new energy station among multiple target new energy stations are as follows: Where: MRSCR m are the short-circuit ratio at the machine terminal of the m-th new energy power station and the short-circuit ratio at the grid connection point of the m-th new energy power station; n refers to the total number of new energy generation units; is the grid connection point voltage between the new energy power station and generating unit i; is the rated voltage at the grid connection point between the new energy power station and generating unit i; is the current injected by the power generation unit j of the new energy power station into the power grid at the point of common coupling; The current injected into the power grid at the self-connected point of the new energy power station and the power generation unit i; is the element of the a-th row and a-th column of the equivalent impedance matrix Z of the AC power grid at the new energy grid connection point busbar eq ; is the element of the a-th row and b-th column of the equivalent impedance matrix Z of the AC power grid at the new energy grid connection point bus eq ​ 3. A synchronous condenser optimization configuration system for enhancing the voltage strength of the power grid, the system comprising: An initial unit, configured to determine the critical values of the short-circuit ratios of multiple target new energy stations when multiple target new energy stations are connected to an AC / DC hybrid power grid to ensure the stable operation of the power grid system; The critical values of the short-circuit ratios of the multiple target new energy stations include: the critical values of the terminal short-circuit ratios of the multiple target new energy stations and the critical values of the short-circuit ratios of the grid connection points of the multiple target new energy stations; The short-circuit ratio of each new energy station among the multiple target new energy stations includes: the terminal short-circuit ratio of each new energy station among the multiple target new energy stations and the short-circuit ratio of the grid connection point of each new energy station; A calculation unit, configured to calculate the short-circuit ratio of each new energy station among the multiple target new energy stations; A comparison unit, configured to sequentially compare the short-circuit ratio of each new energy station with the critical value of the short-circuit ratio; The comparison unit is further configured to sequentially compare the terminal short-circuit ratio of each new energy station with the critical value of the terminal short-circuit ratio, and sequentially compare the short-circuit ratio of the grid connection point of each new energy station with the critical value of the short-circuit ratio of the grid connection point; The comparison unit is further configured to sequentially compare the terminal short-circuit ratio of each new energy station with the critical value of the terminal short-circuit ratio, and sequentially compare the short-circuit ratio of the grid connection point of each new energy station with the critical value of the short-circuit ratio of the grid connection point; A result unit, configured to, when there is a new energy station with a short-circuit ratio less than the critical value of the short-circuit ratio, determine the configuration quantity of the synchronous condenser based on a predetermined synchronous condenser optimization configuration target, so that the short-circuit ratio of each new energy station among the multiple target new energy stations is greater than the critical value of the short-circuit ratio; The comparison unit is further configured to sequentially compare the terminal short-circuit ratio of each new energy station with the critical value of the terminal short-circuit ratio, and sequentially compare the short-circuit ratio of the grid connection point of each new energy station with the critical value of the short-circuit ratio of the grid connection point; The result unit is further configured to, when there is a terminal short-circuit ratio less than the critical value of the terminal short-circuit ratio, and / or, a short-circuit ratio of the grid connection point less than the critical value of the short-circuit ratio of the grid connection point, determine the configuration quantity of the synchronous condenser based on a predetermined synchronous condenser optimization configuration target, so that the terminal short-circuit ratio of each new energy station among the multiple target new energy stations is greater than the critical value of the terminal short-circuit ratio, and the short-circuit ratio of each grid connection point is greater than the critical value of the short-circuit ratio of the grid connection point; The result unit is configured to determine the configuration quantity of the synchronous condenser based on a predetermined synchronous condenser optimization configuration target, and is further configured to: Determine the minimum centralized configuration quantity of synchronous condensers configured only centrally on the AC busbars of the converter station; Respectively, configure different quantities of synchronous condensers within the range of the minimum centralized configuration quantity centrally on the AC busbars of the converter station, and determine the configuration quantity of distributed synchronous condensers based on a pre-determined optimization configuration objective of the synchronous condenser, such that the short-circuit ratio of each new energy power station among multiple target new energy power stations is greater than the critical short-circuit ratio value; The optimization configuration objective of the synchronous condenser is: when the machine-side short-circuit ratio of each new energy power station among multiple target new energy power stations is greater than the critical machine-side short-circuit ratio value, and the short-circuit ratio at the grid connection point of each new energy power station is greater than the critical short-circuit ratio at the grid connection point, determine the optimization configuration scheme of the synchronous condenser based on the optimization objective function of the synchronous condenser; the optimization objective function of the synchronous condenser is: minS = min(S C + S G + S S ) Among them, S is the total configured quantity of synchronous condensers, S C is the quantity of synchronous condensers centrally configured on the AC bus of the converter station, S G is the configured quantity of distributed synchronous condensers on the low-voltage side bus of the new energy grid connection point, S S is the configured quantity of distributed synchronous condensers on the AC bus of the new energy station; Determining the optimization configuration scheme of the synchronous condenser based on the optimization objective function of the synchronous condenser further includes determining a short-circuit ratio judgment formula: Among them, MRSCR G is the machine-side short-circuit ratio, MRSCR Gmin is the critical value of the machine-side short-circuit ratio, MRSCR S is the short-circuit ratio at the point of common coupling, MRSCR Smin is the critical value of the short-circuit ratio