Protection method, device and equipment for network construction type energy storage system and storage medium

Abstract

The invention discloses a protection method, device and equipment for a network construction type energy storage system and a storage medium, and belongs to the technical field of network construction type energy storage. The method comprises the following steps: acquiring node voltage and node current of an observation area in the network-forming type energy storage system and working frequency of the system, and calculating a fault disturbance identification score; simulating the operation characteristics of the synchronous generator by using the virtual synchronous control model, obtaining the electrical angular frequency output by the inverter, the output voltage, the reactive power and the frequency deviation angle of the system, and calculating a frequency control response score and a voltage stability adjustment score; and carrying out superposition calculation on the fault disturbance identification score, the frequency control response score and the voltage stability adjustment score to obtain a comprehensive protection trigger score, and executing a protection action on the system. According to the method, a multi-dimensional disturbance fusion identification mechanism is established, and the steady-state control capability of the network construction type energy storage system is quantified, so that protection is performed, the linkage among disturbance identification, capability evaluation and protection execution is realized, and the real-time performance and the reliability are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of grid-type energy storage, and in particular relates to a protection method, device, equipment and storage medium for a grid-type energy storage system. Background Art

[0002] As the proportion of renewable energy access continues to rise, grid-connected energy storage technology is becoming a key support for grid frequency and voltage regulation, as well as islanded operation. Especially with the widespread integration of distributed power sources, regional power grids are placing higher demands on the real-time, adaptable, and hierarchical response capabilities of system protection.

[0003] Existing grid-connected energy storage technologies typically establish protection criteria based on voltage or current disturbances, and lack dynamic criteria for multi-dimensional disturbance fusion identification. Furthermore, existing methods typically set thresholds based solely on voltage drops or frequency drifts, failing to accurately identify fault conditions in complex scenarios involving transient or coupled disturbances, leading to false protection or refusal to operate. Furthermore, the lack of a dynamic, quantitative mechanism for capacity assessment makes it difficult for grid-connected energy storage systems to autonomously switch operating modes in situations such as disconnection or a weak grid. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a protection method, device, equipment and storage medium for a grid-type energy storage system. By establishing a multi-dimensional disturbance fusion identification mechanism and quantifying the steady-state control capability of the grid-type energy storage system, protection is performed, achieving linkage between disturbance identification, capability assessment and protection execution, and improving real-time performance and reliability.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] In a first aspect, the present invention provides a method for protecting a grid-type energy storage system, the method comprising:

[0007] Collect node voltage, node current and system operating frequency in the observation area of ​​the grid-type energy storage system;

[0008] generating a fault disturbance identification score according to the node voltage, the node current, and the operating frequency;

[0009] The pre-built virtual synchronous control model of the grid-connected energy storage system is used to simulate the operating characteristics of the synchronous generator to obtain the electrical angular frequency, output voltage, reactive power of the inverter output, and the frequency offset angle of the system.

[0010] generating a frequency control response score based on the electrical angular frequency and the frequency offset angle;

[0011] generating a voltage stability regulation score according to the output voltage and the reactive power;

[0012] The fault disturbance identification score, the frequency control response score, and the voltage stability regulation score are superimposed and calculated to obtain a comprehensive protection triggering score;

[0013] A protection action is performed on the grid-connected energy storage system according to the comprehensive protection trigger score.

[0014] In combination with the first aspect, further, the method for generating a fault disturbance identification score based on the node voltage, the node current, and the operating frequency includes:

[0015] Calculating the variation of the node voltage and the node current per unit time respectively to obtain the first-order variation rate of the voltage and the first-order variation rate of the current;

[0016] Normalizing the first-order rate of change of the voltage and the first-order rate of change of the current with a preset reference voltage and a preset reference current to obtain a normalized voltage and a normalized current;

[0017] Assigning a voltage disturbance weight factor and a current disturbance weight factor to the normalized voltage and the normalized current respectively to obtain a voltage disturbance score and a current disturbance score;

[0018] Performing a sinusoidal nonlinear transformation on the operating frequency and assigning a frequency disturbance weight factor to obtain a frequency disturbance score;

[0019] Performing a fusion calculation on the voltage disturbance score, the current disturbance score, and the frequency disturbance score;

[0020] The fault disturbance identification score is obtained through the fault disturbance identification function.

[0021] In combination with the first aspect, further, the expression of the fault disturbance identification function is:

[0022] ,

[0023] Where, for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; is the current time variable; is the voltage disturbance weight factor; for Observe the node voltage in the area at all times; is the preset reference voltage; is the current disturbance weight factor; for Observe the node current in the area at all times; is the preset reference current; is the frequency perturbation weight factor; for The actual operating frequency of the grid-connected energy storage system at all times.

[0024] In combination with the first aspect, further, the method for generating a frequency control response score according to the electrical angular frequency and the frequency offset angle includes:

[0025] Calculating the variation of the electrical angular frequency per unit time and providing initial frequency support using a preconfigured virtual moment of inertia;

[0026] respectively adjusting the electrical angular frequency and the frequency offset angle in combination with a preconfigured virtual damping factor and a frequency adjustment sensitivity;

[0027] The frequency control response score is obtained through the frequency control response evaluation function.

[0028] In combination with the first aspect, further, the frequency control response evaluation function is expressed as:

[0029] ,

[0030] Where, for Frequency control response score of moment-to-moment grid-connected energy storage system; is the current time variable; Preconfigured virtual moment of inertia for virtual synchronous control model; for The electrical angular frequency output by the inverter at any moment; Preconfigured virtual damping factors for virtual synchronous control models; Frequency regulation sensitivity preconfigured for virtual synchronous control model; for The frequency offset angle of the moment-to-moment grid-type energy storage system.

[0031] In combination with the first aspect, further, the method for generating a voltage stability regulation score based on the output voltage and the reactive power includes:

[0032] Calculating the difference between the expected voltage and the output voltage to obtain a voltage deviation;

[0033] Inputting the voltage deviation into a proportional-integral controller to perform proportional regulation and integral regulation on the voltage deviation respectively;

[0034] Introducing the reactive power as a nonlinear adjustment factor for dynamic adjustment;

[0035] The voltage stability regulation score is obtained through the voltage stability regulation evaluation function.

