A Method, Device, Terminal and Storage Medium for Optimizing the Capacity of Grid-Forming Energy Storage

Abstract

The present application provides a method, device, terminal and storage medium for optimizing the capacity of a network-forming energy storage. The method includes: calculating the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities under the grid-connected operation mode; obtaining the network-forming energy storage capacity under the grid-connected operation mode when the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations under the grid-connected operation mode reach their respective control targets; calculating the energy storage capacity under the islanded operation mode with the control target of maximizing the consumption of new energy; calculating the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities under the islanded operation mode; and obtaining the network-forming energy storage capacity under the islanded operation mode when the short-circuit ratio of multiple new energy stations under the islanded operation mode reaches the corresponding control target; thereby obtaining the target network-forming energy storage capacity. The present application can improve the stability of new energy involved in the network.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage, and particularly to a method, device, terminal and storage medium for optimizing the capacity of a network-forming energy storage. Background Art

[0002] With the construction of a new power system, the installed capacity and electricity proportion of new energy will both increase rapidly, and it is expected to surpass conventional power generation units to become the largest power source in the grid. However, new energy represented by wind power and photovoltaic power has power volatility and intermittency. In order to convert the relatively uncertain wind and light resources into high-quality electric energy, it is necessary to configure a certain energy storage system to solve the power and electricity balance problem caused by its power fluctuation. Moreover, the problems brought about by the large-scale access of new energy include not only the power and electricity balance problem, but also the impact on the system safety and stability. In order to solve the problems of insufficient moment of inertia and short-circuit capacity caused by the large-scale access of new energy, existing solutions often need to configure a certain capacity of synchronous condensers to support the system strength. As a rotating device, a synchronous condenser has the disadvantages of high initial investment, large operating losses, and high operation and maintenance costs, and further methods for reducing the overall cost need to be explored for large-scale applications in the power system. Summary of the Invention

[0003] The present application provides a method, device, terminal and storage medium for optimizing the capacity of a network-forming energy storage to solve the problem of reduced system safety and stability during the large-scale access of new energy in the prior art.

[0004] In a first aspect, the present application provides a method for optimizing the capacity of a network-forming energy storage, including:

[0005] Under the grid-connected operation mode, calculating the short-circuit ratio of the new energy grid connection point and the short-circuit ratio of multiple new energy stations in the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities;

[0006] When the short-circuit ratio of the new energy grid connection point and the short-circuit ratio of multiple new energy stations under the grid-connected operation mode reach their respective control targets, taking the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity under the grid-connected operation mode;

[0007] Taking maximizing the consumption of new energy as the control target, calculating the energy storage capacity under the islanded operation mode;

[0008] Under the islanded operation mode, calculating the short-circuit ratio of multiple new energy stations in the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities; and when the short-circuit ratio of multiple new energy stations under the islanded operation mode reaches the corresponding control target, taking the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity under the islanded operation mode;

[0009] Based on the network-forming energy storage capacity under grid-connected operation mode, the energy storage capacity under islanded operation mode, and the network-forming energy storage capacity under islanded operation mode, the target network-forming energy storage capacity is obtained.

[0010] In a second aspect, the present application provides an apparatus for optimizing the network-forming energy storage capacity, including:

[0011] A first calculation module, configured to calculate the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities under grid-connected operation mode;

[0012] A first capacity determination module, configured to use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity under grid-connected operation mode when the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations under grid-connected operation mode reach their respective control targets;

[0013] A second calculation module, configured to calculate the energy storage capacity under the islanded operation mode with the control target of maximizing the consumption of new energy;

[0014] A second capacity determination module, configured to calculate the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities under the islanded operation mode; and use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity under the islanded operation mode when the short-circuit ratio of multiple new energy stations under the islanded operation mode reaches the corresponding control target;

[0015] A determination module, configured to obtain the target network-forming energy storage capacity according to the network-forming energy storage capacity under grid-connected operation mode, the energy storage capacity under islanded operation mode, and the network-forming energy storage capacity under islanded operation mode.

[0016] In a third aspect, the present application provides a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method described in the first aspect or any possible implementation manner of the first aspect above are implemented.

[0017] In a fourth aspect, the present application provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the method described in the first aspect or any possible implementation manner of the first aspect above are implemented.

[0018] The present application provides a method, device, terminal, and storage medium for optimizing the capacity of a network-forming energy storage. When the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations in the source-network-load-storage system under the grid-connected operation mode both reach their respective control targets, the capacity of the network-forming energy storage under the grid-connected operation mode is determined. By taking maximizing the consumption of new energy as the control target, the energy storage capacity under the islanded operation mode is determined, and when the short-circuit ratio of multiple new energy stations in the source-network-load-storage system under the islanded operation mode reaches the corresponding control target, the capacity of the network-forming energy storage under the islanded operation mode is determined. Finally, the target network-forming energy storage capacity is determined based on the capacity of the network-forming energy storage under the grid-connected operation mode, the energy storage capacity under the islanded operation mode, and the capacity of the network-forming energy storage under the islanded operation mode. Without affecting the power balance of the power grid, it not only meets the short-circuit capacity support of the new energy power station but also meets the capacity requirements of the new energy power station under the grid-connected operation mode and the islanded operation mode, improving the stability of the new energy connected to the grid. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a flowchart for implementing the method for optimizing the capacity of the network-forming energy storage provided by the embodiment of the present application;

[0021] Figure 2 It is a schematic structural diagram of the device for optimizing the capacity of the network-forming energy storage provided by the embodiment of the present application;

[0022] Figure 3 It is a schematic diagram of the terminal provided by the embodiment of the present application. Detailed Embodiments

[0023] In the following description, specific details such as specific system structures and technologies are proposed for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0024] To make the purpose, technical solutions, and advantages of the present application clearer, the following will be described through specific embodiments in conjunction with the drawings.

[0025] Figure 1The implementation flowchart of the grid-forming energy storage capacity optimization method provided by the embodiments of the present application is described in detail as follows:

[0026] In step 101, in the grid-connected operation mode, calculate the short-circuit ratios of the new energy connection points and the short-circuit ratios of multiple new energy stations in the source-grid-load-storage system corresponding to multiple alternative grid-forming energy storage capacities.

[0027] Among them, multiple new energy stations are the busbars of the photovoltaic power generation units and wind turbine generator sets. Exemplarily, the photovoltaic is the 400V busbar, and the wind turbine generator set is the 690V busbar.

[0028] In the embodiments of the present application, the grid-forming energy storage includes, but is not limited to, forms such as low-voltage energy storage and high-voltage direct-connected energy storage, and the battery types include, but are not limited to, lithium batteries, lead-carbon batteries, lead-acid batteries, etc.

[0029] In the embodiments of the present application, in the grid-connected operation mode, considering the large-scale generation of new energy, based on different grid-forming energy storage capacities, calculate the short-circuit ratios of the new energy connection points and the short-circuit ratios of multiple new energy stations in the source-grid-load-storage system corresponding to different grid-forming energy storage capacities.

[0030] Among them, considering the large-scale generation of new energy is specifically manifested as the need to consider the large-scale generation of new energy such as wind power and photovoltaic power. For example, the simultaneity rate of new energy is considered to be 0.8.

[0031] In a possible implementation manner, in the grid-connected operation mode, calculating the short-circuit ratios of multiple new energy stations in the source-grid-load-storage system corresponding to multiple alternative grid-forming energy storage capacities may include:

[0032] Calculate the short-circuit ratios of multiple new energy stations in the source-grid-load-storage system corresponding to multiple alternative grid-forming energy storage capacities through the first formula. The first formula is:

[0033]

[0034] Among them, MRSCR i is the short-circuit ratio of the i-th new energy station, is the nominal voltage of the i-th grid-connected bus node, is the voltage generated by the new energy power generation at the i-th node, is the short-circuit current provided by the i-th new energy power generation equipment, is the equivalent impedance.

