A method and system for optimizing the reactive power support capability of a direct current receiving end near-zone energy storage power station

Abstract

The application discloses a kind of reactive power support ability optimization method and system of direct current receiving end near area energy storage power station, comprising: according to the different establishment of starting combination, load level and network frame structure multiple sets of typical operating mode data;For any one set of typical operating mode data, respectively determine the first short-circuit ratio of direct current receiving end near area power grid;For any one set of typical operating mode data, respectively according to the first short-circuit ratio and the first preset comparison threshold value is carried out the segmented control optimization of energy storage power station reactive power support coefficient, to obtain the reactive power support coefficient setting value corresponding to the any one set of typical operating mode data;According to the reactive power support coefficient setting value corresponding to all typical operating mode data, the voltage of direct current receiving end power grid is stably optimized and controlled.The method of the application can make full use of the reactive voltage support ability of direct current receiving end power grid near area electrochemical energy storage power station, improve the voltage stability level of direct current converter station, and optimize the voltage stability characteristics of direct current receiving end power grid.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and more specifically, to a method and system for optimizing the reactive power support capability of a DC receiving-end near-area energy storage power station. Background Technology

[0002] The stability of the DC receiving-end near-field power grid is strongly coupled with the stable operation of the DC system. When there is an AC fault in the near-field of the DC receiving-end converter station, the DC converter station is prone to continuous commutation failure due to voltage fluctuations and low voltage problems, which threatens the safe and stable operation of the receiving-end power grid.

[0003] Energy storage power stations offer flexible control and the ability to provide dynamic reactive power support to the power grid. The national standard GB / T 34120-2017, "Technical Specification for Energy Storage Converters in Electrochemical Energy Storage Systems," explicitly stipulates that energy storage power stations should provide dynamic reactive power support to the AC system during low-voltage ride-through. The reactive power support capability is determined by the coefficient IT. Currently, a typical reactive power support capability coefficient for energy storage power stations is set at 1.6; the higher this value, the stronger the dynamic reactive power support capability. However, this also presents challenges such as higher requirements for the response and adjustment speed of the energy storage converter control system, and more pronounced active power fluctuations during fault ride-through.

[0004] Therefore, a method for optimizing the reactive power support capability of DC receiving-end near-field energy storage power stations is needed. Summary of the Invention

[0005] This invention proposes a method and system for optimizing the reactive power support capability of a DC receiving-end near-area energy storage power station, in order to solve the problem of how to optimize the DC receiving-end grid voltage to maintain voltage stability.

[0006] To address the aforementioned problems, according to one aspect of the present invention, a method for optimizing the reactive power support capability of a DC receiving-end near-field energy storage power station is provided, the method comprising:

[0007] Multiple sets of typical operating mode data were established based on different start-up combinations, load levels, and grid structures.

[0008] For any set of typical operating mode data, determine the first short-circuit ratio of the DC receiving-end near-area power grid;

[0009] For any set of typical operating mode data, the reactive power support coefficient of the energy storage power station is segmented and optimized according to the first short-circuit ratio and the first preset comparison threshold, so as to obtain the reactive power support coefficient set value corresponding to the set of typical operating mode data.

[0010] The DC receiving-end grid voltage is optimized and controlled for stability based on the reactive power support coefficient setpoints corresponding to all typical operating mode data.

[0011] Preferably, the step of performing segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold for any set of typical operating mode data, to obtain the set value of the reactive power support coefficient corresponding to the set of typical operating mode data, includes:

[0012] The reactive power support coefficient setpoint corresponding to any set of typical operating mode data is determined using the following methods:

[0013] S301, determine whether the first short-circuit ratio is less than or equal to the first preset comparison threshold;

[0014] S302, when it is determined that the first short-circuit ratio is less than or equal to the first preset comparison threshold, it is determined whether the first short-circuit ratio is less than or equal to the second preset comparison threshold;

[0015] S303, when the first short-circuit ratio is less than or equal to the second preset comparison threshold, adjust the reactive power support coefficient setting value of the energy storage power station to the first preset adjustment value;

[0016] S304, obtain the first voltage of the DC access point after a near-field fault in the converter station, and determine whether the first voltage is less than or equal to a third preset comparison threshold.

[0017] S305, when it is determined that the first voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the second preset adjustment value.

