Fault section positioning method for grid type seabed direct current power supply system

Abstract

A grid type seabed direct current power supply system fault section positioning method comprises the steps that whether a system breaks down or not is detected, and if the system breaks down, fault section judgment is carried out; each branch unit / shore-based station sends the detected current data to the adjacent branch unit / shore-based station in a message format, and receives a message; if the current branch unit / shore-based station successfully receives the message at the # imgabs0 # moment, the current cosine similarity is used as a fault section positioning criterion; if the branch unit / shore-based station does not receive the message successfully at the # imgabs1 # moment, line communication is abnormal, and message broadcast transmission is carried out; each branch unit / shore-based station generates a power-communication condition summary table according to the broadcast transmission message; and carrying out fault section positioning according to the electric power-communication condition summary sheet. When the communication is abnormal, the current topological information of the network is obtained by using the full-network communication data generated by the redundant communication link of the system, and the influence of the communication abnormality on the positioning of the fault section of the system is eliminated.

Description

Technical Field

[0001] The invention relates to a method for locating a fault section of a submarine direct current power supply system, and in particular to a method for locating a fault section of a grid-type submarine direct current power supply system. Background Art

[0002] The safe and reliable operation of the submarine DC power supply system is the basic premise for ensuring the high-reliability power supply of the equipment of the submarine observation system and improving the deep-sea exploration capability. Among them, the submarine cable line connects the shore-based station, branch unit and load, and the submarine cable between the shore-based station-branch unit and the branch unit-branch unit is the main cable. However, the unique geographical location of the submarine observation network has caused its failure rate to rise year by year, and it remains high. In addition, its scale is large, and it often relies on manual methods to find the system fault area, which is often inefficient. In addition, long-term power outages in the submarine observation network will not only lead to the interruption of valuable observation data, but also bring huge economic losses. Therefore, it is of vital importance to carry out relay protection of the submarine DC power supply system, quickly and accurately identify the fault area of ​​the system main cable, implement fault isolation measures, and locate the fault to ensure the reliable operation of the submarine observation network.

[0003] At present, the fault section location method can be divided into three types according to the communication mode with the adjacent branch units: no communication, two-end communication, and centralized communication. Among them, the method without communication has obvious deficiencies in reliability, selectivity, speed, tolerance to transition resistance, and flexibility compared with two-end protection in single-end protection. The method based on centralized communication relies on the communication center, which may cause information processing delays and reduce decision-making efficiency. At the same time, when the central node fails, the entire system may be paralyzed, and the flexibility and scalability are low.

[0004] The fault area identification method based on two-end communication avoids the limitations of single-end protection and the over-reliance of centralized communication methods on the communication center. However, the submarine observation network uses optoelectronic composite submarine cables as the transmission medium for both power and information. When the submarine cable is damaged or the communication link is abnormal, power data is lost and nodes cannot exchange information, resulting in the inability to accurately identify the fault area.

[0005] Among various types of submarine power supply systems, the grid-type submarine DC power supply system has redundant links, which improves the reliability of power transmission and provides higher stability for the communication network. However, the use of composite submarine cables also introduces a new variable: communication failure may become a misleading signal, making it difficult to accurately determine the fault section.

[0006] CN116699319A discloses a fault location method for a grid-type submarine observation network DC power supply system, and proposes a fault location method suitable for a grid-type submarine observation network without communication. However, this method must select a fault current sampling point with three ends connected to a branch unit as the basis for distinguishing the fault section and fault distance. In a large submarine observation network, the two three-terminal connected branch units may be far apart, and the super-long composite cable length and its high impedance characteristics will cause serious attenuation of fault characteristics. In addition, the method without communication has obvious deficiencies in reliability, selectivity, speed, tolerance to transition resistance and flexibility compared to the other two methods. CN118362835A discloses an electrical-spatial hybrid fault location method and system for a submarine DC power supply system. This method uses centralized communication, which is highly dependent on the communication center, and may cause information processing delays, reduced decision-making efficiency and other problems. At the same time, when the center fails, it may cause the entire system to be paralyzed, and the flexibility and scalability are low. CN118483524A discloses a method for locating a fault section of a submarine DC power supply system taking into account a branch without a measurement node. The method uses two-end communication. The fault section locating method based on two-end communication avoids the limitations of a single-end communication method and the excessive dependence of a centralized communication method on a communication center. However, the method is not suitable for a grid-type submarine DC power supply system.

