Protection configuration device of energy storage system

Abstract

The protection configuration device of the energy storage system comprises a system-level protection layer, the system-level protection layer comprises a valve group-level protection layer, a main control unit and a three-phase power supply, and the valve group-level protection layer comprises a device-level protection layer, a valve control unit and multiple groups of energy storage converter power units. The device-level protection layer comprises a module control protection unit and an energy storage converter power unit; the module control protection unit is respectively connected with a direct-current circuit breaker and an inverter in the energy storage converter power unit; the valve control unit is connected with the module control protection unit, and the multiple groups of energy storage converter power units are in star connection or angle connection; the three-phase power supply is correspondingly connected with the multiple groups of energy storage converter power units, a first end of the main control unit is connected with the valve control unit, a second end of the main control unit is connected with the multiple groups of energy storage converter power units, and a third end of the main control unit is connected with the three-phase power supply.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical automation equipment, and in particular to a protection configuration device for an energy storage system. Background Art

[0002] Driven by the pace of building a national clean energy industry highland, energy storage is an important part of the six major links of "collection, generation, transmission, distribution, use and storage" in the power production process. As an important technology and basic equipment to support the new power system, its large-scale development has become an inevitable trend. Accelerating the construction of energy storage facilities is an effective measure to improve the system regulation capacity and promote the consumption of new energy. It is also an important foundation for building a new power system. After the introduction of energy storage technology in the power system, it can effectively manage the demand side, reduce the peak-to-valley difference of load, reduce the power supply cost, and promote the application of renewable energy. At the same time, it can also improve the system operation stability, adjust the frequency, and compensate for load fluctuations. The energy storage converter is the core component of energy storage technology. As an interface between the power grid and the energy storage device, it is suitable for applications that require dynamic energy storage. In addition, it can also be used as the main power supply to support the operation of the microgrid. Therefore, it is of great significance to the construction of smart grids.

[0003] The current energy storage system lacks a complete protection system with clear levels and reasonable configuration. The setting value of conventional AC products is generally based on the short-circuit current. In addition to considering the short-circuit current, the protection setting value of power electronic equipment represented by direct-mounted energy storage products also needs to consider the tolerance of insulated gate bipolar transistors to protect power electronic devices, so further overall consideration is needed. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a protection configuration device for an energy storage system, which can solve the problems of the direct-mounted energy storage system lacking a complete set of protection systems with clear hierarchies and reasonable configurations and the lack of system protection setting values ​​for power electronic products that take into account the tolerance of insulated gate bipolar transistors, thereby ensuring the reliability and economical operation capability of the energy storage system.

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

[0006] On the one hand, the present invention provides a protection configuration device for an energy storage system, comprising a system-level protection layer, the system-level protection layer comprising a valve group-level protection layer, a main control unit and a three-phase power supply, the valve group-level protection layer comprising a device-level protection layer, a valve control unit and a plurality of groups of energy storage converter power units, the device-level protection layer comprising a module control protection unit and an energy storage converter power unit;

[0007] The module control protection unit is respectively connected to the DC circuit breaker and the inverter in the energy storage converter power unit;

[0008] The valve control unit is connected to the module control protection unit, and the multiple groups of energy storage converter power units are star-connected or delta-connected;

[0009] The three-phase power supply is connected correspondingly to the multiple groups of energy storage converter power units, the first end of the main control unit is connected to the valve control unit, the second end is connected to the multiple groups of energy storage converter power units, and the third end is connected to the three-phase power supply.

[0010] Optionally, the system-level protection layer collects status information through the main control unit and performs fixed value setting calculation;

[0011] The fixed value setting calculation of the system-level protection layer includes the fixed value setting calculation of the system overcurrent protection, the fixed value setting calculation of the system overvoltage protection and the fixed value setting calculation of the system undervoltage protection;

[0012] The fixed value setting calculation of the system overcurrent protection includes the fixed value setting calculation of the system overcurrent instantaneous protection, the fixed value setting calculation of the system overcurrent blocking and the fixed value setting calculation of the system out-of-angle overcurrent protection.

