A method and system for verifying the transmission capacity of ultra-high voltage flexible direct current projects

Abstract

The present invention discloses a method and system for verifying the transmission capacity of an ultra-high voltage flexible direct current (UHVDC) project, which belongs to the field of power grid security technology. The method of the present invention includes: obtaining basic data related to the transmission capacity of the ultra-high voltage flexible direct current (UHVDC) system; calculating the short-circuit current level of the ultra-high voltage flexible direct current (UHVDC) converter station based on the basic data; screening a UHVDC project location plan based on the short-circuit current level of the ultra-high voltage flexible direct current (UHVDC) converter station; and screening a method for verifying the UHVDC transmission capacity based on the UHVDC project location plan to calculate the UHVDC transmission capacity P. dcmax Based on the UHV flexible DC transmission capacity P dcmax The present invention can verify the full transmission conditions of the UHV flexible DC project under different operating modes to determine whether the transmission capacity of the UHV flexible DC project meets the operating requirements. This invention saves manpower and material resources and creates significant economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of power grid security technology, and more particularly, to a method and system for verifying the transmission capacity of an ultra-high voltage flexible direct current (UHVDC) project. Background Art

[0002] my country's energy resources and load centers are showing an "inverse distribution" trend, which inevitably requires the construction of long-distance, large-capacity transmission channels to fully achieve the optimal allocation of energy resources within the country. High Voltage Direct Current (HVDC) transmission technology based on modular multilevel converters (MMC) has the advantages of flexible and controllable DC voltage, no commutation failure, and high power quality. Therefore, it is widely considered to be suitable for multiple application scenarios such as urban grid interconnection, power supply to remote areas, and long-distance, large-capacity transmission of clean energy. State Grid Corporation of China has completed the Zhang Renewable Energy Flexible Direct Current (Flexible Direct Current) Grid Demonstration Project and the Chongqing-Hubei Back-to-Back Flexible Direct Current Project. China Southern Power Grid has completed the Luxi Back-to-Back Flexible Direct Current Project, the Kunliulong Direct Current Project, the Guangdong-Hong Kong-Macao Greater Bay Area Flexible Direct Current Back-to-Back Project, and the Zhoushan Five-Terminal Flexible Direct Current Project.

[0003] The Gansu power grid is located at the heart of the Northwest China power grid and is a key component. Currently, the highest AC grid voltage level is 750kV. State Grid Corporation of China will construct the Gansu-Zhejiang UHVDC Flexible Project. Upon completion, this will be my country's first UHVDC transmission system using Flexible DC technology on both the transmitting and receiving ends. High-proportion renewable energy transmission systems via DC are limited by the grid conditions of the energy bases, often characterized by weak grid structures and insufficient short-circuit capacity. Flexible DC transmission technology for UHVDC projects has been widely adopted because it eliminates the risk of transient overvoltages at converter stations during faults. However, since converter stations provide short-circuit current to the system, planning Flexible DC project locations requires verifying short-circuit current levels in the vicinity of the site. Furthermore, after a Flexible DC system fault, renewable energy generators at the sending end often experience severe transient overvoltages, potentially causing widespread disconnection of renewable energy generators. This risk is currently a common and pressing issue that needs to be addressed.

[0004] Taking the current Gansu-Zhejiang UHV Flexible DC project access system solution as an example, Figure 1As shown, the Gansu-Zhejiang DC project will include 4 million kilowatts of wind power and approximately 7 million kilowatts of photovoltaic power generation, primarily located in the northern Wuwei and northern Liangzhou regions. It will also include 4 million kilowatts of supporting coal-fired power generation in the Yulin region. The Shuiyuan substation connects to the existing 750kV line from Hexi to Baiyin. The Ganzhou-Hexi and Hexi-Shuiyuan lines will be connected outside Hexi Station, ultimately forming a 750kV Ganzhou-Shuiyuan substation-Baiyin line. A new 750kV line will be constructed from Hexi to Shuiyuan to Baiyin. Key factors limiting its DC transmission capacity include excessive short-circuit current levels in the immediate area after the UHVDC project is connected to the grid, system stability constraints after AC faults, and transient voltage rise constraints from renewable energy sources.

