Island detection method and system and distributed power supply access unit device

Abstract

The invention belongs to the technical field of power systems, and discloses an island detection method and system and a distributed power supply access unit device, and the method comprises the steps: obtaining the amplitudes of a current sampling point s1 and a previous sampling point s0; enabling the waveform between the s0 and the s1 to be equivalent to a straight line, and carrying out the calculation through an accurate zero crossing point calculation method according to the amplitudes of two continuous sampling points, and finding out a first zero crossing moment; calculating a time interval between the current sampling point s1 and the sampling point s2 before the next zero passage and a time interval between the next zero passage time and the sampling point s2 before the zero passage, and finding a second zero passage time; and calculating the time interval between the two zero-crossing moments, calculating the voltage frequency according to the time interval between the two zero-crossing moments, and carrying out island detection according to the change of the voltage frequency and the voltage amplitude. According to the method, the accurate frequency can be quickly calculated by finding the accurate zero-crossing time, and the island detection speed and accuracy are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to an island detection method, system and distributed power supply access unit device. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In recent years, distributed photovoltaic power generation, which is characterized by "on-site development and nearby utilization", has developed rapidly, and the total installed capacity has continued to expand. When the power grid is normal, the power grid and distributed power sources jointly supply power to the surrounding loads. When the power grid is disconnected from the loads due to maintenance or failure, the distributed power sources still supply power to the loads, and the distributed power sources and loads form an island that the power company cannot control. Islanding is a special fault state of the microgrid system. After entering the island operation, it is easy to cause damage to the equipment at the distribution network end and the user end, and even endanger personal safety.

[0004] The methods of island detection include passive method and active method. The former mainly makes judgments by detecting the amplitude, frequency, harmonic content, power change and other state quantities of the fundamental voltage, while the latter mainly makes judgments by injecting certain interference signals into the power grid and detecting feedback information.

[0005] The existing passive island detection methods have poor anti-interference ability, large detection accuracy deviation, slow update, long detection time and other problems. Although the existing active island detection methods have a fast detection speed, they have to impose disturbances on the output current frequency, which has a great impact on the output current quality. Or they directly detect electrical parameters such as voltage harmonics and sequence impedance at the common connection point of the power grid. When the voltage harmonics and sequence impedance exceed the set threshold, the island protection is triggered. The calculation amount is large, the controller requirements are high, and the implementation is complex. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes an island detection method, system and distributed power supply access unit device, which can quickly calculate the precise frequency by finding the precise zero-crossing moment, thereby improving the speed and accuracy of island detection.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an island detection method, comprising the following steps:

[0009] Get the current sampling point s 1 and its previous sampling point s 0 The amplitude of

[0010] Will s0 and 1 The waveform between is equivalent to a straight line. According to the amplitude of two consecutive sampling points, the precise zero-crossing point calculation method is used to calculate and find the first zero-crossing moment;

[0011] Calculate the current sampling point s 1 and the sampling point s before the next zero crossing 2 The time interval between the next zero crossing and the sampling point s before zero crossing 2 The time interval between them, find the second zero-crossing moment;

[0012] The time interval between two zero-crossing moments is calculated, the voltage frequency is calculated according to the time interval between the two zero-crossing moments, and island detection is performed according to the changes of the voltage frequency and the voltage amplitude.

[0013] As an optional implementation, after obtaining the amplitude of two consecutive sampling points, before performing calculations based on the amplitude of the two consecutive sampling points using an accurate zero-crossing point calculation method, it is necessary to determine whether the signs of the amplitudes of the two consecutive sampling points obtained have changed, and perform calculations based on the change in the signs of the amplitudes of the two consecutive sampling points to find the first zero-crossing moment.

[0014] As an optional implementation, the time interval between two zero-crossing moments is calculated using the formula:

[0015] T=tx 0 +tx 1 +tx 2

[0016] Among them, tx 0 is the first zero-crossing moment and the current sampling point s 1 The time interval between 1 is the current sampling point s 1 and the sampling point s before the next zero crossing 2 The time interval between 2 is the second zero-crossing moment and the sampling point s before zero-crossing 2 The time interval between.

[0017] As an optional implementation, the first zero-crossing time is equal to the current sampling point s 1 The time interval is calculated as:

[0018]

[0019] y 0 For 0 The sampling amplitude, y 1 For 1 The sampling amplitude of For0 and 1 The time interval between.

[0020] As an optional implementation, the current sampling point s 1 and the sampling point s before the next zero crossing 2 The time interval is calculated as:

[0021]

[0022] Where n is s 1 and 2 The number of sampling points between .

