Energy storage system control method and device, computer equipment and readable storage medium

Abstract

The invention provides an energy storage system control method and device, computer equipment and a readable storage medium, and belongs to the technical field of energy storage systems. The method comprises the following steps: acquiring voltage information and frequency information of a common coupling point of an energy storage system in real time; according to the voltage information and the frequency information, whether the energy storage system is in an island state currently is determined in real time; if not, determining the voltage drop information of the common coupling point of the energy storage system according to the voltage information; according to the voltage drop information and the frequency information of the common coupling point of the energy storage system, a preset rated voltage, a preset rated frequency, a preset voltage range, a preset frequency error threshold value and a preset time threshold value, the operation state of the energy storage system is determined in real time; and determining to-be-executed operation according to the running state of the energy storage system. The method can achieve the effects of improving the judgment accuracy of low voltage ride through and island protection, achieving the coexistence of low voltage ride through and island detection, and improving the safety and stability of an energy storage system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage systems, in particular to an energy storage system control method and device, computer equipment and a readable storage medium. BACKGROUND

[0002] To ensure the safety and stability of the energy storage system in the grid-connected scenario, the energy storage system needs to have both island protection function and low voltage ride through function. Island protection refers to when the grid-side circuit breaker is disconnected, the energy storage system can be timely disconnected to ensure the safety of the equipment and users; low voltage ride through refers to when the grid-side voltage is short-circuited and dropped, the energy storage system can remain in the grid-connected state for a period of time to maintain the voltage stability and frequency stability of the energy storage system. However, when the energy storage system is in an island state, performing a low voltage ride through operation will not only affect the island detection result, but also cause damage to the equipment and users; when the grid-side occurs a transient disturbance, performing an island protection operation will cause the low voltage ride through operation to fail, thereby failing to ensure the voltage stability and frequency stability of the energy storage system. Therefore, when detecting a voltage drop at the point of common coupling of the energy storage system, how to select an island protection operation or a low voltage ride through operation becomes a technical problem that needs to be solved urgently.

[0003] Currently, by adjusting the reactive power of the energy storage system, the current state of the energy storage system is actively detected, and if it is determined that the energy storage system is in an island state, an island protection operation is performed; if it is determined that the energy storage system is in a low voltage ride through state, a low voltage ride through is performed.

[0004] However, when determining the island state or low voltage state of the energy storage system based on the prior art, introducing reactive power adjustment will increase the frequency disturbance at the point of common coupling of the energy storage system, thereby causing errors in the determination of the low voltage ride through state and the island state. In addition, the existing energy storage system cannot continuously detect the island state of the energy storage system when performing a low voltage ride through operation, so that the island detection and low voltage ride through cannot coexist, and the safety and stability of the energy storage system cannot be guaranteed. SUMMARY

[0005] The purpose of the present application is to provide an energy storage system control method, device, computer equipment and readable storage medium, which can improve the accuracy of low voltage ride through and island protection determination, realize the coexistence of low voltage ride through and island detection, and improve the safety and stability of the energy storage system.

[0006] Embodiments of the present application are implemented as follows:

[0007] In a first aspect, an energy storage system control method is provided, comprising:

[0008] Real-time acquisition of voltage information and frequency information of the public coupling point of the energy storage system, the voltage information including voltage value, voltage sine quantity, and amplitude and phase of the voltage sine quantity, and the frequency information including frequency value;

[0009] Real-time determination of whether the energy storage system is currently in an island state according to the voltage information and the frequency information of the public coupling point of the energy storage system;

[0010] If not, determination of voltage drop information of the public coupling point of the energy storage system according to the voltage information of the public coupling point of the energy storage system, the voltage drop information including voltage drop value and voltage drop duration;

[0011] Real-time determination of an operation state of the energy storage system according to the voltage drop information, the frequency information, preset rated voltage, preset rated frequency, preset voltage range, preset frequency error threshold, and preset time threshold of the public coupling point of the energy storage system, the operation state including normal state, island state, low-voltage ride-through state, or low-voltage protection state;

[0012] Determination of a to-be-executed operation of the energy storage system according to the operation state of the energy storage system, the to-be-executed operation including island protection operation, low-voltage ride-through operation, or under-voltage shutdown protection operation.

[0013] As a possible implementation manner, the determination of the voltage drop information of the public coupling point of the energy storage system according to the voltage information of the public coupling point of the energy storage system includes:

[0014] Generation of a first sine quantity and a second sine quantity according to the voltage sine quantity and the phase and amplitude of the voltage sine quantity in the voltage information of the public coupling point of the energy storage system, the first sine quantity and the second sine quantity being orthogonal, wherein the amplitude and the phase of the first sine quantity are the same as those of the voltage sine quantity, and the amplitude of the second sine quantity is the same as that of the voltage sine quantity;

[0015] Determination of an instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system according to the first sine quantity and the second sine quantity;

[0016] Determination of the voltage drop information of the public coupling point of the energy storage system according to the instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system and a preset threshold.

[0017] As a possible implementation manner, the determination of the instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system according to the first sine quantity and the second sine quantity includes:

[0018] Calculation of an absolute value of the first sine quantity according to the amplitude and the phase of the first sine quantity;

[0019] Calculation of an absolute value of the second sine quantity according to the amplitude and the phase of the second sine quantity;

[0020] Adding the absolute value of the first sinusoidal quantity to the absolute value of the second sinusoidal quantity obtains an instantaneous direct current corresponding to the voltage information of the point of common coupling of the energy storage system.

[0021] As a possible implementation manner, the operating state of the energy storage system is determined in real time according to the voltage drop information and the frequency information of the point of common coupling of the energy storage system, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold and the preset time threshold, and includes:

[0022] If the voltage drop value in the voltage drop information of the point of common coupling of the energy storage system reaches the preset threshold, and the voltage drop duration in the voltage drop information is greater than or equal to the preset time threshold, it is determined that the operating state of the energy storage system is a low-voltage protection state;

[0023] If the voltage drop value in the voltage drop information of the point of common coupling of the energy storage system reaches the preset threshold, and the voltage drop duration in the voltage drop information is less than the preset time threshold, the operating state of the energy storage system is determined in real time according to the voltage drop value in the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset frequency error threshold and the preset voltage range, whether the operating state of the energy storage system is a normal state, an island state or a low-voltage ride-through state;

[0024] If the voltage drop value in the voltage drop information of the point of common coupling of the energy storage system does not reach the preset threshold, the operating state of the energy storage system is determined in real time according to the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold and the preset time threshold, whether the operating state of the energy storage system is a normal state, an island state, a low-voltage ride-through state or a low-voltage protection state.

[0025] As a possible implementation manner, the operating state of the energy storage system is determined in real time according to the voltage drop value in the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset frequency error threshold and the preset voltage range, whether the operating state of the energy storage system is a normal state, an island state or a low-voltage ride-through state, and includes:

[0026] If the voltage drop value in the voltage drop information is equal to the preset rated voltage, it is determined that the operating state of the energy storage system is a normal state;

[0027] The frequency error between the frequency value in the frequency information and the preset rated frequency is determined.