[0005] Currently, there is no unified verification process and specifications for verifying the transmission capacity of ultra-high voltage transmission systems based on flexible direct current transmission technology. Most verifications are conducted by summarizing the DC transmission capacity after going through various possible verification methods, which results in large computational complexity and low efficiency. Summary of the Invention

[0006] To address the above issues, the present invention proposes a method for verifying the transmission capacity of a UHVDC flexible project, comprising:

[0007] Obtaining basic data related to the transmission capacity of the UHV Flexible DC system, and calculating the short-circuit current level of the UHV Flexible DC converter station based on the basic data;

[0008] Based on the short-circuit current level of the UHV Flexible DC converter station, select the UHV Flexible DC project location plan;

[0009] Based on the UHVDC Flexible project location plan, the UHVDC Flexible transmission capacity verification method is selected to calculate the UHVDC Flexible transmission capacity P. dcmax ;

[0010] Based on the UHV flexible DC transmission capacity P dcmax , check the full transmission conditions of the UHV flexible DC project under different operating modes to determine whether the transmission capacity of the UHV flexible DC project meets the operating requirements.

[0011] Optional, basic data, including:

[0012] Operational data of the UHVDC Flexible project landing scheme under different grid conditions and model data of different DC Flexible landing schemes;

[0013] The operating mode data includes: different supporting startup combination data, load level data and DC operating condition data.

[0014] Optionally, the short-circuit current level of the UHV flexible DC converter station is calculated, specifically: calculating the short-circuit current level of the converter station and nearby busbars under different landing point schemes of the UHV flexible DC project.

[0015] Optionally, based on the short-circuit current level of the UHV Flexible DC converter station, a UHV Flexible DC project location plan is screened, including:

[0016] Statistics are collected and screened out for stations where the short-circuit current levels do not meet the operating requirements, and short-circuit current suppression measures are added to each station where the short-circuit current exceeds the standard, so as to obtain a landing plan for the UHV flexible DC project.

[0017] Optional verification methods for UHVDC Flexible transmission capacity include:

[0018] Verify AC faults near the flexible DC drop point and DC faults based on the number of power supplies and the amount of new energy connected;

[0019] After an AC fault occurs in the vicinity of the flexible DC point, check the system stability and transient overvoltage level at the new energy generator end;

[0020] After the flexible DC body fails, the system stability and the transient overvoltage level at the new energy generator end are checked;

[0021] Determining that the most serious AC fault in the vicinity of the flexible DC point is a limiting fault that restricts the flexible DC access system;

[0022] Determine the amount of renewable energy that can be connected under different DC operating conditions under the constraints of renewable energy transient overvoltage;

[0023] The AC faults near the flexible DC drop point include: three permanent faults of AC line N-1, main transformer N-1 fault and three permanent faults of AC line N-2;

[0024] The flexible DC body fault includes: DC blocking and DC line grounding fault.

[0025] Optionally, verify the full transmission conditions of the UHVDC Flexible project under different operating modes, including:

[0026] Select the operating mode of the UHV flexible DC project that needs to be verified, use the most serious constrained fault among the AC faults in the vicinity of the flexible DC drop point and the DC body faults, and conduct characteristic verification of the UHV flexible DC project after it is connected to the system to determine the stations where the transient overvoltage at the renewable energy generator end exceeds the standard, and configure distributed phase-shifting machines to suppress the transient overvoltage at the renewable energy generator end after the fault.

[0027] In another aspect, the present invention provides a system for verifying the transmission capacity of a UHVDC flexible project, comprising:

[0028] A collection unit is used to obtain basic data related to the transmission capacity of the UHV Flexible DC system and calculate the short-circuit current level of the UHV Flexible DC converter station based on the basic data;

[0029] a screening unit, configured to screen out a UHVDC flexible project location plan based on the short-circuit current level of the UHVDC flexible converter station;

[0030] The calculation unit is used to screen out the UHVDC flexible transmission capacity verification mode based on the UHVDC flexible project landing plan to calculate the UHVDC flexible transmission capacity P dcmax ;

[0031] A verification unit is used to verify the UHV flexible DC transmission capacity P dcmax , check the full transmission conditions of the UHV flexible DC project under different operating modes to determine whether the transmission capacity of the UHV flexible DC project meets the operating requirements.