[0036] In combination with the first aspect, further, the voltage stability regulation evaluation function is expressed as follows:

[0037] ,

[0038] Where, for Voltage stability regulation score of the moment-to-moment grid-connected energy storage system; is the current time variable; is the proportional gain coefficient of the proportional-integral controller; is the expected voltage of the inverter; for The output voltage of the inverter at this moment; is the integral gain coefficient of the proportional-integral controller; for The reactive power output by the inverter at this moment.

[0039] In combination with the first aspect, further, the expression of the comprehensive protection trigger score is:

[0040] ,

[0041] Where, for Comprehensive protection triggering score of the moment-to-moment grid-connected energy storage system; for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; for Frequency control response score of moment-to-moment grid-connected energy storage system; for Voltage stability regulation score of the time-grid-type energy storage system.

[0042] In combination with the first aspect, further, the method for executing a protection action on the grid-connected energy storage system according to the comprehensive protection trigger score includes:

[0043] In response to the comprehensive protection trigger score being less than 3, maintaining the grid-connected operation of the grid-connected energy storage system and the main grid, and not performing any protection action;

[0044] In response to the comprehensive protection trigger score being greater than or equal to 3 and less than 5, performing a pre-protection action on the grid-type energy storage system;

[0045] In response to the comprehensive protection trigger score being greater than or equal to 5 and the voltage stability regulation score being less than 1.5, adjusting parameters of a proportional-integral controller to synchronize the voltage dynamics within the grid-connected energy storage system with the main grid, causing the system to enter a synchronous switching mode;

[0046] In response to the comprehensive protection trigger score being greater than or equal to 5 and the voltage stability regulation score being greater than or equal to 1.5, the grid-connected energy storage system is disconnected from the main grid, and part of the load is cut off, so that the system enters the off-grid support mode.

[0047] In combination with the first aspect, further, the pre-protection action includes enabling an inverter current limiting mode and optimizing frequency regulation parameters.

[0048] In a second aspect, the present invention further provides a protection device for a grid-type energy storage system, the device comprising:

[0049] Data acquisition module: used to collect node voltage, node current and system operating frequency in the observation area of ​​the grid-type energy storage system;

[0050] A disturbance identification module is configured to generate a fault disturbance identification score according to the node voltage, the node current and the operating frequency;

[0051] Data acquisition module: used to simulate the operating characteristics of synchronous generators using a pre-built virtual synchronous control model of a grid-connected energy storage system to obtain the electrical angular frequency, output voltage, reactive power output by the inverter, and the frequency offset angle of the system;

[0052] A frequency evaluation module: configured to generate a frequency control response score according to the electrical angular frequency and the frequency offset angle;

[0053] A voltage evaluation module is configured to generate a voltage stability regulation score based on the output voltage and the reactive power;

[0054] A superposition calculation module is configured to perform superposition calculation on the fault disturbance identification score, the frequency control response score, and the voltage stability regulation score to obtain a comprehensive protection triggering score;

[0055] Protection execution module: used to execute protection actions on the grid-type energy storage system according to the comprehensive protection trigger score.

[0056] In combination with the second aspect, further, the disturbance identification module includes a voltage disturbance identification module, a current disturbance identification module, a frequency disturbance identification module and an addition module;

[0057] The voltage disturbance identification module is used to calculate the variation amplitude of the node voltage per unit time to obtain the first-order variation rate of the voltage, then normalize the first-order variation rate of the voltage with a preset reference voltage to obtain a normalized voltage, and finally assign a voltage disturbance weight factor to the normalized voltage to obtain a voltage disturbance score;

[0058] The current disturbance identification module is used to calculate the variation amplitude of the node current per unit time to obtain the first-order variation rate of the current, then normalize the first-order variation rate of the current with a preset reference current to obtain a normalized current, and finally assign a current disturbance weight factor to the normalized current to obtain a current disturbance score;

[0059] The frequency disturbance identification module is used to perform a sinusoidal nonlinear transformation on the operating frequency and assign a frequency disturbance weight factor to obtain a frequency disturbance score;

[0060] The adding module is used to perform a fusion calculation on the voltage disturbance score, the current disturbance score and the frequency disturbance score, and obtain a fault disturbance identification score through a fault disturbance identification function;

[0061] Wherein, the expression of the fault disturbance identification function is:

[0062] ,

[0063] Where, for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; is the current time variable; is the voltage disturbance weight factor; for Observe the node voltage in the area at all times; is the preset reference voltage; is the current disturbance weight factor; for Observe the node current in the area at all times; is the preset reference current; is the frequency perturbation weight factor; for The actual operating frequency of the grid-connected energy storage system at all times.

[0064] In combination with the second aspect, further, the frequency evaluation module includes an angular frequency adjustment module, a frequency offset adjustment module and a first output module;

[0065] The angular frequency adjustment module is used to calculate the variation of the electrical angular frequency per unit time, and use a preconfigured virtual moment of inertia to provide initial frequency support, while adjusting the electrical angular frequency in combination with a preconfigured virtual damping factor;

[0066] The frequency offset adjustment module is used to adjust the frequency offset angle in combination with a preconfigured frequency adjustment sensitivity;

[0067] The first output module is used to obtain a frequency control response score through a frequency control response evaluation function;

[0068] Wherein, the expression of the frequency control response evaluation function is:

[0069] ,

[0070] Where, for Frequency control response score of moment-to-moment grid-connected energy storage system; is the current time variable; Preconfigured virtual moment of inertia for virtual synchronous control model; for The electrical angular frequency output by the inverter at any moment; Preconfigured virtual damping factors for virtual synchronous control models; Frequency regulation sensitivity preconfigured for virtual synchronous control model; for The frequency offset angle of the moment-to-moment grid-type energy storage system.

