Adaptive overcurrent protection method and device for power distribution network considering mobile energy storage access

Abstract

The application relates to a power distribution network adaptive overcurrent protection method and device considering mobile energy storage access, wherein the method comprises the following steps: judging whether a fault occurs according to collected current data; when the fault occurs, determining whether an overcurrent protection section acts according to the current data and adaptive overcurrent protection setting values, and locking the overcurrent protection section which does not act; wherein the adaptive overcurrent protection setting values are obtained by the following method: calculating the equivalent impedance of the mobile energy storage device according to fault components; and calculating the overcurrent protection setting values by using the equivalent impedance. The application can eliminate the influence of the change of the output capacity of the mobile energy storage device on the relay protection.

Description

Technical Field

[0001] This invention relates to the field of distribution network relay protection, and in particular to an adaptive overcurrent protection method and device for distribution networks that takes into account the access of mobile energy storage. Background Technology

[0002] In recent years, with the increasing severity of energy crises and environmental pollution, clean and efficient distributed power sources have been increasingly applied to power distribution networks. However, distributed power sources are characterized by randomness, intermittency, and volatility. Coupled with the uncertainty of electricity load, severe source-load imbalance exists in power distribution networks, limiting the further increase in the penetration rate of distributed power sources. Mobile energy storage (MES) devices are a flexible resource with fast charging and discharging speeds and adjustable charging and discharging states, which can effectively alleviate the time-series mismatch between distributed power sources and loads, and have therefore experienced rapid development. However, mobile energy storage devices exhibit different characteristics under different operating modes, which will significantly change the power flow distribution of the power distribution network, leading to maloperation or failure of protection switches, affecting the safe and stable operation of the power distribution network. Therefore, research on protection schemes for power distribution networks connected to mobile energy storage devices is of great significance.

[0003] Currently, research by scholars both domestically and internationally largely focuses on distribution network protection issues when distributed generation (DG) is integrated, which shares similar characteristics with the situation when mobile energy storage devices are integrated. Existing current protection schemes include installing fault current limiters; setting protection operating current values ​​in real time considering the severity of the fault and the grid connection status of DG; proposing setting switching strategies considering both islanded and grid-connected operation modes of DG; updating protection settings based on the power output level and fault current level of DG; and proposing adaptive instantaneous protection based on positive sequence current, considering that photovoltaic power generation only provides positive sequence current. However, with the continuous increase in the penetration rate of DG, staged current protection may experience false tripping and failure to trip. Furthermore, unlike DG, mobile energy storage devices have three operating modes: charging, discharging, and standby. Existing distribution network protection methods for DG integration may not be effective. Therefore, it is necessary to further develop adaptive current protection methods for distribution networks suitable for energy storage device integration, based on the characteristics of mobile energy storage devices. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an adaptive overcurrent protection method and device for distribution networks that takes into account the access of mobile energy storage, which can adaptively change the operating setting value of the staged overcurrent protection and eliminate the impact of changes in the output capacity of the mobile energy storage device on the relay protection.

[0005] The technical solution adopted by this invention to solve its technical problem is: to provide an adaptive overcurrent protection method for distribution networks considering the access of mobile energy storage, comprising the following steps:

[0006] Determine whether a fault has occurred based on the collected current data;

[0007] When a fault occurs, the system determines whether the overcurrent protection section has operated based on the current data and the adaptive overcurrent protection setting value, and blocks the non-operating overcurrent protection section. The adaptive overcurrent protection setting value is obtained by calculating the equivalent impedance of the mobile energy storage device based on the fault component and then calculating the overcurrent protection setting value using the equivalent impedance.

[0008] The calculation of the equivalent impedance of the mobile energy storage device based on the fault components includes:

[0009] The mobile energy storage device is converted into the form of the equivalent impedance of an ideal power supply series by performing Thevenin equivalent;

[0010] The equivalent impedance of the energy storage device after Thevenin equivalent is calculated by using the positive sequence values ​​of the voltage fault component and the current fault component at the grid connection point of the mobile energy storage device.