[0032] Optional, basic data, including:

[0033] Operational data of the UHVDC Flexible project landing scheme under different grid conditions and model data of different DC Flexible landing schemes;

[0034] The operating mode data includes: different supporting startup combination data, load level data and DC operating condition data.

[0035] Optionally, the short-circuit current level of the UHV flexible DC converter station is calculated, specifically: calculating the short-circuit current level of the converter station and nearby busbars under different landing point schemes of the UHV flexible DC project.

[0036] Optionally, based on the short-circuit current level of the UHV Flexible DC converter station, a UHV Flexible DC project location plan is screened, including:

[0037] Statistics are collected and screened out for stations where the short-circuit current levels do not meet the operating requirements, and short-circuit current suppression measures are added to each station where the short-circuit current exceeds the standard, so as to obtain a landing plan for the UHV flexible DC project.

[0038] Optional verification methods for UHVDC Flexible transmission capacity include:

[0039] Verify AC faults near the flexible DC drop point and DC faults based on the number of power supplies and the amount of new energy connected;

[0040] After an AC fault occurs in the vicinity of the flexible DC point, check the system stability and transient overvoltage level at the new energy generator end;

[0041] After the flexible DC body fails, the system stability and the transient overvoltage level at the new energy generator end are checked;

[0042] Determining that the most serious AC fault in the vicinity of the flexible DC point is a limiting fault that restricts the flexible DC access system;

[0043] Determine the amount of renewable energy that can be connected under different DC operating conditions under the constraints of renewable energy transient overvoltage;

[0044] The AC faults near the flexible DC drop point include: three permanent faults of AC line N-1, main transformer N-1 fault and three permanent faults of AC line N-2;

[0045] The flexible DC body fault includes: DC blocking and DC line grounding fault.

[0046] Optionally, verify the full transmission conditions of the UHVDC Flexible project under different operating modes, including:

[0047] Select the operating mode of the UHV flexible DC project that needs to be verified, use the most serious constrained fault among the AC faults in the vicinity of the flexible DC drop point and the DC body faults, and conduct characteristic verification of the UHV flexible DC project after it is connected to the system to determine the stations where the transient overvoltage at the renewable energy generator end exceeds the standard, and configure distributed phase-shifting machines to suppress the transient overvoltage at the renewable energy generator end after the fault.

[0048] In yet another aspect, the present invention further provides a computing device comprising: one or more processors;

[0049] a processor for executing one or more programs;

[0050] When the one or more programs are executed by the one or more processors, the above-described method is implemented.

[0051] In another aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the method described above is implemented.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention provides a method for verifying the transmission capacity of an ultra-high voltage flexible direct current (UHVDC) project, comprising: obtaining basic data related to the transmission capacity of an ultra-high voltage flexible direct current (UHVDC) system, and calculating the short-circuit current level of an ultra-high voltage flexible direct current (UHVDC) converter station based on the basic data; screening a location plan for an ultra-high voltage flexible direct current (UHVDC) project based on the short-circuit current level of the ultra-high voltage flexible direct current (UHVDC) converter station; and screening a method for verifying the ultra-high voltage flexible direct current (UHVDC) transmission capacity based on the location plan, so as to calculate the ultra-high voltage flexible direct current transmission capacity P. dcmax Based on the UHV flexible DC transmission capacity P dcmaxThis method verifies the full transmission conditions of a UHV Flexible DC system under different operating modes to determine whether the system's transmission capacity meets operational requirements. This simple and easy-to-implement method significantly improves computational efficiency, saves manpower and resources, and creates significant economic benefits when used in verifying the transmission capacity of a UHV Flexible DC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a schematic diagram of the area near the sending end of the Gansu-Zhejiang DC line;

[0055] Figure 2 is a flow chart of the method of the present invention;

