Method and system for comparing and selecting site selection schemes of network building type stations based on current short circuit constraint

Abstract

The invention discloses a current short circuit constraint-based network construction type station site selection scheme comparison and selection method and system, and belongs to the technical field of power systems. The method comprises the following steps: establishing an operation mode library of a power grid under different power generation and load conditions; determining a plurality of drop point schemes, and calculating a short-circuit current of a near-area station of the network construction type equipment for each drop point scheme in the plurality of drop point schemes; determining an overproof site set of each drop point scheme; determining the scheme index of each drop point scheme according to the short-circuit current of the near-area station of the network-building equipment and the set of the standard-exceeding stations of each drop point scheme; and selecting the drop point scheme with the minimum scheme index as a recommendation scheme for site selection of the network building type station. According to the short-circuit current standard-exceeding index of the near-region power grid after the access of the network construction type equipment station, the drop point scheme of the network construction type equipment station is reasonably determined, and the short-circuit current standard-exceeding risk after the access of the network construction type equipment of the ultrahigh-proportion new energy power grid can be greatly relieved.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and more specifically, to a method and system for comparing and selecting network-type station site selection schemes based on current short-circuit constraints. Background Art

[0002] In the operation of power systems, short-circuit faults are one of the most common faults. The short-circuit current generated by them will have serious impacts and consequences on the safe and stable operation of power systems. At present, receiving power grids generally face the risk of excessive short-circuit currents. When the overall short-circuit current level of the power grid is low, the main focus of new equipment connection is its impact on the stability characteristics of the power grid, and its effect on the short-circuit current only needs a simple evaluation.

[0003] Grid-type power electronic equipment presents voltage source characteristics to the grid, can approximately simulate the characteristics of conventional synchronous generators, improve short-circuit capacity, provide effective support for weak systems, and have broad application prospects. As the short-circuit current level of the grid gradually approaches or reaches the rated interrupting capacity of the switch, the impact of new equipment, especially grid-type converter equipment, on short-circuit current should be paid attention to after it is connected to the grid.

[0004] From the perspective of the fault ride-through characteristics of the networking equipment and the short-circuit current contribution characteristics, the contribution of the networking equipment to the AC power grid short-circuit current is closely related to its control strategy and access site selection. In the process of planning the location of large-capacity networking-type new energy and energy storage sites, the impact of the networking equipment on the AC short-circuit current of the nearby power grid after access should be comprehensively considered. Summary of the invention

[0005] In view of the above problems, the present invention proposes a method for comparing and selecting network-type station site selection schemes based on current short-circuit constraints, comprising:

[0006] Establish a database of operation modes under different power generation and load conditions of the power grid;

[0007] Determine multiple landing point plans according to the operation mode library, and calculate the short-circuit current of the near-area site of the networking device for each of the multiple landing point plans;

[0008] Determine the set of sites that exceed the standard for each landing plan;

[0009] Determine the scheme indicators of each landing scheme according to the short-circuit current of the near-area sites of the networking equipment and the set of sites exceeding the standard of each landing scheme;

[0010] The landing point scheme with the smallest scheme index is selected as the recommended scheme for the site selection of network-type stations.

[0011] Optionally, operating mode data under different conditions of an ultra-high proportion of new energy power grid are obtained, and the acquired operating mode data are combined into operating mode data suitable for SCCP short-circuit current scanning calculation; based on the operating mode data suitable for SCCP short-circuit current scanning calculation, an operating mode library under different power generation and load conditions of the power grid is established.

[0012] Optionally, different conditions of the ultra-high proportion of new energy grid include at least one of the following:

[0013] Different new energy conditions, different conventional unit startup combination conditions, different load level conditions and different external power transmission conditions.

[0014] Optionally, determining the set of sites exceeding the standard for each landing scheme includes: counting the number of sites exceeding the standard under each operation mode of each landing scheme, and forming the counted sites into a set of sites exceeding the standard.

[0015] Optionally, the calculation formula of the scheme indicator is as follows:

[0016]

[0017] Where n is the number of calculation methods, m is the number of sites exceeding the standard, and I km and I kNm are the short-circuit current and switch rated current of station m respectively.

