Energy storage fault ride-through parameter optimization method and system considering transient frequency recovery

Abstract

The invention discloses an energy storage fault ride-through parameter optimization method and system considering transient frequency recovery, and the method comprises the steps: calculating the equivalent impedance between each energy storage power station and each photovoltaic power station through a power system simulation program; according to the photovoltaic output and the energy storage charge-discharge state, optimizing the voltage threshold of the energy storage entering the low voltage ride-through state; and according to the voltage threshold value of the energy storage power station entering the low-voltage ride-through state, in combination with the equivalent impedance between each energy storage power station and each photovoltaic power station, optimizing a control strategy of the energy storage power station going out of the low-voltage ride-through state. According to the method, the problem of lack of an energy storage fault ride-through parameter optimization method can be solved, and support is provided for energy storage parameter optimization design of a high-proportion photovoltaic access system.

Description

Technical Field

[0001] The present invention relates to a method for optimizing parameters of an energy storage power station, and in particular to a method and system for optimizing parameters of an energy storage fault ride-through taking transient frequency recovery into consideration. Background Art

[0002] The huge power shock generated during the low-power penetration of renewable energy can cause the system transient frequency to exceed the limit, which has become one of the key factors restricting the safe and stable operation of power grids with a high proportion of renewable energy.

[0003] At present, new energy storage has begun to be promoted and applied in many regions, providing high-quality regulation resources for the system, especially in areas with a high proportion of photovoltaic access. The diurnal changes and random fluctuations of photovoltaic output largely rely on the balance of energy storage. Energy storage plays an important role in the safe and stable operation of high-proportion photovoltaic access to the power grid. However, similar to new energy, due to the safety constraints of its own equipment, energy storage will also enter a low voltage ride-through state under a short-circuit fault, introducing new short-term power shocks. Its impact on the stability of the power grid is closely related to its operating state and control strategy. At present, due to the short period of large-scale application of energy storage projects, the optimization of its grid-related parameters has not yet formed a clear plan.

[0004] In order to maximize the supporting capacity of energy storage and reduce the short-term power shock caused by the superposition of energy storage low penetration, it is necessary to optimize the energy storage low penetration control parameters. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a method and system for optimizing energy storage fault ride-through parameters taking transient frequency recovery into consideration, which can make up for the lack of energy storage fault ride-through parameter optimization methods, provide support for the optimal design of energy storage parameters for high-proportion photovoltaic access systems, and reduce short-term power shocks caused by the superposition of energy storage low ride-through.

[0006] Technical solution: The energy storage fault ride-through parameter optimization method considering transient frequency recovery of the present invention comprises:

[0007] The equivalent impedance between each energy storage power station and each photovoltaic power station is calculated using the power system simulation program. The impedance between energy storage power station i and photovoltaic power station j is recorded as Z ij , where i = 1, 2, ..., M, j = 1, 2, ..., N, M is the number of energy storage power stations, and N is the number of photovoltaic power stations;

[0008] According to the photovoltaic output and energy storage charging and discharging status, optimize the voltage threshold for energy storage to enter the low voltage ride-through state;

[0009] According to the voltage threshold of the energy storage power station entering the low voltage ride-through state, combined with the equivalent impedance between each energy storage power station and each photovoltaic power station, the control strategy of the energy storage power station exiting the low voltage ride-through state is optimized.

[0010] Furthermore, the voltage threshold for the energy storage to enter the low voltage ride-through state is optimized, including:

[0011] The output of photovoltaic power station j is recorded as P jset_PV ;

[0012] When the energy storage station is in the discharging state, the power of energy storage station i is recorded as P i_discharge :At this time, the voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmin ;

[0013] When the energy storage station is in the charging state, the power of energy storage station i is recorded as P i_charge :At this time, if The voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmax ;

[0014] if The voltage threshold at which each energy storage power station enters the low voltage ride-through state is determined according to the priority of the energy storage power station support demand.