[0056] Figure 3 Flowchart of an example of the method of the present invention;

[0057] Figure 4 It is a structural diagram of the system of the present invention. DETAILED DESCRIPTION

[0058] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a thorough and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0059] Unless otherwise specified, the terms used herein (including technical terms) have the meanings commonly understood by those skilled in the art. In addition, it is understood that terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0060] Example 1:

[0061] The present invention proposes a method for verifying the transmission capacity of ultra-high voltage flexible direct current projects, such as Figure 2 Shown, including:

[0062] Step 1: obtaining basic data related to the transmission capacity of the UHV Flexible DC system, and calculating the short-circuit current level of the UHV Flexible DC converter station based on the basic data;

[0063] Step 2: Based on the short-circuit current level of the UHV Flexible DC converter station, screening out a UHV Flexible DC project location plan;

[0064] Step 3: Based on the UHVDC Flexible project landing plan, select the UHVDC Flexible transmission capacity verification method to calculate the UHVDC Flexible transmission capacity P dcmax ;

[0065] Step 4: Based on the UHV flexible DC transmission capacity P dcmax , check the full transmission conditions of the UHV flexible DC project under different operating modes to determine whether the transmission capacity of the UHV flexible DC project meets the operating requirements.

[0066] Among them, basic data includes:

[0067] Operational data of the UHVDC Flexible project landing scheme under different grid conditions and model data of different DC Flexible landing schemes;

[0068] The operating mode data includes: different supporting startup combination data, load level data and DC operating condition data.

[0069] Among them, the short-circuit current level of the UHV flexible DC converter station is calculated, specifically: calculating the short-circuit current level of the converter station and nearby busbar under different landing point schemes of the UHV flexible DC project.

[0070] Among them, based on the short-circuit current level of the UHV Flexible DC converter station, the UHV Flexible DC project location plan is screened, including:

[0071] Statistics are collected and screened out for stations where the short-circuit current levels do not meet the operating requirements, and short-circuit current suppression measures are added to each station where the short-circuit current exceeds the standard, so as to obtain a landing plan for the UHV flexible DC project.

[0072] Among them, the verification methods for UHVDC flexible transmission capacity include:

[0073] Verify AC faults near the flexible DC drop point and DC faults based on the number of power supplies and the amount of new energy connected;

[0074] After an AC fault occurs in the vicinity of the flexible DC point, check the system stability and transient overvoltage level at the new energy generator end;

[0075] After the flexible DC body fails, the system stability and the transient overvoltage level at the new energy generator end are checked;

[0076] Determining that the most serious AC fault in the vicinity of the flexible DC point is a limiting fault that restricts the flexible DC access system;

[0077] Determine the amount of renewable energy that can be connected under different DC operating conditions under the constraints of renewable energy transient overvoltage;

[0078] The AC faults near the flexible DC drop point include: three permanent faults of AC line N-1, main transformer N-1 fault and three permanent faults of AC line N-2;

[0079] The flexible DC body fault includes: DC blocking and DC line grounding fault.

[0080] The verification of full transmission conditions of the UHV Flexible DC project under different operation modes includes:

[0081] Select the operating mode of the UHV flexible DC project that needs to be verified, use the most serious constrained fault among the AC faults in the vicinity of the flexible DC drop point and the DC body faults, and conduct characteristic verification of the UHV flexible DC project after it is connected to the system to determine the stations where the transient overvoltage at the renewable energy generator end exceeds the standard, and configure distributed phase-shifting machines to suppress the transient overvoltage at the renewable energy generator end after the fault.

[0082] The present invention will be further described below with reference to examples. Figure 3 Shown, including:

[0083] Step 1 Data preparation process:

[0084] The first step is to prepare the calculation data. This involves collecting operational data for different grid conditions for the UHV Flexible DC project deployment scenarios, as well as model data for different Flexible DC deployment scenarios. This operational data includes different supporting startup combinations, load levels, and DC operating conditions.

[0085] Step 2: Calculate the short-circuit current of the UHVDC flexible converter station:

[0086] Based on the short-circuit current calculation software of the power system analysis comprehensive program SCCP, the short-circuit current levels of the converter station and nearby busbars under different landing point schemes of the UHV flexible DC project are calculated.

