Power distribution network self-healing method in dual-communication mode

Abstract

The invention discloses a power distribution network self-healing method in a dual-communication mode, which comprises a wired communication network built by optical fiber communication equipment and a wireless communication network built by 5G preposed equipment, and can also switch communication channels in time when the optical fiber communication network or the 5G network breaks down through communication channel self-inspection based on the dual-communication network, so that the power distribution network self-healing efficiency is improved. Communication among the substations is ensured; communication networks can be actively switched, and the situation that communication is disconnected when a single communication network breaks down is effectively avoided; according to the method, the fault analysis platform is established, the self-healing process is verified on the fault simulation platform, and the action condition of each transformer substation is obtained, so that the correctness of the line self-healing logic of the power distribution network is verified.

Description

Technical Field

[0001] The present invention belongs to the technical field of substations, and particularly relates to a method for self-healing of a distribution network in a dual communication mode. Background Art

[0002] With the continuous development of China's social economy, a large number of substations have emerged in urban areas and downtown areas. In the urban area, there are still a large number of "hand-in-hand" chain power supply structures in the 110 kV power system. This will lead to multi-station voltage loss and tripping when a line fails, seriously affecting the troubleshooting of accidents by staff, resulting in large-scale power outages and long-time power supply restoration failures. The automatic switching-in technology of standby power provides a very effective solution to this problem. However, the incoming line automatic standby power supply configured at each station can only solve the power supply problem of substations with open-loop points. To break the problem that traditional substations cannot solve the multi-station voltage loss caused by a single fault, a communication system is introduced at each site to achieve two-way mutual backup between substations, reduce the risk of bus voltage loss in multiple substations, and at the same time shorten the operation time of maintenance personnel and improve power supply reliability;

[0003] Regarding the problem of the risk of multi-station voltage loss when a line fails, one method is to equip control sub-machines at each site and connect them to each other to achieve wired communication, forming a panoramic information of a series power supply loop. However, the method used when the communication line fails will completely fail; another method is to equip 5G communication devices at each site to form a wireless communication system. However, the communication delay between customer front-end terminals is longer than that of wired communication and is affected by the signal strength in urban areas. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for self-healing of a distribution network in a dual communication mode in view of the above problems existing in the prior art.

[0005] The above object of the present invention is achieved by the following technical means:

[0006] A method for self-healing of a distribution network in a dual communication mode includes the following steps:

[0007] Step 1, build a self-healing system based on a dual communication network. The self-healing system includes a master station, multiple levels of sub-stations, a communication self-healing system, and a line self-healing system;

[0008] Step 2, perform self-check of the communication channel based on the dual communication network to complete communication self-healing;

[0009] Step 3, build a fault analysis platform and simulate the line self-healing of the self-healing system on the fault analysis platform.

[0010] The communication self-healing system in step 1 as described above includes optical fiber communication devices, 5G customer premise equipment, and a main optical fiber communication channel installed at the master station and each level of sub-stations. Each level of sub-station is also equipped with a communication switching device;

[0011] The main optical fiber communication channel is respectively connected to the optical fiber communication devices at the master station and each level of sub-stations through branch optical fibers, forming a wired communication network;

[0012] The 5G customer premise equipment at each level of sub-stations is all connected to the 5G network, forming a wireless communication network;

[0013] The communication switching device at each level of sub-stations is connected to the optical fiber communication device and the 5G customer premise equipment of the corresponding sub-station. The communication switching device is used to switch the optical fiber communication device to the 5G customer premise equipment to complete the switching from the wired communication network to the wireless communication network; it also switches the 5G customer premise equipment to the optical fiber communication device to complete the switching from the wireless communication network to the wired communication network.

[0014] The line self-healing system in step 1 as described above includes self-healing devices, no-voltage devices, and circuit breakers installed at each level of sub-stations. The self-healing devices at each level of sub-stations are all connected to the no-voltage devices, circuit breakers, optical fiber communication devices, 5G customer premise equipment, and communication switching devices of the corresponding sub-stations. An open-loop point is set at one of the sub-stations;

[0015] The no-voltage devices at each level of sub-stations are used to detect the voltage and current data information of the corresponding sub-stations and transmit the detected voltage and current data information to the self-healing devices of the corresponding sub-stations;

[0016] The self-healing devices at each level of sub-stations are used to control the communication switching devices of the corresponding sub-stations to perform communication network switching, receive the voltage and current data information of the corresponding sub-stations, and control the opening and tripping of the circuit breakers of the corresponding sub-stations;

[0017] The self-healing devices at each level of sub-stations judge whether the station has lost voltage according to the voltage and current data information; if the station has lost voltage, it judges whether a self-healing signal sent by other sub-stations is received within the set time margin; if the self-healing signal is not received, it judges that a line fault has occurred at the station, trips the circuit breaker on the connection side line between the station and the previous-level sub-station to complete the fault disconnection operation, and sends a self-healing signal to other sub-stations at the subsequent level; if the self-healing signal is received, for the stations without an open-loop point, the station does not operate and continues to send the self-healing signal to other sub-stations at the subsequent level. For the stations with an open-loop point, the open-loop point is closed to complete the self-healing operation.

