Method for configuring pure new energy large-base network construction type equipment for direct current delivery through island

Abstract

The invention provides a pure new energy large base network construction type equipment configuration method for direct current delivery through an island, and relates to the field of power grid planning, and the method comprises the steps: obtaining the multi-station short-circuit ratio condition of the boost transformer low-voltage side of a power generation unit of all new energy stations in a pure new energy large base, judging whether the short-circuit ratio condition meets a first preset condition or not, and according to a judgment result, determining whether the short-circuit ratio condition meets the first preset condition; selecting a corresponding new energy station to configure network energy storage, so as to enable the short-circuit ratio of multiple stations at the boost transformer low-voltage side of all power generation units to meet a first preset condition; obtaining an effective short-circuit ratio condition of the isolated island direct current, and configuring a network construction type SVG in the isolated island direct current, so that the effective short-circuit ratio of the isolated island direct current meets a second preset condition; and according to the configured networking type energy storage and the configured networking type SVG, forming a networking type equipment configuration scheme. According to the invention, the reasonable configuration of the network-forming type energy storage and the network-forming type SVG can be realized, and the power grid strength and the voltage supporting capability of the whole system are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of power grid planning, and in particular relates to a method for configuring equipment for a large-scale pure new energy base grid structure that transmits data via isolated DC transmission. Background Technology

[0002] Currently, with the ongoing construction of the large-scale new energy base in the desert region, local load is insufficient to absorb the load, leading to a surge in demand for long-distance power transmission channels. Direct current (DC) transmission is favored due to its advantages such as high transmission capacity and low long-distance losses. However, as the scale of DC transmission increases, the degree of AC-DC coupling also rises. After DC blocking, the transfer of transmitted power poses a challenge to the stable operation of the AC main grid. Therefore, it is necessary to decouple the DC transmission channels of the large-scale new energy base from the AC main grid, avoiding electrical connections (i.e., islanded DC), and achieving point-to-point long-distance power transmission.

[0003] However, the power output fluctuations and randomness of large-scale pure renewable energy bases are not conducive to the stable operation of isolated DC transmission lines. Grid-based equipment, including grid-based energy storage and grid-based static var generators (SG), can not only effectively mitigate the power output fluctuations of large-scale pure renewable energy bases, but also improve the operational stability of large-scale pure renewable energy bases transmitting power through isolated DC transmission lines, providing the necessary grid strength for the stable operation of both large-scale pure renewable energy bases and isolated DC transmission lines.

[0004] Although grid-based equipment can effectively improve the grid strength and operating efficiency of islanded DC and pure renewable energy bases, existing solutions tend to use a single method for configuring the capacity of grid-based equipment, often focusing on a single type of equipment without considering the short-circuit ratio constraints of islanded DC. This results in weak anti-interference capabilities for pure renewable energy bases transmitted via islanded DC and insufficient voltage support in the event of a fault, posing a risk of instability to the entire system. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for configuring grid-type equipment for a large-scale pure new energy base that transmits electricity via isolated DC. By examining the short-circuit ratio of the low-voltage side of the step-up transformer of all new energy power stations in the large-scale pure new energy base and the effective short-circuit ratio of the isolated DC, the grid-type energy storage and grid-type SVG are rationally configured to effectively improve the grid strength and voltage support capability of the entire system, so that the large-scale pure new energy base that transmits electricity via isolated DC has stronger stability in the event of a fault.

[0006] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0007] In a first aspect, the present invention provides a method for configuring a grid-type equipment for large-scale pure new energy base transmission via isolated DC transmission, comprising:

[0008] Obtain the short-circuit ratio of the low-voltage side of the step-up transformer of the power generation unit in all new energy power stations within the pure new energy base;

[0009] Determine whether the short-circuit ratios of the low-voltage side of the step-up transformer of all the acquired new energy power stations meet the first preset condition;

[0010] If the short-circuit ratio of the step-up transformer to the low-voltage side of any new energy power station does not meet the first preset condition, then, in the case that no grid-type energy storage has been configured in any new energy power station, the new energy power station with the smallest short-circuit ratio of the step-up transformer to the low-voltage side of the generation unit is selected for grid-type energy storage configuration, or the configuration capacity of new energy power stations that have been configured with grid-type energy storage but have not reached the capacity limit is adjusted, or the new energy power station with the smallest short-circuit ratio of the step-up transformer to the low-voltage side of the generation unit is selected from the power stations that have not been configured with grid-type energy storage for grid-type energy storage configuration, so that the short-circuit ratio of the step-up transformer to the low-voltage side of all generation units in all new energy power stations meets the first preset condition;

[0011] If the short-circuit ratios of the low-voltage side of the step-up transformers of all new energy power plants meet the first preset condition, the effective short-circuit ratio of the islanded DC is obtained; it is then determined whether the effective short-circuit ratio of the islanded DC meets the second preset condition; if the effective short-circuit ratio of the islanded DC does not meet the second preset condition, the effective short-circuit ratio of the islanded DC is made to meet the second preset condition by configuring a grid-type SVG in the islanded DC sending-end converter station, or by adjusting the configuration capacity of the grid-type SVG already configured in the islanded DC sending-end converter station.

[0012] Based on the configured grid-type energy storage and grid-type SVG, a grid-type equipment configuration scheme is formed for a large-scale pure new energy base that transmits data via isolated DC transmission.

[0013] Optionally, obtaining the short-circuit ratio of the low-voltage side of the step-up transformer of all new energy power stations within the pure new energy base includes:

[0014] Obtain the planned operation parameters of pure new energy large-scale bases for transmission via isolated DC transmission lines;

[0015] Based on the planned operation parameters of the pure new energy large-scale base transmitting power to other regions via isolated DC transmission, a circuit model for the pure new energy large-scale base transmitting power to other regions via isolated DC transmission is established.