[0007] Among various types of submarine power supply systems, the grid-type submarine DC power supply system has redundant links, which improves the reliability of power transmission, provides higher stability for the communication network, and has a higher application rate. In summary, there is currently no fault section location method suitable for the grid-type submarine DC power supply system with obvious fault characteristics, and in-depth research in this field is urgently needed. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a method for locating a fault section of a grid-type submarine DC power supply system. When communication between branch units is abnormal, the method uses the full network communication data generated by the redundant communication link unique to the grid-type submarine DC power supply system to obtain the current network topology information, eliminate the influence of the communication abnormality on the location of the fault section of the submarine DC power supply system, and implement rapid fault isolation.

[0009] The technical solution adopted by the present invention to solve the technical problem is a method for locating a fault section of a grid-type submarine DC power supply system, comprising the following steps: Step S1: Detect whether a fault occurs in the submarine DC power supply system. If a fault occurs, start to identify the fault section; Step S2: Each branch unit / shore base station sends the detected current data to the adjacent branch unit / shore base station in a set message format, and synchronously receives the message transmitted by the adjacent branch unit / shore base station, and starts timing at the same time; Step S3: If the current branch unit / shore base station exist The source adjacent branch unit / shore base station is successfully received at all times If the current data in the received message and the current data in the sent message are used, the current cosine similarity is used as the fault section location criterion; Step S4: If the branch unit / shore base station exist Failed to successfully receive the signal from the branch unit / shore base station If the message is received, it is determined to be a branch unit / shore base station With branch unit / shore base station The lines between Communication is abnormal. At this time, message broadcast transmission is performed; Step S5: Each branch unit / shore base station generates a power-communication status summary table according to the broadcast transmission message; Step S6: Locate the fault section according to the power-communication situation summary table.

[0010] Further, in step S1, the specific method for detecting whether a submarine DC power supply system fails is: Detect all line currents between adjacent branch units / shore base stations and calculate the derivatives of each current. When the maximum current derivative exceeds the preset threshold, as shown in formula (1), it is determined that a fault has occurred. (1) in, For branch unit / shore base station flow Flow to branch unit / shore base station Current ， For current The maximum value of the derivative, is the preset threshold.

[0011] Further, in step S2, the message includes a tag, a source branch unit / shore base station, and current data information; the tag is a mark used to distinguish messages of different purposes; the source branch unit / shore base station is used to indicate the source of the current data contained in this message; the current data is the measured current data of all currents flowing to adjacent branch units / shore base stations, and the current data is time series data.

[0012] Further, in step S3, the specific method of using current cosine similarity as the fault section location criterion is: When the current cosine similarity When the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line; (2) in, For branch unit / shore base station Flow to branch unit / shore base station The current, For branch unit / shore base station Flow to branch unit / shore base station of current.

[0013] Further, in steps S3 and S4 Meaning: branch unit / shore base The current data is sent to the branch unit / shore The minimum time taken.

[0014] Further, in step S4, the specific method for performing message broadcast transmission is: If the branch unit / shore base station Number of adjacent branch units / shore base stations , the branch unit / shore base station It is counted as a Class I branch unit and is used directly as the branch unit / shore base station. Send a startup message; if the branch unit / shore base station Number of adjacent branch units / shore base stations ,like The number of adjacent branch units / shore base stations of the adjacent branch units / shore base stations is not 1. It is counted as a Class I branch unit and is used directly as the branch unit / shore base station. Send a startup message. If The number of adjacent branch units / shore base stations is 1. Counted as a Class II branch unit, use The number of adjacent branch units / shore base stations is 3, and the adjacent branch units send a startup message; if the branch unit / shore base station Number of adjacent branch units / shore base stations , the branch unit / shore base station Counted as a Class III branch unit, using a branch unit / shore base station The adjacent branch unit sends a startup message; after receiving the startup message, the adjacent branch unit broadcasts the message it has and restarts the timing.

[0015] Furthermore, the format of the startup message is consistent with the message format in step S2, and only the marking content is modified to prompt the adjacent branch units that receive this message to broadcast the messages they have and modify the marking content of the forwarded messages.