[0035] Among them, the source-grid-load-storage system includes multiple alternative grid-forming energy storage capacities, and each grid-forming energy storage capacity includes multiple short-circuit ratios of new energy stations. According to the first formula, all the short-circuit ratios of new energy stations in the source-grid-load-storage system in the grid-connected operation mode can be calculated.

[0036] In the embodiments of the present application, the calculation processes of the new energy grid connection point short-circuit ratio ESCR and the new energy multi-station short-circuit ratio MRSCR are the same, and the calculation formulas used are also the same. Therefore, the present application will not elaborate on this in detail.

[0037] In step 102, when the new energy grid connection point short-circuit ratio and the new energy multi-station short-circuit ratio in the grid-connected operation mode reach their respective control targets, the corresponding alternative network-forming energy storage capacity is used as the network-forming energy storage capacity in the grid-connected operation mode.

[0038] In the embodiments of the present application, according to the new energy grid connection point short-circuit ratio ESCR and the new energy multi-station short-circuit ratio MRSCR of the source-grid-load-storage system in the grid-connected operation mode calculated in step 101, when all the new energy grid connection point short-circuit ratios ESCR reach their corresponding control targets, and all the new energy multi-station short-circuit ratios MRSCR reach their corresponding control targets, the corresponding alternative network-forming energy storage capacity is used as the network-forming energy storage capacity S1 of the source-grid-load-storage system in the grid-connected operation mode.

[0039] Among them, in the embodiments of the present application, the set values of the control targets mainly refer to the relevant standard requirements: Article 6.12.3 of GB / T40581-2021 "Code for Safety and Stability Calculation of Power Systems" stipulates that for the case of new energy multi-stations accessing the AC system, the multi-station short-circuit ratio at the low-voltage side of the step-up transformer of the new energy power generation unit should not be less than 1.5, and the multi-station short-circuit ratio at the new energy grid connection point should not be less than 2.0 and preferably greater than 3.0.

[0040] In a possible implementation manner, step 102 may specifically include:

[0041] Judge whether all the new energy grid connection point short-circuit ratios of the source-grid-load-storage system in the grid-connected operation mode are greater than the first preset short-circuit ratio, and whether all the new energy multi-station short-circuit ratios of the source-grid-load-storage system in the grid-connected operation mode are greater than the second preset short-circuit ratio;

[0042] If all the new energy grid connection point short-circuit ratios of the source-grid-load-storage system in the grid-connected operation mode are greater than the first preset short-circuit ratio, and all the new energy multi-station short-circuit ratios of the source-grid-load-storage system in the grid-connected operation mode are greater than the second preset short-circuit ratio, then the corresponding alternative network-forming energy storage capacity is used as the network-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode.

[0043] Among them, for the first preset short-circuit ratio SCR 1 and the second preset short-circuit ratio SCR 2 The specific set values are not limited, but it is required that the first preset short-circuit ratio SCR 1 and the second preset short-circuit ratio SCR 2 be set to meet the actual requirements.

[0044] Based on the short-circuit ratio ESCR of the new energy grid connection point and the multi-station short-circuit ratio MRSCR of the new energy in the source-grid-load-storage system calculated in step 101, it is judged whether all the short-circuit ratios ESCR of the new energy grid connection points in the source-grid-load-storage system in the grid-connected operation mode are greater than the first preset short-circuit ratio SCR 1 , and whether all the multi-station short-circuit ratios MRSCR of the new energy in the source-grid-load-storage system in the grid-connected operation mode are greater than the second preset short-circuit ratio SCR 2 , that is, ESCR i > SCR 1 , and, MRSCR i > SCR 2 .

[0045] If all the short-circuit ratios ESCR of the new energy grid connection points in the source-grid-load-storage system in the grid-connected operation mode are greater than the first preset short-circuit ratio SCR 1 , and all the multi-station short-circuit ratios MRSCR of the new energy in the source-grid-load-storage system in the grid-connected operation mode are greater than the second preset short-circuit ratio SCR 2 , that is, ESCR i > SCR 1 , and, MRSCR i > SCR 2 , take the corresponding alternative grid-forming energy storage capacity S 11 as the grid-forming energy storage capacity S of the source-grid-load-storage system in the grid-connected operation mode 1 , that is, S 1 = S 11 .

[0046] In a possible implementation, after judging whether all the short-circuit ratios of the new energy grid connection points in the source-grid-load-storage system in the grid-connected operation mode are greater than the first preset short-circuit ratio, and whether all the multi-station short-circuit ratios of the new energy in the source-grid-load-storage system in the grid-connected operation mode are greater than the second preset short-circuit ratio, the method may further include:

[0047] If all the short-circuit ratios of the new energy grid connection points in the source-grid-load-storage system in the grid-connected operation mode are greater than the first preset short-circuit ratio, and there is a multi-station short-circuit ratio of the new energy in the source-grid-load-storage system in the grid-connected operation mode that is not greater than the second preset short-circuit ratio, then configure any alternative grid-forming energy storage capacity at the target new energy station; the target new energy station is the new energy station in the source-grid-load-storage system in the grid-connected operation mode where the multi-station short-circuit ratio of the new energy is not greater than the second preset short-circuit ratio;

[0048] Calculate the short - circuit ratio of multiple new - energy stations in the current source - grid - load - storage system. If the short - circuit ratio of multiple new - energy stations in the current source - grid - load - storage system is not greater than the second preset short - circuit ratio, update the current grid - forming energy - storage capacity of the target new - energy station according to the first capacity step, and return to the step of calculating the short - circuit ratio of multiple new - energy stations in the current source - grid - load - storage system to continue execution until the short - circuit ratios of all new - energy stations in the current source - grid - load - storage system are greater than the second preset short - circuit ratio. Then, take the current grid - forming energy - storage capacity configured at the target new - energy station as the grid - forming energy - storage capacity of the source - grid - load - storage system in the grid - connected operation mode;

[0049] If the short - circuit ratio of the new - energy grid - connection point in the source - grid - load - storage system in the grid - connected operation mode is not greater than the first preset short - circuit ratio, and the short - circuit ratio of multiple new - energy stations in the source - grid - load - storage system in the grid - connected operation mode is not greater than the second preset short - circuit ratio, configure any alternative grid - forming energy - storage capacity at the low - voltage bus of the target new - energy collection station; the low - voltage bus of the target new - energy collection station is the low - voltage bus of the new - energy collection station with the lowest short - circuit ratio of the new - energy grid - connection point in the source - grid - load - storage system in the grid - connected operation mode;

[0050] Calculate the short - circuit ratio of the new - energy grid - connection point in the current source - grid - load - storage system. If the short - circuit ratio of the new - energy grid - connection point in the current source - grid - load - storage system is not greater than the first preset short - circuit ratio, update the current grid - forming energy - storage capacity of the low - voltage bus of the target new - energy collection station according to the second capacity step, and return to the step of calculating the short - circuit ratio of the new - energy grid - connection point in the current source - grid - load - storage system to continue execution until the short - circuit ratios of all new - energy grid - connection points in the current source - grid - load - storage system are greater than the first preset short - circuit ratio, and determine the current grid - forming energy - storage capacity configured at the low - voltage bus of the target new - energy collection station;

[0051] Calculate the short - circuit ratio of multiple new - energy stations in the source - grid - load - storage system after configuring the current grid - forming energy - storage capacity. If the short - circuit ratios of all new - energy stations in the source - grid - load - storage system after configuring the current grid - forming energy - storage capacity are greater than the second preset short - circuit ratio, take the current grid - forming energy - storage capacity configured at the low - voltage bus of the target new - energy collection station as the grid - forming energy - storage capacity of the source - grid - load - storage system in the grid - connected operation mode;

[0052] If the source - grid - load - storage system after configuring the current grid - forming energy - storage capacity has a short - circuit ratio of multiple new - energy stations not greater than the second preset short - circuit ratio, return to the step of calculating the short - circuit ratio of the new - energy grid - connection point and the short - circuit ratio of multiple new - energy stations corresponding to multiple alternative grid - forming energy - storage capacities in the source - grid - load - storage system in the grid - connected operation mode to continue execution until the short - circuit ratios of all new - energy stations in the source - grid - load - storage system after configuring the current grid - forming energy - storage capacity are greater than the second preset short - circuit ratio, and take the current grid - forming energy - storage capacity configured at the low - voltage bus of the target new - energy collection station as the grid - forming energy - storage capacity of the source - grid - load - storage system in the grid - connected operation mode.