[0016] Based on the circuit model, a multi-port equivalent model of pure new energy large-scale bases transmitting power to isolated DC transmission areas is obtained.

[0017] Based on the multi-port equivalent model, the impedance matrix and short-circuit capacity of the low-voltage side of the power generation unit's step-up transformer are obtained.

[0018] Based on the impedance matrix and short-circuit capacity of the step-up transformer on the low-voltage side of the power generation unit and the active power of the power generation unit, calculate the short-circuit ratio of the step-up transformer on the low-voltage side of each power generation unit in the new energy power station.

[0019] Optionally, the formula for calculating the short-circuit ratio of the step-up transformer on the low-voltage side of each power generation unit in a new energy power station is as follows:

[0020] ,

[0021] in, This represents the short-circuit ratio on the low-voltage side of the step-up transformer of the i-th power generation unit; This represents the short-circuit capacity of the low-voltage side of the step-up transformer in the i-th power generation unit; and This represents the active power of the i-th and j-th power generation units; This represents the self-impedance of the step-up transformer low-voltage side of the i-th power generation unit; This represents the mutual impedance between the i-th and j-th power generation units on the low-voltage side of the step-up transformer.

[0022] Optionally, the step of configuring grid-type energy storage by selecting the new energy power station with the smallest short-circuit ratio on the low-voltage side of the step-up transformer of the power generation unit when no grid-type energy storage is configured in all new energy power stations, or by adjusting the configuration capacity of new energy power stations that have been configured with grid-type energy storage but have not reached the capacity limit, or by selecting the new energy power station with the smallest short-circuit ratio on the low-voltage side of the step-up transformer of the power generation unit from the power stations that have never been configured with grid-type energy storage, so that the short-circuit ratio on the low-voltage side of the step-up transformer of all power generation units in all new energy power stations meets the first preset condition, includes iteratively performing the following operations:

[0023] If no grid-connected energy storage is configured in any of the new energy power plants, the new energy power plant with the smallest short-circuit ratio on the low-voltage side of the step-up transformer of the generating unit will be selected for grid-connected energy storage configuration. If grid-connected energy storage is already configured in any of the existing new energy power plants, the configuration capacity of those power plants that have been configured with grid-connected energy storage but have not reached their capacity limit will be adjusted. If grid-connected energy storage is already configured in any of the existing new energy power plants and all of them have reached their capacity limit, the new energy power plant with the smallest short-circuit ratio on the low-voltage side of the step-up transformer of the generating unit will be selected from the power plants that have not been configured with grid-connected energy storage for grid-connected energy storage configuration.

[0024] After each new configuration of grid-type energy storage or adjustment of grid-type energy storage capacity, the short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations in the pure new energy base is re-acquired, and it is determined whether the short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations meets the first preset condition. If it meets the condition, the iteration ends; otherwise, the next iteration is executed.

[0025] The first preset condition is that the short-circuit ratio of the low-voltage side of the step-up transformer of the power generation unit of the new energy power station is not less than 1.5.

[0026] Optionally, in the case where no grid-connected energy storage is configured at any of the new energy power stations, selecting the new energy power station with the lowest short-circuit ratio on the low-voltage side of the step-up transformer for the smallest power generation unit to configure grid-connected energy storage includes:

[0027] The capacity range of the grid-type energy storage to be configured is determined based on the capacity of the main transformer of the booster transformer at the new energy power station and the installed capacity of new energy at the new energy power station.

[0028] Starting with the smallest configuration capacity within the capacity range and increasing by a fixed step size, the grid-type energy storage capacity to be configured for the new energy power station is selected sequentially. The short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations in the pure new energy base is calculated until the selected configuration capacity reaches the upper limit of the grid-type energy storage configuration capacity of the new energy power station, or the short-circuit ratio of the step-up transformer to the low-voltage side of all power generation units in all new energy power stations meets the first preset condition.

[0029] If the short-circuit ratios of the step-up transformers on the low-voltage side of all the power generation units of the new energy power stations meet the first preset condition, then the grid-type energy storage will be configured for the power station according to the currently selected configuration capacity.

[0030] The above scheme configures grid-type energy storage in new energy power stations corresponding to the short-circuit ratio on the low-voltage side of the smallest power generation unit step-up transformer. This can make the effect of improving the short-circuit ratio of multiple new energy power stations most obvious, and at the same time, it can prioritize solving the problem of new energy power stations where the short-circuit ratio of multiple power stations does not meet the preset conditions.

[0031] Optionally, the step of adjusting the configuration capacity of existing renewable energy power stations that have been configured with grid-type energy storage but have not reached their capacity limit includes:

[0032] Within the selectable capacity range for configuring grid-type energy storage at the power station, starting from the capacity to be configured that is larger than the current configured capacity and differs by a fixed step size, the capacities to be configured for grid-type energy storage at the power station are selected sequentially. Based on the selected capacity of grid-type energy storage to be configured, the short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations in the pure new energy base is calculated until the short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations meets the first preset condition, and grid-type energy storage is configured for the power station based on the currently selected configuration capacity.

[0033] If the current configuration capacity of grid-type energy storage at a new energy power station reaches the upper limit of the grid-type energy storage configuration capacity of that station, select the new energy power station with the smallest short-circuit ratio on the low-voltage side of the step-up transformer from other new energy power stations that have not been configured with grid-type energy storage, and configure grid-type energy storage for that station.

[0034] Optionally, the step of obtaining the effective short-circuit ratio of the islanded DC power generation system if the short-circuit ratios of the low-voltage side of the step-up transformers of all new energy power plants meet the first preset condition includes:

[0035] Obtain the planned operation parameters of pure new energy large-scale bases transmitted to other regions via isolated DC transmission lines, as well as the configuration scheme of grid-type energy storage supporting new energy power stations;

[0036] Based on the planned operation parameters of pure new energy large-scale bases transmitting power via isolated DC transmission and the configuration scheme of grid-type energy storage supporting new energy power stations, a circuit model of pure new energy large-scale bases transmitting power via isolated DC transmission is established.