[0016] Further, in step S5, the power-communication status summary table includes multiple groups of power and communication data, each group of power and communication data includes message tag, source branch unit, theoretical delivery time, actual delivery time, communication abnormality, and whether the current cosine similarity between the source branch unit / shore base station and the adjacent branch unit / shore base station is greater than 0.9.

[0017] Further, in step S6, the fault section is located according to the power-communication situation summary table, and the specific method is as follows: If the branch unit / shore base station It is a type I branch unit. Use this branch unit / shore base station The power-communication situation summary is used to locate the fault section. Specifically, the fault section is located according to the current cosine similarity in the power-communication situation summary table. When the current cosine similarity When the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line; If the branch unit / shore base station For Class II branch units, use The power-communication situation summary table of the adjacent branch units with the number of adjacent branch units / shore base stations being 3 is used to locate the fault section. Specifically, it is determined that except for the branch unit / shore base station with abnormal communication in step S4, the message receiving time of other branch units / shore base stations in the power-communication situation summary table is normal, and the other current cosine similarity in the table , then the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line; If the branch unit / shore base station For Class III branching units, use The power-communication situation summary table of the adjacent branch units is used to locate the fault section. Specifically, it is determined that except for the branch unit / shore base station with abnormal communication in step S4, the message receiving time of other branch units / shore base stations in the power-communication situation summary table is normal, and the other current cosine similarity in the table , then the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line.

[0018] Compared with the prior art, the advantages of the present invention are as follows: (1) The present invention starts the positioning procedure in time by setting the threshold value derived from the branch unit detection current, which can quickly capture and respond to potential fault signals. In the positioning process, the current cosine similarity is used as the core criterion, and the current data information of the adjacent branch units is combined for comprehensive analysis, so that the fault section can be locked more accurately. In addition, for special cases of communication anomalies, the method designs a broadcast transmission mechanism and a power-communication situation summary table construction process to ensure that all branch units can obtain key information when necessary, further improving the accuracy of fault location and the reliability of the overall system.

[0019] (2) The present invention can design a flexible processing strategy. Whether it is a complex situation with a large number of adjacent branch units or a scenario with only one adjacent branch unit, the fault section can be accurately determined by reading the power-communication situation summary table and combining the fault location criterion, or directly based on the data of the adjacent branch units. This design enables the fault section location method to easily cope with changes in different network structures, showing strong flexibility and wide adaptability to various forms of grid-type submarine DC power supply systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a simulation model of the grid-type submarine DC power supply system according to an embodiment of the present invention.

[0021] Figure 2 It is an equivalent topological diagram of the grid-type submarine DC power supply system according to an embodiment of the present invention.

[0022] Figure 3 It is a flow chart of a method according to an embodiment of the present invention.

[0023] Figure 4 It is an equivalent topology diagram of a grid-type submarine DC power supply system under fault condition 1 of an embodiment of the present invention.

[0024] Figure 5 It is an equivalent topology diagram of a grid-type submarine DC power supply system under fault condition 2 of an embodiment of the present invention.

[0025] Figure 6 It is an equivalent topology diagram of a grid-type submarine DC power supply system under fault condition 3 of an embodiment of the present invention.

[0026] Figure 7 It is an equivalent topology diagram of a grid-type submarine DC power supply system under fault condition 4 of an embodiment of the present invention.

[0027] Figure 8 It is an equivalent topological diagram of a grid-type submarine DC power supply system under fault condition 5 of an embodiment of the present invention.

[0028] Fig. 9It is an equivalent topology diagram of a grid-type submarine DC power supply system under fault condition 6 of an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] The submarine observation network uses optoelectronic composite submarine cables as the transmission medium for both power and information. Damage caused by external forces will not only cause faults, but also cause communication anomalies between branch units. Considering that only single-point faults and single-point communication anomalies occur in the system, the fault point in the system may also have communication anomalies at the same time, or the fault point and communication anomalies may be located on different lines. In this case, communication anomalies may become a misleading signal, making it difficult to accurately determine the faulty section. Nevertheless, thanks to the full coupling characteristics of power and communication in the grid-type submarine DC power supply system, the communication status of the entire network can be comprehensively analyzed through redundant links, effectively eliminating the interference of communication failures on the determination of the faulty section and ensuring the accuracy of positioning.