[0018] Preferably, the method further includes:

[0019] S306, when it is determined that the first short-circuit ratio is greater than the first preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the third preset adjustment value;

[0020] S307, obtain the second voltage of the DC access point after a near-field fault in the converter station, and determine whether the second voltage is less than or equal to a third preset comparison threshold;

[0021] S308, when it is determined that the second voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value;

[0022] S309, obtain the third voltage of the DC access point after a near-field fault in the converter station, and determine whether the third voltage is less than or equal to a third preset comparison threshold;

[0023] S310, when it is determined that the third voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the first preset adjustment value, and the process proceeds to step S304.

[0024] Preferably, the method further includes:

[0025] S311, when it is determined that the first short-circuit ratio is greater than the second preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value, and then the process proceeds to step S309.

[0026] Preferably, the first preset comparison threshold is 6; the second preset comparison threshold is 4; the third preset comparison threshold is 0.95pu; the first preset adjustment value is 2.5; the second preset adjustment value is 3.0; the third preset adjustment value is 1.6; and the fourth preset adjustment value is 2.0.

[0027] Preferably, the step of performing stable optimization control of the DC receiving-end grid voltage based on the reactive power support coefficient setpoint corresponding to all typical operating mode data includes:

[0028] The maximum value among the reactive power support coefficient settings corresponding to all typical operating mode data is selected as the target reactive power support coefficient, and the DC receiving-end grid voltage is stabilized and optimized based on the target reactive power support coefficient.

[0029] According to another aspect of the present invention, a reactive power support capability optimization system for a DC receiving-end near-area energy storage power station is provided, the system comprising:

[0030] The typical operating mode data establishment unit is used to establish multiple sets of typical operating mode data based on different start-up combinations, load levels, and grid structures.

[0031] The first short-circuit ratio acquisition unit is used to determine the first short-circuit ratio of the DC receiving-end near-area power grid for any set of typical operating mode data.

[0032] The segmented control unit is used to perform segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold for any set of typical operating mode data, so as to obtain the reactive power support coefficient set value corresponding to the set of typical operating mode data.

[0033] The stability optimization control unit is used to perform stability optimization control on the DC receiving-end grid voltage based on the reactive power support coefficient setpoint corresponding to all typical operating mode data.

[0034] Preferably, the segmented control unit, for any set of typical operating mode data, performs segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold, to obtain the reactive power support coefficient set value corresponding to the set of typical operating mode data, including:

[0035] The reactive power support coefficient setpoint corresponding to any set of typical operating mode data is determined using the following methods:

[0036] S301, determine whether the first short-circuit ratio is less than or equal to the first preset comparison threshold;

[0037] S302, when it is determined that the first short-circuit ratio is less than or equal to the first preset comparison threshold, it is determined whether the first short-circuit ratio is less than or equal to the second preset comparison threshold;

[0038] S303, when the first short-circuit ratio is less than or equal to the second preset comparison threshold, adjust the reactive power support coefficient setting value of the energy storage power station to the first preset adjustment value;

[0039] S304, obtain the first voltage of the DC access point after a near-field fault in the converter station, and determine whether the first voltage is less than or equal to a third preset comparison threshold.

[0040] S305, when it is determined that the first voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the second preset adjustment value.

[0041] Preferably, the segmented control unit is further configured to:

[0042] S306, when it is determined that the first short-circuit ratio is greater than the first preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the third preset adjustment value;

[0043] S307, obtain the second voltage of the DC access point after a near-field fault in the converter station, and determine whether the second voltage is less than or equal to a third preset comparison threshold;

[0044] S308, when it is determined that the second voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value;

[0045] S309, obtain the third voltage of the DC access point after a near-field fault in the converter station, and determine whether the third voltage is less than or equal to a third preset comparison threshold;

[0046] S310, when it is determined that the third voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the first preset adjustment value, and the process proceeds to step S304.

[0047] Preferably, the segmented control unit is further configured to:

[0048] S311, when it is determined that the first short-circuit ratio is greater than the second preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value, and then the process proceeds to step S309.

[0049] Preferably, the first preset comparison threshold is 6; the second preset comparison threshold is 4; the third preset comparison threshold is 0.95pu; the first preset adjustment value is 2.5; the second preset adjustment value is 3.0; the third preset adjustment value is 1.6; and the fourth preset adjustment value is 2.0.