[0015] Furthermore, the voltage threshold for each energy storage power station to enter the low voltage ride-through state is determined according to the priority of the energy storage power station support demand, including:

[0016] Calculate the support demand priority index S of each energy storage power station i , the priority index S of each energy storage power station support demand i Sorted from small to large, the voltage thresholds for the first m energy storage power stations to enter the low voltage ride-through state are all set to U Lmax The voltage thresholds for the other energy storage power stations to enter the low voltage ride-through state are all set to U Lmin Among them, U Lmax , U Lmin They are respectively the upper and lower limits of the voltage threshold for the energy storage power station to enter the low voltage ride-through state.

[0017] Furthermore, the energy storage power station supports the demand priority index S i The expression is as follows:

[0018]

[0019] The energy storage power station supports the demand priority index S i Sort from small to large, the kth position is recorded as S k , i=1,2,…,M;||Z ij || is the impedance between energy storage station i and photovoltaic station j, denoted by Z ij The modulus value of .

[0020] Furthermore, the method for determining m in the first m energy storage power stations is as follows:

[0021]

[0022] Furthermore, the upper limit U of the voltage threshold at which the energy storage power station enters the low voltage ride-through state Lmax The value ranges from 0.85pu to 0.9pu.

[0023] Furthermore, the control strategy for optimizing the low voltage ride-through state of the energy storage power station includes:

[0024] When the energy storage power station is in the discharging state, the energy storage power station adopts the control mode of immediate active power recovery after fault ride-through;

[0025] When the energy storage station is in charging state, the voltage threshold of low voltage ride-through is set to U Lmax The first m energy storage power stations in the ranking have the same active power recovery mode after fault ride-through as the photovoltaic power station; the voltage threshold of the remaining low voltage ride-through is set to U Lmin All energy storage power stations adopt a control mode in which active power is immediately restored after a fault is crossed.

[0026] Based on the same inventive concept, a system for optimizing energy storage fault ride-through parameters considering transient frequency recovery of the present invention comprises:

[0027] The equivalent impedance calculation module is used to calculate the equivalent impedance between each energy storage power station and each photovoltaic power station using the power system simulation program, and the impedance between the energy storage power station i and the photovoltaic power station j is recorded as Z ij , where i = 1, 2, ..., M, j = 1, 2, ..., N, M is the number of energy storage power stations, and N is the number of photovoltaic power stations;

[0028] The voltage threshold setting module is used to optimize the voltage threshold for the energy storage to enter the low voltage ride-through state according to the photovoltaic output and the energy storage charging and discharging state;

[0029] The control strategy determination module is used to optimize the control strategy of the energy storage station exiting the low voltage ride-through state according to the voltage threshold of the energy storage station entering the low voltage ride-through state and the equivalent impedance between each energy storage station and each photovoltaic station.

[0030] Furthermore, the voltage threshold for the energy storage to enter the low voltage ride-through state is optimized, including:

[0031] The output of photovoltaic power station j is recorded as P jset_PV ;

[0032] When the energy storage station is in the discharging state, the power of energy storage station i is recorded as P i_discharge :At this time, the voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmin ;

[0033] When the energy storage station is in the charging state, the power of energy storage station i is recorded as P i_charge :At this time, if The voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmax ;

[0034] if The voltage threshold at which each energy storage power station enters the low voltage ride-through state is determined according to the priority of the energy storage power station support demand.

[0035] Furthermore, the voltage threshold for each energy storage power station to enter the low voltage ride-through state is determined according to the priority of the energy storage power station support demand, including:

[0036] Calculate the support demand priority index S of each energy storage power station i , the priority index S of each energy storage power station support demand i Sorted from small to large, the voltage thresholds for the first m energy storage power stations to enter the low voltage ride-through state are all set to U Lmax The voltage thresholds for the other energy storage power stations to enter the low voltage ride-through state are all set to U Lmin Among them, U Lmax , U Lmin They are respectively the upper and lower limits of the voltage threshold for the energy storage power station to enter the low voltage ride-through state.