[0053] In the embodiments of the present application, there are also two judgment conditions. One is that the short - circuit ratios of all new - energy grid - connection points of the source - grid - load - storage system in the grid - connected operation mode are all greater than the first preset short - circuit ratio, and there is a new - energy multi - station short - circuit ratio of the source - grid - load - storage system in the grid - connected operation mode that is not greater than the second preset short - circuit ratio. The other is that there is a new - energy grid - connection point short - circuit ratio of the source - grid - load - storage system in the grid - connected operation mode that is not greater than the first preset short - circuit ratio, and there is a new - energy multi - station short - circuit ratio of the source - grid - load - storage system in the grid - connected operation mode that is not greater than the second preset short - circuit ratio.

[0054] For the first case, if the short - circuit ratios (ESCR) of all new - energy grid - connection points of the source - grid - load - storage system in the grid - connected operation mode are all greater than the first preset short - circuit ratio (SCR) 1 , and there is a new - energy multi - station short - circuit ratio (MRSCR) i of the source - grid - load - storage system in the grid - connected operation mode that is not greater than the second preset short - circuit ratio (SCR) 2 , that is, ESCR i > SCR 1 , and, MRSCR i ≤SCR 2 , then configure any alternative network - forming energy - storage capacity S 0 in the target new - energy power station. Among them, the target new - energy power station is the new - energy power station in the source - grid - load - storage system in the grid - connected operation mode whose new - energy multi - station short - circuit ratio is not greater than the second preset short - circuit ratio.

[0055] Calculate the new - energy multi - station short - circuit ratio of the current source - grid - load - storage system after configuring the network - forming energy - storage capacity S 0 in the target new - energy power station. If the current source - grid - load - storage system has a new - energy multi - station short - circuit ratio that is not greater than the second preset short - circuit ratio, that is then recalculate the current network - forming energy - storage capacity of the target new - energy power station with ΔS as the first capacity step, that is, (S 0 +ΔS), and return to calculate the new - energy multi - station short - circuit ratio of the current source - grid - load - storage system after configuring the network - forming energy - storage capacity S 0 in the target new - energy power station. This step continues to be executed until all the new - energy multi - station short - circuit ratios of the current source - grid - load - storage system are greater than the second preset short - circuit ratio to end the iteration, that is and take the current network - forming energy - storage capacity configured in the target new - energy power station as the network - forming energy - storage capacity of the source - grid - load - storage system in the grid - connected operation mode, that is, S 1 = S 0 + kΔS, where k is the number of iterations.

[0056] For the second case, if the short-circuit ratio of the new energy connection point (ESCR) of the source-grid-load-storage system in the grid-connected operation mode is not greater than the first preset short-circuit ratio (SCR) 1 , and the multi-station short-circuit ratio of new energy (MRSCR) of the source-grid-load-storage system in the grid-connected operation mode i is not greater than the second preset short-circuit ratio (SCR) 2 , that is, ESCR i ≤SCR 1 , and MRSCR i ≤SCR 2 , then configure any alternative network-forming energy storage capacity S h0 at the low-voltage bus of the target new energy collection station. Among them, the low-voltage bus of the target new energy collection station is the low-voltage bus of the new energy collection station in the source-grid-load-storage system in the grid-connected operation mode where the short-circuit ratio of the new energy connection point is not greater than the first preset short-circuit ratio.

[0057] Calculate the short-circuit ratio of the new energy connection point of the current source-grid-load-storage system after configuring the network-forming energy storage capacity S h0 at the low-voltage bus of the target new energy collection station If the current source-grid-load-storage system has a short-circuit ratio of the new energy connection point not greater than the first preset short-circuit ratio, that is then recalculate the current network-forming energy storage capacity at the low-voltage bus of the target new energy collection station with △S h as the second capacity step, that is, (S h0 +△S h ), and return to calculate the short-circuit ratio of the new energy connection point of the current source-grid-load-storage system after configuring the network-forming energy storage capacity S h0 at the low-voltage bus of the target new energy collection station. This step continues to execute until all short-circuit ratios of the new energy connection points of the current source-grid-load-storage system are greater than the first preset short-circuit ratio to end the iteration, that is then determine the current network-forming energy storage capacity configured at the low-voltage bus of the target new energy collection station, that is, (S h 0 + kΔS h ), where k is the number of iterations.

[0058] Calculate the multi-station short-circuit ratio of new energy of the source-grid-load-storage system after configuring the current network-forming energy storage capacity at the low-voltage bus of the target new energy collection station If all multi-station short-circuit ratios of new energy of the source-grid-load-storage system after configuring the current network-forming energy storage capacity are greater than the second preset short-circuit ratio, that is then take the current network-forming energy storage capacity configured at the low-voltage bus of the target new energy collection station as the network-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode, that is, S 1 =Sh 0 + k△S h .

[0059] If the source-grid-load-storage system after configuring the current network-forming energy storage capacity has new energy multi-stations with a short-circuit ratio not greater than a second preset short-circuit ratio, that is Then return to step 101 and continue to execute until the short-circuit ratios of all new energy multi-stations in the source-grid-load-storage system after configuring the current network-forming energy storage capacity are greater than the second preset short-circuit ratio, and the iteration ends, that is Take the current network-forming energy storage capacity configured at the low-voltage bus of the target new energy collection station as the network-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode.

[0060] In step 103, with the goal of maximizing the consumption of new energy, calculate the energy storage capacity in the islanded operation mode.

[0061] Among them, the source-grid-load-storage system is in the grid-connected operation mode or for the islanded operation mode, the switch state of the new energy grid connection point is used as the judgment basis. If the switch state of the new energy grid connection point is open, it is determined that the source-grid-load-storage system is in the islanded operation mode. If the switch state of the new energy grid connection point is closed, it is determined that the source-grid-load-storage system is in the grid-connected operation mode.

[0062] In the embodiment of the present application, considering the power and energy balance of the source-grid-load-storage system in the islanded operation mode, and with the goal of maximizing the consumption of new energy as the control target, optimize and calculate the energy storage capacity S of the source-grid-load-storage system in the islanded operation mode 2 And the starting scale in the islanded operation mode. Among them, in the embodiment of the present application, the optimization calculation methods include but are not limited to the branch and bound method, the artificial intelligence method, and the cutting plane method, and are not limited thereto.

[0063] Among them, optimizing the calculation of the starting scale in the islanded operation mode is to verify whether the power and energy of the source-grid-load-storage system in the islanded operation mode are balanced, and the power and energy balance analysis of the source-grid-load-storage system in the islanded operation mode is to calculate the required photovoltaic capacity and / or wind power capacity of the source-grid-load-storage system in the islanded operation mode, so as to determine the required capacity range of the energy storage capacity S of the source-grid-load-storage system in the islanded operation mode 2 The required capacity range.

[0064] In a possible implementation manner, step 103 may include:

[0065] Based on the power and energy balance of the source-grid-load-storage system in the islanded operation mode, and using the maximization of new energy consumption calculated by the second formula as the control target, calculate the energy storage capacity of the source-grid-load-storage system in the islanded operation mode;

[0066] The second formula is:

[0067]

[0068] Among them, maxf is to maximize the accommodation of new energy, and P WT (t) is the power output of wind power at time t, and P PV (t) is the power output of photovoltaic power at time t, and T is the time range.

[0069] In the embodiment of the present application, under the condition of ensuring the power balance of the source-network-load-storage system based on the island operation mode, the maximum accommodation system energy calculated by the second formula is used as the control target, and the energy storage capacity S of the source-network-load-storage system in the island operation mode is calculated 2 . Among them, the control target is also the constraint condition for calculating the energy storage capacity of the source-network-load-storage system in the island operation mode.