[0037] Based on the circuit model of the pure new energy large base transmitting power to the outside via isolated DC, the single-port equivalent model of the pure new energy large base transmitting power to the outside via isolated DC is obtained.

[0038] Based on the single-port equivalent model of pure new energy large base transmitted to the outside via isolated DC, the short-circuit capacity of DC converter bus, the reactive power compensation capacity of DC converter bus in parallel and the active power transmitted to the outside via isolated DC are obtained.

[0039] The effective short-circuit ratio of the islanded DC is calculated based on the short-circuit capacity of the DC converter bus, the reactive power compensation capacity of the DC converter bus in parallel, and the active power transmitted by the islanded DC.

[0040] Optionally, the formula for calculating the effective short-circuit ratio of islanded DC is:

[0041] ,

[0042] in, Indicates the effective short-circuit ratio of islanded DC; Indicates the short-circuit capacity of the DC converter bus; This indicates the reactive power compensation capacity of the DC converter bus connected in parallel; This indicates the active power transmitted from the isolated DC transmission line.

[0043] Optionally, the step of configuring a grid-type SVG within the islanded DC transmitting-end converter station to ensure that the effective short-circuit ratio of the islanded DC meets the second preset condition includes:

[0044] Determine the capacity range of the configured network SVG, which includes multiple configured capacities;

[0045] Starting from the smallest configured capacity within the capacity range, the capacity to be configured for the grid-type SVG is selected in a fixed step size, and the effective short-circuit ratio of the islanded DC is calculated based on the configured capacity of the grid-type SVG selected each time, until the calculated effective short-circuit ratio of the islanded DC meets the second preset condition.

[0046] Based on the currently selected capacity to be configured, a grid-type SVG is configured on the DC converter bus of the isolated DC sending-end converter station;

[0047] The second preset condition is that the effective short-circuit ratio of the islanded DC is greater than 3.0.

[0048] The above scheme can improve the effective short-circuit ratio of the isolated DC power grid by configuring a grid-type SVG on the DC converter bus when the effective short-circuit ratio of the isolated DC power grid does not meet the second preset condition. This ensures that the isolated DC power grid can stably transmit the power of the pure new energy base to other regions.

[0049] Optionally, adjusting the configuration capacity of the grid-type SVG already configured in the islanded DC sending-end converter station to ensure that the effective short-circuit ratio of the islanded DC meets the second preset condition includes:

[0050] If the current configured capacity of the grid-type SVG in the isolated DC-DC converter station has not reached the upper limit of the configured capacity, within the capacity range of configuring the grid-type SVG in the isolated DC-DC converter station, starting from the capacity to be configured which is greater than the current configured capacity and differs by a fixed step size, the capacity to be configured for the grid-type SVG in the isolated DC-DC converter station will be selected in sequence.

[0051] In a second aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for configuring pure new energy large-scale grid-type equipment for transmission via isolated DC as described in the first aspect.

[0052] Thirdly, the present invention provides a computer device, comprising:

[0053] Memory, used to store computer programs;

[0054] A processor is used to execute the computer program to implement the steps of the method for configuring pure new energy large-scale grid-type equipment for transmission via isolated DC as described in the first aspect.

[0055] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0056] This invention examines the short-circuit ratio of multiple power plants and the effective short-circuit ratio of isolated DC power generation units on the low-voltage side of the power generation unit in new energy power plants to determine whether they meet the corresponding preset conditions. Based on different judgment results, it rationally configures grid-type energy storage and grid-type SVG. The selected grid-type energy storage and grid-type SVG capacities can meet the needs of stable operation of all new energy power plants and isolated DC power generation in the pure new energy large-scale base, effectively improving the anti-interference capability and voltage support capability of the entire system, so that the pure new energy large-scale base transmitted through isolated DC power generation has stronger stability in the event of a fault. Attached Figure Description

[0057] Figure 1 The diagram shown is a schematic circuit model of a pure new energy large-scale base transmitting power via isolated DC transmission, provided by the present invention.

[0058] Among them, 1-new energy power station, 11-power generation unit, 12-power generation unit step-up transformer, 13-collecting station step-up transformer, 14-grid connection point, 15-grid-type energy storage, 16-collecting station step-up transformer low-voltage side busbar; 2-island DC, 21-DC transmission line, 22-sending-end converter station, 23-receiving-end converter station, 24-grid-type SVG;

[0059] Figure 2 The diagram shown is a simplified schematic of a pure new energy large-scale base transmitting power via isolated DC transmission, provided by the present invention.

[0060] Among them, 3-Equivalent system of pure new energy large base, 31-Equivalent power supply of pure new energy large base, 32-Equivalent impedance inside pure new energy large base; 4-Island DC sending end converter station system, 41-DC converter valve, 42-DC converter transformer, 43-DC converter bus, 44-Grid-type SVG, 45-Reactive power compensator.