[0037] Furthermore, the energy storage power station supports the demand priority index S i The expression is as follows:

[0038]

[0039] The energy storage power station supports the demand priority index S i Sort from small to large, the kth position is recorded as S k , i=1,2,…,M;||Z ij || is the impedance between energy storage station i and photovoltaic station j, denoted by Z ij The modulus value of .

[0040] Furthermore, the method for determining m in the first m energy storage power stations is as follows:

[0041]

[0042] Furthermore, the upper limit U of the voltage threshold at which the energy storage power station enters the low voltage ride-through state Lmax The value ranges from 0.85pu to 0.9pu.

[0043] Furthermore, the control strategy for optimizing the low voltage ride-through state of the energy storage power station includes:

[0044] When the energy storage power station is in the discharging state, the energy storage power station adopts the control mode of immediate active power recovery after fault ride-through;

[0045] When the energy storage station is in charging state, the voltage threshold of low voltage ride-through is set to U Lmax The first m energy storage power stations in the ranking have the same active power recovery mode after fault ride-through as the photovoltaic power station; the voltage threshold of the remaining low voltage ride-through is set to U Lmin All energy storage power stations adopt a control mode in which active power is immediately restored after a fault is crossed.

[0046] Based on the same inventive concept, a device for optimizing energy storage fault ride-through parameters taking into account transient frequency recovery of the present invention comprises a processor and a memory, wherein the memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the electronic device implements the steps of the above-mentioned method for optimizing energy storage fault ride-through parameters taking into account transient frequency recovery.

[0047] Based on the same inventive concept, a computer-readable storage medium of the present invention stores a computer program thereon, and when the program is executed by a processor, the steps of the energy storage fault ride-through parameter optimization method considering transient frequency recovery as described above are implemented.

[0048] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are:

[0049] In order to solve the problem of transient frequency exceeding the limit caused by the power shock caused by the low-power breakdown of photovoltaic storage under short-circuit fault, the low-power breakdown parameters of energy storage are dynamically optimized according to the distance between energy storage and photovoltaic power station and the charging and discharging status of energy storage, which significantly reduces the risk of transient frequency exceeding the limit caused by the short-term power shock of low-power breakdown of photovoltaic storage under voltage drop, and provides a reference for the optimization of energy storage grid-related parameters of high-ratio photovoltaic storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a flow chart of a method for optimizing energy storage fault ride-through parameters taking transient frequency recovery into consideration disclosed in an embodiment of the present invention;

[0051] Figure 2 This is a comparison diagram of the effects before and after optimization disclosed in an embodiment of the present invention;

[0052] Figure 3 It is a structural schematic diagram of a system for optimizing energy storage fault ride-through parameters taking transient frequency recovery into consideration, disclosed in an embodiment of the present invention;

[0053] Figure 4 It is a structural schematic diagram of a device for optimizing energy storage fault ride-through parameters taking transient frequency recovery into consideration, disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It will be understood by those skilled in the art that the purposes and advantages that can be achieved with the present invention are not limited to the specific description of the above beneficial effects, and the above and other purposes that can be achieved by the present invention will be more clearly understood based on the following detailed description.

[0055] It should be understood by those skilled in the art that the exemplary components, systems and methods described in conjunction with the embodiments disclosed in the present invention can be implemented in hardware, software or a combination of the two. Whether it is implemented in hardware or software depends on the specific application and design of the technical solution. Professional and technical personnel can use different methods to implement the functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0056] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0057] Example 1

[0058] See also Figure 1 , Figure 1 1 is a flow chart of a method for optimizing energy storage fault ride-through parameters taking transient frequency recovery into consideration, disclosed in an embodiment of the present invention. Figure 1 The energy storage fault ride-through parameter optimization method described is applied to power systems, such as for optimizing low-fault ride-through control parameters of energy storage power stations, etc., and the embodiments of the present invention do not limit this. Figure 1 As shown, the energy storage fault ride-through parameter optimization method considering transient frequency recovery may include the following operations:

[0059] S1. Use the commonly used power system simulation program to calculate the equivalent impedance between each energy storage power station and each photovoltaic power station. The impedance between energy storage power station i and photovoltaic power station j is recorded as Z ij , where i = 1, 2, …, M, j = 1, 2, …, N, M is the number of energy storage power stations, and N is the number of photovoltaic power stations.