[0028] If the frequency error is greater than the preset frequency error threshold, it is determined that the operating state of the energy storage system is an island state;

[0029] If the voltage drop value in the voltage drop information is within the preset voltage range, it is determined that the operating state of the energy storage system is a low voltage ride through state.

[0030] As a possible implementation manner, according to the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold and the preset time threshold, it is determined whether the operating state of the energy storage system is the normal state, the island state, the low voltage ride through state or the low voltage protection state in real time, including:

[0031] If the voltage drop value in the voltage drop information is equal to the preset rated voltage, and the voltage drop duration in the voltage drop information is less than the preset time threshold, it is determined that the operating state of the energy storage system is the normal state.

[0032] The frequency error between the frequency value in the frequency information and the preset rated frequency is determined.

[0033] If the frequency error is greater than the preset frequency error threshold, it is determined that the operating state of the energy storage system is the island state.

[0034] If the voltage drop value in the voltage drop information is within the preset voltage range, and the voltage drop time in the voltage drop information is less than the preset time threshold, it is determined that the operating state of the energy storage system is the low voltage ride through state.

[0035] If the voltage drop duration in the voltage drop information is greater than or equal to the preset time threshold, it is determined that the operating state of the energy storage system is the low voltage protection state.

[0036] As a possible implementation manner, the frequency error between the frequency value in the frequency information and the preset rated frequency is determined, including:

[0037] The difference between the frequency value in the frequency information and the preset rated frequency is calculated.

[0038] The product of the preset feedback coefficient and the difference is calculated.

[0039] The sum of the preset initial chopping coefficient and the product is calculated to determine the target chopping coefficient.

[0040] According to the target chopping coefficient, the target reactive current and the frequency value corresponding to the target reactive current are determined.

[0041] According to the frequency value corresponding to the target reactive current and the frequency value in the frequency information, the frequency error is determined.

[0042] As a possible implementation manner, according to the operating state of the energy storage system, the operation to be performed by the energy storage system is determined, including:

[0043] If the operation state of the energy storage system is an island state, the energy storage system is determined to have an island protection operation to be performed;

[0044] If the operation state of the energy storage system is a low-voltage ride-through state, the energy storage system is determined to have a low-voltage ride-through operation to be performed;

[0045] If the operation state of the energy storage system is a low-voltage protection state, the energy storage system is determined to have an under-voltage shutdown protection state to be performed.

[0046] In a second aspect, the embodiment of the present application provides a device for controlling an energy storage system, which comprises:

[0047] An acquisition module is configured to acquire voltage information and frequency information of a point of common coupling (PCC) of the energy storage system in real time, wherein the voltage information comprises a voltage value, a voltage sine quantity, and an amplitude and a phase of the voltage sine quantity, and the frequency information comprises a frequency value;

[0048] An island detection module is configured to determine whether the energy storage system is currently in an island state in real time according to the voltage information and the frequency information of the PCC of the energy storage system.

[0049] If not, a voltage drop detection module is configured to determine voltage drop information of the PCC of the energy storage system according to the voltage information of the PCC of the energy storage system, wherein the voltage drop information comprises a voltage drop value and a voltage drop duration.

[0050] A first determination module is configured to determine an operation state of the energy storage system in real time according to the voltage drop information and the frequency information of the PCC of the energy storage system, a preset rated voltage, a preset rated frequency, a preset voltage range, a preset frequency error threshold, and a preset time threshold, wherein the operation state comprises a normal state, an island state, a low-voltage ride-through state, or a low-voltage protection state.

[0051] A second determination module is configured to determine an operation to be performed by the energy storage system according to the operation state of the energy storage system, wherein the operation to be performed comprises an island protection operation, a low-voltage ride-through operation, or an under-voltage shutdown protection operation.

[0052] In a third aspect, the embodiment of the present application provides a computer device, which comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the computer program is executed by the processor, the computer program implements the energy storage system control method in the first aspect.

[0053] In a fourth aspect, the embodiment of the present application provides a computer readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the computer program implements the energy storage system control method in the first aspect.

[0054] The beneficial effects of the embodiments of the present application include:

[0055] The energy storage system control method provided by the embodiments of the present application actively determines whether the energy storage system is in an island state according to the voltage information and the frequency information of the PCC of the energy storage system; if it is determined that the energy storage system is not in the island state, the voltage drop information of the PCC of the energy storage system is determined according to the voltage information of the PCC of the energy storage system; the operating state of the energy storage system is determined in real time according to the voltage drop information of the PCC of the energy storage system, the frequency information, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold and the preset time range, and corresponding operations are performed according to the operating state of the energy storage system. The energy storage system determines the low voltage ride-through state without introducing reactive power regulation, which can effectively reduce the disturbance of reactive power on the voltage and frequency of the PCC of the energy storage system, and can effectively improve the accuracy of low voltage ride-through and island state determination; while performing the low voltage ride-through operation, the energy storage system continues to determine whether the operating state of the energy storage system is the island state according to the frequency information, the preset rated frequency and the preset frequency error threshold, thereby providing a coexistence basis for low voltage ride-through and island detection of the energy storage system. In this way, the accuracy of low voltage ride-through and island protection determination can be improved, low voltage ride-through and island detection can coexist, and the safety and stability of the energy storage system can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0057] Figure 1 The flow chart of the first energy storage system control method provided by the embodiments of the present application;

[0058] Figure 2 The voltage waveform diagram of the low voltage fault operating standard provided by the present application;

[0059] Figure 3 The flow chart of the second energy storage system control method provided by the embodiments of the present application;

[0060] Figure 4 The principle diagram of the power-down rapid detection of the energy storage system provided by the embodiments of the present application;

[0061] Figure 5An equivalent waveform diagram of a voltage sine quantity provided for an embodiment of the present application;

[0062] Figure 6 A flow chart of a third energy storage system control method provided for an embodiment of the present application;

[0063] Figure 7 A flow chart of a fourth energy storage system control method provided for an embodiment of the present application;

[0064] Figure 8 A flow chart of a fifth energy storage system control method provided for an embodiment of the present application;

[0065] Figure 9 A flow chart of a complete energy storage system control provided for an embodiment of the present application;

[0066] Figure 10 A flow chart of an active islanding state detection method provided for an embodiment of the present application;

[0067] Figure 11 A flow chart of a sixth energy storage system control method provided for an embodiment of the present application;

[0068] Figure 12 A structural schematic diagram of an energy storage system control device provided for an embodiment of the present application;

[0069] Figure 13 A structural schematic diagram of a computer device provided for an embodiment of the present application. DETAILED DESCRIPTION

[0070] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0071] Therefore, the detailed description of the embodiments of the present application provided below in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0072] Currently, both islanding protection and low voltage ride-through (LVRT) operations in energy storage systems are implemented by a host computer issuing corresponding instructions based on the energy storage system's detection results. LVRT detection in energy storage systems often involves reactive power regulation. However, in this approach, the energy storage system cannot perform islanding detection concurrently with executing the LVRT instructions issued by the host computer, making it impossible to promptly address the energy storage system's islanding condition. Furthermore, the introduction of reactive power regulation in the energy storage system increases frequency disturbances at the energy storage system's common coupling point, reducing the accuracy of islanding and LVRT status determinations. This can lead to erroneous triggering of islanding protection during LVRT, resulting in LVRT failure and compromising the stability and safety of the energy storage system.