[0071] In combination with the second aspect, further, the voltage evaluation module includes a voltage regulation module, a power regulation module and a second output module;

[0072] The voltage regulation module is used to calculate the difference between the expected voltage and the output voltage to obtain a voltage deviation, and then input the voltage deviation into the proportional-integral controller to perform proportional regulation and integral regulation on the voltage deviation respectively;

[0073] The power regulation module is used to introduce the reactive power as a nonlinear regulation factor for dynamic regulation;

[0074] The second output module is used to obtain a voltage stability regulation score through a voltage stability regulation evaluation function;

[0075] The voltage stability regulation evaluation function is expressed as follows:

[0076] ,

[0077] Where, for Voltage stability regulation score of the moment-to-moment grid-connected energy storage system; is the current time variable; is the proportional gain coefficient of the proportional-integral controller; is the expected voltage of the inverter; for The output voltage of the inverter at this moment; is the integral gain coefficient of the proportional-integral controller; for The reactive power output by the inverter at this moment.

[0078] In a third aspect, the present invention further provides a computer device comprising a storage medium and a processor;

[0079] The storage medium is used to store instructions;

[0080] The processor is used to operate according to the instructions to execute the steps of any method described in the first aspect.

[0081] In a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the methods described in the first aspect.

[0082] Compared with the prior art, the present invention has the following beneficial effects:

[0083] The protection method for a grid-type energy storage system provided by the present invention introduces frequency disturbance characteristics and combines voltage disturbances with current disturbances to establish a multi-dimensional disturbance fusion identification mechanism, thereby improving the accuracy and real-time performance of fault identification. By constructing a virtual synchronous control model and combining electrical angular frequency, frequency offset angle, output voltage, and reactive power, the frequency control capability and voltage regulation capability of the system are evaluated respectively, thereby achieving a quantitative judgment of the steady-state control capability of the system and improving the reliability of the protection method. By calculating a comprehensive protection trigger score and executing the corresponding protection action based on it, a linkage mechanism between disturbance identification, capability evaluation, and protection execution is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0085] Figure 1 This is a flow chart of a protection method for a grid-type energy storage system provided by an embodiment of the present invention;

[0086] Figure 2 This is a flow chart of a method for executing a protection action provided by an embodiment of the present invention;

[0087] Figure 3 1 is a schematic structural diagram of a protection device for a grid-type energy storage system provided by an embodiment of the present invention;

[0088] Figure 4 This is a diagram of the internal structure of a computer device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0089] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0090] Example 1:

[0091] This embodiment provides a protection method for a grid-type energy storage system, such as Figure 1 FIG. 1 is a flow chart of the method provided in this embodiment, which mainly includes the following steps:

[0092] Step S1: collecting node voltages, node currents and operating frequencies of the observation area in the grid-type energy storage system;

[0093] Step S2: generating a fault disturbance identification score based on the node voltage, node current and operating frequency;

[0094] Step S3: Using a pre-built virtual synchronous control model of a grid-connected energy storage system to simulate the operating characteristics of the synchronous generator, to obtain the electrical angular frequency, output voltage, reactive power output by the inverter, and the frequency offset angle of the system;

[0095] Step S4: generating a frequency control response score according to the electrical angular frequency and the frequency offset angle;

[0096] Step S5: generating a voltage stability regulation score based on the output voltage and reactive power;

[0097] Step S6: superimposing the fault disturbance identification score, the frequency control response score, and the voltage stability regulation score to obtain a comprehensive protection triggering score;

[0098] Step S7: Execute protection actions on the grid-connected energy storage system according to the comprehensive protection trigger score.

[0099] In this embodiment, the method for generating a fault disturbance identification score according to the node voltage, node current, and operating frequency in step S2 includes:

[0100] Based on the real-time node voltage of the observation area in the grid-type energy storage system collected in step S1 and node current , calculate the change amplitude per unit time respectively, and obtain the first-order change rate of voltage and the first-order change rate of current;

[0101] The first-order rate of change of voltage and current are respectively compared with the preset reference voltage. , reference current Perform normalization processing to obtain normalized voltage and normalized current;

[0102] Assign voltage disturbance weight factors to normalized voltage and normalized current respectively and current perturbation weight factor , get the voltage disturbance score and current disturbance score;

[0103] At the same time, the current operating frequency of the grid-type energy storage system collected in step S1 is subjected to a sinusoidal nonlinear transformation, so that the frequency disturbance feature is added to the fault disturbance identification score in a sinusoidal form, and the frequency disturbance weight factor is assigned. , get the frequency disturbance score;

[0104] The voltage disturbance score, current disturbance score and frequency disturbance score are integrated and calculated, and the fault disturbance identification score is obtained through the fault disturbance identification function.

[0105] Specifically, the expression of the fault disturbance identification function is:

[0106] ,

[0107] Where, for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; is the current time variable; is the voltage disturbance weight factor, which indicates the influence of voltage disturbance on the recognition score; for Observe the node voltage in the area at all times; It is a preset reference voltage, usually the rated voltage of the system, used to normalize voltage changes; is the current disturbance weight factor, which indicates the weight of the current disturbance in the recognition score; for Observe the node current in the area at all times; It is a preset reference current, usually the rated current of the system, used to normalize the current change; is the frequency perturbation weight factor, which indicates the influence of frequency perturbation on the recognition score; for The actual operating frequency of the grid-connected energy storage system, measured in Hertz, may deviate slightly due to factors such as load fluctuations, fault disturbances, or island operation.

[0108] The protection method for a grid-type energy storage system provided in this embodiment collects real-time voltage and current, processes them, and assigns disturbance weighting factors to them. This establishes voltage and current disturbance signatures, enabling quantitative capture of sudden voltage and current changes in the system. Furthermore, by introducing a sinusoidal nonlinear transformation of the current operating frequency as a frequency disturbance signature, it integrates the three-dimensional disturbance signatures of voltage, current, and frequency. This method improves the system's ability to detect early signs of faults, facilitates the early deployment of subsequent protection actions, and enhances the accuracy of disturbance assessment and the real-time nature of sudden change responses.

[0109] As an example, after a fault disturbance is identified, the system needs to assess whether the current grid-connected capability is sufficient to withstand or mitigate the fault disturbance. This capability includes frequency control to maintain frequency stability and voltage regulation to maintain voltage stability. Specifically, as described in step S3, a pre-built virtual synchronous control model of a grid-connected energy storage system is used to simulate the operating characteristics of a synchronous generator (VSG), specifically its ability to respond to frequency changes, to obtain the inverter's output electrical angular frequency, output voltage, reactive power, and the system's frequency offset angle.