[0060] S2. According to the photovoltaic output and the energy storage charging and discharging status, optimize the voltage threshold for the energy storage to enter the low voltage ride-through state.

[0061] In one embodiment, optimizing the voltage threshold for energy storage to enter a low voltage ride-through state includes:

[0062] The output of photovoltaic power station j is recorded as Pjset_PV ;

[0063] When the energy storage station is in the discharging state, the power of energy storage station i is recorded as P i_discharge :At this time, the voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmin ;

[0064] When the energy storage station is in the charging state, the power of energy storage station i is recorded as P i_charge :At this time, if The voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmax ;

[0065] if The voltage threshold at which each energy storage power station enters the low voltage ride-through state is determined according to the priority of the energy storage power station support demand.

[0066] In one embodiment, the voltage threshold for each energy storage power station to enter the low voltage ride-through state is determined according to the priority of the energy storage power station support demand, including:

[0067] Calculate the support demand priority index S of each energy storage power station i , the priority index S of each energy storage power station support demand i Sorted from small to large, the voltage thresholds for the first m energy storage power stations to enter the low voltage ride-through state are all set to U Lmax The voltage thresholds for the other energy storage power stations to enter the low voltage ride-through state are all set to U Lmin Among them, U Lmax , U Lmin They are respectively the upper and lower limits of the voltage threshold for the energy storage power station to enter the low voltage ride-through state.

[0068] In this embodiment, the energy storage power station supports the demand priority index S i The expression is as follows:

[0069]

[0070] The energy storage power station supports the demand priority index S i Sort from small to large, the kth position is recorded as S k , i=1,2,…,M;||Z ij || is the impedance between energy storage station i and photovoltaic station j, denoted by Z ij The modulus value of .

[0071] In this embodiment, the method for determining m in the first m energy storage power stations is as follows:

[0072]

[0073] It should be noted that U Lmax, U Lmin The principles for determining the following are respectively:

[0074] U Lmax According to GB / T 36547-2018 Technical Regulations for the Connection of Electrochemical Energy Storage Systems to the Grid and GB / T34120-2017 Technical Specifications for Energy Storage Converters of Electrochemical Energy Storage Systems, the value is generally around 0.85pu to 0.9pu; U Lmin Determined based on equipment safety constraints and through research with equipment manufacturers.

[0075] S3. According to the voltage threshold of the energy storage power station entering the low voltage ride-through state, combined with the equivalent impedance between each energy storage power station and each photovoltaic power station, the control strategy of the energy storage power station exiting the low voltage ride-through state is optimized.

[0076] Optimize the control strategy of the energy storage power station when it exits the low voltage ride-through state, including:

[0077] When the energy storage power station is in the discharging state, the energy storage power station adopts the control mode of immediate active power recovery after fault ride-through;

[0078] When the energy storage station is in charging state, the voltage threshold of low voltage ride-through is set to U Lmax The first m energy storage power stations in the ranking have the same active power recovery mode after fault ride-through as the photovoltaic power station; the voltage threshold of the remaining low voltage ride-through is set to U Lmin All energy storage power stations adopt a control mode in which active power is immediately restored after a fault is crossed.

[0079] The present invention aims at the transient frequency over-limit problem caused by the power shock caused by the low penetration of photovoltaic energy storage under short-circuit fault, takes into account the different requirements for energy storage support performance under different operation modes of the power grid, and proposes a method for optimizing the low penetration parameters of energy storage, providing a reference for the optimization of grid-related parameters of energy storage in high-ratio photovoltaic energy storage systems.