[0018] On the other hand, the present invention also proposes a network-type station site selection scheme comparison system based on current short-circuit constraints, comprising:

[0019] A database establishment unit is used to establish an operation mode library under different power generation and load conditions of the power grid;

[0020] A current calculation unit, used to determine a plurality of landing point schemes according to the operation mode library, and calculate the short-circuit current of a near-area site of a network-forming device for each of the plurality of landing point schemes;

[0021] A statistical unit, used to determine a set of sites exceeding the standard for each landing plan;

[0022] An index calculation unit, used to determine the scheme index of each landing scheme according to the short-circuit current of the near-area site of the networking equipment and the set of sites exceeding the standard of each landing scheme;

[0023] The recommendation unit is used to select the landing point scheme with the smallest scheme index as the recommended scheme for the site selection of network-type stations.

[0024] Optionally, the database establishment unit obtains operating mode data under different conditions of the ultra-high proportion of new energy power grid, combines the acquired operating mode data into operating mode data suitable for SCCP short-circuit current scanning calculation, and establishes an operating mode library under different power generation and load conditions of the power grid based on the operating mode data suitable for SCCP short-circuit current scanning calculation.

[0025] Optionally, different conditions of the ultra-high proportion of new energy grid include at least one of the following:

[0026] Different new energy conditions, different conventional unit startup combination conditions, different load level conditions and different external power transmission conditions.

[0027] Optionally, determining the set of sites exceeding the standard for each landing scheme includes: counting the number of sites exceeding the standard under each operation mode of each landing scheme, and forming the counted sites into a set of sites exceeding the standard.

[0028] Optionally, the calculation formula of the scheme indicator is as follows:

[0029]

[0030] Where n is the number of calculation methods, m is the number of sites exceeding the standard, and I km and I kNm are the short-circuit current and switch rated current of station m respectively.

[0031] In yet another aspect, the present invention further provides a computing device, comprising: one or more processors;

[0032] a processor for executing one or more programs;

[0033] When the one or more programs are executed by the one or more processors, the above-described method is implemented.

[0034] In yet 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.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention provides a method for comparing and selecting site selection schemes for a grid-type station based on current short-circuit constraints, including: establishing an operation mode library under different power generation and load conditions of the power grid; determining multiple site selection schemes based on the operation mode library, and calculating the short-circuit current of the near-area site of the grid-type equipment for each of the multiple site selection schemes; determining the set of sites that exceed the standard for each site selection scheme; determining the scheme index of each site selection scheme based on the short-circuit current and the set of sites that exceed the standard for the near-area site of the grid-type equipment of each site selection scheme; and selecting the site selection scheme with the smallest scheme index as the recommended scheme for the site selection of the grid-type station. The present invention reasonably determines the site selection scheme for the grid-type equipment station based on the short-circuit current exceeding standard index of the near-area power grid after the grid-type equipment station is connected, which can greatly alleviate the risk of short-circuit current exceeding standard after the grid-type equipment of the ultra-high proportion of new energy power grid is connected. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of the method of the present invention;

[0038] Figure 2 is a flow chart of an embodiment of the method of the present invention;

[0039] Figure 3 It is a structural diagram of the system of the present invention. DETAILED DESCRIPTION

[0040] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0041] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the 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.

[0042] Embodiment 1:

[0043] The present invention proposes a method for comparing and selecting network-type station site selection schemes based on current short-circuit constraints, such as Figure 1 As shown, including:

[0044] Step 1: Establish an operation mode library under different power generation and load conditions of the power grid;

[0045] Step 2: Determine multiple landing point plans according to the operation mode library, and calculate the short-circuit current of the near-area site of the networking device for each of the multiple landing point plans;

[0046] Step 3: Determine the set of sites that exceed the standard for each landing plan;

[0047] Step 4: Determine the scheme indicators of each landing scheme according to the short-circuit current of the near-area site of the networking equipment and the set of sites exceeding the standard of each landing scheme;

[0048] Step 5: Select the landing point scheme with the smallest scheme index as the recommended scheme for network-type station site selection.