[0110] Furthermore, the method for generating a frequency control response score according to the electrical angular frequency and the frequency offset angle in step S4 includes:

[0111] Calculate the electrical angular frequency of the inverter output obtained in step S3 The change in unit time and the pre-configured virtual moment of inertia Provides initial frequency support; at the same time, combined with pre-configured virtual damping factors Electrical angular frequency Make adjustments to quantify the system's ability to suppress disturbances;

[0112] Combined with pre-configured frequency adjustment sensitivity The frequency offset angle of the system obtained in step S3 Adjustments are made and a frequency control response score is obtained through a frequency control response evaluation function.

[0113] It should be noted that the expression of the frequency control response evaluation function is:

[0114] ,

[0115] Where, for The frequency control response score of a grid-connected energy storage system is a key performance indicator that measures whether the energy storage system can quickly respond to a fault disturbance and support system frequency stability. The virtual moment of inertia pre-configured in the virtual synchronous control model is used to simulate the inertial response of the traditional synchronous generator and provide initial frequency support when the system is disturbed; for The electrical angular frequency output by the inverter at this moment, in radians per second; It is a pre-configured virtual damping factor in the virtual synchronous control model, which is used to suppress frequency oscillation and improve system stability; Frequency regulation sensitivity preconfigured for virtual synchronous control model; for The frequency offset angle of the moment-to-moment grid-type energy storage system.

[0116] As an optional embodiment, in addition to maintaining frequency stability, the system also needs to maintain voltage stability. Specifically, the method of generating a voltage stability adjustment score based on output voltage and reactive power in step S5 includes:

[0117] Calculate the desired voltage for inverter settings The real-time voltage output by the inverter obtained in step S3 The difference between them is used to obtain the voltage deviation;

[0118] A proportional-integral controller (PI controller) is introduced to perform proportional and integral regulation on the voltage deviation respectively;

[0119] Introduce the reactive power output of the inverter obtained in step S3 As a nonlinear regulation factor, dynamic regulation is formed through the exponential function, thereby affecting the sensitivity of regulation. The voltage stability regulation score is obtained through the voltage stability regulation evaluation function.

[0120] Furthermore, the voltage stability regulation evaluation function is expressed as:

[0121] ,

[0122] Where, for Voltage stability regulation score of the moment-to-moment grid-connected energy storage system; It is the proportional gain coefficient of the proportional-integral controller, which is used to directly output the regulation response according to the current voltage deviation and reflects the regulation sensitivity; The desired voltage of the inverter, usually the rated voltage, is also the target of voltage regulation; for The output voltage of the inverter at this moment; It is the integral gain coefficient of the proportional-integral controller, which is used to simulate the "historical cumulative error response" in voltage regulation and enhance the long-term voltage regulation capability of the system; for The reactive power output by the inverter at any moment is used to reflect the strength of the system's voltage support capability.

[0123] The protection method for a grid-type energy storage system provided in this embodiment evaluates the system's frequency control capability based on the electrical angular frequency and the system's frequency offset angle, combined with the virtual moment of inertia, virtual damping factor, and frequency regulation sensitivity configured in the virtual synchronous control model constructed by the virtual synchronous generator. This method achieves a quantitative expression of the system's dynamic frequency support capability. Furthermore, based on the output voltage and reactive power, a proportional-integral controller and a nonlinear regulation factor are introduced to evaluate the system's voltage regulation capability, achieving a quantitative judgment of the system's steady-state control capability and avoiding the problem of traditional linear control's regulation performance failure under low reactive power conditions. This method enhances the system's ability to autonomously evaluate and self-regulate under disturbance conditions, improving the reliability of system protection.

[0124] In some embodiments, as Figure 2 The figure is a flow chart of the method for performing protection actions on the grid-type energy storage system provided by this embodiment. Figure 2 , the method of how to perform the protection action in step S7 is further described in detail:

[0125] Based on the comprehensive protection trigger score calculated in step S6, the comprehensive protection trigger score is then compared;

[0126] If the comprehensive protection trigger score is less than 3, it indicates that the system is currently operating smoothly with no significant disturbances. The grid-connected energy storage system and the main grid will continue to operate in parallel, and no protection action will be taken.

[0127] If the comprehensive protection trigger score is greater than or equal to 3 and less than 5, it indicates that the system is in a light disturbance or potential instability state and requires heightened vigilance. Pre-protection actions can be taken on the grid-connected energy storage system, including enabling inverter current limiting mode and optimizing frequency regulation parameters.

[0128] In response to a comprehensive protection trigger score greater than or equal to 5 and a voltage stability regulation score less than 1.5, it indicates that the system has significant disturbances but does not yet have the ability to independently support voltage stability. The parameters of the proportional-integral controller can be adjusted to synchronize the voltage dynamics within the grid-connected energy storage system with the main grid, putting the system into synchronous switching mode.

[0129] In response to a comprehensive protection trigger score greater than or equal to 5 and a voltage stability regulation score greater than or equal to 1.5, it indicates that the system is experiencing a significant disturbance or has entered a fault state, and has significant voltage regulation capabilities. It can exist as a voltage source node and can support local voltage stability over a large area. Therefore, the grid-connected energy storage system can be disconnected from the main grid and some loads can be removed, putting the system into off-grid support mode.

[0130] Specifically, the expression of the comprehensive protection trigger score is:

[0131] ,

[0132] Where, for Comprehensive protection triggering score of the moment-to-moment grid-connected energy storage system; for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; for Frequency control response score of moment-to-moment grid-connected energy storage system; for Voltage stability regulation score of the time-grid-type energy storage system.