[0080] In order to verify the beneficial effects of the above method, the beneficial effects are illustrated by comparing data. Based on the IEEE39 node transformation example (including 2 energy storage stations, charging state, charging load is 200MW; 3 photovoltaic stations, output is 100MW), the above method is implemented.

[0081] A method for optimizing energy storage fault ride-through parameters considering transient frequency recovery of the present invention comprises the following steps:

[0082] S1: Calculate the equivalent impedance between each energy storage power station and each photovoltaic power station, the impedance Z from energy storage power station 1 to each photovoltaic power station 1j The module values ​​are 0.020125, 0.005031, and 0.006071 respectively; the impedance Z from the energy storage station 2 to each photovoltaic power station 2jThe module values ​​are 0.005281, 0.019197, and 0.008038 respectively. The unit of the above impedance values ​​is pu.

[0083] S2: Optimize the voltage threshold for energy storage to enter the low voltage ride-through state;

[0084] In this example, the energy storage is in a charging state, and the upper and lower limits of the energy storage low penetration threshold are 0.9pu and 0.5pu respectively.

[0085] Energy storage power meets Then the priority index is calculated according to formula (1):

[0086] The support demand priority indexes of energy storage power station 1 and energy storage power station 2 are S1 = 0.010409 and S2 = 0.010839. Sorted from small to large, they are S1 and S2, so the priority of energy storage power station 1 is higher than that of energy storage power station 2.

[0087] When m=1, equation (2) is satisfied, and the voltage threshold for the energy storage station 1 to enter the low voltage ride-through state is set to U Lmax (i.e. 0.9pu), the voltage threshold for the energy storage station 2 to enter the low voltage ride-through state is set to U Lmin (i.e. 0.5pu).

[0088] S3: Optimize the control strategy of energy storage low penetration;

[0089] The active power recovery mode after fault ride-through of energy storage power station 1 is the same as that of photovoltaic power station; energy storage power station 2 adopts a control mode of immediate active power recovery after fault ride-through.

[0090] Based on the IEEE39 node transformation example, the effects before and after optimization are compared. The results show that the transient frequency changes are smaller after optimization, which is more conducive to transient frequency safety. The comparison effect before and after optimization is as follows: Figure 2 , which verifies the effectiveness of the method.

[0091] Example 2

[0092] See also Figure 3 , Figure 3 This is a schematic diagram of the structure of a system for optimizing energy storage fault ride-through parameters considering transient frequency recovery disclosed in an embodiment of the present invention. The system can optimize energy storage low-frequency ride-through control parameters, specifically including:

[0093] The equivalent impedance calculation module is used to calculate the equivalent impedance between each energy storage power station and each photovoltaic power station using the power system simulation program, and the impedance between the energy storage power station i and the photovoltaic power station j is recorded as Z ij , where i = 1, 2, ..., M, j = 1, 2, ..., N, M is the number of energy storage power stations, and N is the number of photovoltaic power stations;

[0094] The voltage threshold setting module is used to optimize the voltage threshold for the energy storage to enter the low voltage ride-through state according to the photovoltaic output and the energy storage charging and discharging state;

[0095] The control strategy determination module is used to optimize the control strategy of the energy storage station exiting the low voltage ride-through state according to the voltage threshold of the energy storage station entering the low voltage ride-through state and the equivalent impedance between each energy storage station and each photovoltaic station.

[0096] In an optional embodiment, a method for optimizing energy storage fault ride-through parameters taking into account transient frequency recovery includes: a) calculating the equivalent impedance between each energy storage power station and each photovoltaic power station; b) optimizing the voltage threshold for the energy storage to enter a low voltage ride-through state based on the photovoltaic output and the energy storage charging and discharging state; and c) optimizing the control strategy for the energy storage power station to exit the low voltage ride-through state.