[0049] Among them, the operating mode data of the ultra-high proportion of new energy power grid under different conditions are obtained, and the obtained operating mode data are combined into operating mode data suitable for SCCP short-circuit current scanning calculation. Based on the operating mode data suitable for SCCP short-circuit current scanning calculation, an operating mode library under different power generation and load conditions of the power grid is established.

[0050] Among them, different conditions of ultra-high proportion of new energy grid include at least one of the following:

[0051] Different new energy conditions, different conventional unit startup combination conditions, different load level conditions and different external power transmission conditions.

[0052] The step of determining the set of sites exceeding the standard for each landing point scheme includes: counting the number of sites exceeding the standard under each operation mode of each landing point scheme, and forming the counted sites into a set of sites exceeding the standard.

[0053] The calculation formula of the scheme indicator is as follows:

[0054]

[0055] Where n is the number of calculation methods, m is the number of sites exceeding the standard, and I km and I kNm are the short-circuit current and switch rated current of station m respectively.

[0056] The present invention will be further described below in conjunction with specific embodiments:

[0057] Example process as Figure 2 As shown, specifically including:

[0058] Step 1: Calculate data preparation work, prepare the operation mode data under different new energy and conventional unit startup combinations, load levels, and external power transmission conditions of the ultra-high proportion of new energy power grid, and form an operation mode database suitable for SCCP short-circuit current scanning calculation;

[0059] Step 2: Integrate the planned network equipment site model data into the data to be calculated;

[0060] Step 3: Based on the SCCP short-circuit current calculation software, calculate the short-circuit current scanning calculation of the substation site near the different network-type equipment site planning and site selection schemes under each operation mode;

[0061] Step 4: Count the sites that exceed the standard under different network-type equipment site planning and site selection schemes and various operating conditions to form a set of sites that exceed the standard (the set data includes: site name, number of times the site exceeds the standard under different modes, and the amount of excess);

[0062] Step 5: Calculate the scheme indicators for the data set of sites that exceed the standard under the planning and site selection schemes of different network-type equipment sites;

[0063] Step 6: The smaller the indicator value of the indicator scheme, the higher the recommendation priority of the scheme, and the scheme with the smallest indicator value is selected;

[0064] Step 7: End of the method

[0065] index:

[0066] That is: the index calculation value is the cumulative sum of the number of bidding sites under each operation mode in the method library established in step 1 under this site selection plan, divided by the total number of sites with super-high proportion of new energy power grid as the first item of the index formula. The more sites that exceed the standard, the greater the calculated value of this item; under this site selection plan, a total of n calculation methods are scanned and calculated, and each calculation method corresponds to m sites that exceed the standard; divide the short-circuit current of each site in the m sites that exceed the standard under each calculation method by the rated short-circuit current of the site (the rated short-circuit current is the breaking current value of the switch of the station), and then multiply the results of the m sites. Finally, add up the cumulative multiplication results of n calculation methods.

[0067] The present invention can comprehensively consider the impact of the AC short-circuit current in the vicinity of the grid connection point after the grid-building equipment is connected, during the site planning of grid-building equipment sites such as grid-building new energy and energy storage sites, and reasonably determine the site plan of the grid-building equipment site based on the short-circuit current exceeding standard index of the nearby power grid after the grid-building equipment site is connected, which can greatly alleviate the risk of short-circuit current exceeding standard after the grid-building equipment with a very high proportion of new energy is connected.

[0068] The applicability of the present invention is analyzed by taking the scenario of planning the site of a grid-type energy storage power station in a domestic Shagohuang super-high proportion of new energy transmission grid as an example. In the calculation example, the total power of the planned grid-type electrochemical energy storage converter is 300MVA, and a comparative study of two planning site access schemes is carried out, which are:

[0069] Plan 1: The total power of the planned grid-type electrochemical energy storage converter is 300MVA. The landing plan is to access the grid-type system through a 500KV double-circuit AC interconnection line to the vicinity of the flexible DC converter station for external transmission. The capacity of the flexible DC converter station is 4000MVA.