[0011] The calculation of overcurrent protection setting values ​​using equivalent impedance includes:

[0012] The equivalent impedance from the power source to the fault location is obtained based on the equivalent impedance. The ratio of the product of the equivalent power source electromotive force, the reliability coefficient of current I section, and the fault type coefficient to the equivalent impedance from the power source to the fault location is used as the setting value of the overcurrent protection I section.

[0013] The branching coefficient is obtained based on the equivalent impedance. The product of the reliability coefficient of current protection stage II, the setting value of overcurrent protection stage I, and the reciprocal of the branching coefficient is used as the setting value of overcurrent protection stage II. The branching coefficient is the ratio of the current flowing through the faulty line to the current flowing through the upstream line adjacent to the faulty line.

[0014] The process of determining whether an overcurrent protection segment has operated based on current data and an adaptive overcurrent protection setting, and blocking non-operating overcurrent protection segments, includes:

[0015] If the detected current data is not less than the setting value of overcurrent protection stage I, overcurrent protection stage I will activate; otherwise, overcurrent protection stage I will be blocked.

[0016] The detected current data is not less than the overcurrent protection stage II setting value. After increasing the delay time, it coordinates with the overcurrent protection stage I of the adjacent line. If the fault does not disappear, the overcurrent protection stage II will operate.

[0017] If the detected current data is less than the overcurrent protection stage II setting value, then the overcurrent protection stage II will be blocked.

[0018] The step of determining whether a fault has occurred based on the collected current data includes:

[0019] Calculate the rate of change of current based on the collected current data;

[0020] Determine if the rate of change of current exceeds the fault threshold. If the rate of change of current exceeds the fault threshold, a fault occurs; otherwise, no fault occurs.

[0021] The technical solution adopted by this invention to solve its technical problem is: to provide an adaptive overcurrent protection device for distribution networks considering the access of mobile energy storage, comprising:

[0022] The fault diagnosis module is used to determine whether a fault has occurred based on the collected current data.

[0023] The fault action module is used to determine whether the overcurrent protection section should operate when a fault occurs, based on current data and adaptive overcurrent protection setting values, and to block overcurrent protection sections that do not operate.

[0024] An adaptive module is used to adapt the overcurrent protection setting value; the adaptive module includes: an equivalent impedance calculation unit, used to calculate the equivalent impedance of the mobile energy storage device based on the fault component; and an overcurrent protection setting value calculation unit, used to calculate the overcurrent protection setting value using the equivalent impedance.

[0025] The equivalent impedance calculation unit includes:

[0026] The equivalent conversion section is used to perform Thevenin equivalence on the mobile energy storage device and convert it into the form of an ideal power supply series equivalent impedance.

[0027] The equivalent calculation section is used to calculate the equivalent impedance of the energy storage device after Thevenin equivalence by utilizing the positive sequence values ​​of the voltage fault component and current fault component at the grid connection point of the mobile energy storage device.

[0028] The overcurrent protection setting value calculation unit includes:

[0029] The overcurrent protection stage I calculation section is used to obtain the equivalent impedance from the power source to the fault location based on the equivalent impedance. The ratio of the product of the equivalent power source electromotive force, the reliability coefficient of current stage I, and the fault type coefficient to the equivalent impedance from the power source to the fault location is used as the setting value of overcurrent protection stage I.

[0030] The overcurrent protection stage II calculation section is used to obtain the branch coefficient based on the equivalent impedance. The product of the reliability coefficient of current stage II, the setting value of overcurrent protection stage I, and the reciprocal of the branch coefficient is used as the setting value of overcurrent protection stage II. The branch coefficient is the ratio of the current flowing through the faulty line to the current flowing through the upstream line adjacent to the faulty line.

[0031] The technical solution adopted by the present invention to solve its technical problem is: to provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the steps of the above-mentioned adaptive overcurrent protection method for distribution networks considering mobile energy storage access.

[0032] The technical solution adopted by the present invention to solve its technical problem is: to provide a computer-readable storage medium on which a computer program is stored, wherein when the computer program is executed by a processor, the steps of the above-mentioned adaptive overcurrent protection method for distribution networks considering mobile energy storage access are implemented.