[0023] In a second aspect, the present invention provides an island detection system, comprising:

[0024] The data acquisition module is configured to: obtain the current sampling point s 1 and its previous sampling point s 0 The amplitude of

[0025] The first zero-crossing time calculation module is configured to: 0 and 1 The waveform between is equivalent to a straight line. According to the amplitude of two consecutive sampling points, the precise zero-crossing point calculation method is used to calculate and find the first zero-crossing moment;

[0026] The second zero-crossing time calculation module is configured to calculate the current sampling point s 1 and the sampling point s before the next zero crossing 2 The time interval between the next zero crossing and the sampling point s before zero crossing 2 The time interval between them, find the second zero-crossing moment;

[0027] The island detection module is configured to: calculate the time interval between two zero-crossing moments, calculate the voltage frequency according to the time interval between the two zero-crossing moments, and perform island detection according to changes in the voltage frequency and voltage amplitude.

[0028] In the third aspect, the present invention provides a distributed power supply access unit device, including a main control module, a power module, an acquisition module, a communication module and a storage module. The main control module is connected to other modules through an interface circuit, and data is collected through the acquisition module and the collected data is transmitted to the main control module through the interface circuit. The main control module performs island fault detection through the island detection method described in the first aspect, performs voltage and current fault detection through a fast comparison unit, and finally sends the execution protection action command to the distributed energy device through a fast export unit and a downlink communication interface.

[0029] In a fourth aspect, the present invention provides an electronic device comprising a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method described in the first aspect is completed.

[0030] In a fifth aspect, the present invention provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, completes the method described in the first aspect.

[0031] In a sixth aspect, the present invention provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the method described in the first aspect is implemented.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention discloses an island detection method, which obtains the amplitude of the sampling points on both sides of the current continuous period, uses the accurate zero-crossing point calculation method to find the accurate zero-crossing moment, and then can quickly calculate the accurate frequency by finding the accurate zero-crossing moment, and performs island detection according to the changes in voltage frequency and voltage amplitude, thereby improving the speed and accuracy of island detection. It solves the problems of poor anti-interference ability, large detection accuracy deviation, slow update, and long detection time in the passive island detection method, and the problems of large impact on output current quality, large amount of calculation, high requirements on the controller, and complex implementation in the active island detection method.

[0034] The present disclosure proposes a distributed power access unit device, which can realize the local data collection and transmission of a large number of distributed photovoltaic and other equipment in a dispersed area, and can realize the remote data analysis and control of distributed photovoltaic and other equipment as well as local data analysis, fault protection, and operation status regulation. It realizes the interconnection and intercommunication between the system and the distributed power access unit, and meets the construction requirements of "informatization, automation, and interaction" of the smart grid.

[0035] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0037] Figure 1 A flowchart of an island detection method provided in Example 1 of the present invention;

[0038] Figure 2 A system block diagram of fault detection provided by Embodiment 3 of the present invention;

[0039] Figure 3 This is a system block diagram of a distributed power supply access unit device provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0041] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0042] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "include" and "have" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0044] Example 1

[0045] like Figure 1 As shown, this embodiment provides an island detection method, comprising the following steps:

[0046] S1 gets the current sampling point s 1 and its previous sampling point s 0 The amplitude of

[0047] S2 will s 0 and 1 The waveform between is equivalent to a straight line. According to the amplitude of two consecutive sampling points, the precise zero-crossing point calculation method is used to calculate and find the first zero-crossing moment;

[0048] S3 calculates the current sampling point s 1 and the sampling point s before the next zero crossing 2 The time interval between the next zero crossing and the sampling point s before zero crossing 2 The time interval between them, find the second zero-crossing moment;

[0049] S4 calculates the time interval between two zero-crossing moments, calculates the voltage frequency according to the time interval between the two zero-crossing moments, and performs island detection according to changes in the voltage frequency and the voltage amplitude.

[0050] After obtaining the amplitude of two consecutive sampling points, before using the precise zero-crossing point calculation method to calculate based on the amplitude of the two consecutive sampling points, it is necessary to determine whether the signs of the amplitude of the two consecutive sampling points have changed, and calculate based on the change in the signs of the amplitude of the two consecutive sampling points to find the first zero-crossing moment.