[0087] Step 3: Determine the location of the UHVDC Flexible project:

[0088] Statistics are collected and screened out for stations whose short-circuit current levels do not meet the system operation requirements. Short-circuit current suppression measures are added to each station where the short-circuit current exceeds the standard. The landing plan for the UHV flexible DC project is compared and concluded.

[0089] Step 4: Select the verification method for the UHV flexible DC transmission capacity and calculate the DC transmission capacity P dcmax :

[0090] Verify AC faults and DC faults near the flexible DC drop point for different numbers of supporting power sources and the amount of new energy connected. Verify system stability and transient overvoltage levels at the new energy generator end after AC faults near the flexible DC drop point (AC line N-1 three-permanent fault, main transformer N-1 fault, AC line N-2 three-permanent fault); verify system stability and transient overvoltage levels at the new energy generator end after faults in the flexible DC body (DC lockout, DC line grounding fault). Determine the most serious of the above AC faults as the limiting fault that restricts flexible DC access to the system. Determine the amount of new energy that can be connected under different DC operating conditions, taking into account the transient overvoltage constraints of new energy.

[0091] Step 5: Verify the full transmission conditions of the UHVDC Flexible project under different operating modes:

[0092] Select the operating mode for the UHV Flexible DC project requiring verification. Verify the characteristics of the UHV Flexible DC project after it is connected to the system, using the most severe constrained fault from both the AC fault and the DC fault itself. Identify sites where transient overvoltages at the renewable energy generator end exceed the standard and configure distributed phase-converters to suppress transient overvoltages at the renewable energy generator end after the fault. For other operating modes requiring verification (different numbers of supporting power units and different unit combinations), determine the full transmission conditions for the UHV Flexible DC project and implement them throughout the calculations to complete the verification.

[0093] Repeat steps 1 through 5 above for different UHV Flexible DC project locations, supporting power generation units, and unit combinations. Comparing these results allows us to summarize the impact of the scale and location of supporting thermal and renewable energy sources on the UHV Flexible DC system's transmission capacity, and further provide recommendations for long-term supporting thermal and renewable energy planning from the perspective of grid security and stability.

[0094] Example 2:

[0095] The present invention proposes a system 200 for verifying the transmission capacity of a UHVDC flexible project. Figure 4 Shown, including:

[0096] The acquisition unit 201 is configured to acquire basic data related to the transmission capacity of the UHV Flexible DC system and calculate the short-circuit current level of the UHV Flexible DC converter station based on the basic data;

[0097] A screening unit 202 is configured to screen out a UHVDC flexible project location plan based on the short-circuit current level of the UHVDC flexible converter station;

[0098] The calculation unit 203 is used to select the UHVDC Flexible transmission capacity verification method based on the UHVDC Flexible project landing plan to calculate the UHVDC Flexible transmission capacity P dcmax ;

[0099] The verification unit 204 is configured to verify the UHVDC flexible transmission capacity P dcmax , check the full transmission conditions of the UHV flexible DC project under different operating modes to determine whether the transmission capacity of the UHV flexible DC project meets the operating requirements.

[0100] Among them, basic data includes:

[0101] Operational data of the UHVDC Flexible project landing scheme under different grid conditions and model data of different DC Flexible landing schemes;

[0102] The operating mode data includes: different supporting startup combination data, load level data and DC operating condition data.

[0103] Among them, the short-circuit current level of the UHV flexible DC converter station is calculated, specifically: calculating the short-circuit current level of the converter station and nearby busbar under different landing point schemes of the UHV flexible DC project.

[0104] Among them, based on the short-circuit current level of the UHV Flexible DC converter station, the UHV Flexible DC project location plan is screened, including:

[0105] Statistics are collected and screened out for stations where the short-circuit current levels do not meet the operating requirements, and short-circuit current suppression measures are added to each station where the short-circuit current exceeds the standard, so as to obtain a landing plan for the UHV flexible DC project.