[0133] It should be noted that when When , it reflects that the system as a whole is in a healthy, stable and grid-connected operation state without significant disturbances. At this time, the grid-connected energy storage system does not need to assume the task of dominant control, and there is no fault risk warning. The actual control strategy in this state is: the system will continue to maintain grid-connected operation with the main grid, without the need to perform any protection actions or mode switching. This state is the default operating state of the system. No tripping is performed and current limiting is not enabled. It is the most energy-saving and economical operating state. Specifically, all control parameters in the system remain in the default or optimized state, the controller remains in automatic operation, and the regulator performs fine-tuning responses according to load changes to ensure optimal power quality. At the same time, only the system's operating data is recorded, and the changing trend of the score is continuously monitored to prepare for potential disturbances.

[0134] Furthermore, when , it indicates that the system is facing marginal disturbances or gradually accumulating performance degradation. Without intervention, it may continue to deteriorate into a fault state. In this case, the system will not immediately trip or switch modes, but will enter a state of active regulation and strategy optimization, striving to reduce the score to a safe zone (i.e., less than 3) without interrupting power supply to prevent it from evolving into a true fault. The actual control strategy in this state is: the system will actively enter a pre-protection state, implementing lightweight protective measures without affecting the main power supply. For example, it will temporarily enable the inverter's current limiting mode (VSG current limiting), optimize frequency regulation parameters to enhance frequency response, adjust the parameters of the proportional-integral controller to improve voltage steady-state performance, and even control the system's internal preset load reduction strategy.

[0135] Furthermore, when and When the system is experiencing significant disturbances, it is in a relatively stable operating state, but its voltage maintenance and regulation capabilities are limited, and it lacks the ability to independently support voltage stability. The actual control strategy for this state is to place the system in a semi-autonomous regulation state. By optimizing the parameters of the proportional-integral controller, the voltage dynamics within the grid-connected energy storage system are synchronized with the main grid, putting the system into synchronous switching mode. For example, the proportional or integral gain can be increased to enhance response speed and steady-state performance.

[0136] Furthermore, when and When the system is in a high-risk operating state or fault state, it indicates that the system may have entered a high-risk operating state or a fault state. If immediate action is not taken, system stability cannot be guaranteed and may even affect the upper main grid. At this time, the system has significant voltage regulation capabilities and can function as a voltage source node, capable of supporting local voltage stability over a large area. The actual control strategy in this state is: the system will actively disconnect from the main grid, retain critical loads, remove some non-essential loads, and enter off-grid support mode; the inverter assumes responsibility for frequency and voltage control. At the same time, emergency control logic is activated, such as high-frequency tripping, reactive voltage limiting control, and transient recovery strategies, to ensure that the system can maintain its limited power supply capacity even under extreme disturbances.

[0137] The protection method for a grid-connected energy storage system provided in this embodiment transforms multi-source dynamic disturbance signals into a single quantitative scoring metric by superimposing the fault disturbance identification score, frequency control response score, and voltage stability regulation score, thus achieving a shift from rule-based triggering to data-driven control. This method automatically executes different protection actions by comparing comprehensive protection trigger scores, achieving a comprehensive integrated linkage mechanism between disturbance identification, capability assessment, and protection execution. This not only improves the system's frequency and voltage support levels, but also enhances the system's operational adaptability and intelligent protection capabilities.

[0138] Figure 1 Only the logical sequence of the method described in this embodiment is shown. In other possible embodiments of the present invention, different methods may be used without conflict. Figure 1 The steps shown or described are performed in the order shown. The protection method for a grid-type energy storage system provided in this embodiment can be applied to a terminal and can be executed by a protection device for the grid-type energy storage system. The device can be implemented by software and / or hardware and can be integrated into a terminal, such as any smartphone, tablet computer, or computer device with communication capabilities.

[0139] Example 2:

[0140] This embodiment provides a protection method for a grid-type energy storage system. The difference from the first embodiment is that based on the fault disturbance identification score, a threshold can be set to determine whether the system is in different disturbance intervals such as normal, light disturbance, warning disturbance and fault disturbance, so that the system has a clear disturbance threshold and logical layering. Specifically, when When , it means the system has not entered the disturbance state and is in the normal range; when When , it means the system enters the disturbance state and is in the light disturbance range; when When , it means the system is in the warning disturbance range; when , it indicates that the system has entered a high-risk state and is in the fault disturbance range.

[0141] In this embodiment, based on the frequency control response score, a threshold can be set to distinguish the strength of the system frequency control capability and to determine whether the system has the ability to operate synchronously or independently off-grid. When , it means that the system frequency control capability is insufficient and needs the support of the main network, and cannot operate independently off the grid; when When , it means that the system has a certain frequency response capability, but it is not enough to independently support the operation of the entire network and can run synchronously with the main network; when When , it indicates that the system frequency control is stable and has significant independent operation capability, and can maintain power supply after the main grid trips.

[0142] In some embodiments, based on the voltage stability regulation score, a threshold can be set to distinguish the strength of the system voltage regulation capability and used to determine whether the system has the ability to operate synchronously or independently off-grid. When , it means that the system does not have sufficient voltage maintenance capability, especially in the context of grid disturbance, it cannot independently maintain a stable voltage level; when When , it means that the system has certain voltage maintenance and regulation capabilities and is in a relatively stable operating state, but the voltage maintenance and regulation capabilities are limited and it does not have the ability to independently support voltage stability. It can operate synchronously with the main grid; when When , it indicates that the system has significant voltage regulation capability, can exist as a voltage source node, can support local voltage stability in a large range, and has the ability to switch from "following control" to "leading control".

[0143] It should be noted that among the protection actions performed by the grid-connected energy storage system, maintaining grid-connected operation is usually used when the system disturbance is in the normal range, that is, when the fault disturbance identification score is less than 1. When the system enters a disturbance state, the protection actions performed include pre-protection, entering synchronous switching mode, or entering off-grid support mode. Among them, executing pre-protection actions is usually used when the system disturbance is not serious, and the system's frequency control and voltage stability capabilities are insufficient. When the main grid support is required, protection and adjustment can be performed through pre-protection actions. Entering synchronous switching mode is usually used when the system disturbance is serious, but the system's frequency control and voltage stability capabilities are limited, which is not enough for the system to operate independently off-grid. Entering off-grid support mode is usually used when the system disturbance is serious, and the system frequency control is stable, and has significant voltage regulation capabilities, and can switch from "follow-type control" to "dominant control".