[0050] Preferably, the stability optimization control unit performs stability optimization control on the DC receiving-end grid voltage based on the reactive power support coefficient setpoint corresponding to all typical operating mode data, including:

[0051] The maximum value among the reactive power support coefficient settings corresponding to all typical operating mode data is selected as the target reactive power support coefficient, and the DC receiving-end grid voltage is stabilized and optimized based on the target reactive power support coefficient. This invention provides a method and system for optimizing the reactive power support capability of a DC receiving-end near-area energy storage power station, comprising: establishing multiple sets of typical operating mode data based on different start-up combinations, load levels, and grid structures; determining the first short-circuit ratio of the DC receiving-end near-area grid for any set of typical operating mode data; performing segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and a first preset comparison threshold for any set of typical operating mode data to obtain the reactive power support coefficient setting value corresponding to that set of typical operating mode data; and stabilizing and optimizing the DC receiving-end grid voltage based on the reactive power support coefficient setting values ​​corresponding to all typical operating mode data. The method of this invention uses the short-circuit ratio index to determine the voltage stability level of the DC near-field grid and adjusts the reactive power support coefficient of the energy storage station in stages. During DC near-field faults and voltage drops, it can make full use of the reactive power and voltage support capability of the DC receiving-end grid near-field electrochemical energy storage station, improve the voltage stability level of the DC converter station, and optimize the voltage stability characteristics of the DC receiving-end grid. Attached Figure Description

[0052] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0053] Figure 1 A flowchart of a method for optimizing the reactive power support capability of a DC receiving-end near-field energy storage power station according to an embodiment of the present invention;

[0054] Figure 2 This is an example diagram illustrating the optimization of DC receiving-end grid voltage stability according to an embodiment of the present invention;

[0055] Figure 3 A comparison chart of reactive power output curves of energy storage before and after configuration according to the method of the present invention according to an embodiment of the present invention;

[0056] Figure 4A comparison diagram of converter station voltage curves before and after DC near-field faults according to the method of the present invention, according to an embodiment of the present invention;

[0057] Figure 5 This is a schematic diagram of the reactive power support capability optimization system 500 of a DC receiving-end near-area energy storage power station according to an embodiment of the present invention. Detailed Implementation

[0058] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0059] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0060] This invention proposes a method for optimizing the reactive power support capability of a DC receiving-end near-area energy storage power station. By using the AC short-circuit ratio index, the voltage stability level of the DC near-area AC grid is determined. If the voltage stability level is low, the reactive power support capability coefficient of the energy storage power station is adjusted in stages according to the magnitude of the short-circuit ratio index, so that the energy storage can provide support for the voltage stability of the DC converter station during low-voltage ride-through, and ensure the stable operation of the DC system.

[0061] Figure 1 This is a flowchart of a method 100 for optimizing the reactive power support capability of a DC receiving-end near-field energy storage power station according to an embodiment of the present invention. Figure 1 As shown, the reactive power support capability optimization method for DC receiving-end near-area energy storage power stations provided by this invention uses the short-circuit ratio index to determine the voltage stability level of the DC near-area grid and adjusts the reactive power support coefficient of the energy storage power station in stages. During DC near-area faults and voltage drops, it can fully utilize the reactive power and voltage support capability of the DC receiving-end grid near-area electrochemical energy storage power station, improve the voltage stability level of the DC converter station, and optimize the voltage stability characteristics of the DC receiving-end grid. The reactive power support capability optimization method 100 for DC receiving-end near-area energy storage power stations provided by this invention starts from step 101. In step 101, multiple sets of typical operating mode data are established according to different start-up combinations, load levels, and grid structures.

[0062] In step 102, for any set of typical operating mode data, the first short-circuit ratio of the DC receiving end near-area power grid is determined.

[0063] Step 103: For any set of typical operating mode data, perform segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold to obtain the set value of the reactive power support coefficient corresponding to the set of typical operating mode data. Preferably, the segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold to obtain the set value of the reactive power support coefficient corresponding to the set of typical operating mode data includes:

[0064] The reactive power support coefficient setpoint corresponding to any set of typical operating mode data is determined using the following methods:

[0065] S301, determine whether the first short-circuit ratio is less than or equal to the first preset comparison threshold;

[0066] S302, when it is determined that the first short-circuit ratio is less than or equal to the first preset comparison threshold, it is determined whether the first short-circuit ratio is less than or equal to the second preset comparison threshold;

[0067] S303, when the first short-circuit ratio is less than or equal to the second preset comparison threshold, adjust the reactive power support coefficient setting value of the energy storage power station to the first preset adjustment value;

[0068] S304, obtain the first voltage of the DC access point after a near-field fault in the converter station, and determine whether the first voltage is less than or equal to a third preset comparison threshold.

