Ccd file configuration method and device for distribution network series supply system and protection device thereof

Abstract

The application belongs to the technical field of power system relay protection, and particularly relates to a distribution network series supply system and a CCD file configuration method and device of a protection device thereof. The application specifically comprises: in order to solve the problem that the existing technology needs to configure an SCD file when configuring a CCD file, resulting in complex operation of distribution network operation and maintenance, the application first initializes and sets parameters of all protection devices, initializes and configures specific parameter values in SV information and GOOSE information of each device for representing data interaction with the device, then renumbers the protection devices according to real-time positions and quantities of the protection devices, instantiates specific parameters of the SV information and the GOOSE information of the protection devices based on new numbers of the devices, generates a CCD configuration file meeting actual engineering needs, and realizes plug and play of the protection devices, which not only can ensure correct virtual loop connection between the devices, but also is helpful to improving operation and management level of the distribution network.

Description

Technical Field

[0001] This invention belongs to the field of power system relay protection technology, specifically relating to a CCD file configuration method and device for a distribution network series power supply system and its protection device. Background Technology

[0002] A CCD (configured circuit description) file is an indispensable configuration file for intelligent power systems. It describes the virtual circuit connections between various devices, enabling each device to receive and transmit sampled values ​​and status information. Currently, CCD files are mainly used in intelligent substations to solve the interoperability problem of equipment from different manufacturers within the substation. The process involves first establishing virtual circuit connections between the ICD (Id capability description) files of each device within the system, completing the configuration of the SCD (system configuration description), and then using a dedicated tool to export the CCD files of each device.

[0003] With the upgrading of power distribution network systems, intelligent power distribution equipment is gradually being applied. In particular, in power distribution network systems, intelligent protection devices are required in each substation for peer-to-peer communication to complete the transmission and reception of SV and GOOSE between devices. In this system, the connection methods of each protection device are relatively fixed, and from the perspective of convenient operation and maintenance of the power distribution system, the SCD-based CCD file configuration method cannot eliminate the SCD file configuration step to achieve automatic configuration. Even with technical cases that achieve partial automatic CCD configuration, such as the Chinese invention patent application with publication number CN 115220808 A, which discloses a CCD file configuration method and device for substation renovation and expansion bay protection devices, it still relies on SCD files in the intelligent substation renovation and expansion stage. It first decouples the original SCD file, separating the virtual loop information and monitoring information, and then performs automatic CCD file configuration. This cannot meet the requirements of power distribution network engineering applications and cannot achieve plug-and-play protection devices. Summary of the Invention

[0004] The purpose of this invention is to provide a CCD file configuration method and apparatus for a distribution network series power supply system and its protection device, in order to solve the problem that configuring CCD files based on SCD file configuration decoupling during CCD file configuration makes distribution network operation and maintenance operations complex.

[0005] To solve the above technical problems, the present invention provides a CCD file configuration method for a protection device of a multi-level series power supply system in a distribution network, comprising the following steps:

[0006] 1) Initialize the number and number of protection devices in the distribution network system, and initialize the offline configuration of specific parameter values ​​in the SV information and GOOSE information of the CCD file that represent data interaction with the protection device according to the initialization number of the protection device;

[0007] 2) Set the number of protection devices, then set the number of each protection device according to its actual location, and finally power on and restart all protection devices. Update the number of protection devices and the number of each protection device in the protection device. Based on the updated protection device number, instantiate the specific parameter values ​​in the SV information and GOOSE information of each protection device to obtain the CCD configuration file of each protection device.

[0008] Its beneficial effects are as follows: Addressing the problem that existing technologies require integrators or engineering maintenance personnel to configure system-level SCD files when configuring CCD files in protection devices, leading to complex distribution network operation and maintenance, this invention eliminates the SCD file configuration process. First, it initializes the number and number of protection devices. Then, it initializes the SV and GOOSE information in the CCD files of the protection devices through offline configuration. Next, it re-numbers the protection devices based on their real-time location and number. Specific parameters of the SV and GOOSE information in the CCD files of the protection devices are instantiated based on the new device numbers, automatically generating CCD configuration files that meet the needs of actual engineering projects. This enables plug-and-play protection devices, ensuring accurate virtual loop connections between devices and helping to improve the level of distribution network operation and maintenance and management.