[0031] Based on the above analysis, the present invention proposes a method for locating the fault section of a grid-type submarine DC power supply system. The present invention starts the positioning strategy by detecting current anomalies through branch units, and then uses the set message format to transmit current data between adjacent branch units, and judges the communication status based on the message reception within a time limit. If the communication is normal, the fault section is located by current cosine similarity; if the communication is abnormal, the broadcast transmission mechanism is triggered in different ways according to the branch unit type, and a power-communication status summary table is constructed according to the message delivery time, and then the table and the fault location criterion are combined to accurately determine the fault section. When the branch communication is abnormal, the system redundant communication link is used to obtain the entire network data to understand the current network topology, quickly locate and isolate the fault, and is not affected by the communication abnormality.

[0032] The method of this embodiment is aimed at the grid-type submarine DC power supply system of the optoelectronic composite submarine cable. Figure 1 As an example, the grid-type submarine DC power supply system shown in FIG. 1 is an equivalent topological diagram of the grid-type submarine DC power supply system. Figure 2 shown. Figure 3 middle, For branch units or shore base stations, E1-E13 and Figure 1 Corresponding to the branch unit and shore base station. It is the line between adjacent branch units / shore base stations. Each branch unit / shore base station is equipped with an intelligent power device (IED) to detect the line current between two branch units / shore base stations and store the theoretical delivery time. . Branch unit / shore The current data is sent to the branch unit / shore The minimum time taken is defined as the theoretical delivery time ; Branch unit / shore-based The current data is sent to the branch unit / shore The actual time taken is defined as the actual delivery time .

[0033] Reference Figure 3 , the method of this embodiment includes the following steps: Step S1: Detect whether a submarine DC power supply system fails. If a failure occurs, identify the faulty section. In step S1, the specific method for detecting whether a submarine DC power supply system fails is as follows: Detect all line currents between adjacent branch units / shore base stations and calculate the derivatives of each current. When the maximum current derivative exceeds the preset threshold , as shown in formula (1), it is determined that a fault has occurred. Specifically, the current branch unit / shore base station is , its adjacent branch unit / shore base station is , branch unit / shore base station Use intelligent power devices (IEDs) to regularly detect branch unit / shore base station flow direction Flow to branch unit / shore base station Current , and calculate its current derivative When the maximum current derivative exceeds the preset threshold , as shown in formula (1), it is judged that a fault occurs.

[0034] (1) Step S2: Each branch unit / shore base station sends the detected current data to the adjacent branch unit / shore base station in a set message format, and synchronously receives the message transmitted by the adjacent branch unit / shore base station, and starts timing at the same time. Send the detected current data to the adjacent branch unit / shore base station in the set message format , and synchronously receive the adjacent branch unit / shore base station The message is transmitted and the timing starts at the same time. The message format is shown in Table 1. The message includes a tag, a source branch unit / shore base station, and current data information. The tag is used to distinguish messages of different purposes, and the tag is "1" at this time. The source branch unit / shore base station is used to indicate the source of the current data contained in this message, which is convenient for later distinction. The current data is the measured current data of all currents flowing to adjacent branch units / shore base stations. The current data is based on time series data.

[0035]

[0036] Step S3: If the current branch unit / shore base station exist The source adjacent branch unit / shore base station is successfully received at all times The current data of the current branch unit / shore base station and the adjacent branch unit / shore base station are compared and analyzed. When the current cosine similarity is 0, the fault section location criterion is used according to the current data in the received message and the current data in the sent message. When the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line; (2) in, For branch unit / shore base station Flow to branch unit / shore base station The current, For branch unit / shore base station Flow to branch unit / shore base station of current.

[0037] Step S4: If the branch unit / shore base station exist Failed to successfully receive the signal from the branch unit / shore base station The actual delivery time Longer than theoretical delivery time ), it is determined to be a branch unit / shore base station With branch unit / shore base station The lines between Communication is abnormal. At this time, message broadcast transmission is performed.