[0106] Among them, the verification methods for UHVDC flexible transmission capacity include:

[0107] Verify AC faults near the flexible DC drop point and DC faults based on the number of power supplies and the amount of new energy connected;

[0108] After an AC fault occurs in the vicinity of the flexible DC point, check the system stability and transient overvoltage level at the new energy generator end;

[0109] After the flexible DC body fails, the system stability and the transient overvoltage level at the new energy generator end are checked;

[0110] Determining that the most serious AC fault in the vicinity of the flexible DC point is a limiting fault that restricts the flexible DC access system;

[0111] Determine the amount of renewable energy that can be connected under different DC operating conditions under the constraints of renewable energy transient overvoltage;

[0112] The AC faults near the flexible DC drop point include: three permanent faults of AC line N-1, main transformer N-1 fault and three permanent faults of AC line N-2;

[0113] The flexible DC body fault includes: DC blocking and DC line grounding fault.

[0114] The verification of full transmission conditions of the UHV Flexible DC project under different operation modes includes:

[0115] Select the operating mode of the UHV flexible DC project that needs to be verified, use the most serious constrained fault among the AC faults in the vicinity of the flexible DC drop point and the DC body faults, and conduct characteristic verification of the UHV flexible DC project after it is connected to the system to determine the stations where the transient overvoltage at the renewable energy generator end exceeds the standard, and configure distributed phase-shifting machines to suppress the transient overvoltage at the renewable energy generator end after the fault.

[0116] The present invention can be implemented simply by following the calculation process, is simple and easy to implement, and can be adopted in the verification of the transmission capacity of the ultra-high voltage flexible direct current system to significantly improve the calculation efficiency, save manpower and material resources, and create significant economic benefits.

[0117] Example 3:

[0118] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the method in the above embodiment.

[0119] Example 4:

[0120] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It can be understood that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space that stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the method in the above embodiment.

[0121] It will be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented 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. The solutions in the embodiments of the present invention may be implemented in various computer languages, for example, the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0122] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts 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, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0123] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0124] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0125] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0126] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for verifying the transmission capacity of a UHVDC flexible project, characterized in that: The method comprises: Obtaining basic data related to the transmission capacity of the UHV Flexible DC system, and calculating the short-circuit current level of the UHV Flexible DC converter station based on the basic data; Based on the short-circuit current level of the UHV Flexible DC converter station, select the UHV Flexible DC project location plan; Based on the UHVDC Flexible project location plan, the UHVDC Flexible transmission capacity verification method is selected to calculate the UHVDC Flexible transmission capacity P. dcmax ; Based on the UHV flexible DC transmission capacity P dcmax , check the full transmission conditions of the UHV Flexible DC project under different operation modes to determine whether the transmission capacity of the UHV Flexible DC project meets the operation requirements; The verification method for the UHVDC flexible transmission capacity includes: Verify AC faults near the flexible DC drop point and DC faults based on the number of power supplies and the amount of new energy connected; After an AC fault occurs in the vicinity of the flexible DC point, check the system stability and transient overvoltage level at the new energy generator end; After the flexible DC body fails, the system stability and the transient overvoltage level at the new energy generator end are checked; Determining that the most serious AC fault in the vicinity of the flexible DC point is a limiting fault that restricts the flexible DC access system; Determine the amount of renewable energy that can be connected under different DC operating conditions under the constraints of renewable energy transient overvoltage; The AC faults near the flexible DC drop point include: three permanent faults of AC line N-1, main transformer N-1 fault and three permanent faults of AC line N-2; The flexible DC body fault includes: DC blocking and DC line grounding fault; The verification of full transmission conditions of the UHVDC flexible project under different operating modes includes: Select the operating mode of the UHV flexible DC project that needs to be verified, use the most serious constrained fault among the AC faults in the vicinity of the flexible DC drop point and the DC body faults, and conduct characteristic verification of the UHV flexible DC project after it is connected to the system to determine the stations where the transient overvoltage at the renewable energy generator end exceeds the standard, and configure distributed phase-shifting machines to suppress the transient overvoltage at the renewable energy generator end after the fault.