[0033] Beneficial effects

[0034] By adopting the above-mentioned technical solution, the present invention has the following advantages and positive effects compared with the prior art: The present invention calculates the equivalent impedance of the mobile energy storage device under different operating modes based on the fault components, and then adaptively changes the operating setting value of the staged overcurrent protection according to the equivalent impedance, thereby eliminating the influence of the change of the output capability of the mobile energy storage device itself on the relay protection, thus ensuring that the range of overcurrent protection remains basically unchanged and will not change with the change of the output capability of the mobile energy storage device, thereby improving the reliability and selectivity of the relay protection. Attached Figure Description

[0035] Figure 1 This is a flowchart of the adaptive overcurrent protection method for distribution networks considering mobile energy storage access in the first embodiment of the present invention;

[0036] Figure 2 This is a diagram of the power distribution network to which the mobile energy storage device is connected in the first embodiment of the present invention;

[0037] Figure 3 This is a distribution network diagram of positive sequence fault components in the first embodiment of the present invention;

[0038] Figure 4 This is a block diagram of a distribution network adaptive overcurrent protection device considering mobile energy storage access in the second embodiment of the present invention. Detailed Implementation

[0039] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0040] The first embodiment of the present invention relates to an adaptive overcurrent protection method for distribution networks considering the access of mobile energy storage, such as... Figure 1 As shown, it includes the following steps:

[0041] Step 1: Determine if a fault has occurred based on the collected current data. In this step, the rate of change of current can be calculated based on the collected current data, and then it can be determined whether the rate of change of current exceeds the fault threshold. If the rate of change of current exceeds the fault threshold, a fault has occurred; otherwise, no fault has occurred.

[0042] Step 2: When a fault occurs, determine whether the overcurrent protection section has operated based on the current data and the adaptive overcurrent protection setting value, and block the non-operating overcurrent protection section. The adaptive overcurrent protection setting value is obtained through the following method:

[0043] The equivalent impedance of the mobile energy storage device is calculated based on the fault components. Specifically, the mobile energy storage device is converted into the form of an ideal power supply series equivalent impedance by performing Thevenin equivalence on it. The equivalent impedance of the energy storage device after Thevenin equivalence is calculated using the positive sequence values ​​of the voltage fault components and current fault components at the grid connection point of the mobile energy storage device.

[0044] The overcurrent protection setting value is calculated using equivalent impedance, specifically as follows: The equivalent impedance from the power source to the fault location is obtained based on the equivalent impedance. The ratio of the product of the equivalent power source electromotive force, the reliability coefficient of current stage I, and the fault type coefficient to the equivalent impedance from the power source to the fault location is used as the setting value for overcurrent protection stage I. The branching coefficient is obtained based on the equivalent impedance. The product of the reliability coefficient of current stage II, the setting value of overcurrent protection stage I, and the reciprocal of the branching coefficient is used as the setting value for overcurrent protection stage II. The branching coefficient is the ratio of the current flowing through the faulty line to the current flowing through the upstream line adjacent to the faulty line.

[0045] Therefore, this embodiment calculates the equivalent impedance of the mobile energy storage device under different operating modes based on the fault components, and then adaptively changes the operating setting value of the staged overcurrent protection based on the equivalent impedance, thereby eliminating the influence of the change in the output capacity of the mobile energy storage device itself on the relay protection, thus ensuring that the range of overcurrent protection remains basically unchanged.

[0046] This step determines whether the overcurrent protection section has operated based on the current data and the adaptive overcurrent protection setting value, and blocks the non-operating overcurrent protection section, specifically including:

[0047] If the detected current data is not less than the setting value of overcurrent protection stage I, overcurrent protection stage I will activate; otherwise, overcurrent protection stage I will be blocked.

[0048] The detected current data is not less than the overcurrent protection stage II setting value. After increasing the delay time, it coordinates with the overcurrent protection stage I of the adjacent line. If the fault does not disappear, the overcurrent protection stage II will operate.

[0049] If the detected current data is less than the overcurrent protection stage II setting value, then the overcurrent protection stage II will be blocked.

[0050] The following specific embodiment further illustrates this implementation method, such as... Figure 2 As shown, in the distribution network, power source S is connected to bus A and radially supplies power to the loads through four lines AB, BC, AD, and DE. The mobile energy storage device MES is connected to bus D. When a fault f1 occurs on line DE, the positive sequence fault component network diagram of the system can be obtained as follows: Figure 3 As shown. The positive sequence value of the voltage fault component at the grid connection point of the mobile energy storage device. and positive sequence value of current fault component The equivalent impedance on the back side of the mobile energy storage device can be calculated, as shown in equation (1).