[0069] S305, when it is determined that the first voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the second preset adjustment value.

[0070] Preferably, the method further includes:

[0071] S306, when it is determined that the first short-circuit ratio is greater than the first preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the third preset adjustment value;

[0072] S307, obtain the second voltage of the DC access point after a near-field fault in the converter station, and determine whether the second voltage is less than or equal to a third preset comparison threshold;

[0073] S308, when it is determined that the second voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value;

[0074] S309, obtain the third voltage of the DC access point after a near-field fault in the converter station, and determine whether the third voltage is less than or equal to a third preset comparison threshold;

[0075] S310, when it is determined that the third voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the first preset adjustment value, and the process proceeds to step S304.

[0076] Preferably, the method further includes:

[0077] S311, when it is determined that the first short-circuit ratio is greater than the second preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value, and then the process proceeds to step S309.

[0078] Preferably, the first preset comparison threshold is 6; the second preset comparison threshold is 4; the third preset comparison threshold is 0.95pu; the first preset adjustment value is 2.5; the second preset adjustment value is 3.0; the third preset adjustment value is 1.6; and the fourth preset adjustment value is 2.0.

[0079] Step 104: Perform stable optimization control on the DC receiving-end grid voltage based on the reactive power support coefficient setting value corresponding to all typical operating mode data.

[0080] Preferably, the step of performing stable optimization control of the DC receiving-end grid voltage based on the reactive power support coefficient setpoint corresponding to all typical operating mode data includes:

[0081] The maximum value among the reactive power support coefficient settings corresponding to all typical operating mode data is selected as the target reactive power support coefficient, and the DC receiving-end grid voltage is stabilized and optimized based on the target reactive power support coefficient.

[0082] Combination Figure 2 As shown, in this invention, the process of optimizing the DC receiving-end grid voltage stability includes:

[0083] Step 1: Establish multiple sets of typical operating mode data for the DC receiving-end power grid of the power grid to be studied under different start-up combinations, load levels, grid structure and other conditions.

[0084] Step 2: Select each operating mode established in Step 1 in sequence. For any operating mode, calculate the short-circuit ratio of the DC receiving end near the power grid.

[0085] Step 3: Sequentially determine the short-circuit ratio of the DC receiving end near the power grid under each operating mode. If the short-circuit ratio is less than or equal to 6 (first preset comparison threshold), proceed to step 4; if it is higher than 6, proceed to step 5.

[0086] Step 4: Further determine whether the short-circuit ratio is less than or equal to 4 (second preset comparison threshold). If it is less than or equal to 4, proceed to step 7; if it is higher than 4, proceed to step 6.

[0087] Step 5: The dynamic reactive power support coefficient setpoint of the energy storage power station is kept at the typical value I. T =1.6 (third preset adjustment value) remains unchanged, and proceed to step 8.

[0088] Step 6: Adjust the dynamic reactive power support coefficient setting value of the energy storage power station to I. T =2.0 (fourth preset adjustment value), and proceed to step 9.

[0089] Step 7: Adjust the dynamic reactive power support coefficient setting value of the energy storage power station to I. T =2.5 (first preset adjustment value), and proceed to step 10.

[0090] Step 8: Determine whether the DC access point voltage after a near-field fault in the converter station is less than or equal to 0.95 pu. If it is less than or equal to 0.95 pu, proceed to step 6. If it is higher than 0.95 pu, proceed to step 12.

[0091] Step 9: Determine whether the DC access point voltage after a near-field fault in the converter station is less than or equal to 0.95 pu. If it is less than or equal to 0.95 pu, proceed to step 7; if it is higher than 0.95 pu, proceed to step 12.

[0092] Step 10: Determine whether the DC access point voltage after a near-field fault in the converter station is less than or equal to 0.95 pu. If it is less than or equal to 0.95 pu, proceed to step 11. If it is higher than 0.95 pu, proceed to step 12.