[0061] Figure 3 The diagram shown is a schematic diagram of the configuration method of a large-scale pure new energy grid-type equipment for transmission via isolated DC transmission provided by the present invention. Detailed Implementation

[0062] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0063] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0064] Example 1

[0065] This embodiment introduces a method for configuring grid-type equipment for large-scale pure new energy bases that transmit power via isolated DC transmission lines, such as... Figure 3 As shown, it includes:

[0066] Obtain the short-circuit ratio of the low-voltage side of the step-up transformer of the power generation unit in all new energy power stations within the pure new energy base;

[0067] Determine whether the short-circuit ratios of the low-voltage side of the step-up transformer of all the acquired new energy power stations meet the first preset condition;

[0068] If the short-circuit ratio of the step-up transformer to the low-voltage side of any new energy power station does not meet the first preset condition, then, in the case that no grid-type energy storage has been configured in any new energy power station, the new energy power station with the smallest short-circuit ratio of the step-up transformer to the low-voltage side of the generation unit is selected for grid-type energy storage configuration, or the configuration capacity of new energy power stations that have been configured with grid-type energy storage but have not reached the capacity limit is adjusted, or the new energy power station with the smallest short-circuit ratio of the step-up transformer to the low-voltage side of the generation unit is selected from the power stations that have not been configured with grid-type energy storage for grid-type energy storage configuration, so that the short-circuit ratio of the step-up transformer to the low-voltage side of all generation units in all new energy power stations meets the first preset condition;

[0069] If the short-circuit ratios of the low-voltage side of the step-up transformers of all new energy power plants meet the first preset condition, the effective short-circuit ratio of the islanded DC is obtained; it is then determined whether the effective short-circuit ratio of the islanded DC meets the second preset condition; if the effective short-circuit ratio of the islanded DC does not meet the second preset condition, the effective short-circuit ratio of the islanded DC is made to meet the second preset condition by configuring a grid-type SVG in the islanded DC sending-end converter station, or by adjusting the configuration capacity of the grid-type SVG already configured in the islanded DC sending-end converter station.

[0070] Based on the configured grid-type energy storage and grid-type SVG, a grid-type equipment configuration scheme is formed for a large-scale pure new energy base that transmits data via isolated DC transmission.

[0071] Based on the short-circuit ratio of multiple power plants and the effective short-circuit ratio of isolated DC power generation units on the low-voltage side of the power generation unit in this embodiment, grid-type energy storage and grid-type SVG are rationally configured. The selected grid-type energy storage and grid-type SVG capacities can meet the needs of stable operation of all new energy power plants and isolated DC power generation in the pure new energy base, effectively improving the anti-interference capability and voltage support capability of the entire system, so that the pure new energy base transmitted through isolated DC power generation has stronger stability in the event of a fault.

[0072] Example 2

[0073] Based on Example 1, this example provides a detailed description of the technical solution.

[0074] like Figure 1As shown, the pure new energy base includes multiple new energy power stations. The electricity generated by these power stations is collected and then transmitted to the receiving-end grid via a DC transmission channel (i.e., islanded DC) that is not electrically connected to the AC main grid. Each new energy power station includes a power generation unit, a power generation unit step-up transformer, a collection station step-up transformer, a grid connection point, and grid-connected energy storage. The islanded DC transmission includes a sending-end converter station, a receiving-end converter station, DC transmission lines, and a grid-connected SVG (Static Var Generator). The number of power generation units and power generation unit step-up transformers in each new energy power station can be set to one or more according to the actual needs of the new energy power station. Each new energy power station has one collection station and one grid connection point. In this embodiment, the pure new energy base includes five new energy power stations, and each new energy power station has two power generation units and two power generation unit step-up transformers.

[0075] I. Configuring Grid-Based Energy Storage

[0076] When planning the transmission of pure new energy from large-scale bases to isolated DC transmission lines, engineers design the parameters of various equipment within the pure new energy bases and isolated DC transmission lines based on the actual requirements of the transmission. This includes the equipment parameters of the new energy power generation units, power generation unit step-up transformers, collection lines, collection station step-up transformers, sending-end converter stations, receiving-end converter stations, DC transmission lines, etc., as well as the planned operation parameters of the pure new energy bases transmitting to isolated DC transmission lines.

[0077] 1. Scan the short-circuit ratio of the low-voltage side of the step-up transformer of all new energy power stations within the pure new energy base to obtain the short-circuit ratio of the low-voltage side of the step-up transformer of all new energy power stations. The specific process is as follows:

[0078] Obtain the planned operation parameters of pure new energy large-scale bases for transmission via isolated DC transmission lines;

[0079] Based on the planned operation parameters of the pure new energy large-scale base transmitting power to other regions via isolated DC transmission, a circuit model for the pure new energy large-scale base transmitting power to other regions via isolated DC transmission is established.

[0080] Based on the circuit model, the Thevenin equivalent method was used to obtain a multi-port equivalent model of pure new energy large bases transmitting power via isolated DC transmission.

[0081] Based on the multi-port equivalent model, the impedance matrix and short-circuit capacity of the low-voltage side of the power generation unit's step-up transformer, the impedance matrix and short-circuit capacity of the grid connection point, the active power of the power generation unit, the active power of the renewable energy power station, and the active power of the islanded DC transmission are obtained. In this embodiment, for a pure renewable energy base containing five renewable energy power stations, there are five corresponding grid connection points. Based on the multi-port equivalent model of the pure renewable energy base transmitting DC through the islanded DC transmission, the fifth-order grid connection point impedance matrix can be obtained. Represented as:

[0082] ,

[0083] Each new energy power station contains two power generation units. For the low-voltage side of the power generation unit of the new energy power station, the impedance matrix of the low-voltage side of the power generation unit can be obtained according to the multi-port equivalent model of pure new energy large base transmitted through islanded DC.

[0084] Based on the impedance matrix and short-circuit capacity of the low-voltage side of the step-up transformer in the power generation unit, as well as the active power of the power generation unit, the short-circuit ratio of the low-voltage side of the step-up transformer in each power generation unit in the renewable energy power station is calculated using the following formula:

[0085] ,

[0086] in, This represents the short-circuit ratio on the low-voltage side of the step-up transformer of the i-th power generation unit; This represents the short-circuit capacity of the low-voltage side of the step-up transformer in the i-th power generation unit; and This represents the active power of the i-th and j-th power generation units; This represents the self-impedance of the step-up transformer low-voltage side of the i-th power generation unit; This represents the mutual impedance between the i-th and j-th power generation units on the low-voltage side of the step-up transformer.