[0018] As described above, both the wired communication network and the wireless communication network are based on the GOOSE communication protocol. Each level of sub-stations transmits signals in the form of GOOSE messages to the master station and other sub-stations through the wired communication network or the wireless communication network. The master station receives and analyzes the GOOSE messages of each sub-station through the wired communication network or the wireless communication network, so as to obtain the communication status of each sub-station; the master station transmits the GOOSE message including communication confirmation information or communication switching information to each sub-station through the wired communication network or the wireless communication network, and each sub-station receives and analyzes the GOOSE message of the communication confirmation information or communication switching information sent by the master station according to the IP address of its respective wired communication network or wireless communication network.

[0019] As described above, step 2 specifically includes the following steps:

[0020] Step 2.1, construct the communication channel self-check of the wired communication network: Each level of sub-stations sends communication status signals indicating normal communication to the master station through optical fibers at regular intervals. After the master station receives the normal communication status signals sent by each sub-station through the optical fiber, it sends back the received communication confirmation signals to each sub-station to ensure the normal communication between the master station and each sub-station;

[0021] When the wired communication of a certain sub-station is disconnected and the master station does not receive the normal communication status signal of the disconnected sub-station within the set time margin, it is determined that the wired communication of the above sub-station has failed. The master station immediately sends a communication channel switching instruction to the remaining sub-stations. After receiving the communication channel instruction sent by the master station, the remaining sub-stations immediately switch to wireless communication through the communication switching device. For the sub-station with a wired communication failure, since it fails to receive the communication confirmation signal replied by the master station within the set time margin, it is determined that the wired communication has failed and automatically switches to wireless communication to restore communication with the master station, thus realizing the self-healing of the communication network failure;

[0022] Step 2.2, construct the communication channel self-check of the wireless communication network. The communication channel self-check of the wireless communication network is as follows: The master station detects whether each sub-station is in the networked state. If a certain sub-station fails to be networked within the set time margin, it is determined that the wireless communication of the above sub-station has failed. The master station sends a communication channel switching instruction to the remaining sub-stations. After receiving the communication channel instruction sent by the master station, the remaining sub-stations immediately switch to wired communication. For the above un-networked sub-station, after failing to attempt to connect to the network within the set time, it is determined that the wireless communication channel has failed and automatically switches to wired communication, thus completing the self-healing of the communication failure;

[0023] As described above, the user actively sends channel selection signals from the main station to each sub-station. Each level of sub-station determines whether to perform communication switching based on whether the current communication channel is consistent with the channel selection signal sent by the main station. If switching is required, an instruction is sent to the communication switching device of the local station. After determining that the channel switching is completed, a completion signal is transmitted to the control main station. If switching is not required, a completion signal is directly transmitted to the control main station; the communication status signal indicates whether the communication channels of each sub-station are connected. Receiving the completion signal means that the communication of the corresponding site is connected.

[0024] As described above, the fault analysis platform in step 3 includes a line self-healing system model, and the line self-healing system model is:

[0025] Each level of sub-station includes a first-side line and a second-side line. Each level of sub-station also includes a first connection line L1 and a second connection line L2. Both the first-side line and the second-side line are connected to the bus. The first-side line of the sub-station is connected to the first connection line L1. The second-side line of each level of sub-station is connected to the second connection line L2 of the corresponding sub-station. The first connection line L1 of other sub-stations except the first-level sub-station is connected to the second connection line L2 of the previous-level sub-station. The second connection line L2 of other sub-stations except the last-level sub-station is connected to the first connection line L1 of the next-level sub-station. The first connection line L1 of the first-level sub-station is connected to the first power supply. The second connection line L2 of the last-level sub-station is connected to the second power supply. The circuit breaker DL1 of one-level sub-station is set as the open-loop point;

[0026] Among them, the first-side line of each level of sub-station is the connection-side line between the corresponding sub-station and the previous-level sub-station, and the circuit breaker DL1 is the circuit breaker on the connection-side line between the corresponding sub-station and the previous-level sub-station;

[0027] Each level of sub-station also includes a circuit breaker DL1, a circuit breaker DL2, and a circuit breaker DL3. The circuit breaker DL1 is arranged on the first-side line of each level of sub-station. The circuit breaker DL2 is arranged on the second-side line of each level of sub-station. The circuit breaker DL3 is arranged on the bus of each level of sub-station. The circuit breaker DL3 divides the bus of each level of sub-station into a first section and a second section. The first-side line is connected to the first section of the bus. The second-side line is connected to the second section of the bus;

[0028] The no-voltage devices of each level of sub-station include a voltage transformer PT1 and PT2, a capacitive voltage transformer CVT1 and CVT2, and a current transformer CT1 and CT2. The voltage transformers PT1 and PT2 are respectively used to measure the voltages of the first section and the second section of the bus of each level of sub-station. The current transformers CT1 and CT2 are respectively used to measure the currents of the first connection line L1 and the second connection line L2 of each level of sub-station. The capacitive voltage transformers CVT1 and CVT2 are respectively used to measure the voltages on the first connection line L1 and the second connection line L2 of each level of sub-station;

[0029] The self-healing devices of each-level substations are connected to the voltage transformers PT1 and PT2, capacitive voltage transformers CVT1 and CVT2, current transformers CT1 and CT2, and circuit breakers DL1 and DL2 of the corresponding substations. The self-healing devices of each-level substations are used to receive the voltages of the first section and the second section of the busbar of the corresponding substation measured by the voltage transformers PT1 and PT2, the currents of the first connection line L1 and the second connection line L2 of the substation measured by the current transformers CT1 and CT2, and the voltages on the first connection line L1 and the second connection line L2 of the substation measured by the capacitive voltage transformers CVT1 and CVT2.