[0009] Furthermore, when the number and / or number of protection devices are changed, the number and number of protection devices are readjusted and the device is powered on and restarted. Based on the changed number of the protection device, the specific parameter values ​​in its SV information and GOOSE information are automatically instantiated to obtain the CCD configuration file of the protection device.

[0010] Its beneficial effects are: the number of protection devices in the distribution network system can be increased or decreased as needed, enabling the protection devices to generate CCD configuration files to achieve a plug-and-play effect, thereby improving the operation and maintenance level of the distribution network.

[0011] Furthermore, SV information includes SV subscription information and SV release information:

[0012] SV subscription information refers to the SV information issued by the protection devices on the left and right adjacent intervals in a point-to-point manner.

[0013] SV information release refers to the current protection device simultaneously releasing the SV information of this bay to the adjacent protection devices on the left and right.

[0014] Its beneficial effects are: collecting and publishing information from various protection devices, accelerating transmission efficiency, making CCD file configuration more reliable and stable, and improving the level of distribution network operation and maintenance and management.

[0015] Furthermore, GOOSE information includes GOOSE subscription information and GOOSE publication information:

[0016] GOOSE subscription information refers to the fact that each protection device subscribes to GOOSE information published by all other protection devices besides itself from the communication network;

[0017] GOOSE information dissemination refers to the broadcasting of GOOSE information by each protection device to the communication network.

[0018] Its beneficial effects are: collecting and publishing information from various protection devices, accelerating transmission efficiency, making CCD file configuration more reliable and stable, and improving the level of distribution network operation and maintenance and management.

[0019] Furthermore, in step 1), the number of initialization devices is 2 to M, where M is the actual number of protection devices required by the system.

[0020] Its beneficial effects are: it directly uses the factory default CCD file as the basis for CCD file configuration, which ensures compatibility with protection devices from different manufacturers and indirectly improves the operation and maintenance level of distribution network.

[0021] Furthermore, during the instantiation of SV subscription information, if the number of the current protection device is the same as the number of protection devices set, the current protection device subscription includes the SV information of protection device number 1.

[0022] Furthermore, the specific parameters for initializing and instantiating SV information and GOOSE information respectively include at least one of name, smvID, iedName, MAC-Address, and APPID.

[0023] Its beneficial effects are: to collect and publish specific parameter information, to realize the interaction between various devices, to realize the automatic generation of CCD files of protection devices, and to ensure the correct connection of virtual loops between protection devices.

[0024] To address the aforementioned technical problems, this invention also provides a CCD file configuration device for a multi-level series power supply system protection device in a distribution network, comprising a memory and a processor. The processor executes computer program instructions stored in the memory to implement the CCD file configuration method for a multi-level series power supply system protection device in a distribution network described above.

[0025] Its beneficial effect is that the device ensures the effective and reliable execution of the CCD file configuration method for a multi-level series power supply system protection device in a distribution network.

[0026] To address the aforementioned technical problems, this invention also provides a multi-level power supply system for power distribution networks, comprising multiple power distribution rooms connected by optical fibers, and a CCD file configuration method for the protection device of the aforementioned multi-level power supply system for power distribution networks.

[0027] Its beneficial effects are as follows: Based on the power distribution system provided by the present invention, the CCD file configuration of the protection device skips the SCD file configuration process, which provides a basis for the execution of the CCD file configuration method of the protection device of the multi-level series power supply system of the present invention.

[0028] Furthermore, the communication connection method between the protection devices is as follows: each protection device is connected sequentially.

[0029] Its beneficial effects are: numbering and distinguishing each protection device, ensuring that the virtual circuit connection between devices is correct, and helping to improve the operation and maintenance and management level of the distribution network. Attached Figure Description

[0030] Figure 1 This is a topology diagram of the power distribution network chain-type power supply system of the present invention;

[0031] Figure 2 This is a schematic diagram of the information transmission and reception of the power distribution network chain power supply system of the present invention;

[0032] Figure 3 This is a schematic diagram of the parameter initialization of the power distribution network chain power supply system device of the present invention;

[0033] Figure 4 This is a schematic diagram of the offline configuration initialization of SV information in this invention;

[0034] Figure 5 This is a schematic diagram of the offline configuration for initializing GOOSE information according to the present invention;

[0035] Figure 6 This is a schematic diagram illustrating the instantiation of SV information in this invention;