[0087] For a large-scale pure new energy base comprising five new energy power stations, with each power station containing two power generation units, the short-circuit ratio of the low-voltage side of the step-up transformer for each power generation unit is calculated using the formula for the short-circuit ratio of the low-voltage side of the step-up transformer for ten power generation units. , , , , , , , , , .

[0088] 2. Determine whether the short-circuit ratios of the step-up transformers on the low-voltage side of all acquired power generation units in all new energy power plants meet the first preset condition:

[0089] The conditions for the stable operation of all new energy power stations within a large-scale pure new energy base include that the short-circuit ratio of the low-voltage side of the step-up transformer of all power generation units in all new energy power stations meets a first preset condition. In this embodiment, for the case where multiple new energy power stations are connected to the AC system, the first preset condition is that the short-circuit ratio of the low-voltage side of the step-up transformer of the power generation unit of the new energy power station is not less than 1.5.

[0090] If the short-circuit ratio of the step-up transformer to the low-voltage side of any renewable energy power station does not meet the first preset condition, the following steps are taken: First, if no grid-connected energy storage is configured in any renewable energy power station, select the renewable energy power station with the smallest short-circuit ratio of the step-up transformer to the low-voltage side of the generator unit for grid-connected energy storage configuration. Second, adjust the configuration capacity of renewable energy power stations that have configured grid-connected energy storage but have not reached their capacity limit. Third, select the renewable energy power station with the smallest short-circuit ratio of the step-up transformer to the low-voltage side of the generator unit from among the power stations that have never configured grid-connected energy storage for grid-connected energy storage configuration. This ensures that the short-circuit ratio of the step-up transformer to the low-voltage side of all generator units in all renewable energy power stations meets the first preset condition. This includes iteratively performing the following operations:

[0091] If no grid-connected energy storage is configured in any of the new energy power plants, the new energy power plant with the smallest short-circuit ratio on the low-voltage side of the step-up transformer of the generating unit will be selected for grid-connected energy storage configuration. If grid-connected energy storage is already configured in any of the existing new energy power plants, the configuration capacity of those power plants that have been configured with grid-connected energy storage but have not reached their capacity limit will be adjusted. If grid-connected energy storage is already configured in any of the existing new energy power plants and all of them have reached their capacity limit, the new energy power plant with the smallest short-circuit ratio on the low-voltage side of the step-up transformer of the generating unit will be selected from the power plants that have not been configured with grid-connected energy storage for grid-connected energy storage configuration.

[0092] After each new configuration of grid-type energy storage or adjustment of grid-type energy storage capacity, the short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations in the pure new energy base is re-acquired, and it is determined whether the short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations meets the first preset condition. If it meets the condition, the iteration ends; otherwise, the next iteration is executed.

[0093] (1) In the case that no grid-type energy storage is configured in all new energy power stations, grid-type energy storage is configured in the new energy power stations with the short-circuit ratio of multiple power stations on the low-voltage side of the smallest power generation unit step-up transformer, including:

[0094] Based on the capacity of the main transformer at the new energy power station's step-up substation and the installed capacity of new energy at the new energy power station, the capacity range for the configured grid-type energy storage is determined as follows: The capacity range includes multiple configuration capacities, each configured in a fixed step size. To achieve growth;

[0095] Starting with the smallest configured capacity within the capacity range, sequentially select the configured capacities within the capacity range as the grid-type energy storage capacity to be configured for the new energy power station; (Refer to...) Figure 2Each time a configuration capacity is selected, the grid-type energy storage corresponding to that configuration capacity is equivalent to an ideal voltage source connected in series with an impedance and connected to the circuit model of pure new energy base transmitted to the outside via isolated DC. The impedance value is equal to the internal impedance of the grid-type energy storage. Based on this, the corresponding multi-port equivalent model of pure new energy base transmitted to the outside via isolated DC is corrected. The short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations in the pure new energy base is calculated until the selected configuration capacity reaches the upper limit of the grid-type energy storage configuration capacity of the power station, or the short-circuit ratio of the step-up transformer to the low-voltage side of all power generation units in all new energy power stations meets the first preset condition.

[0096] If the calculated short-circuit ratios of the step-up transformers on the low-voltage side of all new energy power plants meet the first preset condition, then the fixed step size is no longer required. The result of the increase is to select the next configuration capacity of the grid-type energy storage, and directly connect the grid-type energy storage corresponding to the currently selected configuration capacity to the low-voltage side bus of the corresponding new energy power station's substation.

[0097] (2) In cases where existing renewable energy power stations are equipped with grid-type energy storage, the capacity of renewable energy power stations that have been equipped with grid-type energy storage but have not reached the capacity limit shall be adjusted, including:

[0098] Within the selectable capacity range for configuring grid-type energy storage at this site, the capacity should be greater than the current configured capacity but with a fixed step size. Starting with the capacity to be configured, the capacity of grid-type energy storage to be configured for the station is selected in sequence; based on the selected capacity of grid-type energy storage to be configured, the short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy stations in the pure new energy base is calculated until the short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy stations meets the first preset condition, and grid-type energy storage is configured for the station according to the currently selected configuration capacity;

[0099] If the current configured capacity of grid-connected energy storage at a new energy power station reaches the upper limit of its grid-connected energy storage capacity, the new energy power station with the smallest short-circuit ratio on the low-voltage side of the step-up transformer is selected from other new energy power stations that have not been configured with grid-connected energy storage, and grid-connected energy storage is configured for that station. Specifically, the process of configuring grid-connected energy storage for this new energy power station includes:

[0100] Based on the capacity of the main transformer at the new energy power station's step-up substation and the installed capacity of new energy at the new energy power station, the capacity range for the configured grid-type energy storage is determined as follows: The capacity range includes multiple configuration capacities, each configured in a fixed step size. To achieve growth;

[0101] Starting with the smallest configured capacity within the capacity range, sequentially select the configured capacities within the capacity range as the grid-type energy storage capacity to be configured for the new energy power station; (Refer to...) Figure 2 Each time a configuration capacity is selected, the grid-type energy storage corresponding to that configuration capacity is equivalent to an ideal voltage source connected in series with an impedance and connected to the circuit model of pure new energy base transmitted to the outside via isolated DC. The impedance value is equal to the internal impedance of the grid-type energy storage. Based on this, the corresponding multi-port equivalent model of pure new energy base transmitted to the outside via isolated DC is corrected. The short-circuit ratio of the step-up transformer to the low-voltage side of the power generation unit of all new energy power stations in the pure new energy base is calculated until the selected configuration capacity reaches the upper limit of the grid-type energy storage configuration capacity of the power station, or the short-circuit ratio of the step-up transformer to the low-voltage side of all power generation units in all new energy power stations meets the first preset condition.