[0030] The line self-healing of the self-healing system described above includes:

[0031] The line self-healing of the first-level substation is as follows: The self-healing device of the first-level substation judges whether the busbar of the first-level substation is de-energized through the voltage transformers PT1 and PT2 of the first-level substation. If the busbar of the first-level substation is de-energized, then it judges whether there is current in the first connection line L1 of the first-level substation through the current transformer CT1 of the first-level substation; if there is no current, the self-healing device of the first-level substation controls the circuit breaker DL1 of the first-level substation to trip and sends a self-healing signal to the self-healing devices of the remaining substations; if there is current, the station does not operate.

[0032] The line self-healing of the remaining substations is as follows: The self-healing device of the substation judges whether the busbar of the corresponding substation is de-energized through the voltage transformers PT1 and PT2 of the corresponding substation. If the busbar of the corresponding substation is de-energized, then it judges whether a self-healing signal is received within the set time margin; if a self-healing signal is received, the station does not operate and sends a self-healing signal to the self-healing devices of each subsequent-level substation; if a self-healing signal is not received, then it judges whether there is current in the first connection line L1 of the corresponding substation through the current transformer CT1 of the corresponding substation; if there is no current, the self-healing device of the corresponding substation controls the circuit breaker DL1 of the corresponding substation to trip and sends a self-healing signal to the self-healing devices of each subsequent-level substation; if there is current, the station does not operate.

[0033] The line self-healing of the substation with an open-loop point set is as follows: The self-healing device of the substation with an open-loop point set judges whether the busbar of the substation with an open-loop point set is de-energized through the voltage transformers PT1 and PT2 of the substation with an open-loop point set. If the busbar of the substation with an open-loop point set is de-energized, then it judges whether a self-healing signal is received within the set time margin; if a self-healing signal is received, it controls the circuit breaker at the open-loop point to close; if a self-healing signal is not received, then it judges whether there is current in the second connection line L2 of the substation with an open-loop point set through the current transformer CT1 of the substation with an open-loop point set; if there is no current, the self-healing device of the substation controls the circuit breaker DL2 of the substation with an open-loop point set to trip and delays closing the circuit breaker DL1 of the substation with an open-loop point set; if there is current, the station does not operate.

[0034] The present invention has the following beneficial effects compared with the prior art:

[0035] (1) By building a dual communication network and performing communication channel self-check based on the dual communication network, the present invention can timely switch the communication channel when a failure occurs in the optical fiber communication network or the 5G network, ensuring the connectivity of communication between substations and effectively avoiding the disconnection of communication when a single communication network fails;

[0036] (2) By building a fault analysis platform and verifying the self-healing process on the fault simulation platform to obtain the action conditions of each substation, the present invention verifies the correctness of the line self-healing logic of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a communication schematic diagram of the wireless communication network of the present invention;

[0038] Figure 2 is a structural schematic diagram for performing communication channel switching of the present invention;

[0039] Figure 3 is a structural schematic diagram of a specific embodiment of Embodiment 1 of the present invention;

[0040] Figure 4 is a line self-healing flow chart of the first substation of the specific embodiment of Embodiment 1 of the present invention;

[0041] Figure 5 is a line self-healing flow chart of the second substation of the specific embodiment of Embodiment 1 of the present invention;

[0042] Figure 6 is a line self-healing flow chart of the third substation of the specific embodiment of Embodiment 1 of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] In order to facilitate the understanding and implementation of the present invention by those of ordinary skill in the art, the present invention will be further described in detail below with reference to the embodiments. The embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0044] Embodiment 1:

[0045] A distribution network self-healing method in a dual communication mode specifically includes the following steps:

[0046] Step 1. Build a self-healing system based on a dual communication network. The self-healing system includes a master station, multiple levels of substations, a communication self-healing system, and a line self-healing system;

[0047] The communication self-healing system includes optical fiber communication devices, 5G customer front-end devices, and a main optical fiber communication channel provided at the master station and each level of substation. Each level of substation is also provided with a communication switching device;

[0048] The main optical fiber communication channel is respectively connected to the optical fiber communication devices of the main station and each level of sub-stations through branch optical fibers, forming a wired communication network;

[0049] The 5G customer front-end devices of each level of sub-stations are all connected to the 5G network, forming a wireless communication network; the signals of each sub-station are transmitted upward to the access network through the 5G customer front-end devices, and the site data is transmitted to the main station or the 5G CPE devices of other sub-stations through the access network - bearer network - core network - bearer network - access network;

[0050] The communication switching devices of each level of sub-stations are connected to the optical fiber communication devices and 5G customer front-end devices of the corresponding sub-stations. The communication switching devices are used to switch the optical fiber communication devices to 5G customer front-end devices to complete the switching from the wired communication network to the wireless communication network; and also switch the 5G customer front-end devices to optical fiber communication devices to complete the switching from the wireless communication network to the wired communication network;

[0051] Both the wired communication network and the wireless communication network are based on the GOOSE communication protocol. Each sub-station transmits the GOOSE messages including signals to the main station through the wired communication network or the wireless communication network. The main station receives and analyzes the GOOSE messages of each sub-station through the wired communication network or the wireless communication network, so as to obtain the communication status of each sub-station; the main station transmits the GOOSE messages including communication confirmation information or communication switching information to each sub-station through the wired communication network or the wireless communication network. Each sub-station receives and analyzes the GOOSE messages of the communication confirmation information or communication switching information sent by the main station according to the IP addresses of their respective wired communication networks or wireless communication networks;