[0070] Among them, the constraint conditions for the source-network-load-storage system include but are not limited to the spinning reserve constraint of the source-network-load-storage system, the primary frequency regulation capacity constraint of the source-network-load-storage system, the power balance constraint of the source-network-load-storage system, the unit output constraint, the tie-line power constraint, the unit ramp rate constraint, the minimum continuous start-stop constraint, the energy storage charge-discharge power constraint, and the energy storage power constraint.

[0071] The following constraints are taken at any moment section, and the relevant conditions should be met:

[0072] (1) Spinning reserve constraint of the source-network-load-storage system:

[0073]

[0074]

[0075] Among them, P n-max is the upper limit of the output of the nth conventional unit, and P n-min is the lower limit of the output of the nth conventional unit, and P WT (t) is the wind power output at time t, and P PV (t) is the photovoltaic output at time t, and P L (t) is the total load at time t, and P re is the positive spinning reserve required by the source-network-load-storage system, and N re is the negative spinning reserve required by the source-network-load-storage system. (2) Primary frequency regulation capacity constraint of the source-network-load-storage system:

[0076]

[0077]

[0078] Among them, fp up is the upward primary frequency regulation space proposed for the entire base, and fp down is the downward primary frequency regulation space proposed for the entire base, and fp up-snFor the nth thermal power unit, the previous frequency space is fp down-sn For the nth thermal power unit, the next frequency space is fp up-hn For the nth hydropower unit, the previous frequency regulation space is fp down-hn For the nth hydropower unit, the next frequency regulation space. It should be noted that at this time, the participation of new energy in primary frequency regulation is not considered, and its frequency regulation ability is mainly provided by energy storage. When the next frequency regulation limit condition cannot be met, the participation of new energy in primary frequency regulation ability can be released.

[0079] (3) Power balance constraint of the source-network-load-energy storage system:

[0080]

[0081] Among them, P h (t, n) is the output of the nth hydropower unit at time t, and L(t, n) is the power of the nth tie line at time t.

[0082] (4) Unit output constraint:

[0083] P n-min ≤P(t, n)S(t, n)≤P n-max .

[0084] (5) Tie line power constraint:

[0085] L n-min ≤L(t, n)≤L n-max

[0086] Among them, L n-min is the lower limit of the transmission capacity of the nth tie line, and L n-max is the upper limit of the transmission capacity of the nth tie line.

[0087] (6) Unit ramp rate constraint:

[0088]

[0089]

[0090] Among them, is the maximum downward ramp rate of the unit when it is in the operating state, is the maximum downward ramp rate of the unit when it is about to be shut down, is the maximum upward ramp rate during the unit operation process, is the maximum upward ramp rate of the unit when it is about to be started up.

[0091] (7) Minimum continuous start-stop constraint:

[0092] S(t + k, n) ≥ S(t, n) - S(t - 1, n) for k = 1, 2, …, T omin -1

[0093] 1 - S(t + k, n) ≥ S(t - 1, n) - S(t, n) for k = 1, 2, …, T smin -1

[0094] where T omin is the minimum continuous startup time limit of the thermal power unit, and T smin is the minimum continuous shutdown time limit of the thermal power unit.

[0095] (8) Energy storage charge and discharge power constraint:

[0096]

[0097]

[0098] where S bat (t) is the energy storage charge and discharge state during this period, 1 for charging and 0 for discharging, is the maximum power limit for energy storage charging, is the maximum power limit for energy storage discharging.

[0099] (9) Energy storage power capacity constraint:

[0100] E min ≤ E(t) ≤ E max

[0101]

[0102] where η is the energy storage battery efficiency. To consider the impact of deep discharge on the battery, the maximum depth of discharge is taken into account this time.

[0103] In step 104, in the islanded operation mode, calculate the short - circuit ratio of multiple new - energy multi - station corresponding to the source - grid - load - storage system under various alternative grid - forming energy storage capacities; and when the short - circuit ratio of the new - energy multi - station in the islanded operation mode reaches the corresponding control target, take the corresponding alternative grid - forming energy storage capacity as the grid - forming energy storage capacity in the islanded operation mode.

[0104] In the embodiment of the present application, in the islanded operation mode, based on different grid - forming energy storage capacities, calculate the short - circuit ratio MRSCR′ of the source - grid - load - storage system corresponding to different grid - forming energy storage capacities, and when the short - circuit ratio MRSCR′ of the new - energy in the source - grid - load - storage system in the islanded operation mode reaches the corresponding control target, take the corresponding alternative grid - forming energy storage capacity as the grid - forming energy storage capacity S of the source - grid - load - storage system in the islanded operation mode 3 .

[0105] Among them, the set values mainly refer to the relevant standard requirements: Article 6.12.3 of GB / T 40581-2021 "Code for Safety and Stability Calculation of Power Systems" stipulates that for the case of multiple new energy power stations connected to an AC system, the short-circuit ratio of multiple new energy power stations at the low-voltage side of the step-up transformer of the new energy power generation unit should not be less than 1.5, and the short-circuit ratio of multiple new energy power stations at the new energy grid connection point should not be less than 2.0 and preferably greater than 3.0. Among them, the control target of the short-circuit ratio of multiple new energy power stations in the islanded operation mode can be the same as or different from that in the grid-connected operation mode, and this application does not make any restrictions.

[0106] In a possible implementation manner, step 104 may include:

[0107] Determine whether all the short-circuit ratios of multiple new energy power stations in the source-grid-load-storage system in the islanded operation mode are greater than a third preset short-circuit ratio;

[0108] If all the short-circuit ratios of multiple new energy power stations in the source-grid-load-storage system in the islanded operation mode are greater than the third preset short-circuit ratio, then use the corresponding alternative grid-forming energy storage capacity as the grid-forming energy storage capacity of the source-grid-load-storage system in the islanded operation mode;

[0109] If there is a short-circuit ratio of multiple new energy power stations in the source-grid-load-storage system in the islanded operation mode that is not greater than the third preset short-circuit ratio, then configure any alternative grid-forming energy storage capacity at the target new energy power station; the target new energy power station is the new energy power station in the source-grid-load-storage system in the islanded operation mode whose short-circuit ratio of multiple new energy power stations is not greater than the third preset short-circuit ratio;

[0110] Calculate the short-circuit ratio of multiple new energy power stations in the current source-grid-load-storage system. If there is a short-circuit ratio of multiple new energy power stations in the current source-grid-load-storage system that is not greater than the third preset short-circuit ratio, then update the current grid-forming energy storage capacity of the target new energy power station according to the third capacity step, and return to the step of calculating the short-circuit ratio of multiple new energy power stations in the current source-grid-load-storage system to continue execution until all the short-circuit ratios of multiple new energy power stations in the current source-grid-load-storage system are greater than the third preset short-circuit ratio, and use the current grid-forming energy storage capacity configured at the target new energy power station as the grid-forming energy storage capacity of the source-grid-load-storage system in the islanded operation mode.

[0111] According to the short-circuit ratio MRSCR' of multiple new energy power stations in the source-grid-load-storage system in the islanded operation mode, determine whether all the short-circuit ratios MRSCR' of multiple new energy power stations in the source-grid-load-storage system in the islanded operation mode are greater than the third preset short-circuit ratio SCR 3 , that is, MRSCR' i > SCR 3 .

[0112] If all the short - circuit ratios MRSCR′ of the new - energy multi - station in the source - grid - load - storage system operating in the islanded mode are greater than the third preset short - circuit ratio SCR 3 , that is, MRSCR′ i >SCR 3 , then the corresponding alternative grid - forming energy - storage capacity S 31 is used as the grid - forming energy - storage capacity S of the source - grid - load - storage system in the islanded mode 3 , that is, S 3 =S 31 .