[0073] To this end, an embodiment of the present application provides an energy storage system control method, which obtains voltage and frequency information of the common coupling point of the energy storage system in real time, and actively detects whether the energy storage system is currently in an island state based on the voltage and frequency information of the common coupling point of the energy storage system. If the energy storage system is not currently in an island state, the voltage drop information of the common coupling point of the energy storage system is determined in real time based on the voltage information of the common coupling point of the energy storage system. The operating status of the energy storage system is determined in real time based on the voltage drop information and frequency information of the common coupling point of the energy storage system, a preset rated voltage, a preset rated frequency, a preset voltage range, a preset frequency error threshold, and a preset time threshold. Based on the operating status of the energy storage system, a pending operation of the energy storage system is determined in real time, and the energy storage system is governed according to the pending operation. The energy storage system determines the low voltage ride-through state without introducing reactive power regulation, effectively reducing the disturbance of reactive power to the voltage and frequency at the energy storage system's common coupling point. While performing low voltage ride-through operations, the energy storage system can also continue to determine whether the energy storage system's operating state is an islanding state based on frequency information, a preset rated frequency, and a preset frequency error threshold, providing a basis for the coexistence of low voltage ride-through and islanding detection. This improves the accuracy of low voltage ride-through and islanding protection judgments, enabling the coexistence of low voltage ride-through and islanding detection, and enhancing the safety and stability of the energy storage system.

[0074] The energy storage system control method provided in the embodiments of the present application is explained in detail below with reference to the accompanying drawings.

[0075] Figure 1 This is a flow chart of a method for controlling an energy storage system provided in this application, see Figure 1 , an embodiment of the present application provides an energy storage system control method, comprising:

[0076] S101. Acquire voltage information and frequency information of a common coupling point of an energy storage system in real time. The voltage information includes a voltage value, a voltage sinusoidal quantity, and an amplitude and phase of the voltage sinusoidal quantity. The frequency information includes a frequency value.

[0077] Optionally, the energy storage system has a grid connection point, an access point, and a common coupling point, wherein when the grid-connected power grid of the energy storage system is provided by a distributed power source with a booster station, the grid connection point of the energy storage system is the high-voltage side bus or node of the distributed power source booster station; when the grid-connected power grid of the energy storage system is provided by a distributed power source without a booster station, the grid connection point of the energy storage system is the output aggregation point of the distributed power source. The access point of the energy storage system refers to the connection point where the power source is connected to the grid, and the common coupling point of the energy storage system refers to the connection point where the energy storage system is connected to the grid. The common coupling point can also be referred to as the PCC (Point of Common Coupling, referred to as PCC) point, which is not specifically limited in this application.

[0078] Optionally, the voltage information of the common coupling point of the energy storage system is used to indicate the voltage change at the common coupling point of the energy storage system. The voltage information includes: voltage value, voltage sinusoidal quantity, phase and amplitude of the voltage sinusoidal quantity, etc., wherein the voltage sinusoidal quantity is used to indicate the voltage component of the common coupling point of the energy storage system that changes sinusoidally over time, the phase is used to characterize the waveform offset of the voltage sinusoidal quantity, and the amplitude is used to characterize the amplitude of the voltage sinusoidal quantity; the frequency information of the common coupling point of the energy storage system is used to indicate the frequency information corresponding to the voltage change at the common coupling point of the energy storage system, and the frequency information includes: frequency value and frequency amplitude.

[0079] S102 : Determine in real time whether the energy storage system is currently in an island state based on voltage information and frequency information of a common coupling point of the energy storage system.

[0080] Optionally, the system can be determined to determine whether the energy storage system is in an islanding state by determining whether the voltage or frequency information at the energy storage system's point of common coupling is abnormal. The islanding state indicates that when the grid-connected power grid suddenly loses voltage, the power generation equipment in the energy storage system continues to serve as an isolated power source to supply power to the load. It is worth noting that an islanding state occurs when the voltage or frequency at the energy storage system's point of common coupling exhibits significant anomalies.

[0081] S103 : If not, determine voltage drop information of the common coupling point of the energy storage system according to the voltage information of the common coupling point of the energy storage system, where the voltage drop information includes: a voltage drop value and a voltage drop duration.

[0082] Optionally, the voltage drop information of the energy storage system point of common coupling is used to indicate a voltage drop of the energy storage system point of common coupling compared with a voltage in a normal operation state of the energy storage system, and the voltage drop information includes a voltage drop value and a voltage drop duration. The voltage drop value is used to indicate a current voltage value after the voltage drop of the energy storage system point of common coupling, and the voltage drop duration is used to indicate a duration of the voltage drop action when the voltage drop occurs at the energy storage system point of common coupling.

[0083] In S104, the operation state of the energy storage system is determined in real time according to the voltage drop information of the energy storage system point of common coupling, the frequency information, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold and the preset time threshold. The operation state includes a normal state, an island state, a low voltage ride through state or a low voltage protection state.

[0084] Optionally, the preset rated voltage is a voltage limit value customized by a user or a manufacturer according to a production specification of the energy storage system. Whether the operation state of the energy storage system is the normal state is determined based on whether the voltage value of the point of common coupling of the energy storage system is equal to the preset rated voltage. The normal state is used to indicate that the operation power and the voltage of the energy storage system are normal.

[0085] Optionally, the preset rated frequency is a frequency limit value customized by the user or the manufacturer according to the production specification of the energy storage system. Whether the frequency value of the energy storage system is abnormal is determined based on whether a frequency error between the frequency value corresponding to the voltage change of the point of common coupling of the energy storage system and the preset rated frequency exceeds the preset frequency error threshold, and then whether the energy storage system is in the island state is determined passively.

[0086] Optionally, the preset voltage range is a low voltage range customized by the user or the manufacturer according to the production specification of the energy storage system, and the preset time threshold is a time threshold of a low voltage ride through operation set by the user or the manufacturer according to international regulations. The preset time threshold can be 2 seconds, and the present application does not make a specific limitation.

[0087] Optionally, whether the energy storage system meets the low voltage ride through condition and whether the energy storage system is in the low voltage ride through state can be determined according to the voltage drop information of the point of common coupling of the energy storage system, the preset voltage range and the preset time threshold. The low voltage ride through state is used to indicate that the voltage of the point of common coupling of the energy storage system temporarily drops or temporarily rises.