[0052] In some embodiments, the line self-healing system includes self-healing devices, non-voltage devices, and circuit breakers arranged at each level of sub-stations. The self-healing devices of each level of sub-stations are connected to the non-voltage devices, circuit breakers, optical fiber communication devices, 5G customer front-end devices, and communication switching devices of the corresponding sub-stations, and an open-loop point is set on one of the sub-stations;

[0053] The non-voltage devices of each level of sub-stations are used to detect the voltage and current data information of the corresponding sub-stations and transmit the detected voltage and current data information to the self-healing devices of the corresponding sub-stations;

[0054] The self-healing devices of each level of sub-stations are used to control the communication switching devices of the corresponding sub-stations to perform communication network switching, receive the voltage and current data information of the corresponding sub-stations, and control the opening and tripping of the circuit breakers of the corresponding sub-stations;

[0055] The self-healing device of each level of sub-station determines whether the station has lost voltage according to the voltage and current data information; if the station has lost voltage, it determines whether it has received the self-healing signal sent by other sub-stations within the set time margin; if the self-healing signal is not received, it determines that a line fault has occurred at the station, trips the circuit breaker on the connection side line between the station and the previous-level sub-station, completes the fault disconnection operation, and sends the self-healing signal to other sub-stations at the subsequent level; if the self-healing signal is received, for the stations without open-loop points, the station does not operate and continues to send the self-healing signal to other sub-stations at the subsequent level. For the stations with open-loop points, the open-loop points are closed to complete the self-healing operation.

[0056] Step 2: Conduct self-check of the communication channel based on the dual communication network to complete communication self-healing, which specifically includes the following steps:

[0057] The self-check of the communication channel is an important means to detect whether the communication channel is faulty and is used to judge whether the current communication channel is normal. For the self-check of the wired communication channel, when each sub-station conducts data transmission, the master station can obtain the communication status information between each sub-station by detecting the communication channel. However, when the distribution network is operating normally, no fault information is sent, and it is impossible to determine whether the communication channel is normal during the long-term non-communication state;

[0058] Step 2.1: Construct the self-check of the communication channel of the wired communication network: Each level of sub-station sends a "normal" communication status signal to the master station through the optical fiber at intervals of the set time. After the master station receives the "normal" communication status signals sent by each sub-station through the optical fiber, it sends a "received" communication confirmation signal to each sub-station to ensure the normal communication between the master station and each sub-station;

[0059] When the wired communication of a certain sub-station is disconnected and the master station does not receive the "normal" communication status signal of the disconnected sub-station within the set time margin, it is determined that the wired communication of the above sub-station has failed. The master station immediately sends a communication channel switching instruction to the remaining sub-stations. After receiving the communication channel instruction sent by the master station, each of the remaining sub-stations immediately switches to wireless communication through the communication switching device. For the sub-station with the failure of the wired communication, since it fails to receive the "received" communication confirmation signal replied by the master station within the set time margin, it is determined that the wired communication has failed and automatically switches to wireless communication through the communication switching device to resume communication with the master station, thereby realizing the fault self-healing of the communication network;

[0060] Step 2.2: Build a self-check for the communication channels of the wireless communication network. The self-check for the communication channels of the wireless communication network is as follows: The master station detects whether each slave station is connected to the network. If a certain slave station fails to connect to the network within the set time margin, it is determined that the wireless communication of the above slave station has failed. The master station sends a communication channel switching instruction to the remaining slave stations. After receiving the communication channel instruction sent by the master station, the remaining slave stations immediately switch to wired communication. For the above unconnected slave station, after failing to connect to the network within the set time, it is determined that the wireless communication channel has failed and automatically switches to wired communication, thus completing the self-healing of communication faults.

[0061] Step 2.3: The user actively sends a channel selection signal to each slave station through the master station. Each slave station determines whether to perform communication switching according to whether the current communication channel is consistent with the channel selection signal sent by the master station. If switching is required, an instruction is sent to the communication switching device of the station. After determining that the channel switching is completed, a "completed" signal is transmitted to the control master station. If no switching is required, a "completed" signal is directly transmitted to the control master station. The communication status signal shows whether the communication channels of each slave station are connected. Receiving the "completed" signal indicates that the corresponding station's communication is connected and can communicate normally.

[0062] Step 3: Build a fault analysis platform and simulate the line self-healing of the self-healing system on the fault analysis platform. The fault analysis platform includes a line self-healing system model. The line self-healing system model is specifically as follows: Each level of slave station includes a first-side line and a second-side line. Each level of slave station also includes a first connection line L1 and a second connection line L2. Both the first-side line and the second-side line are connected to the bus. The first-side line of the slave station is connected to the first connection line L1. The second-side line of each level of slave station is connected to the second connection line L2 of the corresponding slave station. The first connection line L1 of other slave stations except the first-level slave station is connected to the second connection line L2 of the previous-level slave station. The second connection line L2 of other slave stations except the last-level slave station is connected to the first connection line L1 of the next-level slave station. The first connection line L1 of the first-level slave station is connected to the first power supply. The second connection line L2 of the last-level slave station is connected to the second power supply. Among them, the circuit breaker DL1 of one level of slave station is set as the open-loop point;

[0063] Among them, the first-side line of each level of slave station is the connection-side line between the corresponding slave station and the previous-level slave station, and the circuit breaker DL1 is the circuit breaker on the connection-side line between the corresponding slave station and the previous-level slave station;