[0013] Optionally, the fixed value setting calculation of the system overcurrent instantaneous protection is as follows:

[0014] ;

[0015] ;

[0016] In the formula, It is the set value of the system overcurrent instantaneous protection; is the instantaneous tripping reliability coefficient; t is the fixed value setting time of the system overcurrent instantaneous protection; is the effective value of the rated current in the system corner; It is the maximum turn-off current in the safe operating area of ​​the insulated gate bipolar transistor.

[0017] Optionally, the fixed value setting calculation of the system overcurrent lockout includes the fixed value setting calculation of the system instantaneous value overcurrent lockout and the fixed value setting calculation of the system effective value overcurrent lockout, such as the formula:

[0018] ;

[0019] ;

[0020] ;

[0021] In the formula, It is the set value of the instantaneous overcurrent blocking of the system; is the instantaneous value locking reliability coefficient; is the effective value of the rated current in the system corner; It is the fixed value setting value of the system effective value overcurrent lockout; is the effective value locking reliability coefficient; It is the short-term overload capacity of the system.

[0022] Optionally, the fixed value setting calculation of the system out-of-corner overcurrent protection is as follows:

[0023] ;

[0024] In the formula, is the reliability factor of the overcurrent tripping outside the corner; is the overload factor; It is the short-time overload multiple of the system; It is the effective value of the rated current outside the system corner.

[0025] Optionally, the fixed value setting calculation of the system overvoltage protection includes the fixed value setting calculation of the system-side AC overvoltage I stage protection and the fixed value setting calculation of the system-side AC overvoltage lockout.

[0026] Optionally, the fixed value setting calculation of the system-side AC overvoltage I stage protection is as follows:

[0027] ;

[0028] In the formula, It is the maximum voltage coefficient under system operation or the system preset non-tripping overvoltage multiple; It is the effective value of the rated voltage on the system side.

[0029] Optionally, the fixed value setting calculation of the system-side AC overvoltage lockout includes the fixed value setting calculation of the system instantaneous value side AC overvoltage lockout and the fixed value setting calculation of the system effective value side AC overvoltage lockout, such as the formula:

[0030] ;

[0031] ;

[0032] ;

[0033] In the formula, It is the set value of AC overvoltage lockout on the instantaneous value side of the system; is the AC overvoltage lockout reliability coefficient on the instantaneous value side of the system; It is the fixed value setting value of AC overvoltage lockout on the effective value side of the system; It is the system preset non-locking overvoltage multiple; It is the return value of the AC overvoltage lockout on the system side; It is the AC overvoltage lockout return coefficient on the instantaneous value side of the system.

[0034] Optionally, the fixed value setting calculation of the system undervoltage protection includes the fixed value setting calculation of the system side AC undervoltage tripping and the fixed value setting calculation of the system side AC undervoltage lockout, such as the formula:

[0035] ;

[0036] ;

[0037] In the formula, It is the fixed value setting value of the AC undervoltage tripping on the system side; is the AC undervoltage trip coefficient on the system side; is the effective value of the rated voltage on the system side; It is the fixed value setting value of the AC undervoltage tripping on the system side; is the AC undervoltage lockout coefficient on the system side.

[0038] Beneficial Effects

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention forms a complete set of protection system with clear hierarchy and reasonable configuration for energy storage system. The constant value setting method takes into account the tolerance of insulated gate bipolar transistors, ensures the selectivity, sensitivity and speed of the protection action of the energy storage system while ensuring the stable operation of power electronic devices, and realizes the reliable and economical operation of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The figure shows a schematic diagram of the structure of a protection configuration device of an energy storage system in one embodiment of the present invention;

[0042] Figure 2 It is a schematic structural diagram of another embodiment of the protection configuration device of the energy storage system of the present invention;

[0043] Figure 3 FIG. 1 is a schematic diagram of a safe operating area of ​​an insulated gate bipolar transistor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0045] The term "and / or" is only a description of the association relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " generally indicates that the related objects are in an "or" relationship.