[0051]

[0052] The overcurrent setting value can be adaptively adjusted by utilizing the equivalent impedance of the mobile energy storage device. The specific calculation formula is as follows.

[0053] The setting value for overcurrent protection stage I of protection 4 is:

[0054]

[0055] in, Z is the phase electromotive force of the equivalent power source; s Z is the system's equivalent impedance; AD Z DE These are the impedances of lines AD and DE, respectively; Z MES K represents the equivalent impedance of the mobile energy storage device. KIrel is the reliability coefficient for stage I of the current protection, typically taken as 1.2 to 1.3. f This is the fault type coefficient, which is set to 1 for a three-phase short circuit and 1 for a two-phase short circuit.

[0056] The setting value for the overcurrent protection stage II of protection 3 is:

[0057]

[0058] in, K is the reliability coefficient for current segment II, typically taken as 1.1 to 1.2. b It is the branching coefficient, which is the ratio of the current flowing through line DE to the current flowing through line AD. This is the setting value for stage I of the overcurrent protection.

[0059] To demonstrate the protective performance of the adaptive protection method of this embodiment, comparative verification was performed in simulation. (The attached text is incomplete and requires further context.) Figure 2The typical distribution network shown is used as the experimental system, with a bus voltage level of 10kV. The rated capacity of the system power source S is 100MVA, and the equivalent reactance is 0.3Ω. All four feeders are overhead lines with lengths of 5km (AB), 7km (BC), 10km (AD), and 10km (DE), respectively. Their resistance per unit length r1 = 0.138Ω / km, and their reactance per unit length x1 = 0.369Ω / km. The rated power of the loads on buses B and D is 0.95MVA, and the rated power of the loads on buses C and E is 2MVA. In this embodiment, the capacity of the mobile energy storage device connected to bus D is 200kW, and the equivalent impedance is 0.6Ω. Next, the protection performance of the traditional overcurrent protection method is first analyzed, and then compared with the performance of the proposed adaptive overcurrent protection scheme, thus demonstrating the good selectivity and high sensitivity of the proposed method.

[0060] 1) Performance analysis of traditional overcurrent protection after mobile energy storage device is connected

[0061] When the mobile energy storage device is connected, the protection range of each protection is set according to the maximum operating mode (output 33%). The protection range of each protection is shown in Table 1.

[0062] Table 1

[0063]

[0064] Considering the different connection positions of the MES device, and when the operating mode of the MES device changes, the protection range of each protection is shown in Table 2 (connected to bus D) and Table 3 (connected to bus B).

[0065] Table 2

[0066]

[0067] Table 3

[0068]

[0069] As shown in Tables 2 and 3, when the output power of the mobile energy storage device (connected to bus D) decreases in discharge mode, the protection range of protection stage I of protection 4 decreases sharply. When the mobile energy storage device operates in charging or standby mode, the protection range of protection 4 drops to 0, meaning that protection 4 will not operate even when a three-phase fault occurs near bus D, and the main protection fails to operate. Compared with protection 4, the protection range of protection 3 shows the opposite trend, especially in charging and standby modes, where the protection range exceeds the limit. When a three-phase fault occurs near bus E, protection 3 will also operate, causing the backup protection to malfunction and reducing reliability. Similarly, if the MES device is connected to bus B, there are problems with insufficient protection range of protection 2 and excessive protection range of protection 1, resulting in poor selectivity and low sensitivity.

[0070] 2) Adaptive protection performance analysis of mobile energy storage devices after connection to the distribution network

[0071] When the proposed adaptive overcurrent protection scheme is adopted, the protection settings can change with different operating modes of the MES device. The protection range of each protection under different connection positions is shown in Table 4 (connected to bus D) and Table 5 (connected to bus B).