[0064] In some embodiments, each level of slave station also includes a circuit breaker DL1, a circuit breaker DL2, and a circuit breaker DL3. The circuit breaker DL1 is arranged on the first-side line of each level of slave station. The circuit breaker DL2 is arranged on the second-side line of each level of slave station. The circuit breaker DL3 is arranged on the bus of each level of slave station. The circuit breaker DL3 divides the bus of each level of slave station into a first section and a second section. The first-side line is connected to the first section of the bus. The second-side line is connected to the second section of the bus;

[0065] The no-voltage devices of each level of sub-stations include voltage transformers PT1 and PT2, capacitive voltage transformers CVT1 and CVT2, and current transformers CT1 and CT2. The voltage transformers PT1 and PT2 are respectively used to measure the voltages of the first section and the second section of the busbars of each level of sub-stations. The current transformers CT1 and CT2 are respectively used to measure the currents of the first connection line L1 and the second connection line L2 of each level of sub-stations. The capacitive voltage transformers CVT1 and CVT2 are respectively used to measure the voltages on the first connection line L1 and the second connection line L2 of each level of sub-stations.

[0066] The self-healing devices of each level of sub-stations are connected to the voltage transformers PT1 and PT2, capacitive voltage transformers CVT1 and CVT2, current transformers CT1 and CT2, and circuit breakers DL1 and DL2 of the corresponding sub-stations. The self-healing devices of each level of sub-stations are used to receive the voltages of the first section and the second section of the busbars of the corresponding sub-stations measured by the voltage transformers PT1 and PT2, the currents of the first connection line L1 and the second connection line L2 of the sub-stations measured by the current transformers CT1 and CT2, and the voltages on the first connection line L1 and the second connection line L2 of the sub-stations measured by the capacitive voltage transformers CVT1 and CVT2.

[0067] In some embodiments, the line self-healing of the self-healing system includes: The line self-healing of the first-level sub-station is as follows: The self-healing device of the first-level sub-station determines whether the busbar of the first-level sub-station loses voltage through the voltage transformers PT1 and PT2 of the first-level sub-station. If the busbar of the first-level sub-station loses voltage, then it determines whether there is current in the first connection line L1 of the first-level sub-station through the current transformer CT1 of the first-level sub-station. If there is no current, the self-healing device of the first-level sub-station controls the circuit breaker DL1 of the first-level sub-station to trip and sends a self-healing signal to the self-healing devices of the remaining sub-stations. If there is current, then this station does not act.

[0068] The line self-healing of the remaining sub-stations is as follows: The self-healing device of the sub-station determines whether the busbar of the corresponding sub-station loses voltage through the voltage transformers PT1 and PT2 of the corresponding sub-station. If the busbar of the corresponding sub-station loses voltage, then it determines whether a self-healing signal is received within the set time margin. If a self-healing signal is received, then this station does not act and sends a self-healing signal to the self-healing devices of each subsequent-level sub-station. If a self-healing signal is not received, then it determines whether there is current in the first connection line L1 of the corresponding sub-station through the current transformer CT1 of the corresponding sub-station. If there is no current, the self-healing device of the corresponding sub-station controls the circuit breaker DL1 of the corresponding sub-station to trip and sends a self-healing signal to the self-healing devices of each subsequent-level sub-station. If there is current, then this station does not act.

[0069] The line self-healing of the substation with the open-loop point set is as follows: The self-healing device of the substation with the open-loop point set determines whether the bus of the substation with the open-loop point set is out of voltage through the potential transformers PT1 and PT2 of the substation with the open-loop point set. If the bus of the substation with the open-loop point set is out of voltage, it is determined whether a self-healing signal is received within the set time margin; if a self-healing signal is received, the circuit breaker at the open-loop point is controlled to close; if a self-healing signal is not received, it is further determined through the current transformer CT1 of the substation with the open-loop point set whether there is current in the second connection line L2 of the substation with the open-loop point set; if there is no current, the self-healing device of the substation controls the circuit breaker DL2 of the substation with the open-loop point set to trip, and delays to close the circuit breaker DL1 of the substation with the open-loop point set; if there is current, the local station does not operate.

[0070] In a specific embodiment, the line self-healing system includes a first-level substation, a second-level substation, and a third-level substation. The first connection line L1 of the first-level substation is connected to the first power supply, the second connection line L2 of the third-level substation is connected to the second power supply, the circuit breaker DL1 of the third-level substation is set as the open-loop point, and the circuit breaker DL1 of the third-level substation as the open-loop point is in hot standby. The circuit breakers DL1 and DL2 of the remaining substations are both closed. Then the line self-healing logic is as follows:

[0071] To verify the correctness of the line self-healing, the self-healing process is verified on a fault simulation platform. The actions of the substations in four cases are respectively simulated, namely, the fault of the first connection line L1 of the first-level substation, the fault of the second connection line L2 of the first-level substation or the first connection line L1 of the second-level substation, the fault of the second connection line L2 of the second-level substation or the first connection line L1 of the third-level substation, and the fault of the second connection line L2 of the third-level substation. Specifically:

[0072] (1) The fault of the first connection line L1 of the first-level substation:

[0073] For the first-level substation: The line overcurrent protection is started, the circuit breaker DL1 automatically trips. The self-healing device of the first-level substation determines that the bus of the first-level substation is out of voltage through the potential transformers PT1 and PT2 of the first-level substation, and then determines through the current transformer CT1 of the first-level substation that there is no current in the first connection line L1 of the first-level substation. The self-healing device of the first-level substation controls the circuit breaker DL1 of the first-level substation to trip (although the circuit breaker DL1 automatically trips when the line overcurrent protection is started, the self-healing device of the first-level substation still sends a trip command to the circuit breaker DL1 of the first-level substation to ensure isolating the faulty line), and sends a self-healing signal to the self-healing devices of the remaining substations;

[0074] For the secondary substation: The self-healing device of the secondary substation determines the loss of bus voltage of the secondary substation through the voltage transformers PT1 and PT2 of the secondary substation. If the secondary substation receives the self-healing signal within the set time margin (0.3 s), the secondary substation does not operate and sends the self-healing signal to the self-healing devices of each subsequent-level substation.