[0038] If the branch unit / shore base station Number of adjacent branch units / shore base stations , the branch unit / shore base station It is counted as a Class I branch unit and is used directly as the branch unit / shore base station. Send a startup message. If the number of adjacent branch units of E3 is 3, E3 is counted as a Class I branch unit and E3 is used directly to send the startup message. Number of adjacent branch units / shore base stations ,like The number of adjacent branch units / shore base stations of the adjacent branch units / shore base stations is not 1. It is counted as a Class I branch unit and is used directly as the branch unit / shore base station. Send a startup message. If the number of adjacent branch units of E5 is 2, and the numbers of adjacent branch units of E5, E4 and E6 are both 3 (neither is 1), E5 is considered a Class I branch unit and is directly used to send the startup message. The number of adjacent branch units / shore base stations is 1. Counted as a Class II branch unit (Class II branch units are at the edge of the system and must be connected to another adjacent branch unit whose number of adjacent branch units / shore base station is 3), using BU i The number of adjacent branch units / shore base stations is 3, and the number of adjacent branch units of E2 is 2. The number of adjacent branch units of E2 and E1 is 1. E2 is counted as a Class II branch unit. The number of adjacent branch units / shore base stations of E2 is 3, and the adjacent branch unit is E3. E3 is used to send the startup message. Number of adjacent branch units / shore base stations , the branch unit / shore base station Counted as a Class III branch unit, using a branch unit / shore base station The adjacent branch unit sends a startup message, such as E 13 The number of adjacent branch units is 1, E 13 Counted as type III branch unit, E 13 The adjacent branch unit is E6, and the startup message is sent using E6. After receiving the startup message, the adjacent branch unit broadcasts the message it has and restarts the timing. The startup message format is the same as the message format shown in Table 1, except that the mark is changed to "1+", prompting the adjacent branch unit that receives this message to broadcast the message it has and change the forwarded message mark to "2". After the startup message is sent, the timing is restarted to ensure that all branch units can obtain the necessary information.

[0039] Step S5: Each branch unit / shore base station generates a power-communication status summary table according to the broadcast transmission message. The power-communication status summary table of each branch unit / shore base station includes multiple groups of power and communication data, each group of power and communication data includes message tag, source branch unit, theoretical delivery time, actual delivery time, communication abnormality (0 indicates normal communication, 1 indicates abnormal communication), whether the current cosine similarity between the source branch unit / shore base station and the adjacent branch unit / shore base station is greater than 0.9 (0 indicates that the current cosine similarity is not greater than 0.9, 1 indicates that the current cosine similarity is greater than 0.9). The format of the power-communication status summary table is shown in Table 2.

[0040]

[0041] Step S6: locate the fault section according to the power-communication situation summary table. The specific method is as follows: For type I branch units, type II branch units, and type III branch units, the power-communication situation summary table in the branch unit / shore base station that sends the startup message is used to locate the faulty section.

[0042] If the branch unit / shore base station It is a type I branch unit. Use this branch unit / shore base station The power-communication situation summary is used to locate the fault section. Specifically, the fault section is located according to the current cosine similarity in the power-communication situation summary table. When the current cosine similarity When the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line.

[0043] If the branch unit / shore base station For Class II branch units, use The power-communication situation summary table of the adjacent branch units with the number of adjacent branch units / shore base stations being 3 is used to locate the fault section. Specifically, it is determined that except for the branch unit / shore base station with abnormal communication in step S4, the message receiving time of other branch units / shore base stations in the power-communication situation summary table is normal, and the other current cosine similarity in the table , then the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line.

[0044] If the branch unit / shore base station For Class III branching units, use The power-communication situation summary table of the adjacent branch units is used to locate the fault section. Specifically, it is determined that except for the branch unit / shore base station with abnormal communication in step S4, the message receiving time of other branch units / shore base stations in the power-communication situation summary table is normal, and the other current cosine similarity in the table , then the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line.

[0045] Set as Figure 4-9 There are six fault conditions shown, among which "F" indicates that the line fails but the communication is normal, "A" indicates that only the communication is abnormal, and "Fa" indicates that the line fails and the communication is abnormal.

[0046] Reference Figure 4, under fault condition 1, a fault occurs in line L3 between E3 and E4, and communication anomalies occur in line L4 between E4 and E5. The message marked as "1" is transmitted normally between E3 and E4. Using the fault criterion formula (2), it can be determined that , E4 and E5 are both Class I branch units. This branch unit (E4 and E5) sends an opening message and uses the power-communication situation summary table of this branch unit (E4 and E5) to make a fault judgment. The power-communication situation summary table of E4 is shown in Table 3. Since only the communication between E4 and E5 is abnormal, .

[0047]

[0048] Reference Figure 5 ,Under fault condition 2, a fault and abnormal communication occurred in line L3 between E3 and E4. E3 and E4 are both Class I branch units. This branch unit (E3 and E4) sends an open message and uses the power-communication situation summary table of this branch unit (E3 and E4) to make a fault judgment. The power-communication situation summary table of E4 is shown in Table 4. Due to the fault and abnormal communication between E3 and E4, .