[0036] Figure 7 This is a schematic diagram illustrating the instantiation of GOOSE information in this invention;

[0037] Figure 8 This is a flowchart of the method of the present invention. Detailed Implementation

[0038] The basic concept of this invention is as follows: To solve the problem that existing technologies require integrators or engineering maintenance personnel to configure system-level SCD files for CCD file configuration, leading to complex distribution network operation and maintenance, this invention first initializes the quantity and number of all protection devices. Then, it initializes the offline configuration of specific parameter values ​​in the SV information (sampled values) and GOOSE information (status variables) of each device used to characterize data interaction with it. Next, it instantiates the CCD configuration file for each protection device to obtain the configuration file for each device. If the number of the protection device is changed, the feature values ​​in the SV information and GOOSE information of each device are instantiated based on the changed device number to obtain the CCD configuration file for each device.

[0039] The present invention will now be described in detail with reference to the accompanying drawings and method embodiments.

[0040] Example of CCD file configuration method for protection devices in multi-level series power supply systems in power distribution networks:

[0041] The present invention provides a multi-level series power supply system for a distribution network, the structural topology of which is shown in the figure below. Figure 1 As shown: Power supplies S1-S2 form a chain power supply system. Protection devices in each distribution room are connected sequentially using optical fibers, starting with the first device, forming a daisy-chain communication network. In this network, protection devices are numbered from left to right; the first protection device is numbered 1 and is called the first device; the last protection device is numbered M (based on the number of devices in the system) and is called the last device.

[0042] Each device transmits and receives information such as Figure 2 As shown, it specifically includes:

[0043] 1) Each protection device transmits and receives SV information.

[0044] Each protection device subscribes to the SV information issued by the protection devices in the adjacent bays on the left and right in a point-to-point manner, and at the same time publishes the SV information of its own protection device to the adjacent protection devices on the left and right. For example, protection device #2 subscribes to the SV information published by protection device #1 on the left and protection device #3 on the right, and at the same time publishes the SV information of protection device #2 to protection device #1 on the left and protection device #3 on the right.

[0045] 2) Each protection device transmits and receives GOOSE information.

[0046] Each protection device subscribes to GOOSE information published by all other protection devices except itself from the communication network, and at the same time broadcasts its own GOOSE information to the communication network.

[0047] To eliminate the need for configuring SCD files and enable plug-and-play operation of the protection device, the multi-level series power supply system in the distribution network adopts a CCD file configuration method for the protection device of the multi-level series power supply system in the present invention, as shown in the flowchart below. Figure 8 As shown, the specific steps include:

[0048] Step 1, as follows Figure 3 As shown, initialize the number and number of protection devices.

[0049] 1) Initialize the number of protection devices X in the system. The default value is 15. The parameter setting range of this embodiment is designed according to "2 to 15", but the parameter setting range can be expanded to "2 to M" (M is the actual number required by the system).

[0050] 2) Initialize the numbering of all devices in the system, with the default value being 01.

[0051] Step 2: Initialize the CCD configuration file of the protection device offline.

[0052] 1) such as Figure 4 As shown, the offline configuration for initializing SV information is performed.

[0053] ① Initialize the offline configuration of SV subscription information. Initialize one group of SV subscription information (fixed number of groups) in the specified CCD file. Specific parameters for each type of SV subscription information are initialized based on the device number, while other parameters are fixed to preset values. Tables 1 and 2 below show the initialization settings for specific parameters of each type of SV subscription information based on protection device #01.

[0054] Table 1. Initialization of Specific Parameters for Group 1 SV Subscription Information

[0055]

[0056] Table 2. Initialization of Specific Parameters for SV Subscription Information in Group 2

[0057]

[0058] ② Initialize the offline configuration for SV release information. Initialize one group of SV release information (fixed number of groups) in the specified CCD file. Specific parameters for each type of SV release information are initialized based on the device number, while other parameters remain fixed at preset values ​​and do not change with the device number. Table 3 below shows the initialization settings for specific parameters of each type of SV release information based on protection device #01.

[0059] Table 3. Initialization of Specific Parameters for SV Publication Information

[0060]

[0061] 2) such as Figure 5 As shown, initialize the offline configuration for GOOSE information.