[0144] To verify the protection method of the present invention, a simulated disturbance experiment was conducted. The experimental system consisted of a typical low-voltage distribution mains and distributed energy storage. The energy storage system used a bidirectional energy storage inverter with a virtual synchronous controller, capable of both frequency and voltage regulation, and had a rated output of 100 kW. The integration time resolution of the entire experimental system was 50 milliseconds, and the test period was approximately 15 minutes. The experimental results are shown in Table 1.

[0145] Table 1 Comparative experimental results

[0146]

[0147] As shown in Table 1, during fault disturbance identification, the fault disturbance identification scores of different samples vary significantly due to varying degrees of voltage, current, and frequency disturbances. Sample C achieved a fault disturbance identification score of 3.5, well above the light disturbance threshold, demonstrating the method's ability to capture sudden changes in behavior. Next, when evaluating frequency control capability, samples A and D achieved frequency control response scores of 2.6 and 2.3, respectively, demonstrating the method's ability to quantify the differences in the system's frequency control capability under varying disturbances. Furthermore, through a continuous scoring mechanism, the method overcomes the limitations of traditional fixed threshold settings, enabling hierarchical and predictive protection behavior. Specifically, sample E's comprehensive protection trigger score of 3.6, close to the threshold, led to the implementation of preemptive protection action, avoiding frequent tripping and improving system stability. Sample A, in particular, achieved a comprehensive protection trigger score of 6.5 despite high scores in all three categories. The system then implemented "offline support mode" according to the protection strategy, validating the effectiveness and feasibility of the score-driven strategy.

[0148] In summary, the protection method for a grid-connected energy storage system provided by the embodiments of the present invention improves the accuracy and real-time nature of fault identification by establishing a multi-dimensional disturbance fusion identification mechanism. It also enhances the reliability of the protection method by quantifying the system's frequency control and voltage regulation capabilities. Furthermore, by calculating a comprehensive protection trigger score and executing the corresponding protection actions, it implements a linkage mechanism between disturbance identification, capability assessment, and protection execution, providing insights into intelligent protection strategies in grid-connected scenarios.

[0149] Example 3:

[0150] This embodiment provides a protection device for a grid-type energy storage system, such as Figure 3 FIG. 1 is a schematic diagram of the structure of the device provided in this embodiment, which mainly includes:

[0151] Data acquisition module: used to collect node voltage, node current and system operating frequency in the observation area of ​​the grid-type energy storage system;

[0152] Disturbance identification module: used to generate fault disturbance identification scores based on node voltage, node current and operating frequency;

[0153] Data acquisition module: used to simulate the operating characteristics of synchronous generators using a pre-built virtual synchronous control model of a grid-connected energy storage system to obtain the electrical angular frequency, output voltage, reactive power output by the inverter, and the frequency offset angle of the system;

[0154] Frequency evaluation module: used to generate frequency control response scores based on electrical angular frequency and frequency offset angle;

[0155] Voltage evaluation module: used to generate voltage stability regulation scores based on output voltage and reactive power;

[0156] Superposition calculation module: used to superimpose the fault disturbance identification score, frequency control response score and voltage stability regulation score to obtain a comprehensive protection triggering score;

[0157] Protection execution module: used to execute protection actions on the grid-type energy storage system based on the comprehensive protection trigger score.

[0158] In this embodiment, the disturbance identification module mainly includes a voltage disturbance identification module, a current disturbance identification module, a frequency disturbance identification module and an addition module. Specifically, the voltage disturbance identification module is used to calculate the variation amplitude of the node voltage in a unit time to obtain the first-order variation rate of the voltage, and then normalize the first-order variation rate of the voltage with the preset reference voltage to obtain the normalized voltage, and finally assign a voltage disturbance weight factor to the normalized voltage to obtain a voltage disturbance score. The current disturbance identification module is used to calculate the variation amplitude of the node current in a unit time to obtain the first-order variation rate of the current, and then normalize the first-order variation rate of the current with the preset reference current to obtain the normalized current, and finally assign a current disturbance weight factor to the normalized current to obtain a current disturbance score. The frequency disturbance identification module is used to perform a sinusoidal nonlinear transformation on the operating frequency and assign a frequency disturbance weight factor to obtain a frequency disturbance score. The addition module is used to fuse the voltage disturbance score, the current disturbance score and the frequency disturbance score, and obtain a fault disturbance identification score through the fault disturbance identification function. Among them, the expression of the fault disturbance identification function is:

[0159] ,

[0160] Where, for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; is the current time variable; is the voltage disturbance weight factor; for Observe the node voltage in the area at all times; is the preset reference voltage; is the current disturbance weight factor; for Observe the node current in the area at all times; is the preset reference current; is the frequency perturbation weight factor; for The actual operating frequency of the grid-connected energy storage system at all times.

[0161] As an embodiment, the frequency evaluation module mainly includes an angular frequency adjustment module, a frequency offset adjustment module and a first output module. Furthermore, the angular frequency adjustment module is used to calculate the variation amplitude of the electrical angular frequency per unit time, and use a preconfigured virtual moment of inertia to provide initial frequency support, while adjusting the electrical angular frequency in combination with a preconfigured virtual damping factor. The frequency offset adjustment module is used to adjust the frequency offset angle in combination with a preconfigured frequency adjustment sensitivity. The first output module is used to obtain a frequency control response score through a frequency control response evaluation function. The expression of the frequency control response evaluation function is:

[0162] ,

[0163] Where, for Frequency control response score of moment-to-moment grid-connected energy storage system; is the current time variable; Preconfigured virtual moment of inertia for virtual synchronous control model; for The electrical angular frequency output by the inverter at any moment; Preconfigured virtual damping factors for virtual synchronous control models; Frequency regulation sensitivity preconfigured for virtual synchronous control model; for The frequency offset angle of the moment-to-moment grid-type energy storage system.