[0102] If the calculated short-circuit ratios of the step-up transformers on the low-voltage side of all new energy power plants meet the first preset condition, then the fixed step size is no longer required. The result of the increase is to select the next configuration capacity of the grid-type energy storage, and directly connect the grid-type energy storage corresponding to the currently selected configuration capacity to the low-voltage side bus of the corresponding new energy power station's substation.

[0103] II. Configuring Mesh-based SVG

[0104] If the short-circuit ratios of the low-voltage side of the step-up transformers of all new energy power plants meet the first preset condition, the effective short-circuit ratio of the islanded DC is obtained; it is then determined whether the effective short-circuit ratio of the islanded DC meets the second preset condition; if the effective short-circuit ratio of the islanded DC does not meet the second preset condition, the effective short-circuit ratio of the islanded DC is made to meet the second preset condition by configuring a grid-type SVG in the islanded DC sending-end converter station, or by adjusting the configuration capacity of the grid-type SVG already configured in the islanded DC sending-end converter station.

[0105] 1. If the short-circuit ratio of the low-voltage side of the step-up transformer in all new energy power plants meets the first preset condition, the effective short-circuit ratio of the islanded DC power generation system is obtained, specifically as follows:

[0106] Obtain the planned operation parameters of pure new energy large-scale bases transmitted to other regions via isolated DC transmission lines, as well as the configuration scheme of grid-type energy storage supporting new energy power stations;

[0107] Based on the planned operation parameters of pure new energy large-scale bases transmitting power via isolated DC transmission and the configuration scheme of grid-type energy storage supporting new energy power stations, a circuit model of pure new energy large-scale bases transmitting power via isolated DC transmission is established.

[0108] Based on the circuit model of the pure new energy large base transmitted to the outside via isolated DC, the Thevenin equivalent method can be used to convert the pure new energy large base into an equivalent ideal voltage source connected in series with an equivalent internal impedance of the pure new energy large base, and obtain the single-port equivalent model of the pure new energy large base transmitted to the outside via isolated DC.

[0109] Based on the single-port equivalent model of pure new energy large base transmitted to the outside via isolated DC, the short-circuit capacity of DC converter bus, the reactive power compensation capacity of DC converter bus in parallel and the active power transmitted to the outside via isolated DC are obtained.

[0110] Based on the short-circuit capacity of the DC converter bus, the reactive power compensation capacity of the DC converter bus in parallel, and the active power transmitted by the islanded DC, the effective short-circuit ratio of the islanded DC is calculated using the following formula:

[0111] ,

[0112] in, Indicates the effective short-circuit ratio of islanded DC; Indicates the short-circuit capacity of the DC converter bus; This indicates the reactive power compensation capacity of the DC converter bus connected in parallel; This indicates the active power transmitted from the isolated DC transmission line.

[0113] 2. Determine whether the calculated effective short-circuit ratio of the islanded DC meets the second preset condition:

[0114] If the effective short-circuit ratio of the islanded DC does not meet the second preset condition, the effective short-circuit ratio of the islanded DC can be made to meet the second preset condition by configuring a grid-type SVG in the islanded DC sending-end converter station, or by adjusting the configuration capacity of the grid-type SVG already configured in the islanded DC sending-end converter station; in this embodiment, the second preset condition is that the effective short-circuit ratio (ESCR) of the islanded DC is greater than 3.0.

[0115] (1) By configuring a grid-type SVG in the islanded DC sending-end converter station, the effective short-circuit ratio of the islanded DC meets the second preset condition, including:

[0116] The capacity range of the configured mesh SVG is determined as follows: The capacity range includes multiple configuration capacities, each configured in a fixed step size. To achieve growth;

[0117] Start with the smallest configuration capacity within the capacity range and increase in fixed increments. The configuration capacity of the network-type SVG is selected sequentially, and the effective short-circuit ratio of the islanded DC is calculated based on the configuration capacity of the network-type SVG selected each time. For each configuration capacity selected, the network-type SVG corresponding to the configuration capacity is equivalent to an ideal voltage source connected in series with an impedance and connected to the circuit model of the pure new energy base transmitted to the outside via islanded DC. The impedance value is equal to the internal impedance of the network-type SVG. Then the effective short-circuit ratio of the islanded DC is calculated until the effective short-circuit ratio of the islanded DC meets the second preset condition.

[0118] Based on the currently selected capacity to be configured, a grid-type SVG is configured on the DC converter bus of the isolated DC sending-end converter station.

[0119] (2) By adjusting the configuration capacity of the grid-type SVG already configured in the islanded DC sending-end converter station, the effective short-circuit ratio of the islanded DC meets the second preset condition, including:

[0120] If the current configured capacity of the grid-type SVG at the isolated DC-DC transmitting-end converter station has not reached the upper limit of the configured capacity, within the capacity range of configuring the grid-type SVG at the isolated DC-DC transmitting-end converter station, the capacity will be increased from a level greater than the current configured capacity by a fixed step size. Starting with the capacity to be configured, the capacity to be configured for the grid-type SVG within the islanded DC transmitting-end converter station is selected sequentially.