[0072] Table 4

[0073]

[0074] Table 5

[0075]

[0076] As can be seen from Tables 4 and 5, according to the adaptive overcurrent protection scheme, the equivalent back-side impedance of the mobile energy storage device during a fault is measured in real time and substituted into the adaptive setting formula to determine the protection setting value. This ensures that the protection range does not change with the output of the connected mobile energy storage device and remains stable within the normal range, thereby improving the reliability of the protection.

[0077] Therefore, it can be seen that when a mobile energy storage device is connected to the distribution network, the traditional protection scheme set according to the maximum operating mode will change with the change of the output capacity of the mobile energy storage device, which will seriously affect the reliability and selectivity of the relay protection. However, the protection set by the adaptive overcurrent protection scheme of this embodiment will not change with the change of the output capacity of the mobile energy storage device, and will remain basically unchanged, which greatly improves the reliability and selectivity of the relay protection.

[0078] The second embodiment of the present invention relates to an adaptive overcurrent protection device for distribution networks that takes into account the access of mobile energy storage, such as... Figure 4 As shown, it includes:

[0079] The fault diagnosis module is used to determine whether a fault has occurred based on the collected current data.

[0080] The fault action module is used to determine whether the overcurrent protection section should operate when a fault occurs, based on current data and adaptive overcurrent protection setting values, and to block overcurrent protection sections that do not operate.

[0081] An adaptive module is used to adapt the overcurrent protection setting value; the adaptive module includes: an equivalent impedance calculation unit, used to calculate the equivalent impedance of the mobile energy storage device based on the fault component; and an overcurrent protection setting value calculation unit, used to calculate the overcurrent protection setting value using the equivalent impedance.

[0082] The equivalent impedance calculation unit includes:

[0083] The equivalent conversion section is used to perform Thevenin equivalence on the mobile energy storage device and convert it into the form of an ideal power supply series equivalent impedance.

[0084] The equivalent calculation section is used to calculate the equivalent impedance of the energy storage device after Thevenin equivalence by utilizing the positive sequence values ​​of the voltage fault component and current fault component at the grid connection point of the mobile energy storage device.

[0085] The overcurrent protection setting value calculation unit includes:

[0086] The overcurrent protection stage I calculation section is used to obtain the equivalent impedance from the power source to the fault location based on the equivalent impedance. The ratio of the product of the equivalent power source electromotive force, the reliability coefficient of current stage I, and the fault type coefficient to the equivalent impedance from the power source to the fault location is used as the setting value of overcurrent protection stage I.

[0087] The overcurrent protection stage II calculation section is used to obtain the branch coefficient based on the equivalent impedance. The product of the reliability coefficient of the current stage II, the setting value of the overcurrent protection stage I, and the reciprocal of the branch coefficient is used as the setting value of the overcurrent protection stage II. The branch coefficient is the ratio of the current flowing through the faulty line to the current flowing through the upstream line adjacent to the faulty line.

[0088] The fault action module includes:

[0089] The first action unit is used to activate the overcurrent protection stage I if the detected current data is not less than the setting value of the overcurrent protection stage I; otherwise, it blocks the overcurrent protection stage I.

[0090] The second action unit is used to detect current data that is not less than the overcurrent protection stage II setting value. After adding the delay time, it works in conjunction with the overcurrent protection stage I of the adjacent line. If the fault does not disappear, the overcurrent protection stage II will operate.

[0091] The third action unit is used to block overcurrent protection stage II if the detected current data is less than the overcurrent protection stage II setting value.

[0092] The fault diagnosis module includes:

[0093] The current change rate calculation unit is used to calculate the current change rate based on the collected current data.

[0094] The judgment unit is used to determine whether the rate of change of current exceeds the fault threshold. If the rate of change of current exceeds the fault threshold, a fault occurs; otherwise, no fault occurs.

[0095] The third embodiment of the present invention relates to an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the adaptive overcurrent protection method for distribution networks considering mobile energy storage access in the first embodiment.

[0096] The fourth embodiment of the present invention relates to a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the adaptive overcurrent protection method for distribution networks considering mobile energy storage access in the first embodiment.