[0062] ① Initialize the offline configuration for GOOSE subscription information. Initialize the 15 groups of GOOSE subscription information in the specified CCD file (the number of groups can be adjusted). Specific parameters for each type of GOOSE subscription information are initialized based on the device number. As shown in Table 4 below, the specific parameters for each type of GOOSE subscription information are initialized based on protection device #1.

[0063] Table 4. Initialization of specific parameters for GOOSE subscription information

[0064]

[0065] ② Initialize the offline configuration for GOOSE release information. Initialize one group of GOOSE release information in the specified CCD file offline. Specific parameters for each type of GOOSE release information are initialized based on the device number. As shown in Table 5 below, the specific parameters for each type of GOOSE release information are initialized based on protection device #1.

[0066] Table 5. Initialization of Specific Parameters for GOOSE Publication Information

[0067]

[0068] Step 3: Instantiate the number and number of protection devices.

[0069] 1) Set the “number of devices” to X according to the actual number of protection devices in the system.

[0070] 2) According to the actual location of each protection device in the system, from the first device to the last device, set the protection device numbers in the system as “1 to Y”.

[0071] 3) After completion, the protection device is powered on and restarted, and the internal system updates the number and serial number of the above devices in real time.

[0072] Step 4: Instantiate the CCD configuration file for the protection device.

[0073] 1) such as Figure 6 As shown, the SV information of the protection device is instantiated.

[0074] ① Instantiation of SV subscription information. The instantiation method for SV subscription information parameters that change with the protection device number is shown in Tables 6 and 7 below.

[0075] Table 6. Instantiation of SV Subscription Information in Group 1

[0076]

[0077] Table 7, Instantiation of SV Subscription Information in Group 2

[0078]

[0079] ② Instantiate SV release information. The instantiation method for SV release information parameters that change with the protection device number is shown in Table 8 below.

[0080] Table 8. Instantiation of SV Release Information

[0081]

[0082]

[0083] 2) such as Figure 7 As shown, GOOSE information is instantiated for devices whose protection device numbers have changed.

[0084] ① Instantiate the GOOSE subscription information. Since all received GOOSE subscription information has been configured, the GOOSE subscription information does not change with the device number.

[0085] ② Instantiate the GOOSE published information. The instantiation method for GOOSE published information parameters that vary with the protection device number is shown in Table 9 below.

[0086] Table 9. Instantiation of GOOSE Published Information

[0087]

[0088] At this point, the SV and GOOSE configuration information in the CCD files of each device has been updated, and SV and GOOSE subscriptions and transmissions can be performed normally. If the number of protection devices in the system changes again, causing a change in the device number setting, then after executing step three again, the relevant information in the CCD configuration file will be automatically instantiated according to the actual number of the protection device after the change.

[0089] In this embodiment, when instantiating the SV subscription information in the Y# protection device, if the device number Y = the number of devices X, that is, when this device is an end device, the parameters of the second group of SV subscription information are shown in Table 10 below:

[0090] Table 10, Instantiation of SV Subscription Information in Group 2

[0091]

[0092] The method of this invention is applicable to chain-type power supply systems, and can also be applied to ring-type power supply systems similar to chain-type power supply systems.

[0093] This invention eliminates the need for system integrators or engineering maintenance personnel to configure system-level SCD files. Based on the factory default CCD file, it automatically generates CCD configuration files that meet the actual engineering needs according to the actual number of the device in the system, enabling the protection device to be used plug and play. This not only ensures that the virtual loop connection between devices is correct, but also helps to improve the level of distribution network operation and maintenance and management.

[0094] Example of a CCD file configuration device for a multi-level series power supply system protection device in a distribution network:

[0095] This invention discloses a CCD file configuration device for a multi-level series power supply system protection device in a distribution network, comprising a memory and a processor. The processor executes computer program instructions stored in the memory to implement the CCD file configuration method for a multi-level series power supply system protection device in a distribution network as described in the method embodiments of this invention. The processor can be a programmable logic device (FPGA) or similar processing device. The memory can be any type of memory that stores information using electrical energy, such as RAM or ROM, or other types of memory.

[0096] Example of a multi-level series power supply system for distribution networks

[0097] The specific topology and transmission and reception process of the multi-level power supply system for distribution networks of the present invention have been described in detail in an embodiment of a CCD file configuration method for a protection device of a multi-level power supply system for distribution networks, and will not be repeated here.