[0093] Step 11: Adjust the dynamic reactive power support coefficient setting value of the energy storage power station to I. T =3.0 (Second preset adjustment value).

[0094] Step 12: End of method.

[0095] Finally, the DC receiving-end grid voltage is stabilized and optimized based on the reactive power support coefficient settings corresponding to all typical operating mode data.

[0096] In this invention, based on the grid structure data of a certain region in China, BPA simulation is used to optimize the DC stable operation level by adopting the method proposed in this patent and utilizing the flexible control and reactive voltage support capabilities of the energy storage power station configured in the near-field of the DC receiving end, so as to verify the applicability of the method proposed in this patent.

[0097] Before adopting this patented method, the dynamic voltage support capability of the energy storage power station after a near-area AC fault in the DC converter station was as follows: Figure 3As shown in the curve below, the peak value of the dynamic reactive power support capability after a fault is 360MVar, and the steady-state value is 202MVar.

[0098] After adopting the method of this patent, the AC short-circuit ratio of the near-area power grid of the DC converter station is first calculated using the following formula.

[0099]

[0100] In the formula, P di Z si Z represents the operating power of the i-th DC line and the self-impedance of the converter bus, respectively; ij Let be the mutual impedance between the converter buses i and j of the DC line.

[0101] In actual engineering calculations, the "short-circuit ratio scan" function of BPA-SCCP software can be used to quickly calculate the actual power grid short-circuit ratio index. Through calculation, the near-field short-circuit ratio index of the example power grid DC converter station used in this example is 5.2. Therefore, proceed to step 6 to adjust the reactive power support coefficient I of the energy storage power station. T Up to version 2.0.

[0102] Then calculate the reactive power support coefficient I of the energy storage power station. T After adjustment, the AC bus voltage level of the converter station after a DC near-area fault.

[0103] like Figure 4 As shown, before adopting this patented method, after a three-phase short-circuit fault on a DC near-field bus, the AC side voltage curve of the DC converter station is shown as the curve at the bottom. After adopting this patented method, under the same fault conditions, by adjusting the reactive power support coefficient of the energy storage station, the bus voltage curve is shown as the curve at the top. It can be seen that the voltage recovery level is significantly improved compared to before the method was adopted, optimizing the voltage stability level of the receiving-end DC under the impact of near-field AC faults.

[0104] Figure 5 This is a schematic diagram of the reactive power support capability optimization system 500 for a DC receiving-end near-field energy storage power station according to an embodiment of the present invention. Figure 5 As shown, the reactive power support capability optimization system 500 for DC receiving-end near-area energy storage power stations provided in this embodiment of the invention includes: a typical operation mode data establishment unit 501, a first short-circuit ratio acquisition unit 502, a segmented control unit 503, and a stability optimization control unit 504.

[0105] Preferably, the typical operation mode data establishment unit 501 is used to establish multiple sets of typical operation mode data according to different start-up combinations, load levels and grid structures.

[0106] Preferably, the first short-circuit ratio acquisition unit 502 is used to determine the first short-circuit ratio of the DC receiving-end near-area power grid for any set of typical operating mode data.

[0107] Preferably, the segmented control unit 503 is used to perform segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold for any set of typical operating mode data, so as to obtain the reactive power support coefficient set value corresponding to the set of typical operating mode data.

[0108] Preferably, the segmented control unit 503, for any set of typical operating mode data, performs segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold, to obtain the reactive power support coefficient set value corresponding to the any set of typical operating mode data, including:

[0109] The reactive power support coefficient setpoint corresponding to any set of typical operating mode data is determined using the following methods:

[0110] S301, determine whether the first short-circuit ratio is less than or equal to the first preset comparison threshold;

[0111] S302, when it is determined that the first short-circuit ratio is less than or equal to the first preset comparison threshold, it is determined whether the first short-circuit ratio is less than or equal to the second preset comparison threshold;

[0112] S303, when the first short-circuit ratio is less than or equal to the second preset comparison threshold, adjust the reactive power support coefficient setting value of the energy storage power station to the first preset adjustment value;

[0113] S304, obtain the first voltage of the DC access point after a near-field fault in the converter station, and determine whether the first voltage is less than or equal to a third preset comparison threshold.