[0097] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take 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 code. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0098] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0099] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0100] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0101] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0102] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A power distribution network adaptive overcurrent protection method considering mobile energy storage access, characterized in that, The method comprises the following steps: determining whether a fault occurs according to collected current data; when the fault occurs, determining whether over-current protection sections act according to the current data and adaptive over-current protection setting values, and locking over-current protection sections that do not act; wherein the adaptive over-current protection setting values are obtained by the following method: calculating the equivalent impedance of a mobile energy storage device according to fault components; and calculating over-current protection setting values by using the equivalent impedance; the method of calculating the equivalent impedance of the mobile energy storage device according to the fault components comprises: equivalent conversion of the mobile energy storage device into the form of an ideal power source in series with an equivalent impedance; calculating the equivalent impedance of the mobile energy storage device after the equivalent conversion by using the positive sequence values of the voltage fault components and the current fault components at the grid-connected point of the mobile energy storage device; the method of calculating over-current protection setting values by using the equivalent impedance comprises: obtaining the equivalent impedance from the power source to the fault location, and taking the ratio of the product of the equivalent power source electromotive force, the current I section reliability coefficient and the fault type coefficient to the equivalent impedance from the power source to the fault location as the setting value of the over-current protection I section; obtaining a branch coefficient from the equivalent impedance, and taking the product of the reciprocal of the branch coefficient, the current II section reliability coefficient and the setting value of the over-current protection I section as the setting value of the over-current protection II section; the branch coefficient is the ratio of the current flowing through the fault line to the current flowing through the adjacent upstream line of the fault line.

2. The method for adaptive overcurrent protection of a power distribution network considering mobile energy storage access of claim 1, wherein, the method of determining whether over-current protection sections act according to the current data and adaptive over-current protection setting values, and locking over-current protection sections that do not act, comprises: if the detected current data is not less than the setting value of the over-current protection I section, the over-current protection I section acts; otherwise, the over-current protection I section is locked; if the detected current data is not less than the setting value of the over-current protection II section, the over-current protection II section acts after a delay time and cooperates with the over-current protection I section of the adjacent line, and if the fault has not disappeared, the over-current protection II section acts; if the detected current data is less than the setting value of the over-current protection II section, the over-current protection II section is locked.

3. The method for adaptive overcurrent protection of a power distribution network considering mobile energy storage access of claim 1, wherein, the method of determining whether a fault occurs according to collected current data comprises: calculating the current change rate according to the collected current data; determining whether the current change rate exceeds a fault threshold, and if the current change rate exceeds the fault threshold, a fault occurs; otherwise, no fault occurs.

4. A power distribution network adaptive overcurrent protection device considering mobile energy storage access, characterized in that, comprise: a fault determination module for determining whether a fault occurs according to collected current data; a fault action module for determining whether over-current protection sections act according to the current data and adaptive over-current protection setting values when the fault occurs, and locking over-current protection sections that do not act; an adaptive module for adaptive over-current protection setting values; the adaptive module comprises: an equivalent impedance calculation unit for calculating the equivalent impedance of a mobile energy storage device according to fault components; and an over-current protection setting value calculation unit for calculating over-current protection setting values by using the equivalent impedance; the equivalent impedance calculation unit comprises: an equivalent conversion part for equivalent conversion of the mobile energy storage device into the form of an ideal power source in series with an equivalent impedance; An equivalent calculation part is configured to calculate the equivalent impedance of the energy storage device after Thevenin equivalence by using the positive sequence values of the voltage fault component and the current fault component of the mobile energy storage device and the grid point; The current protection setting value calculation unit comprises: An overcurrent protection I section calculation part is configured to obtain an equivalent impedance from a power source to a fault position according to the equivalent impedance, and take the ratio of the product of an equivalent power source electromotive force, a current I section reliability coefficient and a fault type coefficient to the equivalent impedance from the power source to the fault position as a setting value of overcurrent protection I section. An overcurrent protection II section calculation part is configured to obtain a branch coefficient according to the equivalent impedance, and take the product of the reciprocal of the branch coefficient, a current II section reliability coefficient and the setting value of overcurrent protection I section as a setting value of overcurrent protection II section; the branch coefficient is the ratio of the current flowing through the fault line to the current flowing through the upstream line adjacent to the fault line.

5. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the steps of the adaptive overcurrent protection method of the power distribution network considering mobile energy storage access when executing the computer program.

6. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the adaptive overcurrent protection method of the power distribution network considering mobile energy storage access.

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