[0088] Optionally, whether the energy storage system is in the low voltage protection state can be determined according to the voltage drop information of the point of common coupling of the energy storage system, the voltage value indicated by the preset rated voltage and the preset time threshold. The low voltage protection state is used to indicate an operation state in which a duration of the energy storage system operating at a lower voltage exceeds a specified time.

[0089] S105, determining an operation to be performed of the energy storage system according to the operating state of the energy storage system, the operation to be performed including island protection operation, low voltage ride through operation or under-voltage shutdown protection operation.

[0090] Optionally, the operation to be performed of the energy storage system is used to indicate an operation for governing a current operating state of the energy storage system, each operating state having a corresponding governing operation. The island protection operation is used to govern the island state of the energy storage system, and can disconnect the continuous power supply of the isolated power supply in the island state, thereby improving the safety of the energy storage system. The low voltage ride through operation can effectively govern voltage fluctuation problems such as voltage transient rise, voltage transient drop and short-time terminal voltage of the energy storage system, and can effectively improve the stability of the energy storage system. The under-voltage shutdown protection operation can effectively govern the long-time low voltage continuous operation of the energy storage system, and can effectively reduce the energy consumption of the energy storage device in the energy storage system.

[0091] In the embodiments of the present application, the voltage value of the point of common coupling of the energy storage system and the frequency value generated by the change of the voltage value are obtained in real time, and whether the energy storage system is in an island state is actively determined according to the voltage information and the frequency information of the point of common coupling of the energy storage system. If it is determined that the energy storage system is not in an island state, the voltage drop information of the point of common coupling of the energy storage system is further determined according to the voltage information of the point of common coupling of the energy storage system. The operating state of the energy storage system is determined in real time according to the voltage drop information of the point of common coupling of the energy storage system, the frequency information, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold and the preset time range, and the corresponding operation is performed according to the operating state of the energy storage system. The energy storage system determines the low voltage ride through state without introducing reactive power regulation, which can effectively reduce the disturbance of reactive power to the voltage and frequency of the point of common coupling of the energy storage system, and can effectively improve the accuracy of low voltage ride through and island state determination. The energy storage system continues to determine whether the operating state of the energy storage system is an island state according to the frequency information, the preset rated frequency and the preset frequency error threshold while performing the low voltage ride through operation, thereby providing a coexistence basis for low voltage ride through and island detection of the energy storage system. In this way, the accuracy of low voltage ride through and island protection determination can be improved, low voltage ride through and island detection can coexist, and the safety and stability of the energy storage system can be improved.

[0092] Figure 2 The voltage waveform diagram of the low voltage fault operation standard provided in the present application is shown in Figure 2, the preset rated voltage is set to 1, the preset time threshold is set to 2 seconds, and the energy storage system is in a normal operation state when the ordinate of the voltage profile line is greater than or equal to 0.9; the voltage profile line has a temporary drop at 0 seconds and a temporary rise at 0.15 seconds, the voltage is 0.2 from 0.15 seconds to 0.625 seconds, and the duration of the low voltage 0.2 is 0.625-0.15=0.475, so it is determined that the energy storage system enters a low voltage state at 0 seconds, and the voltage profile line performs low voltage ride-through operation from 0.625 seconds to 2 seconds, so that the energy storage system recovers to 90% of the preset rated power at the node of 2 seconds.

[0093] In an optional embodiment, referring to Figure 3 The operation of step S103 can be specifically as follows:

[0094] S301, generating a first sinusoidal quantity and a second sinusoidal quantity according to a voltage sinusoidal quantity in voltage information of a point of common coupling of the energy storage system and a phase and an amplitude of the voltage sinusoidal quantity, the first sinusoidal quantity and the second sinusoidal quantity being orthogonal, wherein the amplitude and the phase of the first sinusoidal quantity are the same as those of the voltage sinusoidal quantity, and the amplitude of the second sinusoidal quantity is the same as that of the voltage sinusoidal quantity.

[0095] Optionally, the first sinusoidal quantity and the second sinusoidal quantity are voltage components of the voltage sinusoidal quantity, the first sinusoidal quantity and the second sinusoidal quantity are orthogonal, the phase of the first sinusoidal quantity is the same as that of the voltage sinusoidal quantity, and the amplitude of the first sinusoidal quantity is also equal to that of the voltage sinusoidal quantity, that is, the first sinusoidal quantity is the same as the voltage sinusoidal quantity; the amplitude of the second sinusoidal quantity is equal to that of the voltage sinusoidal quantity, and the first sinusoidal quantity and the second sinusoidal quantity are orthogonal, that is, the phase of the second sinusoidal quantity lags behind that of the voltage sinusoidal quantity by 90 degrees.

[0096] S302, determining an instantaneous direct current quantity corresponding to the voltage information of the point of common coupling of the energy storage system according to the first sinusoidal quantity and the second sinusoidal quantity.

[0097] Optionally, according to the first sinusoidal quantity and the second sinusoidal quantity, the instantaneous direct current quantity corresponding to the voltage information of the point of common coupling of the energy storage system can be determined, the instantaneous direct current quantity is used to indicate the voltage direct current quantity of the point of common coupling of the energy storage system at each moment, and the value of the instantaneous direct current quantity is not affected by the change of the voltage direction of the voltage sinusoidal quantity.

[0098] S303, determining voltage drop information of the point of common coupling of the energy storage system according to the instantaneous direct current quantity corresponding to the voltage information of the point of common coupling of the energy storage system and a preset threshold.

[0099] Optionally, the preset threshold is a voltage drop limit value set by a person, and the preset threshold is taken as 0V in the present application, but it does not mean that the preset threshold can only be 0V, which is not limited in the present application.

[0100] Optionally, the voltage drop information of the public coupling point of the energy storage system is determined according to a comparison result of the instantaneous direct current corresponding to the voltage information of the public coupling point of the energy storage system and a preset threshold.

[0101] In an optional implementation, the operation of step S302 can be specifically as follows:

[0102] The absolute value of the first sinusoidal quantity is calculated according to the amplitude and phase of the first sinusoidal quantity;

[0103] The absolute value of the second sinusoidal quantity is calculated according to the amplitude and phase of the second sinusoidal quantity;

[0104] The absolute value of the first sinusoidal quantity is added to the absolute value of the second sinusoidal quantity to obtain the instantaneous direct current corresponding to the voltage information of the public coupling point of the energy storage system.