[0097] In one embodiment, a voltage threshold setting module is used to optimize the voltage threshold for energy storage to enter a low voltage ride-through state, including:

[0098] The output of photovoltaic power station j is recorded as P jset_PV ;

[0099] When the energy storage station is in the discharging state, the power of energy storage station i is recorded as P i_discharge :At this time, the voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmin ;

[0100] When the energy storage station is in the charging state, the power of energy storage station i is recorded as P i_charge :At this time, if The voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmax ;

[0101] if The voltage threshold at which each energy storage power station enters the low voltage ride-through state is determined according to the priority of the energy storage power station support demand.

[0102] In one embodiment, the voltage threshold setting module is used to determine the voltage threshold for each energy storage power station to enter the low voltage ride-through state according to the priority of the energy storage power station support demand, including:

[0103] Calculate the support demand priority index S of each energy storage power station i , the priority index S of each energy storage power station support demand i Sorted from small to large, the voltage thresholds for the first m energy storage power stations to enter the low voltage ride-through state are all set to U Lmax The voltage thresholds for the other energy storage power stations to enter the low voltage ride-through state are all set to U Lmin Among them, U Lmax , ULmin They are respectively the upper and lower limits of the voltage threshold for the energy storage power station to enter the low voltage ride-through state.

[0104] In one embodiment, the voltage threshold setting module is used to calculate the energy storage power station support demand priority index S i The expression is as follows:

[0105]

[0106] The energy storage power station supports the demand priority index S i Sort from small to large, the kth position is recorded as S k , i=1,2,…,M;||Z ij || is the impedance between energy storage station i and photovoltaic station j, denoted by Z ij The modulus value of .

[0107] In one embodiment, the voltage threshold setting module is used to determine m of the first m energy storage power stations as follows:

[0108]

[0109] In one embodiment, in the control strategy determination module, the upper limit U of the voltage threshold at which the energy storage power station enters the low voltage ride-through state Lmax The value ranges from 0.85pu to 0.9pu.

[0110] In one embodiment, a control strategy determination module is used to optimize the control strategy of the energy storage power station when it exits the low voltage ride-through state, including:

[0111] When the energy storage power station is in the discharging state, the energy storage power station adopts the control mode of immediate active power recovery after fault ride-through;

[0112] When the energy storage station is in charging state, the voltage threshold of low voltage ride-through is set to U Lmax The first m energy storage power stations in the ranking have the same active power recovery mode after fault ride-through as the photovoltaic power station; the voltage threshold of the remaining low voltage ride-through is set to U Lmin All energy storage power stations adopt a control mode in which active power is immediately restored after a fault is crossed.

[0113] Example 3

[0114] See also Figure 4 , Figure 4 1 is a schematic diagram of a structure of a device for optimizing energy storage fault ride-through parameters taking transient frequency recovery into consideration, disclosed in an embodiment of the present invention. Figure 4 The described device can be applied to a power system, such as for optimizing low-breakdown control parameters of an energy storage power station, etc., and the embodiments of the present invention do not limit this.

[0115] like Figure 4 As shown, the device may include a processor and a memory, wherein the memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the electronic device implements the steps of the method described in the above embodiment and can achieve the technical effect consistent with the above method.

[0116] The memory may include computer system readable media in the form of volatile memory, such as random access memory (RAM) and / or cache memory. The device may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the memory may be used to read and write non-removable, non-volatile magnetic media (commonly referred to as a "hard drive"). A program / utility having a set (at least one) of program modules may be stored in, for example, the memory, such program modules including but not limited to an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include the implementation of a network environment. The program modules typically perform the functions and / or methods in the embodiments described herein.

[0117] The processor executes various functional applications and data processing by running the program stored in the memory, such as implementing the method provided in the first embodiment of the present invention.

[0118] Example 4

[0119] Embodiment 4 of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the method described in the above embodiment are implemented and the technical effect consistent with the above method can be achieved.

[0120] The computer storage medium of the embodiment of the present invention can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, a device or a device or used in combination with it.