[0046] Example 1

[0047] like Figure 1 , 2 As shown, this embodiment introduces a protection configuration device for an energy storage system, which is divided into three layers of protection, including a device-level protection layer, a valve group-level protection layer, and a system-level protection layer.

[0048] The system-level protection layer includes a valve group-level protection layer, a main control unit (PCP) and a three-phase power supply, the valve group-level protection layer includes a device-level protection layer, a valve control unit (VBC) and multiple groups of energy storage converter power units, and the device-level protection layer includes a module control protection unit (SMC) and an energy storage converter power unit.

[0049] The module control protection unit (SMC) is respectively connected to the DC circuit breaker and the inverter in the power unit of the energy storage converter.

[0050] The valve control unit (VBC) is connected to the module control protection unit (SMC), and the multiple groups of energy storage converter power units are star-connected or delta-connected. Figure 1 As shown, the multiple groups of energy storage converter power units are delta-connected; Figure 2 As shown, the multiple groups of energy storage converter power units are star-connected.

[0051] The three-phase power supply is connected correspondingly to the multiple groups of energy storage converter power units, the first end of the main control unit (PCP) is connected to the valve control unit (VBC), the second end is connected to the multiple groups of energy storage converter power units, and the third end is connected to the three-phase power supply.

[0052] The device-level protection layer collects its own status information through a module control protection unit (SMC), sends the status information of the device-level protection layer to a valve control unit, and receives a signal sent by the valve control unit, thereby realizing control and protection of the device-level protection layer.

[0053] The module control protection unit (SMC) is equipped with a drive board hardware protection circuit, a capacitor DC voltage sampling circuit, a temperature protection circuit, a power supply monitoring circuit, a drive logic generation and verification circuit, and collects the status information of the energy storage converter power unit.

[0054] The valve group level protection layer collects its own status information through the valve control unit (VBC), sends the status information of the valve group level protection layer to the main control unit and receives the signal sent by the main control unit, so as to realize the control and protection of the valve group level protection layer.

[0055] The system-level protection layer processes and performs logical calculations on the status information of the device-level protection layer and the valve group-level protection layer through the main control unit (PCP), and collects and performs logical calculations on its own status information, thereby realizing control protection of the system-level protection layer.

[0056] In this embodiment, information is transmitted through optical fiber, and the position indicated by the arrow is the position from which data information is collected.

[0057] The main control unit (PCP) is equipped with an incoming line voltage and current sampling circuit and a system detection circuit to collect status information of the system-level protection layer.

[0058] The device-level protection includes insulated gate bipolar transistor (IGBT) overvoltage protection and insulated gate bipolar transistor (IGBT) overcurrent protection; the valve group-level protection includes valve group DC side overvoltage and undervoltage protection, valve group overtemperature protection, valve group drive abnormality protection and valve group power supply failure protection.

[0059] The system-level protection includes system overvoltage protection, system undervoltage protection, system overfrequency protection, system underfrequency protection, system zero-sequence voltage protection, system overcurrent protection, system overload protection, system zero-sequence overcurrent protection, system negative-sequence overcurrent protection and system main circuit breaker failure protection.

[0060] Example 2

[0061] Based on Example 1, this embodiment also has the following designs:

[0062] The system-level protection layer collects status information through the main control unit and performs fixed value setting calculations.

[0063] The fixed value setting calculation of the system-level protection layer includes the fixed value setting calculation of system overcurrent protection, the fixed value setting calculation of system overvoltage protection and the fixed value setting calculation of system undervoltage protection.

[0064] The fixed value setting calculation of the system overcurrent protection includes the fixed value setting calculation of the system overcurrent instantaneous protection, the fixed value setting calculation of the system overcurrent blocking and the fixed value setting calculation of the system out-of-angle overcurrent protection.