[0113] If there is a new - energy multi - station short - circuit ratio MRSCR′ in the source - grid - load - storage system operating in the islanded mode i not greater than the third preset short - circuit ratio SCR 3 , that is, MRSCR′ i ≤SCR 3 , then any alternative grid - forming energy - storage capacity S′ 0 is configured in the target new - energy station, where the target new - energy station is the new - energy station in the source - grid - load - storage system operating in the islanded mode with a new - energy multi - station short - circuit ratio not greater than the third preset short - circuit ratio.

[0114] Calculate the new - energy multi - station short - circuit ratio MRSCR″ 0 of the current source - grid - load - storage system after configuring the grid - forming energy - storage capacity S′ i in the target new - energy station. If there is a new - energy multi - station short - circuit ratio in the current source - grid - load - storage system not greater than the third preset short - circuit ratio, that is, MRSCR″ i ≤SCR 3 , then recalculate the current grid - forming energy - storage capacity of the target new - energy station with ΔS′ as the third capacity step, that is, (S′ 0 +ΔS′), and return to calculate the new - energy multi - station short - circuit ratio MRSCR″ 0 of the current source - grid - load - storage system after configuring the grid - forming energy - storage capacity S′ i This step continues to be executed until all the new - energy multi - station short - circuit ratios of the current source - grid - load - storage system are greater than the third preset short - circuit ratio to end the iteration, that is, MRSCR″ i >SCR 3 , and the current grid - forming energy - storage capacity configured in the target new - energy station is used as the grid - forming energy - storage capacity of the source - grid - load - storage system in the islanded mode, that is, S 3 =S′ 0 +kΔS′, where k is the number of iterations.

[0115] In step 105, the target grid-forming energy storage capacity is obtained based on the grid-forming energy storage capacity in the grid-connected operation mode, the energy storage capacity in the islanded operation mode, and the grid-forming energy storage capacity in the islanded operation mode.

[0116] According to the grid-forming energy storage capacity S of the source-grid-load-storage system in the grid-connected operation mode in step 102 1 and the energy storage capacity S of the source-grid-load-storage system in the islanded operation mode in step 103 2 and the grid-forming energy storage capacity S of the source-grid-load-storage system in the islanded operation mode in step 104 3 , determine the target grid-forming energy storage capacity S of the source-grid-load-storage system n .

[0117] In a possible implementation, step 105 may include:

[0118] If the maximum value of the grid-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode and the grid-forming energy storage capacity of the source-grid-load-storage system in the islanded operation mode is greater than the energy storage capacity in the islanded operation mode, then take the maximum value of the grid-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode and the grid-forming energy storage capacity of the source-grid-load-storage system in the islanded operation mode as the target grid-forming energy storage capacity;

[0119] If the maximum value of the grid-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode and the grid-forming energy storage capacity of the source-grid-load-storage system in the islanded operation mode is less than the energy storage capacity in the islanded operation mode, then take the maximum value of the grid-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode and the grid-forming energy storage capacity of the source-grid-load-storage system in the islanded operation mode as the first grid-forming energy storage capacity, take the difference between the energy storage capacity in the islanded operation mode and the maximum value as the conventional energy storage capacity, and take the sum of the first grid-forming energy storage capacity and the grid-forming energy storage capacity as the target grid-forming energy storage capacity.

[0120] In the embodiment of the present application, select the maximum value of the grid-forming energy storage capacity S of the source-grid-load-storage system in the grid-connected operation mode 1 and the grid-forming energy storage capacity S of the source-grid-load-storage system in the islanded operation mode as S 3 , and determine whether the maximum value S m is greater than the energy storage capacity S of the source-grid-load-storage system in the islanded operation mode m . If the maximum value S 2 is greater than the energy storage capacity S of the source-grid-load-storage system in the islanded operation mode m , then take the maximum value S 2 as the target grid-forming energy storage capacity S m , and all are configured as grid-forming energy storage; if the maximum value S n , and all are configured as grid-forming energy storage; if the maximum value S mLess than the energy storage capacity S of the source-grid-load-storage system in the islanded operation mode 2 , then take the maximum value S m as the first grid-forming energy storage capacity S I , and take the difference between the energy storage capacity S of the source-grid-load-storage system in the islanded operation mode 2 minus the maximum value S m as the conventional energy storage capacity S II , that is, S II = S 2 - S m = S 2 - max(S 1 , S 3 ), and then take the sum of the first grid-forming energy storage capacity S I and the conventional energy storage capacity S II as the target grid-forming energy storage capacity S n , that is, S n = S I + S II .

[0121] In a possible implementation, substitute the target grid-forming energy storage capacity S n into the source-grid-load-storage system for transient fault scanning calculation. If the scanning calculation result does not meet the safety and stability requirements of the source-grid-load-storage system, return to step 101 to continue execution, increase the grid-forming energy storage capacity until the scanning calculation result meets the safety and stability requirements of the source-grid-load-storage system, and determine the target grid-forming energy storage capacity as the final grid-forming energy storage capacity of the source-grid-load-storage system.

[0122] Among them, the fault set considered in the transient fault scanning calculation mainly includes: faults such as near-area DC commutation failure, monopole blocking, converter line N-1, main transformer N-1, etc. The assessment criteria include frequency, voltage, and power angle stability. In the embodiments of the present application, the transient fault scanning calculation can be modeled based on mainstream electromechanical and electromagnetic transient simulation platforms, including but not limited to BPA, PSASP, PSCAD, etc., and the present application does not limit this.

[0123] The steps of the transient fault scanning calculation are as follows:

[0124] Set the fault set: mainly including line, main transformer N-1 fault, N-2 fault, double-circuit line N-2 fault, etc.; based on large power grid simulation tools such as PSASP and BPA, conduct one-by-one scanning calculations based on the fault set; judge whether the source-grid-load-storage system can maintain stability after each fault.

[0125] The present application provides a method for optimizing the capacity of a network-forming energy storage. When the short-circuit ratios of the new energy connection points and the short-circuit ratios of multiple new energy stations in the source-network-load-storage system under the grid-connected operation mode reach their respective control targets, the capacity of the network-forming energy storage under the grid-connected operation mode is determined. By taking the maximization of new energy consumption as the control target, the energy storage capacity under the islanded operation mode is determined, and when the short-circuit ratio of multiple new energy stations in the source-network-load-storage system under the islanded operation mode reaches the corresponding control target, the capacity of the network-forming energy storage under the islanded operation mode is determined. Finally, the target network-forming energy storage capacity is determined based on the capacity of the network-forming energy storage under the grid-connected operation mode, the energy storage capacity under the islanded operation mode, and the capacity of the network-forming energy storage under the islanded operation mode. Without affecting the power balance of the power grid, it not only meets the short-circuit capacity support of the new energy power station but also meets the capacity requirements of the new energy power station under the grid-connected operation mode and the islanded operation mode, improving the stability of new energy connected to the grid.

[0126] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0127] The following is an apparatus embodiment of the present application. For the details not described in detail, reference can be made to the corresponding method embodiment above.

[0128] Figure 2 The structural schematic diagram of the network-forming energy storage capacity optimization device provided by the embodiment of the present application is shown. For the sake of convenience of description, only the parts related to the embodiment of the present application are shown and are described in detail as follows:

[0129] As Figure 2 shown, the network-forming energy storage capacity optimization device 2 includes:

[0130] A first calculation module 21, configured to calculate the short-circuit ratios of the new energy connection points and the short-circuit ratios of multiple new energy stations corresponding to multiple alternative network-forming energy storage capacities in the source-network-load-storage system under the grid-connected operation mode;

[0131] A first capacity determination module 22, configured to use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity under the grid-connected operation mode when the short-circuit ratios of the new energy connection points and the short-circuit ratios of multiple new energy stations under the grid-connected operation mode reach their respective control targets;

[0132] A second calculation module 23, configured to calculate the energy storage capacity under the islanded operation mode with the maximization of new energy consumption as the control target;

[0133] The second capacity determination module 24 is configured to calculate the short-circuit ratios of multiple new energy multi-station fields corresponding to the source-network-load-storage system under various alternative grid-forming energy storage capacities in the island operation mode; and when the short-circuit ratios of the new energy multi-station fields in the island operation mode reach the corresponding control targets, use the corresponding alternative grid-forming energy storage capacity as the grid-forming energy storage capacity in the island operation mode;

[0134] The determination module 25 is configured to obtain the target grid-forming energy storage capacity according to the grid-forming energy storage capacity in the grid-connected operation mode, the energy storage capacity in the island operation mode, and the grid-forming energy storage capacity in the island operation mode.