Claims

1. A CCD file configuration method for a protection device in a multi-level series power supply system of a distribution network, characterized in that, Includes the following steps: 1) Initialize the number and numbering of protection devices in the distribution network system that constitutes the chain communication network; 2) Based on the initialization number of the protection device, the specific parameter values ​​in the SV information and GOOSE information of the CCD file used to characterize data interaction with it are initialized offline. The remaining parameters are fixed to preset values ​​and do not change with the device number. SV information includes SV subscription information and SV publishing information. SV subscription information refers to the SV information issued by the current protection device in a point-to-point manner from the protection devices in the left and right adjacent bays. SV subscription information is configured as 2 groups. SV publishing information refers to the current protection device simultaneously publishing the SV information of this bay protection device to the protection devices in the left and right adjacent bays. GOOSE subscription information is configured as M groups, where M is the number of protection devices. GOOSE information includes GOOSE subscription information and GOOSE publication information. GOOSE subscription information refers to each protection device subscribing to GOOSE information published by all other protection devices except itself from the communication network. GOOSE publication information refers to each protection device publishing its own GOOSE information to the communication network in the form of broadcast. 3) Set the number of protection devices, and then set the number of each protection device in sequence according to the actual location of the protection devices. Power on and restart all protection devices, and update the set number of protection devices and the number of each protection device in the protection device. 4) Based on the updated protection device number, instantiate the specific parameter values ​​in the SV information and GOOSE information of each protection device to obtain the CCD configuration file of each protection device; during the instantiation of SV subscription information, if the number of the current protection device is the same as the number of protection devices set, the current protection device subscription includes the SV information of protection device number 1.

2. The CCD file configuration method for the protection device of a multi-level series power supply system in a distribution network according to claim 1, characterized in that, When the number and / or number of protection devices are changed, the number and number of protection devices are reset and the device is powered on and restarted. Based on the changed number of the protection device, the specific parameter values ​​in its SV information and GOOSE information are automatically instantiated to obtain the CCD configuration file of the protection device.

3. The CCD file configuration method for the protection device of a multi-level series power supply system in a distribution network according to claim 1, characterized in that, In step 1), the number of initialization devices is 2~M.

4. The CCD file configuration method for the protection device of a multi-level series power supply system in a distribution network according to any one of claims 1-3, characterized in that, The specific parameters for initializing and instantiating SV and GOOSE information respectively include at least one of name, smvID, iedName, MAC-Address, and APPID.

5. The CCD file configuration method for the protection device of a multi-level series power supply system in a distribution network according to claim 4, characterized in that, name, smvID, and iedName are stored in decimal number format.

6. The CCD file configuration method for the protection device of a multi-level series power supply system in a distribution network according to claim 4, characterized in that, MAC-Address and APPID are stored in hexadecimal number format.

7. A CCD file configuration device for a protection device of a multi-level series power supply system in a distribution network, characterized in that, Includes a memory and a processor, the processor being used to execute computer program instructions stored in the memory to implement the following CCD file configuration method for a multi-level series power supply system protection device: 1) Initialize the number and numbering of protection devices in the distribution network system that constitutes the chain communication network; 2) Based on the initialization number of the protection device, the specific parameter values ​​in the SV information and GOOSE information of the CCD file used to characterize data interaction with it are initialized offline. The remaining parameters are fixed to preset values ​​and do not change with the device number. SV information includes SV subscription information and SV publishing information. SV subscription information refers to the SV information issued by the current protection device in a point-to-point manner from the protection devices in the left and right adjacent bays. SV subscription information is configured as 2 groups. SV publishing information refers to the current protection device simultaneously publishing the SV information of this bay protection device to the protection devices in the left and right adjacent bays. GOOSE subscription information is configured as M groups, where M is the number of protection devices. GOOSE information includes GOOSE subscription information and GOOSE publication information. GOOSE subscription information refers to each protection device subscribing to GOOSE information published by all other protection devices except itself from the communication network. GOOSE publication information refers to each protection device publishing its own GOOSE information to the communication network in the form of broadcast. 3) Set the number of protection devices, and then set the number of each protection device in sequence according to the actual location of the protection devices. Power on and restart all protection devices, and update the set number of protection devices and the number of each protection device in the protection device. 4) Based on the updated protection device number, instantiate the specific parameter values ​​in the SV information and GOOSE information of each protection device to obtain the CCD configuration file of each protection device; during the instantiation of SV subscription information, if the number of the current protection device is the same as the number of protection devices set, the current protection device subscription includes the SV information of protection device number 1.