[0065] The steps of the fixed value setting calculation method of the system overcurrent instantaneous protection are as follows:

[0066] First, the time t for the constant value setting calculation of the system overcurrent instantaneous protection is set. In this embodiment, t is set to 0.001s.

[0067] Secondly, considering the margin, the system overcurrent instantaneous protection setting is set according to the effective value of the rated current in the corner, as shown in the formula:

[0068] ;

[0069] In the formula, It is the set value of the system overcurrent instantaneous protection; is the instantaneous tripping reliability coefficient; t is the fixed value setting time of the system overcurrent instantaneous protection; It is the effective value of the rated current in the system corner.

[0070] Finally, the overcurrent transient protection setting value of the system is adjusted taking into account the tolerance of the insulated gate bipolar transistor, which must meet the following requirements:

[0071] ;

[0072] In the formula, It is the maximum turn-off current in the safe working area of ​​the insulated gate bipolar transistor. Figure 3 As shown, in this embodiment The value is 900A.

[0073] The fixed value setting calculation of the system overcurrent blocking includes the fixed value setting calculation of the system instantaneous value overcurrent blocking and the fixed value setting calculation of the system effective value overcurrent blocking. The steps of the fixed value setting calculation method are as follows:

[0074] First, set the effective value overcurrent lockout delay time t l2 In this embodiment, t l2 Take 0.1s.

[0075] Secondly, considering the margin, the system instantaneous overcurrent closing value and the system effective overcurrent closing value are set according to the effective value of the rated current in the corner and the instantaneous value of the current in the corner, respectively, as calculated by the formula:

[0076] ;

[0077] ;

[0078] In the formula, It is the set value of the instantaneous overcurrent blocking of the system; is the instantaneous value locking reliability coefficient; is the effective value of the rated current in the system corner; It is the fixed value setting value of the system effective value overcurrent lockout; is the effective value locking reliability coefficient.

[0079] In this embodiment, K can be set rel,l1= K rel,t = 2.25; K rel,l2 Take 1.8.

[0080] Finally, the system effective value overcurrent shutdown value is adjusted taking into account the system short-time overload capacity and the tolerance capacity of the insulated gate bipolar transistor, which must meet the following requirements:

[0081] ;

[0082] In the formula, is the short-term overload capacity of the system. Take 1.5 times the effective value of the rated current in the system corner.

[0083] The steps of the fixed value setting calculation method of the system corner overcurrent protection are as follows:

[0084] First, set the time t for setting the overcurrent setting value outside the corner T In this embodiment, t T Take 0.01s.

[0085] Secondly, considering the margin, the overcurrent protection setting value outside the corner of the system is adjusted according to the effective value of the rated current inside the corner and the short-term overload condition, as calculated by the formula:

[0086] ;

[0087] In the formula, is the reliability factor of the overcurrent tripping outside the corner; is the overload factor; It is the short-time overload multiple of the system; It is the effective value of the rated current outside the system corner.

[0088] In this embodiment, Take 1.2; Take 1.3; Take 1.5.

[0089] The fixed value setting calculation of the system overvoltage protection includes the fixed value setting calculation of the system side AC overvoltage I stage protection and the fixed value setting calculation of the system side AC overvoltage lockout.

[0090] The steps of the fixed value setting calculation method of the system side AC overvoltage I stage protection are as follows:

[0091] First, set the time t of the fixed value setting of the AC overvoltage I stage protection on the side I In this embodiment, t I Take 0.1s.

[0092] Secondly, on the basis of considering the margin, taking into account the effective value of the rated voltage on the system side and the system overvoltage without tripping, the system side AC overvoltage I stage protection setting value is set, and the calculation is as follows:

[0093] ;

[0094] In the formula, It is the maximum voltage coefficient under system operation or the system preset non-tripping overvoltage multiple; is the effective value of the rated voltage on the system side. In this embodiment, Take 1.5.