at the point of common coupling; When the machine-side short-circuit ratio or the short-circuit ratio at the grid connection point of the multi-station new energy does not satisfy the short-circuit ratio judgment formula, determine the quantity of synchronous condensers configured only centrally on the AC busbars of the converter station based on the critical machine-side short-circuit ratio value and the critical short-circuit ratio value at the grid connection point; recalculate the machine-side short-circuit ratio and the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers centrally on the AC busbars of the converter station, and determine whether the calculated machine-side short-circuit ratio or the short-circuit ratio at the grid connection point of the multi-station new energy satisfies the short-circuit ratio judgment formula; when the calculated machine-side short-circuit ratio and the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers centrally on the AC busbars of the converter station satisfy the short-circuit ratio judgment formula, the quantity of synchronous condensers configured centrally on the AC busbars of the converter station is the minimum configuration quantity of the centralized synchronous condenser; After respectively configuring different quantities of synchronous condensers within the range of the minimum centralized configuration quantity centrally on the AC busbars of the converter station, when the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers centrally on the AC busbars of the converter station is greater than the critical short-circuit ratio at the grid connection point, and the machine-side short-circuit ratio is not greater than the critical machine-side short-circuit ratio value, configure a distributed synchronous condenser on the low-voltage side busbar of the new energy grid connection point with the lowest calculated machine-side short-circuit ratio until the calculated machine-side short-circuit ratio of the multi-station new energy after configuring the distributed synchronous condenser is greater than the critical machine-side short-circuit ratio value, and then stop configuring the distributed synchronous condenser on the low-voltage side busbar of the new energy grid connection point; or After respectively configuring different quantities of synchronous condensers within the range of the minimum centralized configuration quantity centrally on the AC busbars of the converter station, when the short-circuit ratio at the grid connection point of the multi-station new energy after configuring the synchronous condensers centrally on the AC busbars of the converter station is not greater than the critical short-circuit ratio at the grid connection point, and the machine-side short-circuit ratio is greater than the critical machine-side short-circuit ratio value, configure a distributed synchronous condenser on the collecting busbar with the lowest calculated short-circuit ratio at the grid connection point until the calculated short-circuit ratio at the grid connection point of the multi-station new energy is greater than the critical short-circuit ratio at the grid connection point, and then stop configuring the distributed synchronous condenser on the collecting busbar with the lowest calculated short-circuit ratio at the grid connection point; or After different numbers of synchronous condensers within the range of the minimum centralized configuration quantity are centrally configured on the AC busbars of the converter station respectively, when the short-circuit ratio of the grid connection point of the new energy multi-station after the synchronous condensers centrally configured on the AC busbars of the converter station is calculated and is not greater than the critical value of the short-circuit ratio of the grid connection point, and the short-circuit ratio at the machine terminal is not greater than the critical value of the short-circuit ratio at the machine terminal, a distributed synchronous condenser is configured on the low-voltage side busbar of the new energy grid connection point with the lowest calculated short-circuit ratio at the machine terminal until the short-circuit ratio at the machine terminal of the new energy multi-station after the distributed synchronous condenser is re-calculated is greater than the critical value of the short-circuit ratio at the machine terminal, and then stop configuring the distributed synchronous condenser at the node with the lowest calculated short-circuit ratio at the machine terminal; re-calculate the short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured, and determine whether the calculated short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured is greater than the critical value of the short-circuit ratio of the grid connection point; When the calculated short-circuit ratio of the grid connection point of the new energy multi-station after the distributed synchronous condenser is configured is not greater than the critical value of the short-circuit ratio of the grid connection point, a distributed synchronous condenser is configured on the collection busbar with the lowest calculated short-circuit ratio of the grid connection point until the calculated short-circuit ratio of the grid connection point of the new energy multi-station is greater than the critical value of the short-circuit ratio of the grid connection point, and then stop configuring the distributed synchronous condenser on the collection busbar with the lowest calculated short-circuit ratio of the grid connection point.

4. The system according to claim 3, wherein, For each new energy station among multiple target new energy stations, the short-circuit ratio at the machine terminal and the short-circuit ratio of the grid connection point of each new energy station, the calculation formula is: Wherein: MRSCR m is the short-circuit ratio at the machine terminal of the m-th new energy power station and the short-circuit ratio at the grid connection point of the m-th new energy power station; n refers to the total number of new energy power generation units; is the grid connection point voltage between the new energy power station and the generating unit i; is the rated voltage at the grid connection point of the new energy power station and the power generation unit i; is the current injected by the power generation unit j of the new energy power station into the power grid from the grid connection point; The current injected into the power grid at the self-connection point of the new energy power station and power generation unit i; is the element in the a-th row and a-th column of the equivalent impedance matrix Z of the AC power grid at the new energy grid-connected bus point eq ; is the element in the a-th row and b-th column of the equivalent impedance matrix Z of the AC power grid at the new energy grid-connected bus point eq ​ 5. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1-2 above.

6. An electronic device, characterized in that, The electronic device includes: A processor; A memory for storing executable instructions of the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method according to any one of claims 1-2 above.

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