[0105] Figure 4 A schematic diagram of the energy storage system power-off rapid detection provided by the present application is shown in FIG. 1. Figure 4 The orthogonal signal generator generates a set of orthogonal sinusoidal quantities from the voltage sinusoidal quantity Vin of the voltage of the public coupling point of the energy storage system, which are a first sinusoidal quantity Va and a second sinusoidal quantity Vb. The first sinusoidal quantity Va has the same amplitude and phase as the voltage sinusoidal quantity Vin, and the second sinusoidal quantity Vb has the same amplitude as the voltage sinusoidal quantity Vin but a phase lag of 90 degrees compared with the phase of the voltage sinusoidal quantity Vin. W0 is the sine power frequency angle frequency value. After the controller obtains the voltage values of the first sinusoidal quantity Va and the second sinusoidal quantity Vb, the sum of the absolute values of the first sinusoidal quantity Va and the second sinusoidal quantity Vb is calculated to obtain the voltage value of Vd, as follows: Vd = |Va| + |Vb|. Vd can equivalently reflect the instantaneous direct current corresponding to the voltage information of the public coupling point of the energy storage system, and thus the voltage drop condition of the public coupling point of the energy storage system can be rapidly determined.

[0106] Figure 5 An equivalent waveform diagram of the voltage sinusoidal quantity provided by the present application is shown in FIG. 2. Figure 5 Vd is used to reflect the instantaneous direct current corresponding to the voltage information of the public coupling point of the energy storage system, Va is used to represent the first sinusoidal quantity, Vb is used to represent the second sinusoidal quantity, and Va and Vb are combined to represent the voltage sinusoidal quantity of the public coupling point of the energy storage system.

[0107] In an optional implementation, the operation of step S104 can be specifically as follows: Figure 6

[0108] S601, if the voltage drop value in the voltage drop information of the public coupling point of the energy storage system reaches a preset threshold, and the voltage drop duration in the voltage drop information is greater than or equal to a preset time threshold, it is determined that the operating state of the energy storage system is a low-voltage protection state.​

[0109] Optionally, if it is determined that the voltage drop value in the voltage drop information of the PCC of the energy storage system reaches 0 volt and the voltage drop duration in the voltage drop information exceeds the preset time threshold, it is determined that the energy storage system is in overvoltage operation, and the operation state of the energy storage system is a low-voltage protection state.

[0110] S602, if the voltage drop value in the voltage drop information of the PCC of the energy storage system reaches the preset threshold value, and the voltage drop duration in the voltage drop information is less than the preset time threshold, the operation state of the energy storage system is determined in real time according to the voltage drop value in the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset frequency error threshold and the preset voltage range, whether it is a normal state, an island state or a low-voltage ride-through state.

[0111] Optionally, if it is determined that the voltage drop value in the voltage drop information of the PCC of the energy storage system reaches 0 volt, but the voltage drop duration in the voltage drop information does not exceed the preset time threshold, the operation state of the energy storage system is further determined according to the voltage drop value in the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset frequency error threshold and the preset voltage range, whether it is a normal state, an island state or a low-voltage ride-through state.

[0112] S603, if the voltage drop value in the voltage drop information of the PCC of the energy storage system does not reach the preset threshold value, the operation state of the energy storage system is determined in real time according to the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold and the preset time threshold, whether it is a normal state, an island state, a low-voltage ride-through state or a low-voltage protection state.

[0113] Optionally, if it is determined that the voltage drop value in the voltage drop information of the PCC of the energy storage system does not reach 0 volt, the operation state of the energy storage system is further determined according to the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold and the preset time threshold, whether it is a normal state, an island state, a low-voltage ride-through or a low-voltage protection state.

[0114] In an optional embodiment, referring to Figure 7 , the operation of step S602 can be specifically:

[0115] S701, if the voltage drop value in the voltage drop information is equal to the preset rated voltage, it is determined that the operation state of the energy storage system is a normal state.

[0116] Optionally, if the voltage drop value in the voltage drop information is exactly equal to the preset rated voltage, it can be determined that the energy storage system is in a normal operation state.

[0117] S702, determine a frequency error between the frequency value in the frequency information and the preset rated frequency.

[0118] Optionally, the frequency error between the frequency value of the energy storage system point of common coupling and the preset rated frequency is determined.

[0119] S703, if the frequency error is greater than the preset frequency error threshold, it is determined that the operation state of the energy storage system is an island state.

[0120] Optionally, if the frequency error of the energy storage system point of common coupling is greater than the preset frequency error threshold, it is determined that the frequency of the energy storage system point of common coupling is abnormal, that is, the current operation state of the energy storage system is determined to be an island state.

[0121] S704, if the voltage drop value in the voltage drop information is within the preset voltage range, it is determined that the operation state of the energy storage system is a low voltage ride through state.

[0122] Optionally, if the voltage value in the voltage drop information of the energy storage system point of common coupling falls within the preset voltage range, and the voltage drop duration in the voltage drop information satisfies the preset time threshold, it is determined that the current operation state of the energy storage system is a low voltage ride through state.

[0123] In an optional embodiment, referring to Figure 8 , the operation of step S603 can be specifically:

[0124] S801, if the voltage drop value in the voltage drop information is equal to the preset rated voltage, and the voltage drop duration in the voltage drop information is less than the preset time threshold, it is determined that the operation state of the energy storage system is a normal state.

[0125] Optionally, only when the voltage drop value in the voltage drop information of the energy storage system point of common coupling is equal to the preset rated voltage, and the voltage drop duration indicated by the voltage drop information does not exceed the preset time threshold, it is determined that the energy storage system is in a normal operation state.

[0126] S802, determine a frequency error between the frequency value in the frequency information and the preset rated frequency.

[0127] S803, if the frequency error is greater than the preset frequency error threshold, it is determined that the operation state of the energy storage system is an island state.

[0128] S804, if the voltage drop value in the voltage drop information is within the preset voltage range, and the voltage drop time in the voltage drop information is less than the preset time threshold, it is determined that the operating state of the energy storage system is a low voltage ride through state.

[0129] Optionally, only when the voltage drop value in the voltage drop information of the energy storage system public coupling point falls within the preset voltage range, and the voltage drop duration indicated by the voltage drop information does not exceed the preset time threshold, it is determined that the current operating state of the energy storage system is a low voltage ride through state.

[0130] S805, if the voltage drop duration in the voltage drop information is greater than or equal to the preset time threshold, it is determined that the operating state of the energy storage system is a low voltage protection state.