[0095] The fixed value setting calculation of the system side AC overvoltage lockout includes the fixed value setting calculation of the system instantaneous value side AC overvoltage lockout and the fixed value setting calculation of the system effective value side AC overvoltage lockout. The steps of the fixed value setting calculation method are as follows:

[0096] First, set the effective value side AC overvoltage lockout delay time t L2 In this embodiment, t L2 Take 0.05s.

[0097] Secondly, on the basis of considering the margin, the AC overvoltage lockout value on the instantaneous value side of the system and the AC overvoltage lockout value on the effective value side of the system are set according to the effective value of the rated voltage on the system side and the instantaneous value of the rated voltage on the system side, taking into account the system overvoltage without lockout, and the calculation is as follows:

[0098] ;

[0099] ;

[0100] In the formula, It is the set value of AC overvoltage lockout on the instantaneous value side of the system; is the AC overvoltage lockout reliability coefficient on the instantaneous value side of the system; It is the fixed value setting value of AC overvoltage lockout on the effective value side of the system; It is the system preset non-locking overvoltage multiple;.

[0101] In this embodiment, The value is generally the same as the reliability factor K of the overcurrent tripping outside the corner max,T Same, you can set K max,L1 = K max,T = 1.5; Take 1.4.

[0102] Finally, the return value of the AC overvoltage lockout on the system side is set according to the maximum long-term operating voltage multiple on the system side, as calculated by the formula:

[0103] ;

[0104] In the formula, It is the return value of the AC overvoltage lockout on the system side; It is the AC overvoltage lockout return coefficient on the instantaneous value side of the system. The value is greater than the maximum long-term operating voltage multiple of the system side. In this embodiment, Take 1.25.

[0105] The fixed value setting calculation of the system undervoltage protection includes the fixed value setting calculation of the system side AC undervoltage tripping and the fixed value setting calculation of the system side AC undervoltage lockout, and the steps of the fixed value setting calculation method are as follows:

[0106] First, set the fixed value setting time t of the system side AC undervoltage lockout lT And the fixed value setting time t of the system side AC undervoltage trip lL In this embodiment, t lT Take 0.001s, t lL Take 5s.

[0107] Finally, on the basis of considering the margin, taking into account the effective value of the system-side rated voltage and the system minimum voltage operation multiple, the system-side AC undervoltage trip setting value and the system-side AC undervoltage lock setting value are set, as shown in the formula:

[0108] ;

[0109] ;

[0110] In the formula, It is the fixed value setting value of the AC undervoltage tripping on the system side; is the AC undervoltage trip coefficient on the system side; is the effective value of the rated voltage on the system side; It is the fixed value setting value of the AC undervoltage tripping on the system side; is the AC undervoltage lockout coefficient on the system side.

[0111] In this embodiment, and Designed according to the system's minimum voltage operating multiple, which is 0.1.

[0112] Example 3

[0113] This embodiment introduces an experimental design of a fixed value setting method for protection configuration of an energy storage system, which specifically includes:

[0114] Taking two groups of typical energy storage system parameters as examples, the setting calculation is performed on the fixed values.

[0115] The typical system-side rated voltage RMS value is U N= 35kV, the corresponding two groups of typical system corner rated current effective values ​​and system corner rated current effective values, and the setting results calculated according to the fixed value setting method are shown in Table 1.

[0116] Table 1 Fixed value setting results

[0117]

[0118] 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 adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0119] 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 box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes 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 generate 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.

[0120] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0121] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0122] 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 enlightenment 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 all fall within the protection of the present invention.

Claims

1. A protection configuration device for an energy storage system, characterized in that: It includes a system-level protection layer, which includes a valve group-level protection layer, a main control unit and a three-phase power supply. The valve group-level protection layer includes a device-level protection layer, a valve control unit and multiple groups of energy storage converter power units. The device-level protection layer includes a module control protection unit and an energy storage converter power unit. The module control protection unit is respectively connected to the DC circuit breaker and the inverter in the energy storage converter power unit; The valve control unit is connected to the module control protection unit, and the multiple groups of energy storage converter power units are star-connected or delta-connected; The three-phase power supply is correspondingly connected to the multiple groups of energy storage converter power units, the first end of the main control unit is connected to the valve control unit, the second end is connected to the multiple groups of energy storage converter power units, and the third end is connected to the three-phase power supply.