[0121] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, which carry computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0122] The program code embodied on the computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0123] Computer program code for performing the operation of the present invention may be written in one or more programming languages ​​or combinations thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0124] Of course, the storage medium containing computer executable instructions provided by an embodiment of the present invention, whose computer executable instructions are not limited to the above method operations, can also execute related operations in the method provided by any embodiment of the present invention.

[0125] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for optimizing energy storage fault ride-through parameters considering transient frequency recovery, characterized in that: include: The equivalent impedance between each energy storage power station and each photovoltaic power station is calculated using the power system simulation program. The impedance between energy storage power station i and photovoltaic power station j is recorded as Z ij , where i = 1, 2, ..., M, j = 1, 2, ..., N, M is the number of energy storage power stations, and N is the number of photovoltaic power stations; According to the photovoltaic output and energy storage charging and discharging status, optimize the voltage threshold for energy storage to enter the low voltage ride-through state; According to the voltage threshold of the energy storage power station entering the low voltage ride-through state, combined with the equivalent impedance between each energy storage power station and each photovoltaic power station, the control strategy of the energy storage power station exiting the low voltage ride-through state is optimized.

2. The method for optimizing energy storage fault ride-through parameters considering transient frequency recovery according to claim 1 is characterized in that: Optimize the voltage threshold for energy storage to enter the low voltage ride-through state, including: The output of photovoltaic power station j is recorded as P jset_PV ; When the energy storage station is in the discharging state, the power of energy storage station i is recorded as P i_discharge :At this time, the voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmin , where U Lmin The lower limit of the voltage threshold for the energy storage power station to enter the low voltage ride-through state; When the energy storage station is in the charging state, the power of energy storage station i is recorded as P i_charge :At this time, if The voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmax Among them, U Lmax The upper limit of the voltage threshold for the energy storage power station to enter the low voltage ride-through state; if The voltage threshold at which each energy storage power station enters the low voltage ride-through state is determined according to the priority of the energy storage power station support demand.

3. The method for optimizing energy storage fault ride-through parameters considering transient frequency recovery according to claim 2 is characterized in that: The voltage threshold for each energy storage station to enter the low voltage ride-through state is determined according to the priority of the energy storage station support demand, including: Calculate the support demand priority index S of each energy storage power station i , the priority index S of each energy storage power station support demand i Sorted from small to large, the voltage thresholds for the first m energy storage power stations to enter the low voltage ride-through state are all set to U Lmax The voltage thresholds for the other energy storage power stations to enter the low voltage ride-through state are all set to U Lmin Among them, U Lmax , U Lmin They are respectively the upper and lower limits of the voltage threshold for the energy storage power station to enter the low voltage ride-through state.

4. The method for optimizing energy storage fault ride-through parameters considering transient frequency recovery according to claim 3 is characterized in that: Energy storage power station support demand priority index S i The expression is as follows: The energy storage power station supports the demand priority index S i Sort from small to large, the kth position is recorded as S k , i=1,2,…,M;||Z ij || is the impedance between energy storage station i and photovoltaic station j, that is, Z ij The modulus value of .

5. The method for optimizing energy storage fault ride-through parameters considering transient frequency recovery according to claim 3 is characterized in that: The method for determining m in the first m energy storage power stations is as follows:

6. The method for optimizing energy storage fault ride-through parameters considering transient frequency recovery according to claim 1, characterized in that: Optimize the control strategy of the energy storage power station when it exits the low voltage ride-through state, including: When the energy storage power station is in the discharging state, the energy storage power station adopts the control mode of immediate active power recovery after fault ride-through; When the energy storage station is in charging state, the voltage threshold of low voltage ride-through is set to U Lmax The first m energy storage power stations in the ranking have the same active power recovery mode after fault ride-through as the photovoltaic power station; the voltage threshold of the remaining low voltage ride-through is set to U Lmin All energy storage power stations adopt a control mode in which active power is immediately restored after a fault is crossed.