[0070] Plan 2: The total power of the planned grid-type electrochemical energy storage converter is 300MVA. The landing plan is to access the hub substation on the new energy station side through a 500KV double-circuit AC interconnection line. The new energy-grid-type energy storage system has an external flexible direct current converter station capacity of 4000MVA.

[0071] The example selects the summer large mode of the receiving power grid as a typical mode (in actual application, multiple groups of operation modes that can cover different conditions in multiple planning years should be established to ensure the accuracy of the method evaluation results). The calculation value of the short-circuit current of the near-area power grid under the two planning location schemes of the grid-type energy storage is analyzed. The upper limit of the short-circuit current (switch breaking capacity) of the calculated 500KV station is 63kA. That is, the short-circuit current exceeds 63KA, and the station is considered to be an over-standard station. The analysis of the nodes where the short-circuit current exceeds the standard in Scheme 1 is shown in Table 1, and the analysis of the nodes where the short-circuit current exceeds the standard in Scheme 2 is shown in Table 2.

[0072] Table 1

[0073]

[0074] Table 2

[0075]

[0076] Calculation index analysis under two schemes:

[0077] Scheme 1: A total of 15 AC stations are calculated, and the short-circuit current rating of the 500kV station (switch breaking capacity) is 63kA. Under typical conditions, there are 2 stations that exceed the standard, with short-circuit currents of 66.89 and 64.47kA respectively.

[0078] Scheme 2: A total of 15 AC stations are calculated, and the short-circuit current rating of the 500kV station (switch breaking capacity) is 63kA. In a typical mode, there is one station that exceeds the standard, and the short-circuit current is 67.54kA.

[0079]

[0080] Scheme 1 calculation indicators:

[0081] Scheme 2 calculation indicators:

[0082] It can be seen that under Scheme 1, the calculation index is smaller and can be used as the recommended scheme.

[0083] From the perspective of engineering feasibility, under Scheme 1, there are fewer sites with excessive short-circuit current and the sites are more concentrated, making it easier to take short-circuit current control measures such as replacing high-impedance lines and adding fast-switching fault current limiters. This verifies the feasibility of Scheme 1 as the recommended solution for selecting a grid-type site site that takes short-circuit current control into consideration.

[0084] Embodiment 2:

[0085] The present invention also proposes a grid-type station site selection scheme comparison system 200 based on current short-circuit constraints, such as Figure 3 As shown, including:

[0086] A database establishment unit 201 is used to establish an operation mode library under different power generation and load conditions of the power grid;

[0087] The current calculation unit 202 is used to determine multiple landing point schemes according to the operation mode library, and calculate the short-circuit current of the near-area site of the network-forming device for each of the multiple landing point schemes;

[0088] A statistical unit 203, configured to determine a set of sites exceeding the standard for each landing solution;

[0089] An index calculation unit 204 is used to determine the scheme index of each landing scheme according to the short-circuit current of the near-area site of the networking type equipment and the set of sites exceeding the standard of each landing scheme;

[0090] The recommendation unit 205 is used to select the landing point scheme with the smallest scheme index as the recommended scheme for the site selection of the network-type station.

[0091] The database establishment unit 201 obtains the operating mode data under different conditions of the ultra-high proportion of new energy power grid, combines the obtained operating mode data into operating mode data suitable for SCCP short-circuit current scanning calculation, and establishes an operating mode library under different power generation and load conditions of the power grid based on the operating mode data suitable for SCCP short-circuit current scanning calculation.

[0092] Among them, different conditions of ultra-high proportion of new energy grid include at least one of the following:

[0093] Different new energy conditions, different conventional unit startup combination conditions, different load level conditions and different external power transmission conditions.

[0094] The step of determining the set of sites exceeding the standard for each landing point scheme includes: counting the number of sites exceeding the standard under each operation mode of each landing point scheme, and forming the counted sites into a set of sites exceeding the standard.

[0095] The calculation formula of the scheme indicator is as follows:

[0096]

[0097] Where n is the number of calculation methods, m is the number of sites exceeding the standard, and I km and I kNm are the short-circuit current and switch rated current of station m respectively.