[0131] Figure 9 A complete energy storage system control flowchart is provided for the present application, see Figure 9 When the energy storage system is normally connected with the grid-connected power grid, it is judged whether the energy storage system is currently in an island state through active island detection or passive island detection, wherein the active island detection is based on the frequency corresponding to the voltage change trend of the energy storage system public coupling point, and the passive island detection is based on the voltage of the energy storage system public coupling point. If the detection result shows that the voltage or frequency of the energy storage system public coupling point is abnormal, the energy storage system is currently in an island state, and the island protection inverter is directly shut down to realize island protection operation; if the detection result shows that the voltage or frequency of the energy storage system public coupling point is normal, the energy storage system currently does not exist in an island state, and it is further judged whether the energy storage system exists in a low voltage ride through state or a low voltage protection state; if the voltage drop information of the energy storage system public coupling point is detected, it is further judged whether the voltage drop value in the voltage drop information of the energy storage system public coupling point drops to the preset threshold of 0 volts, if the voltage drop value reaches 0 volts, it is further judged whether the duration of the voltage drop value of 0 volts exceeds the preset time threshold, when the duration exceeds the preset time threshold, the current operating state of the energy storage system is a low voltage protection state, and the under-voltage protection inverter is directly shut down; if the voltage drop value reaches 0 volts, and the duration of the voltage drop value of 0 volts does not exceed the preset time threshold, the current operating state of the energy storage system is a low voltage ride through state, and the low voltage ride through operation is directly performed; if the voltage drop value does not reach 0 volts, it is further judged whether the voltage drop value of the energy storage system is within the preset voltage range, if it is within the preset voltage range, it is further judged whether the voltage drop duration exceeds the preset time threshold, and it is continuously judged whether the voltage or power of the energy storage system is abnormal, and whether the current operating state of the energy storage system is an island state or a low voltage ride through state.

[0132] It is worth mentioning that when judging whether the energy storage system is in island state for the first time, passive island detection is usually adopted, and when the energy storage system performs low voltage ride through operation, active island detection method needs to be adopted.

[0133] Figure 10 A flow chart of an active island detection method provided in the present application is shown in Figure 10 , cf represents the chopping coefficient, cf0 represents the initial chopping coefficient, k represents the feedback coefficient, fg represents the preset rated frequency, f represents the frequency corresponding to the voltage change trend of the point of common coupling of the energy storage system, and the reactive current given quantity of the energy storage system is set according to the chopping coefficient.

[0134] Optionally, the initial chopping coefficient is set to a small value, which can reduce the frequency disturbance to the energy storage system and reduce the influence on the operation power quality of the energy storage system, and the reactive current given quantity is used to provide an initial frequency offset for the energy storage system.

[0135] Optionally, the frequency difference value can improve the drift speed of the energy storage system, accelerate the response speed of the island state judgment of the energy storage system, and shorten the island state judgment time.

[0136] In an optional embodiment, the operation of step S801 or S902 can be specifically as follows:

[0137] The difference between the frequency value in the frequency information and the preset rated frequency is calculated;

[0138] The product of the preset feedback coefficient and the difference value is calculated;

[0139] The sum of the preset initial chopping coefficient and the product is calculated to determine the target chopping coefficient;

[0140] According to the target chopping coefficient, the target reactive current and the frequency value corresponding to the target reactive current are determined;

[0141] According to the frequency value corresponding to the target reactive current and the frequency value in the frequency information, the frequency error is determined.

[0142] Optionally, the actual frequency error of the energy storage system PCC can be determined according to the difference between the frequency value corresponding to the voltage variation trend of the energy storage system PCC and the preset rated power. The preset feedback coefficient is a user or manufacturer self-defined setting, and the preset feedback coefficient is used to expand the multiple of the actual frequency error of the energy storage system PCC, thereby accelerating the response speed of the island state judgment; the preset initial chopping coefficient is used to increase the initial frequency offset of the energy storage system; the target chopping coefficient is used to indicate the direct current amount of the given reactive current; the target reactive current refers to the reactive current loaded on the energy storage system when the energy storage system performs active island detection; and the frequency value corresponding to the target reactive current is used to indicate the preset rated frequency.

[0143] Optionally, the given target reactive current on the energy storage system is used to detect the frequency error of the energy storage system, thereby quickly responding to the island protection operation.

[0144] In an optional implementation, referring to Figure 11 , the operation of step S105 can be specifically:

[0145] S1101, if the running state of the energy storage system is an island state, determining that the to-be-executed operation of the energy storage system is an island protection operation.

[0146] Optionally, when the energy storage system is in an island state, it is determined that the energy storage system needs to perform an island protection operation to ensure the safety of the energy storage system.

[0147] S1102, if the running state of the energy storage system is a low-voltage ride-through state, determining that the to-be-executed operation of the energy storage system is a low-voltage ride-through operation.

[0148] Optionally, when the current running state of the energy storage system meets the low-voltage ride-through condition, it is determined that the energy storage system needs to perform a low-voltage ride-through operation to ensure the stability of the energy storage system.

[0149] S1103, if the running state of the energy storage system is a low-voltage protection state, determining that the to-be-executed operation of the energy storage system is an under-voltage shutdown protection state.

[0150] Optionally, when the current running state of the energy storage system is a low-voltage protection state, it is determined that the energy storage system needs to immediately perform an under-voltage shutdown protection to improve the service life of the energy storage system.

[0151] The following describes the device, equipment and computer readable storage medium provided by the energy storage system control method of the present application, and the specific implementation process and technical effects are described above, and the following will not be described.

[0152] Figure 12 is a structure diagram of an energy storage system control device provided by an embodiment of the present application, referring toFigure 12 The device comprises:

[0153] The acquisition module 1201 is configured to acquire voltage information and frequency information of a public coupling point of the energy storage system in real time, the voltage information comprising a voltage value, a voltage sine quantity, and an amplitude and a phase of the voltage sine quantity, and the frequency information comprising a frequency value;

[0154] The island detection module 1202 is configured to determine whether the energy storage system is currently in an island state in real time according to the voltage information and the frequency information of the public coupling point of the energy storage system.

[0155] If not, the voltage drop detection module 1203 is configured to determine voltage drop information of the public coupling point of the energy storage system according to the voltage information of the public coupling point of the energy storage system, the voltage drop information comprising a voltage drop value and a voltage drop duration.

[0156] The first determination module 1204 is configured to determine a running state of the energy storage system in real time according to the voltage drop information and the frequency information of the public coupling point of the energy storage system, a preset rated voltage, a preset rated frequency, a preset voltage range, a preset frequency error threshold, and a preset time threshold, the running state comprising a normal state, an island state, a low-voltage ride-through state, or a low-voltage protection state.

[0157] The second determination module 1205 is configured to determine a to-be-executed operation of the energy storage system according to the running state of the energy storage system, the to-be-executed operation comprising an island protection operation, a low-voltage ride-through operation, or an under-voltage shutdown protection operation.

[0158] As an optional implementation, the voltage drop detection module 1203 is configured to:

[0159] generate a first sine quantity and a second sine quantity according to the voltage sine quantity and the phase and the amplitude of the voltage sine quantity in the voltage information of the public coupling point of the energy storage system, the first sine quantity and the second sine quantity being orthogonal, wherein the amplitude and the phase of the first sine quantity are the same as those of the voltage sine quantity, and the amplitude of the second sine quantity is the same as that of the voltage sine quantity;

[0160] determine an instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system according to the first sine quantity and the second sine quantity;

[0161] determine the voltage drop information of the public coupling point of the energy storage system according to the instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system and a preset threshold.

[0162] As an optional implementation, the voltage drop detection module 1203 is specifically configured to:

[0163] calculate an absolute value of the first sine quantity according to the amplitude and the phase of the first sine quantity.