[0051] The specific calculation method for island detection using precise zero-crossing points in the present disclosure is as follows:

[0052] first step:

[0053] In the process of calculating the frequency, we need to find the exact zero-crossing moment. We know that the sine function is y=sinx. When x is close to 0, the waveform is approximated as y=x, that is, s 0 and 1 The waveform between is equivalent to a straight line. Assuming that the first precise zero-crossing point is at ta and s 1 The time interval between sampling moments is tx 0 , then the following calculation formula is obtained

[0054]

[0055] Among them, y 0 For 0 The sampling amplitude, y 1 For 1 The sampling amplitude of For 0 and 1 The time interval between the two messages, in seconds.

[0056] According to this formula, it can be calculated that: the zero-crossing point ta and the current sampling point s 1 The exact time interval between them is:

[0057]

[0058] Step 2:

[0059] After finding the first zero crossing, the current sampling point s 1 and the sampling point s before the next zero crossing 2 The time between 1 and 2 The time elapsed between 1 , Where n is s 1 and 2The number of sampling points between .

[0060] Step 3:

[0061] Calculate the time between the next zero crossing and the sampling point before zero crossing, assuming that the exact zero crossing time tb is the same as s 2 The time interval to be collected is tx 2 , the calculation formula is as follows:

[0062]

[0063] in, For 1 and 2 The time interval between the two, in seconds, y 2 For 1 The sampling amplitude, y 3 For 2 The sampling amplitude of .

[0064] According to this formula, it can be calculated that: the zero-crossing point tb and the previous sampling point s 2 The exact time interval between them is:

[0065]

[0066] Step 4:

[0067] The time interval between two exact zero crossings is:

[0068] T=tx 0 +tx 1 +tx 2

[0069] Among them, tx 0 is the first zero-crossing moment and the current sampling point s 1 The time interval between 1 is the current sampling point s 1 and the sampling point s before the next zero crossing 2 The time interval between 2 is the second zero-crossing moment and the sampling point s before zero-crossing 2 The time interval between.

[0070] Step 5:

[0071] Calculate frequency

[0072] Island detection is performed based on changes in voltage frequency and voltage amplitude.

[0073] The basis for determining an island is as follows:

[0074] Voltage frequency change: If the voltage frequency swing exceeds 0.2Hz within 100ms or exceeds the range of [49.5Hz~50.2Hz], an island is determined.

[0075] Voltage amplitude change: If the voltage amplitude swing range exceeds 20V or exceeds the range of [187V, 242V]V within 100ms, an island is determined. The swing range refers to the difference between the maximum and minimum swing values ​​within a period of time.

[0076] The above criteria are mainly based on voltage frequency swing and supplemented by voltage amplitude swing. When the voltage frequency swing criteria are met, the grid connection point will be cut off within 2 seconds and reported.

[0077] Example 2

[0078] This embodiment provides an island detection system, including:

[0079] The data acquisition module is configured to: obtain the current sampling point s 1 and its previous sampling point s 0 The amplitude of

[0080] The first zero-crossing time calculation module is configured to: 0 and 1 The waveform between is equivalent to a straight line. According to the amplitude of two consecutive sampling points, the precise zero-crossing point calculation method is used to calculate and find the first zero-crossing moment;

[0081] The second zero-crossing time calculation module is configured to calculate the current sampling point s 1 and the sampling point s before the next zero crossing 2 The time interval between the next zero crossing and the sampling point s before zero crossing 2 The time interval between them, find the second zero-crossing moment;

[0082] The island detection module is configured to: calculate the time interval between two zero-crossing moments, calculate the voltage frequency according to the time interval between the two zero-crossing moments, and perform island detection according to changes in the voltage frequency and voltage amplitude.

[0083] Example 3

[0084] like Figure 3As shown, this embodiment provides a distributed power supply access unit device, including a main control module, a power module, an acquisition module, a communication module and a storage module. The main control module is connected to other modules through an interface circuit, and data is collected through the acquisition module and the collected data is transmitted to the main control module through the interface circuit. The main control module performs island fault detection through the island detection method described in Example 1, performs voltage and current fault detection through the fast comparison unit, and finally sends the execution protection action command to the distributed energy device through the fast export unit and the downlink communication interface.

[0085] Among them, the main control module is based on the main control MCU, and the clock circuit, backup power circuit, and interface circuit form the control core of the distributed power access unit, which is responsible for the coordination of the various component systems and the execution of control strategies. It provides interface circuits for each sub-module, is responsible for the local status acquisition of the distributed photovoltaic system, is responsible for receiving the instructions of the master station system, and sends the distributed photovoltaic operation status and parameters to manage the connected distributed photovoltaic equipment, including real-time parameter acquisition, fault detection and other functions.