[0075] For the tertiary substation: The self-healing device of the tertiary substation determines that the bus of the tertiary substation has not lost voltage through the voltage transformers PT1 and PT2 of the tertiary substation. If the tertiary substation receives the self-healing signal within the set time margin (0.6 s), the tertiary substation controls the closing of the circuit breaker DL1.

[0076] (2) Failure of the second connecting line L2 of the primary substation or the first connecting line L1 of the secondary substation:

[0077] For the primary substation: The line overcurrent protection is activated, and the circuit breaker DL2 trips automatically. The self-healing device of the primary substation determines that the bus of the primary substation has not lost voltage through the voltage transformers PT1 and PT2 of the primary substation, so the primary substation does not operate.

[0078] For the secondary substation: The self-healing device of the secondary substation determines the loss of bus voltage of the secondary substation through the voltage transformers PT1 and PT2 of the secondary substation. If the secondary substation does not receive the self-healing signal within the set time margin (0.3 s), and then determines that there is no current in the first connecting line L1 through the current transformer CT1, the self-healing device of the secondary substation controls the circuit breaker DL1 of the secondary substation to trip and sends the self-healing signal to the self-healing devices of each subsequent-level substation.

[0079] For the tertiary substation: The self-healing device of the tertiary substation determines that the bus of the tertiary substation has not lost voltage through the voltage transformers PT1 and PT2 of the tertiary substation. If the tertiary substation receives the self-healing signal within the set time margin (0.6 s), the tertiary substation controls the closing of the circuit breaker DL1.

[0080] (3) Failure of the connecting line L2 of the secondary substation or the first connecting line L1 of the tertiary substation: The line overcurrent protection is activated, and the circuit breaker DL5 trips automatically. Since the circuit breaker DL1 of the tertiary substation is the open-loop point, the faulty line is completely isolated, and the buses of each level of substation have not lost voltage, so each level of substation does not operate.

[0081] (4) Failure of the second connecting line L2 of the tertiary substation: The line overcurrent protection is activated, and the circuit breaker DL8 trips automatically;

[0082] For the primary substation: The self-healing device of the primary substation determines that the bus of the primary substation has not lost voltage through the voltage transformers PT1 and PT2 of the primary substation, so the primary substation does not operate.

[0083] For the secondary substation: If the self-healing device of the secondary substation determines through the potential transformers PT1 and PT2 of the secondary substation that the bus of the secondary substation is not de-energized, the secondary substation does not operate;

[0084] For the tertiary substation: If the self-healing device of the tertiary substation determines through the potential transformers PT1 and PT2 of the tertiary substation that the bus of the tertiary substation is de-energized, and the tertiary substation does not receive a self-healing signal within the set time margin (0.6 s), and then determines through the current transformer CT1 of the tertiary substation that there is no current in the second connection line L2 of the tertiary substation, the self-healing device of the tertiary substation controls the circuit breaker DL2 of the tertiary substation to trip and delays the closing of the circuit breaker DL1 of the tertiary substation.

[0085] To verify that the data transmission speed can meet the requirements in the dual communication mode, communication delay verification is required. For the wired communication transmission mechanism in the GOOSE communication mode, since it uses an optical fiber network for transmission and has a relatively high speed, its transmission delay is less than 4 ms. Therefore, the 5G communication delay in the GOOSE communication mode is mainly tested. During the test, the first substation sends data to the second site through the 5G CPE device. Since the connection between the substation and the device is through an optical fiber and has a relatively high speed, the end-to-end delay of the 5G CPE is mainly considered. The test results are shown in Table 1.

[0086] Table 1 5G CPE End-to-End Delay Statistics

[0087]

[0088] The test data shows that the average end-to-end communication delay in the 5G stand-alone networking mode is less than 33.5 ms. Considering that the breaker protection action takes about 90 ms, the time required between each site in the two communication modes is about 130 ms, which can fully meet the 0.3 s waiting time for the "self-healing" signal during the power grid self-healing process.

[0089] In one embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, it implements the communication channel self-check in step 2 and the line self-healing of the self-healing system in step 3 in the above method embodiments.

[0090] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by the processor, it implements the communication channel self-check in step 2 and the line self-healing of the self-healing system in step 3 in the above method embodiments.

[0091] In one embodiment, a computer program product is provided, including a computer program which, when executed by a processor, implements the communication channel self-check in step 2 and the line self-healing of the self-healing system in step 3 in the above method embodiments.

[0092] Those of ordinary skill in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium, and when the computer program is executed, it can include the processes of the above method embodiments.