2. The protection configuration device of the energy storage system according to claim 1, characterized in that: The system-level protection layer collects status information through the main control unit and performs fixed value setting calculations; The fixed value setting calculation of the system level protection layer includes the fixed value setting calculation of the system overcurrent protection, the fixed value setting calculation of the system overvoltage protection and the fixed value setting calculation of the system undervoltage protection; The fixed value setting calculation of the system overcurrent protection includes the fixed value setting calculation of the system overcurrent instantaneous protection, the fixed value setting calculation of the system overcurrent blocking and the fixed value setting calculation of the system out-of-angle overcurrent protection.

3. The protection configuration device of the energy storage system according to claim 2, characterized in that: The setting calculation of the system overcurrent instantaneous protection is as follows: ； ； Where, It is the set value of the system overcurrent instantaneous protection; is the instantaneous tripping reliability coefficient; t is the fixed value setting time of the system overcurrent instantaneous protection; is the effective value of the rated current in the system angle; It is the maximum turn-off current in the safe operating area of ​​the insulated gate bipolar transistor.

4. The protection configuration device of the energy storage system according to claim 2, characterized in that: The fixed value setting calculation of the system overcurrent lock includes the fixed value setting calculation of the system instantaneous value overcurrent lock and the fixed value setting calculation of the system effective value overcurrent lock, as shown in the formula: ； ； ； Where, It is the set value of the instantaneous overcurrent blocking of the system; is the instantaneous value locking reliability coefficient; is the effective value of the rated current in the system angle; It is the set value of the system effective value overcurrent blocking; is the effective value locking reliability coefficient; It is the short-term overload capacity of the system.

5. The protection configuration device of the energy storage system according to claim 2, characterized in that: The setting calculation formula of the system out-of-corner overcurrent protection is as follows: ； Where, is the reliability factor of the out-of-angle overcurrent tripping; is the overload factor; It is the system short-time overload multiple; It is the effective value of the rated current outside the system corner.

6. The protection configuration device of the energy storage system according to claim 2, characterized in that: The fixed value setting calculation of the system overvoltage protection includes the fixed value setting calculation of the system side AC overvoltage I stage protection and the fixed value setting calculation of the system side AC overvoltage lockout.

7. The protection configuration device of the energy storage system according to claim 6, characterized in that: The setting calculation formula for the system-side AC overvoltage stage I protection is as follows: ； Where, It is the maximum voltage coefficient under system operation or the system preset non-tripping overvoltage multiple; is the effective value of the rated voltage on the system side.

8. The protection configuration device of the energy storage system according to claim 6, characterized in that: The fixed value setting calculation of the system-side AC overvoltage lockout includes the fixed value setting calculation of the system instantaneous value side AC overvoltage lockout and the fixed value setting calculation of the system effective value side AC overvoltage lockout, as shown in the formula: ； ； ； Where, It is the set value of AC overvoltage lockout on the instantaneous value side of the system; is the AC overvoltage lockout reliability coefficient on the instantaneous value side of the system; It is the set value of AC overvoltage lockout on the effective value side of the system; It is the system’s preset non-locking overvoltage multiple; It is the return value of the AC overvoltage lockout on the system side; is the AC overvoltage lockout return coefficient on the instantaneous value side of the system.

9. The protection configuration device of the energy storage system according to claim 2, characterized in that: The fixed value setting of the system undervoltage protection includes the fixed value setting of the system side AC undervoltage tripping and the fixed value setting of the system side AC undervoltage lockout, which are calculated as follows: ； ； Where, It is the set value of the AC undervoltage tripping on the system side; is the AC undervoltage trip coefficient on the system side; is the effective value of the rated voltage on the system side; It is the set value of the AC undervoltage tripping on the system side; is the AC undervoltage lockout coefficient on the system side.

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