[0086] The fault detection module includes power quality detection, voltage detection, current detection, island detection, and equipment operation status detection and protection.

[0087] The current detection method refers to the principle of fast overcurrent protection and outputs the output result to the fast comparison unit. The acquisition chip is designed with a fast effective value register to detect the half-cycle or cycle effective value. This function can be used for overcurrent detection. The overcurrent waveform I_WAVE_F comes from the internal circuit of the acquisition chip. I_WAVE_F takes the absolute value and accumulates the half-cycle or cycle time. The accumulation time is selected by FAST_RMS_CTRL. The default selection is cycle accumulation. The maximum response time is 40ms. After comparing the accumulation result with the threshold, the flag flag and the effective value FAST_RMS of the current current are output.

[0088] The voltage detection method collects raw voltage data V_RMS through an acquisition module, transmits the voltage data to a fast comparison unit, and outputs an output result to the fast comparison unit.

[0089] The island detection method collects raw data through the acquisition module and transmits the data to the island detection unit. The island detection unit uses an algorithm to detect voltage changes and frequency changes to determine whether there is an island fault and outputs the output result to the fast comparison unit.

[0090] The power module is based on the AC / DC power supply circuit, and consists of an AC / DC power supply circuit, a DC / DC power supply circuit and an output protection circuit. It realizes AC power supply, hardware system power supply and output power supply, and includes the necessary protection circuits and implementation methods.

[0091] The acquisition module is centered on the acquisition chip and consists of a voltage acquisition circuit, a current acquisition circuit and an interface circuit, realizing a calibration-free voltage and current acquisition method.

[0092] The communication module includes an uplink communication module to realize the uplink communication function, which is used to connect to the uplink system such as the concentrator, and a downlink communication module to realize the downlink communication function, which is used to connect to the downlink equipment such as the inverter. The local communication module realizes the local communication function, which is used for local system upgrade, constant parameter setting and other functions.

[0093] The storage module includes a local fixed value storage module for storing system operation fixed value parameters, and a local data storage module for storing system operation event records, work logs and other data. The block storage method is adopted, EEPROM realizes the local fixed value storage module, and FLASH realizes the local data storage module. Both storage modules use three-segment redundancy technology.

[0094] The storage space is divided according to the capacity of the storage chip, including the index table storage area, the first storage area, and the second storage area. The first storage area and the second storage area have the same capacity and storage mode, which are used for redundant backup. The index table storage area is used to store the directory of the data or parameter storage area and the checksum of the storage interval corresponding to each directory.

[0095] When performing a storage operation, first establish an index table, define the storage space size, and record the starting and ending addresses of the first and second storage areas. Then, store the data in the first storage area and the second storage area respectively. After the data is stored in the first storage area and the second storage area respectively, calculate the checksum of the two areas and compare them. Only when the checksums are consistent, the stored data is considered valid and stored in the corresponding index table after verification. When the checksums are inconsistent, the storage operation needs to be performed again.

[0096] When performing a read operation, the data in the first storage area and the second storage area are read respectively according to the position of the index table to be read and a checksum is calculated. When the calculated checksum is consistent with the checksum recorded in the index table, the read is considered valid. When one of the checksums is inconsistent with the index table, the inconsistent data is updated. When all of them are inconsistent, it is considered that the storage space is wrong, and a fault alarm is issued, which requires manual intervention to handle.

[0097] It should be noted that the above modules correspond to the steps described in Example 1, and the examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the contents disclosed in the above Example 1. It should be noted that the above modules, as part of the system, can be executed in a computer system such as a set of computer executable instructions.

[0098] In further embodiments, there is also provided:

[0099] An electronic device includes a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method described in Embodiment 1 is performed. For the sake of brevity, it will not be described in detail here.

[0100] It should be understood that in this embodiment, the processor may be a central processing unit CPU, and the processor may also be other general-purpose processors, digital signal processors DSP, application-specific integrated circuits ASIC, off-the-shelf programmable gate arrays FPGA or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0101] The memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0102] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the method described in Example 1 is completed.

[0103] The method in Example 1 can be directly embodied as a hardware processor, or a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware. To avoid repetition, it is not described in detail here.

[0104] A computer program product includes a computer program, and when the computer program is executed by a processor, the method described in embodiment 1 is implemented.

[0105] The present invention also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer executable instructions, such as instructions included in a program module, which are executed in a device on a real or virtual processor of the target to perform the process / method as described above. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functions of program modules can be combined or divided between program modules as needed. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in local and remote storage media.