[0164] In some embodiments, the voltage assessment module primarily includes a voltage regulation module, a power regulation module, and a second output module. The voltage regulation module is configured to calculate the difference between the desired voltage and the output voltage to obtain a voltage deviation, which is then input into a proportional-integral controller to perform proportional and integral regulation on the voltage deviation, respectively. The power regulation module is configured to introduce reactive power as a nonlinear regulation factor for dynamic regulation. The second output module is configured to obtain a voltage stability regulation score using a voltage stability regulation evaluation function. The voltage stability regulation evaluation function is expressed as follows:

[0165] ,

[0166] Where, for Voltage stability regulation score of the moment-to-moment grid-connected energy storage system; is the current time variable; is the proportional gain coefficient of the proportional-integral controller; is the expected voltage of the inverter; for The output voltage of the inverter at this moment; is the integral gain coefficient of the proportional-integral controller; for The reactive power output by the inverter at this moment.

[0167] The protection device for the grid-type energy storage system provided in this embodiment can execute the protection method for the grid-type energy storage system provided in any embodiment of the present invention, and has functional modules and beneficial effects corresponding to the execution method.

[0168] Example 4:

[0169] This embodiment also provides a computer device, which can be a server, and its internal structure can be as shown in FIG. Figure 4 As shown. The computer device includes a processor, a memory, an input / output interface (I / O), and a communication interface. The processor, memory, and I / O interface are connected via a system bus, and the communication interface is connected to the system bus via the I / O interface.

[0170] The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store data acquired and generated during the method of autonomously entering a packaging container by a robot. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal via a network connection. When executed by the processor, the computer program implements the method of the aforementioned first or second embodiment.

[0171] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0172] The computer device provided in this embodiment can execute the protection method of the grid-type energy storage system provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0173] Embodiment 5:

[0174] This embodiment 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-mentioned embodiment 1 or embodiment 2 are implemented.

[0175] The computer-readable storage medium provided in this embodiment can execute the protection method of the grid-type energy storage system provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0176] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0177] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0178] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0179] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0180] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all protected by the present invention.

Claims

1. A protection method for a grid-type energy storage system, characterized in that: The method comprises: Collect node voltage, node current and system operating frequency in the observation area of ​​the grid-type energy storage system; generating a fault disturbance identification score according to the node voltage, the node current, and the operating frequency; The pre-built virtual synchronous control model of the grid-connected energy storage system is used to simulate the operating characteristics of the synchronous generator to obtain the electrical angular frequency, output voltage, reactive power of the inverter output, and the frequency offset angle of the system. generating a frequency control response score based on the electrical angular frequency and the frequency offset angle; generating a voltage stability regulation score according to the output voltage and the reactive power; The fault disturbance identification score, the frequency control response score, and the voltage stability regulation score are superimposed and calculated to obtain a comprehensive protection triggering score; A protection action is performed on the grid-connected energy storage system according to the comprehensive protection trigger score.

2. The protection method of the grid-type energy storage system according to claim 1, characterized in that: The method for generating a fault disturbance identification score according to the node voltage, the node current, and the operating frequency includes: Calculating the variation of the node voltage and the node current per unit time respectively to obtain the first-order variation rate of the voltage and the first-order variation rate of the current; Normalizing the first-order rate of change of the voltage and the first-order rate of change of the current with a preset reference voltage and a preset reference current to obtain a normalized voltage and a normalized current; Assigning a voltage disturbance weight factor and a current disturbance weight factor to the normalized voltage and the normalized current respectively to obtain a voltage disturbance score and a current disturbance score; Performing a sinusoidal nonlinear transformation on the operating frequency and assigning a frequency disturbance weight factor to obtain a frequency disturbance score; Performing a fusion calculation on the voltage disturbance score, the current disturbance score, and the frequency disturbance score; The fault disturbance identification score is obtained through the fault disturbance identification function.

3. The protection method of the grid-type energy storage system according to claim 2, characterized in that: The expression of the fault disturbance identification function is: ， Where, for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; is the current time variable; is the voltage disturbance weight factor; for Observe the node voltage in the area at all times; is the preset reference voltage; is the current disturbance weight factor; for Observe the node current in the area at all times; is the preset reference current; is the frequency perturbation weight factor; for The actual operating frequency of the grid-connected energy storage system at all times.

4. The protection method of the grid-type energy storage system according to claim 1, characterized in that: The method for generating a frequency control response score according to the electrical angular frequency and the frequency offset angle comprises: Calculating the variation of the electrical angular frequency per unit time and providing initial frequency support using a preconfigured virtual moment of inertia; respectively adjusting the electrical angular frequency and the frequency offset angle in combination with a preconfigured virtual damping factor and a frequency adjustment sensitivity; The frequency control response score is obtained through the frequency control response evaluation function.

5. The protection method of the grid-type energy storage system according to claim 4, characterized in that: The expression of the frequency control response evaluation function is: ， Where, for Frequency control response score of moment-to-moment grid-connected energy storage system; is the current time variable; Preconfigured virtual moment of inertia for virtual synchronous control model; for The electrical angular frequency output by the inverter at any moment; Preconfigured virtual damping factors for virtual synchronous control models; Frequency regulation sensitivity preconfigured for virtual synchronous control model; for The frequency offset angle of the moment-to-moment grid-type energy storage system.

6. The protection method of the grid-type energy storage system according to claim 1, characterized in that: The method for generating a voltage stability regulation score according to the output voltage and the reactive power includes: Calculating the difference between the expected voltage and the output voltage to obtain a voltage deviation; Inputting the voltage deviation into a proportional-integral controller to perform proportional regulation and integral regulation on the voltage deviation respectively; Introducing the reactive power as a nonlinear adjustment factor for dynamic adjustment; The voltage stability regulation score is obtained through the voltage stability regulation evaluation function.

7. The protection method of the grid-type energy storage system according to claim 6, characterized in that: The expression of the voltage stability regulation evaluation function is: ， Where, for Voltage stability regulation score of the moment-to-moment grid-connected energy storage system; is the current time variable; is the proportional gain coefficient of the proportional-integral controller; is the expected voltage of the inverter; for The output voltage of the inverter at this moment; is the integral gain coefficient of the proportional-integral controller; for The reactive power output by the inverter at this moment.