[0164] According to the amplitude and the phase of the second sinusoidal quantity, the absolute value of the second sinusoidal quantity is calculated;

[0165] The absolute value of the first sinusoidal quantity and the absolute value of the second sinusoidal quantity are added to obtain the instantaneous direct current corresponding to the voltage information of the point of common coupling of the energy storage system.

[0166] As an optional implementation, the first determination module 1204 is configured to:

[0167] If the voltage drop value in the voltage drop information of the point of common coupling of the energy storage system reaches the preset threshold value, and the voltage drop duration in the voltage drop information is greater than or equal to the preset time threshold value, it is determined that the operating state of the energy storage system is a low-voltage protection state;

[0168] If the voltage drop value in the voltage drop information of the point of common coupling of the energy storage system reaches the preset threshold value, and the voltage drop duration in the voltage drop information is less than the preset time threshold value, the operating state of the energy storage system is determined in real time according to the voltage drop value in the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset frequency error threshold value, and the preset voltage range, whether it is a normal state, an island state or a low-voltage ride-through state;

[0169] If the voltage drop value in the voltage drop information of the point of common coupling of the energy storage system does not reach the preset threshold value, the operating state of the energy storage system is determined in real time according to the voltage drop information, the frequency information, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold value, and the preset time threshold value, whether it is a normal state, an island state, a low-voltage ride-through state or a low-voltage protection state.

[0170] As an optional implementation, the first determination module 1204 is specifically configured to:

[0171] If the voltage drop value in the voltage drop information is equal to the preset rated voltage, the operating state of the energy storage system is a normal state;

[0172] The frequency error between the frequency value in the frequency information and the preset rated frequency is determined;

[0173] If the frequency error is greater than the preset frequency error threshold value, it is determined that the operating state of the energy storage system is an island state;

[0174] If the voltage drop value in the voltage drop information is within the preset voltage range, the operating state of the energy storage system is a low-voltage ride-through state.

[0175] As an optional implementation, the first determination module 1204 is specifically further configured to:

[0176] If the voltage drop value in the voltage drop information is equal to the preset rated voltage, and the voltage drop duration in the voltage drop information is less than the preset time threshold, the operation state of the energy storage system is a normal state.

[0177] determining a frequency error between the frequency value in the frequency information and the preset rated frequency;

[0178] If the frequency error is greater than the preset frequency error threshold, it is determined that the operation state of the energy storage system is an island state.

[0179] If the voltage drop value in the voltage drop information is within the preset voltage range, and the voltage drop time in the voltage drop information is less than the preset time threshold, the operation state of the energy storage system is a low voltage ride through state.

[0180] If the voltage drop duration in the voltage drop information is greater than or equal to the preset time threshold, the operation state of the energy storage system is a low voltage protection state.

[0181] As an optional implementation, the first determination module 1204 can be specifically used for:

[0182] calculating a difference value between the frequency value in the frequency information and the preset rated frequency;

[0183] calculating a product of the preset feedback coefficient and the difference value;

[0184] calculating a sum of the preset initial chopping coefficient and the product, to determine a target chopping coefficient;

[0185] determining a target reactive current and a frequency value corresponding to the target reactive current according to the target chopping coefficient;

[0186] determining a frequency error according to the frequency value corresponding to the target reactive current and the frequency value in the frequency information.

[0187] As an optional implementation, the second determination module 1205 can be specifically used for:

[0188] If the operation state of the energy storage system is an island state, it is determined that the to-be-executed operation of the energy storage system is an island protection operation.

[0189] If the operation state of the energy storage system is a low voltage ride through state, it is determined that the to-be-executed operation of the energy storage system is a low voltage ride through operation.

[0190] If the operation state of the energy storage system is a low voltage protection state, it is determined that the to-be-executed operation of the energy storage system is an under-voltage shutdown protection state.

[0191] The device is used for executing the method provided by the foregoing embodiments, and has similar implementation principles and technical effects, which will not be repeated here.

[0192] The above modules can be one or more integrated circuits configured to implement the above method, for example, one or more application specific integrated circuits (ASICs), or one or more microprocessors, or one or more field programmable gate arrays (FPGAs), or the like. For another example, when a certain module above is implemented in the form of a processing element scheduling code, the processing element can be a general-purpose processor, for example, a central processing unit (CPU) or other processor that can invoke program code. For another example, the modules can be integrated together to be implemented in the form of a system on a chip (SOC).

[0193] Figure 13 is a structural schematic diagram of a computer device provided by an embodiment of the present application. Referring to Figure 13 The computer device includes a memory 1301 and a processor 1302. The memory 1301 stores a computer program that can run on the processor 1302. When the processor 1302 executes the computer program, the steps in any of the above method embodiments are implemented.

[0194] An embodiment of the present application further provides a computer readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in any of the above method embodiments can be implemented.

[0195] Optionally, the present application further provides a program product, for example, a computer readable storage medium, including a program. When the program is executed by a processor, the program is used for executing any of the above energy storage system control method embodiments.

[0196] In several embodiments of the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic, for example, the division of units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0197] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e. may be located in one place, or may be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment of the present application.

[0198] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of hardware plus software functional unit.

[0199] The integrated unit realized in the form of software functional unit can be stored in a computer readable storage medium. The software functional unit stored in a storage medium includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to execute part of the steps of the method of each embodiment of the present application. The foregoing storage medium includes: U disk, mobile hard disk, read-only memory (English: Read-Only Memory, for short: ROM), random access memory (English: Random Access Memory, for short: RAM), magnetic disk or optical disk and various program code storage media.

[0200] The foregoing is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be limited by the protection scope of the claims.

[0201] The above is only the preferred embodiment of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of controlling an energy storage system, characterized by, The method comprises: real-time acquisition of voltage information and frequency information of a public coupling point of an energy storage system, the voltage information comprising a voltage value, a voltage sine quantity, and an amplitude and a phase of the voltage sine quantity, and the frequency information comprising a frequency value; real-time determination of whether the energy storage system is currently in an island state according to the voltage information and the frequency information of the public coupling point of the energy storage system; if not, determination of voltage drop information of the public coupling point of the energy storage system according to the voltage information of the public coupling point of the energy storage system, the voltage drop information comprising a voltage drop value and a voltage drop duration; real-time determination of an operating state of the energy storage system according to the voltage drop information and the frequency information of the public coupling point of the energy storage system, a preset rated voltage, a preset rated frequency, a preset voltage range, a preset frequency error threshold, and a preset time threshold, the operating state comprising a normal state, an island state, a low-voltage ride-through state, or a low-voltage protection state; determination of a to-be-executed operation of the energy storage system according to the operating state of the energy storage system, the to-be-executed operation comprising an island protection operation, a low-voltage ride-through operation, or an under-voltage shutdown protection operation.