[0121] If the calculated effective short-circuit ratio of the islanded DC meets the second preset condition, then it is no longer based on the fixed step size. After the increase, select the next configuration capacity of the grid-type SVG and directly connect the grid-type SVG corresponding to the currently selected configuration capacity to the DC converter bus of the islanded DC transmitting-end converter station.

[0122] Based on the configured grid-type energy storage and grid-type SVG, a grid-type equipment configuration scheme for a large-scale pure new energy base that transmits data via isolated DC transmission is finally formed.

[0123] In summary, this embodiment examines the short-circuit ratio of multiple power plants and the effective short-circuit ratio of isolated DC power generation units on the low-voltage side of the power generation unit of the new energy power plant to determine whether they meet the corresponding preset conditions. Based on different judgment results, grid-type energy storage and grid-type SVG are reasonably configured. The selected grid-type energy storage and grid-type SVG have capacities that can meet the needs of stable operation of all new energy power plants and isolated DC power generation in the pure new energy base, effectively improving the anti-interference capability and voltage support capability of the entire system, so that the pure new energy base transmitted through isolated DC power generation has stronger stability in the event of a fault.

[0124] Furthermore, this invention also takes into account the construction and maintenance costs of grid-type equipment, providing a basis for the technical and economic considerations of the capacity configuration of grid-type equipment for new energy power plants and sending-end converter stations, and taking into account the technical and economic requirements of the capacity configuration of grid-type equipment for pure new energy large-scale bases that are transmitted via isolated DC transmission.

[0125] Example 3

[0126] This embodiment provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the steps of the pure new energy large-scale base grid-type equipment configuration method described in Embodiment 1, which transmits pure new energy via isolated DC.

[0127] Example 4

[0128] This embodiment provides a computer device, including:

[0129] Memory, used to store computer programs;

[0130] A processor is used to execute the computer program to implement the steps of the pure new energy large-scale base grid-type equipment configuration method for transmission via isolated DC as described in Embodiment 1.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for configuring a large-scale new energy base grid type equipment for island direct current power transmission, characterized in that, The method comprises the following steps: acquiring short-circuit ratio conditions of a generating unit step-up transformer low-voltage side of all new energy stations in a pure new energy large base; determining whether the short-circuit ratio of the generating unit step-up transformer low-voltage side of all new energy stations meets a first preset condition; if the short-circuit ratio of the generating unit step-up transformer low-voltage side of any new energy station does not meet the first preset condition, configuring a network-type energy storage for the new energy station corresponding to the minimum short-circuit ratio of the generating unit step-up transformer low-voltage side, adjusting the configuration capacity of the network-type energy storage of the new energy station that has been configured but does not reach the capacity upper limit, or configuring the network-type energy storage for the new energy station with the minimum short-circuit ratio of the generating unit step-up transformer low-voltage side from the new energy stations that have not been configured with the network-type energy storage, so that the short-circuit ratio of the generating unit step-up transformer low-voltage side of all new energy stations meets the first preset condition; if the short-circuit ratio of the generating unit step-up transformer low-voltage side of all new energy stations meets the first preset condition, acquiring an effective short-circuit ratio condition of an islanded direct current; determining whether the effective short-circuit ratio of the islanded direct current meets a second preset condition; if the effective short-circuit ratio of the islanded direct current does not meet the second preset condition, configuring a network-type SVG in a sending end converter station of the islanded direct current, or adjusting the configuration capacity of the network-type SVG that has been configured in the sending end converter station of the islanded direct current, so that the effective short-circuit ratio of the islanded direct current meets the second preset condition; forming a network-type equipment configuration scheme of the pure new energy large base sent out through the islanded direct current according to the configured network-type energy storage and the network-type SVG.

2. The method according to claim 1, wherein, The method comprises the following steps: acquiring a planned operation parameter of the pure new energy large base sent out through the islanded direct current; establishing a circuit model of the pure new energy large base sent out through the islanded direct current according to the planned operation parameter of the pure new energy large base sent out through the islanded direct current; acquiring a multi-port equivalent model of the pure new energy large base sent out through the islanded direct current according to the circuit model; acquiring an impedance matrix and a short-circuit capacity of the generating unit step-up transformer low-voltage side according to the multi-port equivalent model; calculating the short-circuit ratio of the generating unit step-up transformer low-voltage side of each generating unit in the new energy station according to the impedance matrix and the short-circuit capacity of the generating unit step-up transformer low-voltage side and the active power of the generating unit.

3. The method of claim 2, wherein the method is characterized by, The calculation formula of the short-circuit ratio of the generating unit step-up transformer low-voltage side of each generating unit in the new energy station is: ， wherein, represents the short circuit ratio of the boost transformer low voltage side of the i-th generating unit; represents the short circuit capacity of the boost transformer low voltage side of the i-th generating unit; and represents the active power of the i-th and j-th generating unit; represents the self impedance of the boost transformer low voltage side of the i-th generating unit; represents the mutual impedance of the boost transformer low voltage side of the i-th and j-th generating unit.

4. The method of claim 1, wherein the islanded DC power transmission pure new energy large base station network configuration method is characterized in that, The method for making the short-circuit ratio of the generating unit step-up transformer low-voltage side of all new energy stations meet the first preset condition comprises the following steps: iteratively performing the following operation process: In the case that no network-forming energy storage is configured in all new energy stations, a new energy station corresponding to the minimum short-circuit ratio of the power generation unit step-up transformer low-voltage side is selected to be configured with the network-forming energy storage; in the case that the network-forming energy storage is configured in the existing new energy stations, the new energy station configured with the network-forming energy storage but not reaching the capacity upper limit is adjusted in configuration capacity; in the case that the network-forming energy storage is configured in the existing new energy stations and all reach the capacity upper limit, the new energy station with the minimum short-circuit ratio of the power generation unit step-up transformer low-voltage side is selected from the new energy stations not configured with the network-forming energy storage to be configured with the network-forming energy storage; After each new configuration of the network-forming energy storage or adjustment of the network-forming energy storage capacity, the short-circuit ratio of the power generation unit step-up transformer low-voltage side of all new energy stations in the pure new energy large base is re-acquired, and it is judged whether the short-circuit ratio of the power generation unit step-up transformer low-voltage side of all new energy stations meets the first preset condition, if yes, the iteration is ended, if not, the next iteration is performed; The first preset condition is that the short-circuit ratio of the power generation unit step-up transformer low-voltage side of the new energy station is not less than 1.