7. A system for optimizing energy storage fault ride-through parameters considering transient frequency recovery, characterized in that: include: The equivalent impedance calculation module is used to calculate the equivalent impedance between each energy storage power station and each photovoltaic power station using the power system simulation program, and the impedance between the energy storage power station i and the photovoltaic power station j is recorded as Z ij ,in, i=1,2,…,M,j=1,2,…,N,M is the number of energy storage power stations, N is the number of photovoltaic power stations; The voltage threshold setting module is used to optimize the voltage threshold for the energy storage to enter the low voltage ride-through state according to the photovoltaic output and the energy storage charging and discharging state; The control strategy determination module is used to optimize the control strategy of the energy storage station exiting the low voltage ride-through state according to the voltage threshold of the energy storage station entering the low voltage ride-through state and the equivalent impedance between each energy storage station and each photovoltaic station.

8. The energy storage fault ride-through parameter optimization system considering transient frequency recovery according to claim 7 is characterized in that: Optimize the voltage threshold for energy storage to enter the low voltage ride-through state, including: The output of photovoltaic power station j is recorded as P jset_PV ; When the energy storage station is in the discharging state, the power of energy storage station i is recorded as P i_discharge :At this time, the voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmin Among them, U Lmin The lower limit of the voltage threshold for the energy storage power station to enter the low voltage ride-through state; When the energy storage station is in the charging state, the power of energy storage station i is recorded as P i_charge :At this time, if The voltage threshold for each energy storage station to enter the low voltage ride-through state is set to U Lmax ; if The voltage threshold at which each energy storage power station enters the low voltage ride-through state is determined according to the priority of the energy storage power station support demand.

9. The energy storage fault ride-through parameter optimization system considering transient frequency recovery according to claim 8 is characterized in that: The voltage threshold for each energy storage station to enter the low voltage ride-through state is determined according to the priority of the energy storage station support demand, including: Calculate the support demand priority index S of each energy storage power station i , the priority index S of each energy storage power station support demand i Sorted from small to large, the voltage thresholds for the first m energy storage power stations to enter the low voltage ride-through state are all set to U Lmax The voltage thresholds for the other energy storage power stations to enter the low voltage ride-through state are all set to U Lmin Among them, U Lmax , U Lmin They are respectively the upper and lower limits of the voltage threshold for the energy storage power station to enter the low voltage ride-through state.

10. The energy storage fault ride-through parameter optimization system considering transient frequency recovery according to claim 9, characterized in that: Energy storage power station support demand priority index S i The expression is as follows: The energy storage power station supports the demand priority index S i Sort from small to large, the kth position is recorded as S k , i=1,2,…,M;||Z ij || is the impedance between energy storage station i and photovoltaic station j, denoted by Z ij The modulus value of .

11. The energy storage fault ride-through parameter optimization system considering transient frequency recovery according to claim 9, characterized in that: The method for determining m in the first m energy storage power stations is as follows:

12. The energy storage fault ride-through parameter optimization system considering transient frequency recovery according to claim 7, characterized in that: Optimize the control strategy of the energy storage power station when it exits the low voltage ride-through state, including: When the energy storage power station is in the discharging state, the energy storage power station adopts the control mode of immediate active power recovery after fault ride-through; When the energy storage station is in charging state, the voltage threshold of low voltage ride-through is set to U Lmax The first m energy storage power stations in the ranking have the same active power recovery mode after fault ride-through as the photovoltaic power station; the voltage threshold of the remaining low voltage ride-through is set to U Lmin All energy storage power stations adopt a control mode in which active power is immediately restored after a fault is crossed.

13. A device for optimizing energy storage fault ride-through parameters considering transient frequency recovery, characterized in that: The electronic device comprises a processor and a memory, wherein the memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the electronic device implements the steps of the energy storage fault ride-through parameter optimization method considering transient frequency recovery as described in any one of claims 1 to 6.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the energy storage fault ride-through parameter optimization method considering transient frequency recovery as described in any one of claims 1 to 6.

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