2. The method according to claim 1, characterized in that The basic data include: Operational data of the UHVDC Flexible project landing scheme under different grid conditions and model data of different DC Flexible landing schemes; The operating mode data includes: different supporting startup combination data, load level data and DC operating condition data.

3. The method according to claim 1, characterized in that The calculation of the short-circuit current level of the UHV flexible DC converter station specifically includes: calculating the short-circuit current level of the converter station and the nearby busbar under different landing point schemes of the UHV flexible DC project.

4. The method according to claim 1, wherein The screening of a UHV Flexible DC project location plan based on the UHV Flexible DC converter station short-circuit current level includes: Statistics are collected and screened out for stations where the short-circuit current levels do not meet the operating requirements, and short-circuit current suppression measures are added to each station where the short-circuit current exceeds the standard, so as to obtain a landing plan for the UHV flexible DC project.

5. A system for verifying the transmission capacity of a UHVDC flexible project, characterized in that: The system comprises: A collection unit, configured to obtain basic data related to the transmission capacity of the UHV Flexible DC system, and calculate the short-circuit current level of the UHV Flexible DC converter station based on the basic data; a screening unit, configured to screen out a UHVDC flexible project location plan based on the short-circuit current level of the UHVDC flexible converter station; The calculation unit is used to screen out the UHVDC flexible transmission capacity verification mode based on the UHVDC flexible project landing plan to calculate the UHVDC flexible transmission capacity P dcmax ; A verification unit is used to verify the UHV flexible DC transmission capacity P dcmax , check the full transmission conditions of the UHV Flexible DC project under different operation modes to determine whether the transmission capacity of the UHV Flexible DC project meets the operation requirements; The verification method for the UHVDC flexible transmission capacity includes: Verify AC faults near the flexible DC drop point and DC faults based on the number of power supplies and the amount of new energy connected; After an AC fault occurs in the vicinity of the flexible DC point, check the system stability and transient overvoltage level at the new energy generator end; After the flexible DC body fails, the system stability and the transient overvoltage level at the new energy generator end are checked; Determining that the most serious AC fault in the vicinity of the flexible DC point is a limiting fault that restricts the flexible DC access system; Determine the amount of renewable energy that can be connected under different DC operating conditions under the constraints of renewable energy transient overvoltage; The AC faults near the flexible DC drop point include: three permanent faults of AC line N-1, main transformer N-1 fault and three permanent faults of AC line N-2; The flexible DC body fault includes: DC blocking and DC line grounding fault; The verification of full transmission conditions of the UHVDC flexible project under different operating modes includes: Select the operating mode of the UHV flexible DC project that needs to be verified, use the most serious constrained fault among the AC faults in the vicinity of the flexible DC drop point and the DC body faults, and conduct characteristic verification of the UHV flexible DC project after it is connected to the system to determine the stations where the transient overvoltage at the renewable energy generator end exceeds the standard, and configure distributed phase-shifting machines to suppress the transient overvoltage at the renewable energy generator end after the fault.

6. The system according to claim 5, characterized in that The basic data include: Operational data of the UHVDC Flexible project landing scheme under different grid conditions and model data of different DC Flexible landing schemes; The operating mode data includes: different supporting startup combination data, load level data and DC operating condition data.

7. The system according to claim 5, characterized in that The calculation of the short-circuit current level of the UHV flexible DC converter station specifically includes: calculating the short-circuit current level of the converter station and the nearby busbar under different landing point schemes of the UHV flexible DC project.

8. The system according to claim 5, wherein: The screening of a UHV Flexible DC project location plan based on the UHV Flexible DC converter station short-circuit current level includes: Statistics are collected and screened out for stations where the short-circuit current levels do not meet the operating requirements, and short-circuit current suppression measures are added to each station where the short-circuit current exceeds the standard, so as to obtain a landing plan for the UHV flexible DC project.

9. A computer device, characterized in that: include: one or more processors; a processor for executing one or more programs; When the one or more programs are executed by the one or more processors, the method according to any one of claims 1 to 4 is implemented.

10. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed, the method according to any one of claims 1 to 4 is implemented.

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