[0093] It should be noted that the embodiments described in the present invention are only examples of the spirit of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described embodiments or use similar ways to replace them, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A method for self-healing of a distribution network in a dual communication mode, characterized in that, It includes the following steps: Step 1: Build a self-healing system based on a dual communication network. The self-healing system includes a master station, multiple levels of sub-stations, a communication self-healing system, and a line self-healing system; Step 2: Conduct a self-check of the communication channels based on the dual communication network to complete communication self-healing; Step 3: Build a fault analysis platform and simulate the line self-healing of the self-healing system on the fault analysis platform.

2. The self-healing method for a distribution network in a dual communication mode according to claim 1, characterized in that The communication self-healing system in Step 1 includes optical fiber communication devices, 5G customer premise equipment, and a main optical fiber communication channel set at the master station and each level of sub-stations. Communication switching devices are also set at each level of sub-stations; The main optical fiber communication channel is connected to the optical fiber communication devices of the master station and each level of sub-stations through branch optical fibers to form a wired communication network; The 5G customer premise equipment of each level of sub-stations is connected to the 5G network to form a wireless communication network; The communication switching devices of each level of sub-stations are connected to the optical fiber communication devices and 5G customer premise equipment of the corresponding sub-stations. The communication switching devices are used to switch the optical fiber communication devices to 5G customer premise equipment to complete the switching from the wired communication network to the wireless communication network; and also switch the 5G customer premise equipment to optical fiber communication devices to complete the switching from the wireless communication network to the wired communication network.

3. The self-healing method for a distribution network in a dual communication mode according to claim 2, characterized in that, The line self-healing system in Step 1 includes self-healing devices, no-voltage devices, and circuit breakers set at each level of sub-stations. The self-healing devices of each level of sub-stations are connected to the no-voltage devices, circuit breakers, optical fiber communication devices, 5G customer premise equipment, and communication switching devices of the corresponding sub-stations. An open-loop point is set at one of the sub-stations; The no-voltage devices of each level of sub-stations are used to detect the voltage and current data information of the corresponding sub-stations and transmit the detected voltage and current data information to the self-healing devices of the corresponding sub-stations; The self-healing devices of each level of sub-stations are used to control the communication switching devices of the corresponding sub-stations to perform communication network switching, receive the voltage and current data information of the corresponding sub-stations, and control the opening and tripping of the circuit breakers of the corresponding sub-stations.

4. The self-healing method for a distribution network in a dual communication mode according to claim 3, characterized in that, The self-healing devices of each level of sub-stations judge whether the station has lost voltage according to the voltage and current data information; if the station has lost voltage, it judges whether a self-healing signal sent by other sub-stations is received within a set time margin; If no self-healing signal is received, it is judged that a line fault has occurred at the station, the circuit breaker on the connection side line between the station and the previous-level sub-station is tripped to complete the fault disconnection operation, and a self-healing signal is sent to other subsequent sub-stations; if a self-healing signal is received, for the stations without an open-loop point, the station does not act and continues to send the self-healing signal to other subsequent sub-stations. For the stations with an open-loop point, the open-loop point is closed to complete the self-healing operation.

5. The self-healing method for a distribution network in a dual communication mode according to claim 2, wherein Both the wired communication network and the wireless communication network are based on the GOOSE communication protocol. Each level of sub-stations transmits signals to the master station and other sub-stations in the form of GOOSE messages through the wired communication network or the wireless communication network. The master station receives and analyzes the GOOSE messages of each sub-station through the wired communication network or the wireless communication network, so as to obtain the communication status of each sub-station; the master station transmits the GOOSE message including communication confirmation information or communication switching information to each sub-station through the wired communication network or the wireless communication network. Each sub-station receives and analyzes the GOOSE message of the communication confirmation information or communication switching information sent by the master station according to the IP address of its respective wired communication network or wireless communication network.

6. The self-healing method for a distribution network in a dual communication mode according to claim 2, characterized in that, Step 2 specifically includes the following steps: Step 2.

1. Build a self-check of the communication channel of the wired communication network: Each level of sub-stations sends communication status signals indicating normal communication to the master station through optical fibers at regular intervals. After the master station receives the normal communication status signals sent by each sub-station through the optical fibers, it sends back the received communication confirmation signals to each sub-station to ensure normal communication between the master station and each sub-station; When the wired communication of a certain sub-station is disconnected and the master station does not receive the normal communication status signal of the disconnected sub-station within the set time margin, it is determined that the wired communication of the above sub-station has a fault. The master station immediately sends a communication channel switching instruction to the remaining sub-stations. After receiving the communication channel instruction sent by the master station, the remaining sub-stations immediately switch to wireless communication through the communication switching device. For the sub-station with a fault in the wired communication, since it fails to receive the received communication confirmation signal replied by the master station within the set time margin, it is determined that the wired communication has a fault and automatically switches to wireless communication through the communication switching device to resume communication with the master station, thus realizing the self-healing of the communication network fault; Step 2.

2. Build a self-check of the communication channel of the wireless communication network. The self-check of the communication channel of the wireless communication network is as follows: The master station detects whether each sub-station is in an online state. If a certain sub-station is not online within the set time margin, it is determined that the wireless communication of the above sub-station has a fault. The master station sends a communication channel switching instruction to the remaining sub-stations. After receiving the communication channel instruction sent by the master station, the remaining sub-stations immediately switch to wired communication. For the above unconnected sub-station, after failing to connect to the network within the set time, it is determined that there is a fault in the wireless communication channel and automatically switches to wired communication, thus completing the self-healing of the communication fault.