2. The energy storage system control method of claim 1, wherein, The determination of the voltage drop information of the public coupling point of the energy storage system according to the voltage information of the public coupling point of the energy storage system comprises: generation of a first sine quantity and a second sine quantity according to the voltage sine quantity and the amplitude and the phase of the voltage sine quantity in the voltage information of the public coupling point of the energy storage system, the first sine quantity and the second sine quantity being orthogonal, wherein the amplitude and the phase of the first sine quantity are the same as those of the voltage sine quantity, and the amplitude of the second sine quantity is the same as that of the voltage sine quantity; determination of an instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system according to the first sine quantity and the second sine quantity; determination of the voltage drop information of the public coupling point of the energy storage system according to the instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system and a preset threshold.

3. The energy storage system control method of claim 2, wherein, The determination of the instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system according to the first sine quantity and the second sine quantity comprises: calculation of an absolute value of the first sine quantity according to the amplitude and the phase of the first sine quantity; calculation of an absolute value of the second sine quantity according to the amplitude and the phase of the second sine quantity; addition of the absolute value of the first sine quantity and the absolute value of the second sine quantity to obtain the instantaneous direct current quantity corresponding to the voltage information of the public coupling point of the energy storage system.

4. The energy storage system control method of claim 1, wherein The real-time determination of the operating state of the energy storage system according to the voltage drop information and the frequency information of the public coupling point of the energy storage system, the preset rated voltage, the preset rated frequency, the preset voltage range, the preset frequency error threshold, and the preset time threshold comprises: if the voltage drop value in the voltage drop information of the public coupling point of the energy storage system reaches a preset threshold, and the voltage drop duration in the voltage drop information is greater than or equal to the preset time threshold, it is determined that the operating state of the energy storage system is a low-voltage protection state. If the voltage drop value in the voltage drop information of the point of common coupling of the energy storage system reaches a preset threshold value, and the voltage drop duration in the voltage drop information is less than the preset time threshold value, the running state of the energy storage system is determined in real time according to the voltage drop value in the voltage drop information, the frequency information, a preset rated voltage, a preset rated frequency, a preset frequency error threshold value and a preset voltage range, whether the running state is a normal state, an island state or a low voltage ride through state. If the voltage drop value in the voltage drop information of the point of common coupling of the energy storage system does not reach a preset threshold value, the running state of the energy storage system is determined in real time according to the voltage drop information, the frequency information, a preset rated voltage, a preset rated frequency, a preset voltage range, a preset frequency error threshold value and a preset time threshold value, whether the running state is a normal state, an island state, a low voltage ride through state or a low voltage protection state.

5. The energy storage system control method of claim 4, wherein, The determination of the running state of the energy storage system in real time according to the voltage drop value in the voltage drop information, the frequency information, a preset rated voltage, a preset rated frequency, a preset frequency error threshold value and a preset voltage range, whether the running state is a normal state, an island state or a low voltage ride through state, comprises: If the voltage drop value in the voltage drop information is equal to the preset rated voltage, it is determined that the running state of the energy storage system is a normal state. The frequency error between the frequency value in the frequency information and the preset rated frequency is determined. If the frequency error is greater than the preset frequency error threshold value, it is determined that the running state of the energy storage system is an island state. If the voltage drop value in the voltage drop information is within the preset voltage range, it is determined that the running state of the energy storage system is a low voltage ride through state.

6. The energy storage system control method of claim 4, wherein, The determination of the running state of the energy storage system in real time according to the voltage drop information, the frequency information, a preset rated voltage, a preset rated frequency, a preset voltage range, a preset frequency error threshold value and a preset time threshold value, whether the running state is a normal state, an island state, a low voltage ride through state or a low voltage protection state, comprises: If the voltage drop value in the voltage drop information is equal to the preset rated voltage, and the voltage drop duration in the voltage drop information is less than the preset time threshold value, it is determined that the running state of the energy storage system is a normal state. The frequency error between the frequency value in the frequency information and the preset rated frequency is determined. If the frequency error is greater than the preset frequency error threshold value, it is determined that the running state of the energy storage system is an island state. If the voltage drop value in the voltage drop information is within the preset voltage range, and the voltage drop time in the voltage drop information is less than the preset time threshold value, it is determined that the running state of the energy storage system is a low voltage ride through state. If the voltage drop duration in the voltage drop information is greater than or equal to the preset time threshold value, it is determined that the running state of the energy storage system is a low voltage protection state.

7. The energy storage system control method of claim 5 or 6, wherein, The determining the frequency error between the frequency value in the frequency information and the preset rated frequency comprises: calculating a difference between the frequency value in the frequency information and the preset rated frequency; calculating a product of a preset feedback coefficient and the difference; calculating a sum of a preset initial chopping coefficient and the product to determine a target chopping coefficient; determining a target reactive current and a frequency value corresponding to the target reactive current according to the target chopping coefficient; determining the frequency error according to the frequency value corresponding to the target reactive current and the frequency value in the frequency information.

8. The energy storage system control method of claim 1, wherein, The determining the operation to be performed by the energy storage system according to the operating state of the energy storage system comprises: if the operating state of the energy storage system is the island state, determining that the operation to be performed by the energy storage system is the island protection operation; if the operating state of the energy storage system is the low-voltage ride-through state, determining that the operation to be performed by the energy storage system is the low-voltage ride-through operation; if the operating state of the energy storage system is the low-voltage protection state, determining that the operation to be performed by the energy storage system is the under-voltage shutdown protection state.

9. An energy storage system control device, characterized by, The device comprises: an acquisition module configured to acquire voltage information and frequency information of a point of common coupling (PCC) of an energy storage system in real time, wherein the voltage information comprises a voltage value, a voltage sine quantity, and an amplitude and a phase of the voltage sine quantity, and the frequency information comprises a frequency value; an island detection module configured to determine whether the energy storage system is currently in an island state in real time according to the voltage information and the frequency information of the PCC of the energy storage system; if not, a voltage drop detection module is configured to determine voltage drop information of the PCC of the energy storage system according to the voltage information of the PCC of the energy storage system, wherein the voltage drop information comprises a voltage drop value and a voltage drop duration; a first determination module configured to determine an operating state of the energy storage system in real time according to the voltage drop information and the frequency information of the PCC of the energy storage system, a preset rated voltage, a preset rated frequency, a preset voltage range, a preset frequency error threshold, and a preset time threshold, wherein the operating state comprises a normal state, an island state, a low-voltage ride-through state, or a low-voltage protection state; a second determination module configured to determine an operation to be performed by the energy storage system according to the operating state of the energy storage system, wherein the operation to be performed comprises an island protection operation, a low-voltage ride-through operation, or an under-voltage shutdown protection operation.

10. A computer device, comprising: comprise: a memory and a processor, wherein the memory stores a computer program capable of being run on the processor, and the processor implements the steps of the method of any one of claims 1 to 8 when executing the computer program.

11. A computer readable storage medium, characterized in that, The computer program is stored on the computer readable storage medium and is executed by the processor to implement the steps of the method of any one of claims 1 to 8.

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