[0135] This application provides a grid-forming energy storage capacity optimization device. When the short-circuit ratios of the new energy connection points and the new energy multi-station fields of the source-network-load-storage system in the grid-connected operation mode both reach their respective control targets, the grid-forming energy storage capacity in the grid-connected operation mode is determined. By taking maximizing the consumption of new energy as the control target, the energy storage capacity in the island operation mode is determined, and when the short-circuit ratio of the new energy multi-station fields of the source-network-load-storage system in the island operation mode reaches the corresponding control target, the grid-forming energy storage capacity in the island operation mode is determined. Finally, the target grid-forming energy storage capacity is determined through the grid-forming energy storage capacity in the grid-connected operation mode, the energy storage capacity in the island operation mode, and the grid-forming energy storage capacity in the island operation mode. Without affecting the power balance of the power grid, it not only meets the short-circuit capacity support of the new energy power station but also meets the capacity requirements of the new energy power station in the grid-connected operation mode and the island operation mode, improving the stability of the new energy connected to the grid.

[0136] In a possible implementation manner, in the grid-connected operation mode, calculating the short-circuit ratios of the new energy multi-station fields corresponding to the source-network-load-storage system under various alternative grid-forming energy storage capacities includes:

[0137] Calculating the short-circuit ratios of the new energy multi-station fields corresponding to the source-network-load-storage system under various alternative grid-forming energy storage capacities through the first formula. The first formula is:

[0138]

[0139] where MRSCR i is the short-circuit ratio of the i-th new energy multi-station field, is the nominal voltage of the i-th grid-connected bus node, is the voltage generated by the new energy power generation at the i-th node, is the short-circuit current provided by the i-th new energy power generation equipment, is the equivalent impedance.

[0140] In a possible implementation manner, the first capacity determination module is specifically configured to:

[0141] Determine whether the short-circuit ratios of all new energy grid connection points of the source-grid-load-storage system in the grid-connected operation mode are all greater than the first preset short-circuit ratio, and whether the short-circuit ratios of all new energy multi-station of the source-grid-load-storage system in the grid-connected operation mode are all greater than the second preset short-circuit ratio;

[0142] If the short-circuit ratios of all new energy grid connection points of the source-grid-load-storage system in the grid-connected operation mode are all greater than the first preset short-circuit ratio, and the short-circuit ratios of all new energy multi-station of the source-grid-load-storage system in the grid-connected operation mode are all greater than the second preset short-circuit ratio, then use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode.

[0143] In a possible implementation, the first capacity determination module is further configured to:

[0144] If the short-circuit ratios of all new energy grid connection points of the source-grid-load-storage system in the grid-connected operation mode are all greater than the first preset short-circuit ratio, and there is a new energy multi-station short-circuit ratio of the source-grid-load-storage system in the grid-connected operation mode that is not greater than the second preset short-circuit ratio, then configure any alternative network-forming energy storage capacity at the target new energy station; the target new energy station is a new energy station in the source-grid-load-storage system in the grid-connected operation mode whose new energy multi-station short-circuit ratio is not greater than the second preset short-circuit ratio;

[0145] Calculate the short-circuit ratio of the new energy multi-station of the current source-grid-load-storage system. If there is a new energy multi-station short-circuit ratio of the current source-grid-load-storage system that is not greater than the second preset short-circuit ratio, then update the current network-forming energy storage capacity of the target new energy station according to the first capacity step size, and return to the step of calculating the short-circuit ratio of the new energy multi-station of the current source-grid-load-storage system to continue execution until the short-circuit ratios of all new energy multi-station of the current source-grid-load-storage system are all greater than the second preset short-circuit ratio, and use the current network-forming energy storage capacity configured at the target new energy station as the network-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode;

[0146] If there is a new energy grid connection point short-circuit ratio of the source-grid-load-storage system in the grid-connected operation mode that is not greater than the first preset short-circuit ratio, and there is a new energy multi-station short-circuit ratio of the source-grid-load-storage system in the grid-connected operation mode that is not greater than the second preset short-circuit ratio, then configure any alternative network-forming energy storage capacity at the low-voltage bus of the target new energy collection station; the low-voltage bus of the target new energy collection station is the low-voltage bus of the new energy collection station with the lowest new energy grid connection point short-circuit ratio in the source-grid-load-storage system in the grid-connected operation mode;

[0147] Calculate the short - circuit ratio of the new - energy grid - connection point of the current source - network - load - storage system. If there is a new - energy grid - connection point in the current source - network - load - storage system whose short - circuit ratio is not greater than the first preset short - circuit ratio, update the current grid - forming energy - storage capacity of the low - voltage bus of the target new - energy collection station according to the second capacity step, and return to the step of calculating the short - circuit ratio of the new - energy grid - connection point of the current source - network - load - storage system to continue execution until the short - circuit ratios of all new - energy grid - connection points of the current source - network - load - storage system are greater than the first preset short - circuit ratio, and determine the current grid - forming energy - storage capacity configured on the low - voltage bus of the target new - energy collection station;

[0148] Calculate the short - circuit ratio of multiple new - energy stations of the source - network - load - storage system after configuring the current grid - forming energy - storage capacity. If the short - circuit ratios of all multiple new - energy stations of the source - network - load - storage system after configuring the current grid - forming energy - storage capacity are greater than the second preset short - circuit ratio, then use the current grid - forming energy - storage capacity configured on the low - voltage bus of the target new - energy collection station as the grid - forming energy - storage capacity of the source - network - load - storage system in the grid - connected operation mode;

[0149] If there is a short - circuit ratio of multiple new - energy stations of the source - network - load - storage system after configuring the current grid - forming energy - storage capacity that is not greater than the second preset short - circuit ratio, then return to the step of calculating the short - circuit ratio of the new - energy grid - connection point and the short - circuit ratio of multiple new - energy stations corresponding to multiple alternative grid - forming energy - storage capacities of the source - network - load - storage system in the grid - connected operation mode to continue execution until the short - circuit ratios of all multiple new - energy stations of the source - network - load - storage system after configuring the current grid - forming energy - storage capacity are greater than the second preset short - circuit ratio, and use the current grid - forming energy - storage capacity configured on the low - voltage bus of the target new - energy collection station as the grid - forming energy - storage capacity of the source - network - load - storage system in the grid - connected operation mode.

[0150] In a possible implementation manner, the second calculation module may specifically be used for:

[0151] Based on the power and electricity balance of the source - network - load - storage system in the island - grid operation mode, and taking the maximization of new - energy consumption calculated by the second formula as the control target, calculate the energy - storage capacity of the source - network - load - storage system in the island - grid operation mode;

[0152] The second formula is:

[0153]

[0154] Where maXf is the maximization of new - energy consumption, P WT (t) is the power output of wind power at time t, P PV (t) is the power output of photovoltaic power at time t, and T is the time range.

[0155] In a possible implementation manner, the second capacity determination module may specifically be used for:

[0156] Determine whether the short-circuit ratios of all new energy multi-stations in the source-grid-load-storage system operating in islanded mode are all greater than the third preset short-circuit ratio;

[0157] If the short-circuit ratios of all new energy multi-stations in the source-grid-load-storage system operating in islanded mode are all greater than the third preset short-circuit ratio, then use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity of the source-grid-load-storage system in islanded mode;

[0158] If there is a new energy multi-station in the source-grid-load-storage system operating in islanded mode whose short-circuit ratio is not greater than the third preset short-circuit ratio, then configure any alternative network-forming energy storage capacity at the target new energy station; the target new energy station is the new energy station in the source-grid-load-storage system operating in islanded mode whose short-circuit ratio of the new energy multi-station is not greater than the third preset short-circuit ratio;

[0159] Calculate the short-circuit ratio of the new energy multi-stations of the current source-grid-load-storage system. If there is a new energy multi-station in the current source-grid-load-storage system whose short-circuit ratio is not greater than the third preset short-circuit ratio, then update the current network-forming energy storage capacity of the target new energy station according to the third capacity step, and return to the step of calculating the short-circuit ratio of the new energy multi-stations of the current source-grid-load-storage system to continue execution until the short-circuit ratios of all new energy multi-stations of the current source-grid-load-storage system are all greater than the third preset short-circuit ratio, and use the current network-forming energy storage capacity configured at the target new energy station as the network-forming energy storage capacity of the source-grid-load-storage system in islanded mode.