8. The CCD file configuration device for the protection device of a multi-level series power supply system in a distribution network according to claim 7, characterized in that, When the number and / or number of protection devices are changed, the number and number of protection devices are reset and the device is powered on and restarted. Based on the changed number of the protection device, the specific parameter values ​​in its SV information and GOOSE information are automatically instantiated to obtain the CCD configuration file of the protection device.

9. The CCD file configuration device for the protection device of a multi-level series power supply system in a distribution network according to claim 7, characterized in that, In step 1), the number of initialization devices is 2~M.

10. The CCD file configuration device for a multi-level series power supply system protection device in a distribution network according to any one of claims 7-9, characterized in that, The specific parameters for initializing and instantiating SV and GOOSE information respectively include at least one of name, smvID, iedName, MAC-Address, and APPID.

11. The CCD file configuration device for the protection device of a multi-level series power supply system in a distribution network according to claim 10, characterized in that, name, smvID, and iedName are stored in decimal number format.

12. The CCD file configuration device for the protection device of a multi-level series power supply system in a distribution network according to claim 10, characterized in that, MAC-Address and APPID are stored in hexadecimal number format.

13. A multi-level series power supply system for a power distribution network, comprising multiple protection devices, wherein the protection devices are communicatively connected, characterized in that, It also includes a CCD file configuration device for a multi-level series power supply system protection device in a distribution network. This device includes a memory and a processor, the processor executing computer program instructions stored in the memory to implement the following CCD file configuration method for the multi-level series power supply system protection device in a distribution network: 1) Initialize the number and numbering of protection devices in the distribution network system that constitutes the chain communication network; 2) Based on the initialization number of the protection device, the specific parameter values ​​in the SV information and GOOSE information of the CCD file used to characterize data interaction with it are initialized offline. The remaining parameters are fixed to preset values ​​and do not change with the device number. SV information includes SV subscription information and SV publishing information. SV subscription information refers to the SV information issued by the current protection device in a point-to-point manner from the protection devices in the left and right adjacent bays. SV subscription information is configured as 2 groups. SV publishing information refers to the current protection device simultaneously publishing the SV information of this bay protection device to the protection devices in the left and right adjacent bays. GOOSE subscription information is configured as M groups, where M is the number of protection devices. GOOSE information includes GOOSE subscription information and GOOSE publication information. GOOSE subscription information refers to each protection device subscribing to GOOSE information published by all other protection devices except itself from the communication network. GOOSE publication information refers to each protection device publishing its own GOOSE information to the communication network in the form of broadcast. 3) Set the number of protection devices, and then set the number of each protection device in sequence according to the actual location of the protection devices. Power on and restart all protection devices, and update the set number of protection devices and the number of each protection device in the protection device. 4) Based on the updated protection device number, instantiate the specific parameter values ​​in the SV information and GOOSE information of each protection device to obtain the CCD configuration file of each protection device; during the instantiation of SV subscription information, if the number of the current protection device is the same as the number of protection devices set, the current protection device subscription includes the SV information of protection device number 1.

14. The multi-level series power supply system for distribution networks according to claim 13, characterized in that, When the number and / or number of protection devices are changed, the number and number of protection devices are reset and the device is powered on and restarted. Based on the changed number of the protection device, the specific parameter values ​​in its SV information and GOOSE information are automatically instantiated to obtain the CCD configuration file of the protection device.

15. The multi-level series power supply system for distribution networks according to claim 13, characterized in that, In step 1), the number of initialization devices is 2~M.

16. The multi-level series power supply system for distribution networks according to any one of claims 13-15, characterized in that, The specific parameters for initializing and instantiating SV and GOOSE information respectively include at least one of name, smvID, iedName, MAC-Address, and APPID.

17. The multi-level series power supply system for distribution networks according to claim 16, characterized in that, name, smvID, and iedName are stored in decimal number format.

18. The multi-level series power supply system for distribution networks according to claim 16, characterized in that, MAC-Address and APPID are stored in hexadecimal number format.

19. The multi-level series power supply system for distribution networks according to claim 13, characterized in that, The communication connection method between protection devices is as follows: each protection device is connected sequentially.

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