[0049]

[0050] Reference Figure 6 , under fault condition 3, a fault occurred in line L8 between E4 and E9, and communication anomaly occurred in line L2 between E2 and E3. The message marked as "1" was transmitted normally between E4 and E9. Using the fault criterion formula (2), it can be determined that E2 is a Class II branch unit, and E3 is a Class I branch unit. According to the rules, E3 sends an open message, and the power-communication situation summary table of E3 is used for fault determination. The power-communication situation summary table of E3 is shown in Table 5. Due to the fault and communication abnormality between E2 and E3, the table does not contain E2 data. The other branch units E4~E 13 All meet , between E4 and E9 ,Considering a single point of failure, only the communication abnormality occurs between E2 and E3.

[0051]

[0052] Reference Figure 7,Under fault condition 4, a fault and communication anomaly occurred in line L2 between E2 and E3. E2 is a type II branch unit and E3 is a type I branch unit. According to the rules, E3 sends an open message and uses the power-communication situation summary table of E3 to make a fault judgment. The power-communication situation summary table of E3 is shown in Table 6. Due to the fault and communication anomaly between E2 and E3, the table does not contain E2 data. The other branch units E4~E 13 All meet .

[0053]

[0054] Reference Figure 8 , under fault condition 5, a fault occurs on line L8 between E4 and E9, and a fault occurs on line L8 between E6 and E 13 The communication abnormality occurs in the line L6 between E4 and E9. The message marked as "1" is transmitted normally between E4 and E9. Using the fault judgment formula (2), it can be judged that , E 13 It is a Class III branch unit, and E6 is a Class I branch unit. According to the rules, E6 sends an open message, and the power-communication situation summary table of E6 is used to make a fault judgment. The power-communication situation summary table of E6 is shown in Table 7. 13 Due to communication anomalies, E is not included in the table. 13 Data, other branch units meet , between E4 and E9 , considering single point failure, E6 and E 13 There is only a communication anomaly.

[0055]

[0056] Reference Fig. 9 , under fault condition 6, E6 and E 13 There was a fault and communication abnormality in the line L6, E 13 It is a Class III branch unit, and E6 is a Class I branch unit. According to the rules, E6 sends an open message, and the power-communication situation summary table of E6 is used to make a fault judgment. The power-communication situation summary table of E6 is shown in Table 8. 13 Due to communication anomalies, E is not included in the table. 13 Data, E6 and E 13 Due to faults and communication anomalies, other branch units meet .

[0057]

[0058] This embodiment also includes a data processing device, which includes a memory and a processor; wherein the memory is used to store one or more computer instructions, and the one or more computer instructions are executed by the processor to perform the steps of the method.

[0059] Those skilled in the art may make various modifications and variations to the present invention. If these modifications and variations are within the scope of the claims of the present invention and their equivalents, then these modifications and variations are also within the protection scope of the present invention.

[0060] The contents not described in detail in the specification are prior art known to those skilled in the art.

Claims

1. A method for locating a fault section of a grid-type submarine DC power supply system, characterized in that: The following steps are involved: Step S1: Detect whether a fault occurs in the submarine DC power supply system. If a fault occurs, start to identify the fault section; Step S2: Each branch unit / shore base station sends the detected current data to the adjacent branch unit / shore base station in a set message format, and synchronously receives the message transmitted by the adjacent branch unit / shore base station, and starts timing at the same time; Step S3: If the current branch unit / shore base station exist The source adjacent branch unit / shore base station is successfully received at all times If the current data in the received message and the current data in the sent message are used, the current cosine similarity is used as the fault section location criterion; Step S4: If the branch unit / shore base station exist Failed to successfully receive the signal from the branch unit / shore base station If the message is received, it is determined to be a branch unit / shore base station With branch unit / shore base station The lines between Communication is abnormal. At this time, message broadcast transmission is performed; Step S5: Each branch unit / shore base station generates a power-communication status summary table according to the broadcast transmission message; Step S6: Locate the fault section according to the power-communication situation summary table.

2. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 1, characterized in that: In step S1, the specific method for detecting whether a submarine DC power supply system fails is as follows: Detect all line currents between adjacent branch units / shore base stations and calculate the derivatives of each current. When the maximum current derivative exceeds the preset threshold, as shown in formula (1), it is determined that a fault has occurred. （1） in, Branch unit / shore base station flow direction Flow to branch unit / shore base station Current ， For current The maximum value of the derivative, is the preset threshold.

3. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 1, characterized in that: In step S2, the message includes a tag, a source branch unit / shore base station, and current data information; the tag is a mark used to distinguish messages of different purposes; the source branch unit / shore base station is used to indicate the source of the current data contained in this message; the current data is all measured current data flowing to adjacent branch units / shore base stations, and the current data is based on time series data.

4. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 1, characterized in that: In step S3, the specific method of using current cosine similarity as the fault section location criterion is: When the current cosine similarity When the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line; （2） in, For branch unit / shore base station Flow to branch unit / shore base station The current, For branch unit / shore base station Flow to branch unit / shore base station of current.

5. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 1, characterized in that: Steps S3 and S4 Meaning: branch unit / shore base The current data is sent to the branch unit / shore The minimum time taken.

6. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 3, characterized in that: In step S4, the specific method for performing message broadcast transmission is: If the branch unit / shore base station Number of adjacent branch units / shore base stations , the branch unit / shore base station It is counted as a Class I branch unit and is used directly as the branch unit / shore base station. Send a startup message; if the branch unit / shore base station Number of adjacent branch units / shore base stations ,like The number of adjacent branch units / shore base stations of the adjacent branch units / shore base stations is not 1. It is counted as a Class I branch unit and is used directly as the branch unit / shore base station. Send a startup message. If The number of adjacent branch units / shore base stations is 1. Counted as a Class II branch unit, use The number of adjacent branch units / shore base stations is 3, and the adjacent branch units send a startup message; if the branch unit / shore base station Number of adjacent branch units / shore base stations , the branch unit / shore base station Counted as a Class III branch unit, using a branch unit / shore base station The adjacent branch unit sends a startup message; after receiving the startup message, the adjacent branch unit broadcasts the message it has and restarts the timing.

7. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 6, characterized in that: The format of the startup message is consistent with the message format in step S2, and only the marking content is modified to prompt the adjacent branch units that receive this message to broadcast the messages they have and modify the marking content of the forwarded messages.

8. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 4, characterized in that: In step S5, the power-communication status summary table includes multiple groups of power and communication data, each group of power and communication data includes message tag, source branch unit, theoretical delivery time, actual delivery time, communication abnormality, and whether the current cosine similarity between the source branch unit / shore base station and the adjacent branch unit / shore base station is greater than 0.

9.

9. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 8, characterized in that: In step S6, the fault section is located according to the power-communication status summary table. The specific method is as follows: if the branch unit / shore base station It is a type I branch unit. Use this branch unit / shore base station The power-communication situation is summarized to locate the fault section; If the branch unit / shore base station For Class II branch units, use The power-communication situation summary table of the adjacent branch units with the number of adjacent branch units / shore base stations being 3 is used to locate the fault section; if the branch unit / The shore base station is a Class III branch unit, using The fault section is located based on the summary table of power-communication conditions in adjacent branch units.

10. The method for locating a fault section of a grid-type submarine DC power supply system according to claim 9, characterized in that: If the branch unit / shore base station It is a type I branch unit. Use this branch unit / shore base station The power-communication situation summary is used to locate the fault section. Specifically, the fault section is located according to the current cosine similarity in the power-communication situation summary table. When the current cosine similarity When the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line; If the branch unit / shore base station For Class II branch units, use The power-communication situation summary table of the adjacent branch units with the number of adjacent branch units / shore base stations being 3 is used to locate the fault section. Specifically, it is determined that except for the branch unit / shore base station with abnormal communication in step S4, the message receiving time of other branch units / shore base stations in the power-communication situation summary table is normal, and the other current cosine similarity in the table , then the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line; If the branch unit / shore base station For Class III branching units, use The power-communication situation summary table of the adjacent branch units is used to locate the fault section. Specifically, it is determined that except for the branch unit / shore base station with abnormal communication in step S4, the message receiving time of other branch units / shore base stations in the power-communication situation summary table is normal, and the other current cosine similarity in the table , then the fault section is determined to be the current branch unit / shore base station With adjacent branch unit / shore base station Inter-line.

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