[0160] In a possible implementation manner, the determining module may specifically be used for:

[0161] If the maximum value of the network-forming energy storage capacity of the source-grid-load-storage system in grid-connected operation mode and the network-forming energy storage capacity of the source-grid-load-storage system in islanded operation mode is greater than the energy storage capacity in islanded operation mode, then use the maximum value of the network-forming energy storage capacity of the source-grid-load-storage system in grid-connected operation mode and the network-forming energy storage capacity of the source-grid-load-storage system in islanded operation mode as the target network-forming energy storage capacity;

[0162] If the maximum value of the network-forming energy storage capacity of the source-grid-load-storage system in grid-connected operation mode and the network-forming energy storage capacity of the source-grid-load-storage system in islanded operation mode is less than the energy storage capacity in islanded operation mode, then use the maximum value of the network-forming energy storage capacity of the source-grid-load-storage system in grid-connected operation mode and the network-forming energy storage capacity of the source-grid-load-storage system in islanded operation mode as the first network-forming energy storage capacity, use the difference between the energy storage capacity in islanded operation mode and the maximum value as the conventional energy storage capacity, and use the sum of the first network-forming energy storage capacity and the network-forming energy storage capacity as the target network-forming energy storage capacity.

[0163] Figure 3 It is a schematic diagram of the terminal provided by the embodiments of the present application. AsFigure 3 As shown, the terminal 3 of this embodiment includes: a processor 30, a memory 31, and a computer program 32 stored in the memory 31 and executable on the processor 30. When the processor 30 executes the computer program 32, it implements the steps in the above-described embodiments of the network-forming energy storage capacity optimization method, such as Figure 1 the steps 101 to 105 shown. Alternatively, when the processor 30 executes the computer program 32, it implements the functions of each module / unit in the above-described device embodiments, such as Figure 2 the functions of the modules 21 to 25 shown.

[0164] Exemplarily, the computer program 32 can be divided into one or more modules. The one or more modules are stored in the memory 31 and executed by the processor 30 to complete this application. The one or more modules can be a series of computer program instruction segments capable of performing specific functions, and these instruction segments are used to describe the execution process of the computer program 32 in the terminal 3. For example, the computer program 32 can be divided into Figure 2 the modules 21 to 25 shown.

[0165] The terminal 3 can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal 3 may include, but is not limited to, a processor 30 and a memory 31. Those skilled in the art can understand that Figure 3 these are merely examples of the terminal 3 and do not constitute a limitation on the terminal 3. It may include more or fewer components than shown in the figure, or combine certain components, or have different components. For example, the terminal may further include input / output devices, network access devices, a bus, etc.

[0166] The so-called processor 30 may be a central processing unit (CPU), or may also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0167] The memory 31 may be an internal storage unit of the terminal 3, such as the hard disk or memory of the terminal 3. The memory 31 may also be an external storage device of the terminal 3, such as a plug-in hard disk equipped on the terminal 3, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Further, the memory 31 may also include both the internal storage unit of the terminal 3 and the external storage device. The memory 31 is used to store the computer program and other programs and data required by the terminal. The memory 31 may also be used to temporarily store the data that has been output or will be output.

[0168] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above division of each functional unit and module is used as an example. In practical applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiment and will not be elaborated herein.

[0169] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0170] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0171] In the embodiments provided in the present application, it should be understood that the disclosed device / terminal and method can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections between each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0172] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0173] In addition, in each embodiment of the present application, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0174] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above method embodiments, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above method embodiments for optimizing the capacity of the networked energy storage can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device that can carry the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0175] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for optimizing the capacity of a network-forming energy storage system, characterized in that, it includes: Under the grid-connected operation mode, calculate the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities; When the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations under the grid-connected operation mode reach their respective control targets, use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity under the grid-connected operation mode; with maximizing the consumption of new energy as the control target, calculate the energy storage capacity under the island operation mode; under the island operation mode, calculate the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities; And when the short-circuit ratio of multiple new energy stations under the island operation mode reaches the corresponding control target, use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity under the island operation mode; Based on the network-forming energy storage capacity under the grid-connected operation mode, the energy storage capacity under the island operation mode, and the network-forming energy storage capacity under the island operation mode, obtain the target network-forming energy storage capacity; Among them, under the grid-connected operation mode, calculating the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities includes: Calculate the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities through the first formula, and the first formula is: Among them, is the th short-circuit ratio of multiple new energy power stations, is the th nominal voltage of the grid-connected bus node, is the voltage generated by the new energy power generation at the th node, is the th short-circuit current provided by the new energy power generation equipment, is the equivalent impedance; Taking maximizing the consumption of new energy as the control target, calculating the energy storage capacity of the source-network-load-storage system under the island operation mode includes: Based on the power and energy balance of the source-network-load-storage system under the island operation mode, and using the maximum consumption of new energy calculated through the second formula as the control target, calculate the energy storage capacity of the source-network-load-storage system under the island operation mode; The second formula is: Among them, For maximizing the accommodation of new energy, is the power output of wind power at time, is the power output of photovoltaic at time, is the time range.

2. The method for optimizing the capacity of a network-forming energy storage system according to claim 1, characterized in that, When the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations under the grid-connected operation mode reach their respective control targets, using the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity under the grid-connected operation mode includes: Judge whether all the short-circuit ratios of the new energy connection points of the source-network-load-storage system under the grid-connected operation mode are greater than the first preset short-circuit ratio, and whether all the short-circuit ratios of multiple new energy stations of the source-network-load-storage system under the grid-connected operation mode are greater than the second preset short-circuit ratio; If all the short-circuit ratios of the new energy connection points of the source-network-load-storage system under the grid-connected operation mode are greater than the first preset short-circuit ratio, and all the short-circuit ratios of multiple new energy stations of the source-network-load-storage system under the grid-connected operation mode are greater than the second preset short-circuit ratio, then use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity of the source-network-load-storage system under the grid-connected operation mode.