[0098] The present invention reasonably determines the site location plan of the networking type equipment station based on the short-circuit current exceeding standard index of the nearby power grid after the networking type equipment station is connected, which can greatly alleviate the risk of short-circuit current exceeding standard after the networking type equipment with a super-high proportion of new energy power grid is connected.

[0099] Embodiment 3:

[0100] 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 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, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of the method in the above embodiment.

[0101] Embodiment 4:

[0102] 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 is understandable that the computer-readable storage medium here can include both a built-in storage medium in a computer device and an extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and 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.

[0103] It will be appreciated by those skilled in the art that 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. Moreover, 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 codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0104] 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 flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to 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 flowchart and / or block diagram. 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.

[0105] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0106] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0107] 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.

[0108] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for comparing and selecting site selection schemes for grid-type stations based on current short-circuit constraints, characterized in that: include: Establish a database of operation modes under different power generation and load conditions of the power grid; Determine multiple landing point plans according to the operation mode library, and calculate the short-circuit current of the near-area site of the networking device for each of the multiple landing point plans; Determine the set of sites that exceed the standard for each landing plan; Determine the scheme indicators of each landing scheme according to the short-circuit current of the near-area sites of the networking equipment and the set of sites exceeding the standard of each landing scheme; The landing point scheme with the smallest scheme index is selected as the recommended scheme for the site selection of network-type stations.

2. The method according to claim 1, characterized in that The operation mode data of the ultra-high proportion of new energy power grid under different conditions are obtained, and the obtained operation mode data are combined into operation mode data suitable for SCCP short-circuit current scanning calculation. Based on the operation mode data suitable for SCCP short-circuit current scanning calculation, an operation mode library under different power generation and load conditions of the power grid is established.

3. The method according to claim 2, characterized in that The different conditions of the ultra-high proportion of new energy power grid include at least one of the following: Different new energy conditions, different conventional unit startup combination conditions, different load level conditions and different external power transmission conditions.

4. The method according to claim 1, characterized in that: Determining the set of over-standard sites for each landing scheme includes: counting the over-standard sites under each operation mode of each landing scheme, and forming the over-standard sites into a set of over-standard sites.

5. The method according to claim 1, characterized in that The calculation formula of the scheme indicator is as follows: Where n is the number of calculation methods, m is the number of sites exceeding the standard, and I km and I kNm are the short-circuit current and switch rated current of station m respectively.

6. A network-type station site selection scheme comparison system based on current short-circuit constraints, characterized in that: include: A database establishment unit is used to establish an operation mode library under different power generation and load conditions of the power grid; A current calculation unit, used to determine a plurality of landing point schemes according to the operation mode library, and calculate the short-circuit current of a near-area site of a network-forming device for each of the plurality of landing point schemes; A statistical unit, used to determine a set of sites exceeding the standard for each landing plan; An index calculation unit, used to determine the scheme index of each landing scheme according to the short-circuit current of the near-area site of the networking equipment and the set of sites exceeding the standard of each landing scheme; The recommendation unit is used to select the landing point scheme with the smallest scheme index as the recommended scheme for the site selection of network-type stations.

7. The system according to claim 6, characterized in that The database establishment unit obtains the operating mode data of the ultra-high proportion of new energy power grid under different conditions, combines the obtained operating mode data into operating mode data suitable for SCCP short-circuit current scanning calculation, and establishes an operating mode library under different power generation and load conditions of the power grid based on the operating mode data suitable for SCCP short-circuit current scanning calculation.

8. The system according to claim 7, characterized in that The different conditions of the ultra-high proportion of new energy power grid include at least one of the following: Different new energy conditions, different conventional unit startup combination conditions, different load level conditions and different external power transmission conditions.

9. The system according to claim 6, characterized in that Determining the set of over-standard sites for each landing scheme includes: counting the over-standard sites under each operation mode of each landing scheme, and forming the over-standard sites into a set of over-standard sites.

10. The system according to claim 6, characterized in that The calculation formula of the scheme indicator is as follows: Where n is the number of calculation methods, m is the number of sites exceeding the standard, and I km and I kNm are the short-circuit current and switch rated current of station m respectively.

11. 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 5 is implemented.

12. 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 5 is implemented.

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