[0114] S305, when it is determined that the first voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the second preset adjustment value.

[0115] Preferably, the segmented control unit 303 is further configured to:

[0116] S306, when it is determined that the first short-circuit ratio is greater than the first preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the third preset adjustment value;

[0117] S307, obtain the second voltage of the DC access point after a near-field fault in the converter station, and determine whether the second voltage is less than or equal to a third preset comparison threshold;

[0118] S308, when it is determined that the second voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value;

[0119] S309, obtain the third voltage of the DC access point after a near-field fault in the converter station, and determine whether the third voltage is less than or equal to a third preset comparison threshold;

[0120] S310, when it is determined that the third voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the first preset adjustment value, and the process proceeds to step S304.

[0121] Preferably, the segmented control unit 303 is further configured to:

[0122] S311, when it is determined that the first short-circuit ratio is greater than the second preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value, and then the process proceeds to step S309.

[0123] Preferably, the first preset comparison threshold is 6; the second preset comparison threshold is 4; the third preset comparison threshold is 0.95pu; the first preset adjustment value is 2.5; the second preset adjustment value is 3.0; the third preset adjustment value is 1.6; and the fourth preset adjustment value is 2.0.

[0124] Preferably, the stability optimization control unit 504 performs stability optimization control on the DC receiving-end grid voltage based on the reactive power support coefficient set value corresponding to all typical operating mode data.

[0125] Preferably, the stability optimization control unit 504 performs stability optimization control on the DC receiving-end grid voltage based on the reactive power support coefficient setpoint corresponding to all typical operating mode data, including:

[0126] The maximum value among the reactive power support coefficient settings corresponding to all typical operating mode data is selected as the target reactive power support coefficient, and the DC receiving-end grid voltage is stabilized and optimized based on the target reactive power support coefficient.

[0127] The reactive power support capability optimization system 500 of the DC receiving-end near-area energy storage power station in this embodiment corresponds to the reactive power support capability optimization method 100 of the DC receiving-end near-area energy storage power station in another embodiment of this invention, and will not be described again here.

[0128] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0129] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0130] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0131] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0132] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0133] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0134] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing the reactive power support capability of a DC receiving-end near-area energy storage power station, characterized in that, The method includes: Multiple sets of typical operating mode data were established based on different start-up combinations, load levels, and grid structures. For any set of typical operating mode data, determine the first short-circuit ratio of the DC receiving-end near-area power grid; For any set of typical operating mode data, the reactive power support coefficient of the energy storage power station is segmented and optimized according to the first short-circuit ratio and the first preset comparison threshold, so as to obtain the reactive power support coefficient set value corresponding to the set of typical operating mode data. The DC receiving-end grid voltage is optimized and controlled for stability based on the reactive power support coefficient setpoints corresponding to all typical operating mode data. The step of performing stable optimization control of the DC receiving-end grid voltage based on the reactive power support coefficient setpoint corresponding to all typical operating mode data includes: The maximum value among the reactive power support coefficient settings corresponding to all typical operating mode data is selected as the target reactive power support coefficient, and the DC receiving-end grid voltage is stabilized and optimized based on the target reactive power support coefficient.

2. The method according to claim 1, characterized in that, For any set of typical operating mode data, the reactive power support coefficient of the energy storage power station is optimized through segmented control based on the first short-circuit ratio and the first preset comparison threshold, to obtain the set value of the reactive power support coefficient corresponding to that set of typical operating mode data, including: The reactive power support coefficient setpoint corresponding to any set of typical operating mode data is determined using the following methods: S301, determine whether the first short-circuit ratio is less than or equal to the first preset comparison threshold; S302, when it is determined that the first short-circuit ratio is less than or equal to the first preset comparison threshold, it is determined whether the first short-circuit ratio is less than or equal to the second preset comparison threshold; S303, when the first short-circuit ratio is less than or equal to the second preset comparison threshold, adjust the reactive power support coefficient setting value of the energy storage power station to the first preset adjustment value; S304, obtain the first voltage of the DC access point after a near-field fault in the converter station, and determine whether the first voltage is less than or equal to a third preset comparison threshold. S305, when it is determined that the first voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the second preset adjustment value.