3. The method for optimizing the capacity of a network-forming energy storage system according to claim 2, characterized in that, After determining whether all the short-circuit ratios of the new energy connection points of the source-network-load-storage system in the grid-connected operation mode are greater than a first preset short-circuit ratio, and whether all the short-circuit ratios of the new energy multi-station of the source-network-load-storage system in the grid-connected operation mode are greater than a second preset short-circuit ratio, the method further includes: If all the short-circuit ratios of the new energy connection points of the source-network-load-storage system in the grid-connected operation mode are greater than the first preset short-circuit ratio, and there is a new energy multi-station short-circuit ratio of the source-network-load-storage system in the grid-connected operation mode that is not greater than the second preset short-circuit ratio, then configure any alternative network-forming energy storage capacity at the target new energy station; the target new energy station is the new energy station in the source-network-load-storage system in the grid-connected operation mode whose new energy multi-station short-circuit ratio is not greater than the second preset short-circuit ratio; Calculate the new energy multi-station short-circuit ratio of the current source-network-load-storage system. If there is a new energy multi-station short-circuit ratio of the current source-network-load-storage system that is not greater than the second preset short-circuit ratio, then update the current network-forming energy storage capacity of the target new energy station in accordance with a first capacity step, and return to the step of calculating the new energy multi-station short-circuit ratio of the current source-network-load-storage system to continue execution until all the new energy multi-station short-circuit ratios of the current source-network-load-storage system are greater than the second preset short-circuit ratio, and use the current network-forming energy storage capacity configured at the target new energy station as the network-forming energy storage capacity of the source-network-load-storage system in the grid-connected operation mode; If there is a new energy connection point short-circuit ratio of the source-network-load-storage system in the grid-connected operation mode that is not greater than the first preset short-circuit ratio, and there is a new energy multi-station short-circuit ratio of the source-network-load-storage system in the grid-connected operation mode that is not greater than the second preset short-circuit ratio, then configure any alternative network-forming energy storage capacity at the low-voltage bus of the target new energy collection station; the low-voltage bus of the target new energy collection station is the low-voltage bus of the new energy collection station with the lowest new energy connection point short-circuit ratio in the source-network-load-storage system in the grid-connected operation mode; Calculate the new energy connection point short-circuit ratio of the current source-network-load-storage system. If there is a new energy connection point short-circuit ratio of the current source-network-load-storage system that is not greater than the first preset short-circuit ratio, then update the current network-forming energy storage capacity of the low-voltage bus of the target new energy collection station in accordance with a second capacity step, and return to the step of calculating the new energy connection point short-circuit ratio of the current source-network-load-storage system to continue execution until all the new energy connection point short-circuit ratios of the current source-network-load-storage system are greater than the first preset short-circuit ratio, and determine the current network-forming energy storage capacity configured at the low-voltage bus of the target new energy collection station; Calculate the new energy multi-station short-circuit ratio of the source-network-load-storage system after configuring the current network-forming energy storage capacity. If all the new energy multi-station short-circuit ratios of the source-network-load-storage system after configuring the current network-forming energy storage capacity are greater than the second preset short-circuit ratio, then use the current network-forming energy storage capacity configured at the low-voltage bus of the target new energy collection station as the network-forming energy storage capacity of the source-network-load-storage system in the grid-connected operation mode; If, after configuring the current network-forming energy storage capacity of the source-grid-load-storage system, the short-circuit ratios of multiple new energy power stations in the source-grid-load-storage system are not greater than the second preset short-circuit ratio, then return to the step of calculating the short-circuit ratios of new energy grid connection points and the short-circuit ratios of multiple new energy power stations in the source-grid-load-storage system under various alternative network-forming energy storage capacities in the grid-connected operation mode and continue to execute until all the short-circuit ratios of multiple new energy power stations in the source-grid-load-storage system after configuring the current network-forming energy storage capacity are greater than the second preset short-circuit ratio, and take the current network-forming energy storage capacity configured at the low-voltage bus of the target new energy collection station as the network-forming energy storage capacity of the source-grid-load-storage system in the grid-connected operation mode.

4. The method for optimizing the network-forming energy storage capacity according to claim 1, wherein, when the short-circuit ratios of multiple new energy power stations in the islanded operation mode reach the corresponding control targets, taking the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity in the islanded operation mode includes: judging whether all the short-circuit ratios of multiple new energy power stations in the source-grid-load-storage system in the islanded operation mode are greater than a third preset short-circuit ratio; if all the short-circuit ratios of multiple new energy power stations in the source-grid-load-storage system in the islanded operation mode are greater than the third preset short-circuit ratio, then taking the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity of the source-grid-load-storage system in the islanded operation mode; if there are short-circuit ratios of multiple new energy power stations in the source-grid-load-storage system in the islanded operation mode that are not greater than the third preset short-circuit ratio, then configure any alternative network-forming energy storage capacity at the target new energy power station; the target new energy power station is a new energy power station in the source-grid-load-storage system in the islanded operation mode whose short-circuit ratio of multiple new energy power stations is not greater than the third preset short-circuit ratio; calculate the short-circuit ratios of multiple new energy power stations in the current source-grid-load-storage system. If there are short-circuit ratios of multiple new energy power stations in the current source-grid-load-storage system that are not greater than the third preset short-circuit ratio, then update the current network-forming energy storage capacity of the target new energy power station according to the third capacity step length, and return to the step of calculating the short-circuit ratios of multiple new energy power stations in the current source-grid-load-storage system and continue to execute until all the short-circuit ratios of multiple new energy power stations in the current source-grid-load-storage system are greater than the third preset short-circuit ratio, and take the current network-forming energy storage capacity configured at the target new energy power station as the network-forming energy storage capacity of the source-grid-load-storage system in the islanded operation mode.

5. The method for optimizing the network-forming energy storage capacity according to claim 1, wherein, obtaining the target network-forming energy storage capacity according to the network-forming energy storage capacity in the grid-connected operation mode, the energy storage capacity in the islanded operation mode, and the network-forming energy storage capacity in the islanded operation mode includes: If the maximum value of the network-forming energy storage capacity of the source-network-load-storage system in the grid-connected operation mode and the network-forming energy storage capacity of the source-network-load-storage system in the islanded operation mode is greater than the energy storage capacity in the islanded operation mode, then the maximum value of the network-forming energy storage capacity of the source-network-load-storage system in the grid-connected operation mode and the network-forming energy storage capacity of the source-network-load-storage system in the islanded operation mode is used as the target network-forming energy storage capacity; If the maximum value of the network-forming energy storage capacity of the source-network-load-storage system in the grid-connected operation mode and the network-forming energy storage capacity of the source-network-load-storage system in the islanded operation mode is less than the energy storage capacity in the islanded operation mode, then the maximum value of the network-forming energy storage capacity of the source-network-load-storage system in the grid-connected operation mode and the network-forming energy storage capacity of the source-network-load-storage system in the islanded operation mode is used as the first network-forming energy storage capacity, the difference between the energy storage capacity in the islanded operation mode and the maximum value is used as the conventional energy storage capacity, and the sum of the first network-forming energy storage capacity and the network-forming energy storage capacity is used as the target network-forming energy storage capacity.

6. A device for optimizing the network-forming energy storage capacity Characterized in that Comprising: A first calculation module, configured to calculate the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities in the grid-connected operation mode; A first capacity determination module, configured to use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity in the grid-connected operation mode when the short-circuit ratio of the new energy connection point and the short-circuit ratio of multiple new energy stations in the grid-connected operation mode reach their respective control targets; A second calculation module, configured to calculate the energy storage capacity in the islanded operation mode with the control target of maximizing the consumption of new energy; A second capacity determination module, configured to calculate the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities in the islanded operation mode; And use the corresponding alternative network-forming energy storage capacity as the network-forming energy storage capacity in the islanded operation mode when the short-circuit ratio of multiple new energy stations in the islanded operation mode reaches the corresponding control target; A determination module, configured to obtain the target network-forming energy storage capacity of the source-network-load-storage system according to the network-forming energy storage capacity in the grid-connected operation mode, the energy storage capacity in the islanded operation mode, and the network-forming energy storage capacity in the islanded operation mode; Wherein, in the grid-connected operation mode, the first calculation module is used for: Calculating the short-circuit ratio of multiple new energy stations of the source-network-load-storage system corresponding to multiple alternative network-forming energy storage capacities through a first formula, and the first formula is: Among them, is the th short-circuit ratio of multiple new energy power stations, is the nominal voltage of the th grid-connected bus node, is the voltage generated by the new energy power generation at the th node, is the th short-circuit current provided by the new energy power generation equipment, is the equivalent impedance; The second calculation module is used for: Based on the power and energy balance of the source-network-load-storage system in the islanded operation mode, and using the maximization of new energy consumption calculated through a second formula as the control target, calculating the energy storage capacity of the source-network-load-storage system in the islanded operation mode; The second formula is: Among them, for maximizing the accommodation of new energy, is the power output of wind power at time, is the power output of photovoltaic power at time, is the time range.

7. A terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor Characterized in that When the processor executes the computer program, the steps of the network-constructing energy storage capacity optimization method according to any one of claims 1 to 5 above are implemented.

8. A computer-readable storage medium storing a computer program, wherein, when the computer program is executed by a processor, the steps of the network-constructing energy storage capacity optimization method according to any one of claims 1 to 5 above are implemented.

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