5.

5. The method according to claim 4, wherein, The case that no network-forming energy storage is configured in all new energy stations, a new energy station corresponding to the minimum short-circuit ratio of the power generation unit step-up transformer low-voltage side is selected to be configured with the network-forming energy storage, comprising: The capacity interval of the configured network-forming energy storage is determined according to the step-up transformer main transformer capacity of the new energy station gathering station and the new energy station installed capacity; From the smallest configured capacity in the capacity interval and increasing by a fixed step, the network-forming energy storage capacity to be configured for the new energy station is selected in turn, and the short-circuit ratio of the power generation unit step-up transformer low-voltage side of all new energy stations in the pure new energy large base is calculated, until the selected configured capacity reaches the network-forming energy storage configuration capacity upper limit of the new energy station, or the short-circuit ratio of the power generation unit step-up transformer low-voltage side of all new energy stations meets the first preset condition; If the short-circuit ratio of the power generation unit step-up transformer low-voltage side of all new energy stations meets the first preset condition, the network-forming energy storage is configured for the new energy station according to the currently selected configured capacity.

6. The method of claim 4, wherein the island DC transmission pure new energy large base station network configuration method is characterized in that, The case that the network-forming energy storage is configured in the existing new energy stations, the new energy station configured with the network-forming energy storage but not reaching the capacity upper limit is adjusted in configuration capacity, comprising: In the selectable capacity interval of the network-forming energy storage configured in the station, the network-forming energy storage capacity to be configured for the station is selected in turn from the configured capacity greater than the current configured capacity and different by a fixed step; the short-circuit ratio of the power generation unit step-up transformer low-voltage side of all new energy stations in the pure new energy large base is calculated according to the selected network-forming energy storage capacity to be configured, until the short-circuit ratio of the power generation unit step-up transformer low-voltage side of all new energy stations meets the first preset condition, and the network-forming energy storage is configured for the station according to the currently selected configured capacity; If the current configured capacity of the network-forming energy storage configured in the new energy station reaches the network-forming energy storage configuration capacity upper limit of the station, the new energy station corresponding to the minimum short-circuit ratio of the power generation unit step-up transformer low-voltage side is selected from other new energy stations not configured with the network-forming energy storage, and the network-forming energy storage is configured for the station.

7. The method of claim 1, wherein the islanded DC power transmission pure new energy large base station network configuration method is characterized by, If the short-circuit ratios of the boosting units of all new energy stations satisfy the first preset condition, the effective short-circuit ratio of the islanded DC is obtained, including: Obtaining the planning operation parameters of the pure new energy large base through the islanded DC and the configuration scheme of the network type energy storage matched with the new energy station; According to the planning operation parameters of the pure new energy large base through the islanded DC and the configuration scheme of the network type energy storage matched with the new energy station, a circuit model of the pure new energy large base through the islanded DC is established; According to the circuit model of the pure new energy large base through the islanded DC, a single-port equivalent model of the pure new energy large base through the islanded DC is obtained; According to the single-port equivalent model of the pure new energy large base through the islanded DC, the short-circuit capacity of the DC bus, the reactive power compensation capacity of the DC bus in parallel, and the active power of the islanded DC are obtained; According to the short-circuit capacity of the DC bus, the reactive power compensation capacity of the DC bus in parallel, and the active power of the islanded DC, the effective short-circuit ratio of the islanded DC is calculated.

8. The method according to claim 7, wherein, The calculation formula of the effective short-circuit ratio of the islanded DC is: ， wherein, represents the effective short circuit ratio of the islanded DC; represents the short circuit capacity of the DC converter bus; represents the reactive compensation capacity of the DC converter bus in parallel; represents the active power delivered by the islanded DC.

9. The method of claim 1, wherein the islanded DC power transmission pure new energy large base station network configuration method is characterized in that, The effective short-circuit ratio of the islanded DC is calculated by configuring the network type SVG in the islanded DC sending end converter station, so that the effective short-circuit ratio of the islanded DC satisfies the second preset condition, including: Determine the capacity interval of the configured network type SVG, which includes multiple configuration capacities in the capacity interval; From the smallest configuration capacity in the capacity interval, start increasing by a fixed step, and select the configuration capacity as the network type SVG in turn, and calculate the effective short-circuit ratio of the islanded DC according to the configuration capacity of the network type SVG selected each time, until the effective short-circuit ratio of the islanded DC calculated satisfies the second preset condition; According to the currently selected configuration capacity, configure the network type SVG on the DC bus of the islanded DC sending end converter station; The second preset condition is that the effective short-circuit ratio of the islanded DC is greater than 3.

0.

10. The method according to claim 9, wherein the method is characterized in that, The effective short-circuit ratio of the islanded DC is calculated by adjusting the configuration capacity of the network type SVG configured in the islanded DC sending end converter station, so that the effective short-circuit ratio of the islanded DC satisfies the second preset condition, including: If the current configuration capacity of the network type SVG of the islanded DC sending end converter station does not reach the upper limit of the configuration capacity, in the capacity interval of the network type SVG configured in the islanded DC sending end converter station, from the configuration capacity greater than the current configuration capacity and the difference of the fixed step, select the configuration capacity as the network type SVG in the islanded DC sending end converter station in turn.

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