7. The self-healing method for a distribution network in a dual communication mode according to claim 2, characterized in that, The user actively sends a channel selection signal to each sub-station through the master station. Each level of sub-stations judges whether to perform communication switching according to whether the current communication channel is consistent with the channel selection signal sent by the master station. If switching is required, an instruction is sent to the communication switching device of this station. After determining that the channel switching is completed, a completion signal is transmitted to the control master station. If switching is not required, a completion signal is directly transmitted to the control master station; The communication status signal shows whether the communication channels of each sub-station are connected. Receiving the completion signal means that the corresponding station's communication is connected.

8. The self-healing method for a distribution network in a dual communication mode according to claim 4, characterized in that, The fault analysis platform in Step 3 includes a line self-healing system model. The line self-healing system model is: Each level of substation includes a first-side line and a second-side line. Each level of substation also includes a first connection line L1 and a second connection line L2. Both the first-side line and the second-side line are connected to the bus. The first-side line of the substation is connected to the first connection line L1. The second-side line of each level of substation is connected to the second connection line L2 of the corresponding substation. The first connection line L1 of other substations except the first-level substation is connected to the second connection line L2 of the previous-level substation. The second connection line L2 of other substations except the last-level substation is connected to the first connection line L1 of the next-level substation. The first connection line L1 of the first-level substation is connected to the first power supply. The second connection line L2 of the last-level substation is connected to the second power supply. The circuit breaker DL1 of the first-level substation is set as the open-loop point; Among them, the first-side line of each level of substation is the connection-side line between the corresponding substation and the previous-level substation, and the circuit breaker DL1 is the circuit breaker on the connection-side line between the corresponding substation and the previous-level substation; Each level of substation also includes a circuit breaker DL1, a circuit breaker DL2, and a circuit breaker DL3. The circuit breaker DL1 is arranged on the first-side line of each level of substation. The circuit breaker DL2 is arranged on the second-side line of each level of substation. The circuit breaker DL3 is arranged on the bus of each level of substation. The circuit breaker DL3 divides the bus of each level of substation into a first section and a second section. The first-side line is connected to the first section of the bus. The second-side line is connected to the second section of the bus; The no-voltage devices of each level of substation include voltage transformers PT1 and PT2, capacitive voltage transformers CVT1 and CVT2, and current transformers CT1 and CT2. The voltage transformers PT1 and PT2 are respectively used to measure the voltages of the first section and the second section of the bus of each level of substation. The current transformers CT1 and CT2 are respectively used to measure the currents of the first connection line L1 and the second connection line L2 of each level of substation. The capacitive voltage transformers CVT1 and CVT2 are respectively used to measure the voltages on the first connection line L1 and the second connection line L2 of each level of substation; The self-healing devices of each level of substation are connected to the voltage transformers PT1 and PT2, the capacitive voltage transformers CVT1 and CVT2, the current transformers CT1 and CT2, and the circuit breakers DL1 and DL2 of the corresponding substation. The self-healing devices of each level of substation are used to receive the voltages of the first section and the second section of the bus of the corresponding substation measured by the voltage transformers PT1 and PT2, the currents of the first connection line L1 and the second connection line L2 of the substation measured by the current transformers CT1 and CT2, and the voltages on the first connection line L1 and the second connection line L2 of the substation measured by the capacitive voltage transformers CVT1 and CVT2.

9. The method for self-healing of a distribution network in a dual communication mode according to claim 8, wherein, The line self-healing of the self-healing system includes: The line self-healing of the first-level substation is as follows: The self-healing device of the first-level substation determines whether the bus of the first-level substation has lost voltage through the voltage transformers PT1 and PT2 of the first-level substation. If the bus of the first-level substation has lost voltage, it then determines whether there is current in the first connection line L1 of the first-level substation through the current transformer CT1 of the first-level substation. If there is no current, the self-healing device of the first-level substation controls the circuit breaker DL1 of the first-level substation to trip and sends a self-healing signal to the self-healing devices of the remaining substations. If there is current, the local station does not operate. The line self-healing of the remaining substations is as follows: The self-healing device of the substation determines whether the bus of the corresponding substation has lost voltage through the voltage transformers PT1 and PT2 of the corresponding substation. If the bus of the corresponding substation has lost voltage, it then determines whether a self-healing signal is received within the set time margin. If a self-healing signal is received, the local station does not operate and sends a self-healing signal to the self-healing devices of each subsequent substation. If a self-healing signal is not received, it then determines whether there is current in the first connection line L1 of the corresponding substation through the current transformer CT1 of the corresponding substation. If there is no current, the self-healing device of the corresponding substation controls the circuit breaker DL1 of the corresponding substation to trip and sends a self-healing signal to the self-healing devices of each subsequent substation. If there is current, the local station does not operate. The line self-healing of the substation with an open-loop point set is as follows: The self-healing device of the substation with an open-loop point set determines whether the bus of the substation with an open-loop point set has lost voltage through the voltage transformers PT1 and PT2 of the substation with an open-loop point set. If the bus of the substation with an open-loop point set has lost voltage, it then determines whether a self-healing signal is received within the set time margin. If a self-healing signal is received, it controls the circuit breaker at the open-loop point to close. If a self-healing signal is not received, it then determines whether there is current in the second connection line L2 of the substation with an open-loop point set through the current transformer CT1 of the substation with an open-loop point set. If there is no current, the self-healing device of the substation controls the circuit breaker DL2 of the substation with an open-loop point set to trip and delays closing the circuit breaker DL1 of the substation with an open-loop point set. If there is current, the local station does not operate.

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