[0106] The computer program code for implementing the method of the present invention can be written in one or more programming languages. These computer program codes can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the computer or other programmable data processing device, causes the function / operation specified in the flow chart and / or block diagram to be implemented. The program code can be executed completely on a computer, partially on a computer, as an independent software package, partially on a computer and partially on a remote computer or completely on a remote computer or server.

[0107] In the context of the present invention, computer program codes or related data may be carried by any appropriate carrier to enable a device, apparatus or processor to perform the various processes and operations described above. Examples of carriers include signals, computer readable media, and the like. Examples of signals may include electrical, optical, radio, acoustic or other forms of propagation signals, such as carrier waves, infrared signals, and the like.

[0108] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with this embodiment can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0109] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. An island detection method, characterized in that: The following steps are involved: Get the amplitude of the current sampling point s1 and its previous sampling point s0; The waveform between s0 and s1 is equivalent to a straight line, and the first zero-crossing moment is found by using the precise zero-crossing point calculation method based on the amplitude of two consecutive sampling points; Calculate the time interval between the current sampling point s1 and the sampling point s2 before the next zero crossing, and the time interval between the next zero crossing moment and the sampling point s2 before the zero crossing, and find the second zero crossing moment; The time interval between two zero-crossing moments is calculated, the voltage frequency is calculated according to the time interval between the two zero-crossing moments, and island detection is performed according to the changes of the voltage frequency and the voltage amplitude.

2. The island detection method according to claim 1, characterized in that: After obtaining the amplitude of two consecutive sampling points, before using the precise zero-crossing point calculation method to calculate based on the amplitude of the two consecutive sampling points, it is necessary to determine whether the signs of the amplitude of the two consecutive sampling points have changed, and calculate based on the change in the signs of the amplitude of the two consecutive sampling points to find the first zero-crossing moment.

3. The island detection method according to claim 1, characterized in that: Calculate the time interval between two zero-crossing moments using the formula: T=tx0+tx1+tx2 Among them, tx0 is the time interval between the first zero-crossing moment and the current sampling point s1, tx1 is the time interval between the current sampling point s1 and the sampling point s2 before the next zero-crossing, and tx2 is the time interval between the second zero-crossing moment and the sampling point s2 before the zero-crossing.

4. The island detection method according to claim 1, characterized in that: The calculation formula for the time interval between the first zero-crossing moment and the current sampling point s1 is: y0 is the sampling amplitude of s0, y1 is the sampling amplitude of s1, is the time interval between s0 and s1.

5. The island detection method according to claim 1, characterized in that: The calculation formula for the time interval between the current sampling point s1 and the next sampling point s2 before zero crossing is: Where n is the number of sampling points between s1 and s2.

6. An island detection system, characterized in that: include: The data acquisition module is configured to: acquire the amplitude of the current sampling point s1 and the previous sampling point s0; The first zero-crossing moment calculation module is configured to: equate the waveform between s0 and s1 to a straight line, and calculate the first zero-crossing moment using an accurate zero-crossing point calculation method according to the amplitude of two consecutive sampling points; The second zero-crossing time calculation module is configured to: calculate the time interval between the current sampling point s1 and the sampling point s2 before the next zero-crossing and the time interval between the next zero-crossing time and the sampling point s2 before the zero-crossing, and find the second zero-crossing time; The island detection module is configured to: calculate the time interval between two zero-crossing moments, calculate the voltage frequency according to the time interval between the two zero-crossing moments, and perform island detection according to changes in the voltage frequency and voltage amplitude.

7. A distributed power supply access unit device, characterized in that: It includes a main control module, a power module, an acquisition module, a communication module and a storage module. The main control module is connected to other modules through an interface circuit. Data is collected through the acquisition module and the collected data is transmitted to the main control module through the interface circuit. The main control module performs island fault detection through the island detection method according to any one of claims 1 to 5, performs voltage and current fault detection through a fast comparison unit, and finally sends the execution protection action command to the distributed energy device through a fast export unit and a downlink communication interface.

8. An electronic device, characterized in that: The method comprises a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method according to any one of claims 1 to 5 is completed.

9. A computer-readable storage medium, characterized in that: Used to store computer instructions, which, when executed by a processor, complete the method described in any one of claims 1 to 5.

10. A computer program product, characterized in that The invention comprises a computer program, which, when executed by a processor, implements the method according to any one of claims 1 to 5.

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