3. The method according to claim 2, characterized in that, The method further includes: S306, When it is determined that the first short-circuit ratio is greater than the first preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the third preset adjustment value; S307, obtain the second voltage of the DC access point after a near-field fault in the converter station, and determine whether the second voltage is less than or equal to a third preset comparison threshold; S308, when it is determined that the second voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value; S309, obtain the third voltage of the DC access point after a near-field fault in the converter station, and determine whether the third voltage is less than or equal to a third preset comparison threshold; S310, when it is determined that the third voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the first preset adjustment value, and the process proceeds to step S304.

4. The method according to claim 3, characterized in that, The method further includes: S311, when it is determined that the first short-circuit ratio is greater than the second preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value, and then the process proceeds to step S309.

5. The method according to claim 3, characterized in that, The first preset comparison threshold is 6; the second preset comparison threshold is 4; the third preset comparison threshold is 0.95pu; the first preset adjustment value is 2.5; the second preset adjustment value is 3.0; the third preset adjustment value is 1.6; and the fourth preset adjustment value is 2.

0.

6. A reactive power support capability optimization system for a DC receiving-end near-area energy storage power station, characterized in that, The system includes: The typical operating mode data establishment unit is used to establish multiple sets of typical operating mode data based on different start-up combinations, load levels, and grid structures. The first short-circuit ratio acquisition unit is used to determine the first short-circuit ratio of the DC receiving-end near-area power grid for any set of typical operating mode data. The segmented control unit is used to perform segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold for any set of typical operating mode data, so as to obtain the reactive power support coefficient set value corresponding to the set of typical operating mode data. The stability optimization control unit is used to optimize the voltage of the DC receiving-end grid based on the reactive power support coefficient setpoint corresponding to all typical operating mode data. The stability optimization control unit performs stability optimization control on the DC receiving-end grid voltage based on the reactive power support coefficient setpoint corresponding to all typical operating mode data, including: The maximum value among the reactive power support coefficient settings corresponding to all typical operating mode data is selected as the target reactive power support coefficient, and the DC receiving-end grid voltage is stabilized and optimized based on the target reactive power support coefficient.

7. The system according to claim 6, characterized in that, The segmented control unit, for any set of typical operating mode data, performs segmented control optimization of the reactive power support coefficient of the energy storage power station based on the first short-circuit ratio and the first preset comparison threshold, to obtain the set value of the reactive power support coefficient corresponding to that set of typical operating mode data, including: The reactive power support coefficient setpoint corresponding to any set of typical operating mode data is determined using the following methods: S301, determine whether the first short-circuit ratio is less than or equal to the first preset comparison threshold; S302, when it is determined that the first short-circuit ratio is less than or equal to the first preset comparison threshold, it is determined whether the first short-circuit ratio is less than or equal to the second preset comparison threshold; S303, when the first short-circuit ratio is less than or equal to the second preset comparison threshold, adjust the reactive power support coefficient setting value of the energy storage power station to the first preset adjustment value; S304, obtain the first voltage of the DC access point after a near-field fault in the converter station, and determine whether the first voltage is less than or equal to a third preset comparison threshold. S305, when it is determined that the first voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the second preset adjustment value.

8. The system according to claim 7, characterized in that, The segmented control unit is also used for: S306, When it is determined that the first short-circuit ratio is greater than the first preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the third preset adjustment value; S307, obtain the second voltage of the DC access point after a near-field fault in the converter station, and determine whether the second voltage is less than or equal to a third preset comparison threshold; S308, when it is determined that the second voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value; S309, obtain the third voltage of the DC access point after a near-field fault in the converter station, and determine whether the third voltage is less than or equal to a third preset comparison threshold; S310, when it is determined that the third voltage is less than or equal to the third preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the first preset adjustment value, and the process proceeds to step S304.

9. The system according to claim 8, characterized in that, The segmented control unit is also used for: S311, when it is determined that the first short-circuit ratio is greater than the second preset comparison threshold, the reactive power support coefficient setting value of the energy storage power station is adjusted to the fourth preset adjustment value, and then the process proceeds to step S309.

10. The system according to claim 8, characterized in that, The first preset comparison threshold is 6; the second preset comparison threshold is 4; the third preset comparison threshold is 0.95pu; the first preset adjustment value is 2.5; the second preset adjustment value is 3.0; the third preset adjustment value is 1.6; and the fourth preset adjustment value is 2.0.

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