8. The protection method of the grid-type energy storage system according to claim 1, characterized in that: The expression of the comprehensive protection trigger score is: ， Where, for Comprehensive protection triggering score of the moment-to-moment grid-connected energy storage system; for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; for Frequency control response score of moment-to-moment grid-connected energy storage system; for Voltage stability regulation score of the time-grid-type energy storage system.

9. The protection method of the grid-type energy storage system according to claim 1, characterized in that: The method for executing a protection action on the grid-type energy storage system according to the comprehensive protection trigger score includes: In response to the comprehensive protection trigger score being less than 3, maintaining the grid-connected operation of the grid-connected energy storage system and the main grid, and not performing any protection action; In response to the comprehensive protection trigger score being greater than or equal to 3 and less than 5, performing a pre-protection action on the grid-type energy storage system; In response to the comprehensive protection trigger score being greater than or equal to 5 and the voltage stability regulation score being less than 1.5, adjusting parameters of a proportional-integral controller to synchronize the voltage dynamics within the grid-connected energy storage system with the main grid, causing the system to enter a synchronous switching mode; In response to the comprehensive protection trigger score being greater than or equal to 5 and the voltage stability regulation score being greater than or equal to 1.5, the grid-connected energy storage system is disconnected from the main grid, and part of the load is cut off, so that the system enters the off-grid support mode.

10. The protection method of the grid-type energy storage system according to claim 9, characterized in that: The pre-protection action includes enabling the inverter current limiting mode and optimizing the frequency regulation parameters.

11. A protection device for a grid-type energy storage system, characterized in that: The device comprises: Data acquisition module: used to collect node voltage, node current and system operating frequency in the observation area of ​​the grid-type energy storage system; A disturbance identification module is configured to generate a fault disturbance identification score according to the node voltage, the node current and the operating frequency; Data acquisition module: used to simulate the operating characteristics of synchronous generators using a pre-built virtual synchronous control model of a grid-connected energy storage system to obtain the electrical angular frequency, output voltage, reactive power output by the inverter, and the frequency offset angle of the system; A frequency evaluation module: configured to generate a frequency control response score according to the electrical angular frequency and the frequency offset angle; A voltage evaluation module is configured to generate a voltage stability regulation score based on the output voltage and the reactive power; A superposition calculation module is configured to perform superposition calculation on the fault disturbance identification score, the frequency control response score, and the voltage stability regulation score to obtain a comprehensive protection triggering score; Protection execution module: used to execute protection actions on the grid-type energy storage system according to the comprehensive protection trigger score.

12. The protection device for the grid-type energy storage system according to claim 11, characterized in that: The disturbance identification module includes a voltage disturbance identification module, a current disturbance identification module, a frequency disturbance identification module and an addition module; The voltage disturbance identification module is used to calculate the variation amplitude of the node voltage per unit time to obtain the first-order variation rate of the voltage, then normalize the first-order variation rate of the voltage with a preset reference voltage to obtain a normalized voltage, and finally assign a voltage disturbance weight factor to the normalized voltage to obtain a voltage disturbance score; The current disturbance identification module is used to calculate the variation amplitude of the node current per unit time to obtain the first-order variation rate of the current, then normalize the first-order variation rate of the current with a preset reference current to obtain a normalized current, and finally assign a current disturbance weight factor to the normalized current to obtain a current disturbance score; The frequency disturbance identification module is used to perform a sinusoidal nonlinear transformation on the operating frequency and assign a frequency disturbance weight factor to obtain a frequency disturbance score; The adding module is used to perform a fusion calculation on the voltage disturbance score, the current disturbance score and the frequency disturbance score, and obtain a fault disturbance identification score through a fault disturbance identification function; Wherein, the expression of the fault disturbance identification function is: ， Where, for Fault disturbance identification scoring of moment-to-moment grid-connected energy storage systems; is the current time variable; is the voltage disturbance weight factor; for Observe the node voltage in the area at all times; is the preset reference voltage; is the current disturbance weight factor; for Observe the node current in the area at all times; is the preset reference current; is the frequency perturbation weight factor; for The actual operating frequency of the grid-connected energy storage system at all times.

13. The protection device of the grid-type energy storage system according to claim 11, characterized in that: The frequency evaluation module includes an angular frequency adjustment module, a frequency offset adjustment module and a first output module; The angular frequency adjustment module is used to calculate the variation of the electrical angular frequency per unit time, and use a preconfigured virtual moment of inertia to provide initial frequency support, while adjusting the electrical angular frequency in combination with a preconfigured virtual damping factor; The frequency offset adjustment module is used to adjust the frequency offset angle in combination with a preconfigured frequency adjustment sensitivity; The first output module is used to obtain a frequency control response score through a frequency control response evaluation function; Wherein, the expression of the frequency control response evaluation function is: ， Where, for Frequency control response score of moment-to-moment grid-connected energy storage system; is the current time variable; Preconfigured virtual moment of inertia for virtual synchronous control model; for The electrical angular frequency output by the inverter at any moment; Preconfigured virtual damping factors for virtual synchronous control models; Frequency regulation sensitivity preconfigured for virtual synchronous control model; for The frequency offset angle of the moment-to-moment grid-type energy storage system.

14. The protection device for a grid-type energy storage system according to claim 11, characterized in that: The voltage evaluation module includes a voltage regulation module, a power regulation module and a second output module; The voltage regulation module is used to calculate the difference between the expected voltage and the output voltage to obtain a voltage deviation, and then input the voltage deviation into the proportional-integral controller to perform proportional regulation and integral regulation on the voltage deviation respectively; The power regulation module is used to introduce the reactive power as a nonlinear regulation factor for dynamic regulation; The second output module is used to obtain a voltage stability regulation score through a voltage stability regulation evaluation function; The voltage stability regulation evaluation function is expressed as follows: ， Where, for Voltage stability regulation score of the moment-to-moment grid-connected energy storage system; is the current time variable; is the proportional gain coefficient of the proportional-integral controller; is the expected voltage of the inverter; for The output voltage of the inverter at this moment; is the integral gain coefficient of the proportional-integral controller; for The reactive power output by the inverter at this moment.

15. A computer device, characterized in that: including storage media and processors; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 10.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 10 are implemented.

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