Self-healing control method, self-healing control device and self-healing control system for ungrounded system of power grid

Abstract

The invention provides a self-healing control method, a self-healing control device and a self-healing control system for an ungrounded system of a power grid. The method comprises the steps that a target branch is selected from the ungrounded system of the power grid, the ungrounded system of the power grid comprises a plurality of branches, and the target branch is a fault grounded branch in the plurality of branches; the type of the target branch is obtained, the type comprises a power supply type and a motor type, the power supply type is a branch connected with a power supply and a transformer, the motor type is a branch connected with a motor, and the branch and the type are in one-to-one correspondence; according to the type of the target branch, self-healing control is carried out on the ungrounded system of the power grid, and according to the self-healing control, the target branch with the fault is isolated from the ungrounded system of the power grid. According to the scheme, the problem that in the prior art, when single-phase grounding happens to a power grid ungrounded system, faults cannot be handled in time in a manual handling mode is solved.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a self-healing control method, device, computer program product and self-healing control system for an ungrounded power grid system. Background Art

[0002] When a single-phase grounding occurs in an ungrounded power grid system, the voltage relative to the ground drops to 0V, and the voltages relative to the other two phases increase from the original phase voltage to the line voltage; however, the three-phase electrical equipment is not affected by normal operation, but long-term operation is not allowed.

[0003] When a single-phase grounding occurs in an ungrounded system of an existing power grid, a small current grounding line selection device selects the grounding interval and sends out an alarm signal, and then relies on manual removal of the grounding interval. This method requires manual detection through an electrical monitoring system or on-site inspection. There are manual omissions, resulting in the grounding fault cannot be discovered and removed in time, which can easily cause a two-phase grounding short circuit and expand the fault. Therefore, the current manual processing method cannot handle the fault in time. Summary of the invention

[0004] The main purpose of the present application is to provide a self-healing control method, device, computer program product and self-healing control system for an ungrounded power grid system, so as to at least solve the problem in the prior art that the manual processing method cannot handle the fault in time when a single-phase grounding occurs in an ungrounded power grid system.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a self-healing control method for an ungrounded power grid system is provided, comprising: selecting a target branch from the ungrounded power grid system, wherein the ungrounded power grid system includes multiple branches, and the target branch is a branch that has a ground fault among the multiple branches; obtaining the type of the target branch, wherein the type includes a power supply type and a motor type, the power supply type is the branch connecting the power supply and the transformer, and the motor type is the branch connecting the motor, and the branches and the types correspond one to one; performing self-healing control on the ungrounded power grid system according to the type of the target branch, wherein the self-healing control is to isolate the faulty target branch from the ungrounded power grid system.

[0006] Optionally, selecting a target branch from an ungrounded power grid system includes: obtaining a first initial branch, wherein the first initial branch is a fault branch selected from all the branches using a small current grounding line selection device; obtaining a second initial branch, wherein the second initial branch is the branch with the largest zero-sequence current value among all the branches; when the first initial branch and the second initial branch are the same, determining the first initial branch as the target branch; when the first initial branch and the second initial branch are not the same, determining the second initial branch as the target branch.

[0007] Optionally, when the type is the motor type, self-healing control is performed on the ungrounded system of the power grid according to the type of the target branch, including: when the branch where the i-th motor is located is the target branch, controlling the first circuit breaker of the branch where the j-th motor is located to close, wherein i∈[1, N], j∈[N+1, M], N is the number of the motors that meet the process requirements, and M is the total number of the motors; when the first closing signal of the first circuit breaker of the branch where the j-th motor is located is obtained, controlling the second circuit breaker of the branch where the i-th motor is located to open; when the first opening signal of the second circuit breaker of the branch where the i-th motor is located is obtained, determining that the branch where the i-th motor is located has been isolated.

[0008] Optionally, before controlling the closing of the first circuit breaker of the branch where the j-th motor is located, the method further includes: obtaining the current state of the j-th motor; when the current state of the j-th motor is a maintenance state, deleting the j-th motor from a sequence of spare motors, wherein the sequence of spare motors is a sequence of MN.

[0009] Optionally, when the type is the power supply type, self-healing control is performed on the ungrounded system of the power grid according to the type of the target branch, including: when the branch where the transformer is located is the target branch, controlling the third circuit breaker connected to the bus to close; when a second closing signal of the third circuit breaker connected to the bus is obtained, controlling the fourth circuit breaker connected to the transformer to open; when a second opening signal of the fourth circuit breaker connected to the transformer is obtained, determining that the branch where the transformer is located has been isolated.

[0010] Optionally, when the type is the power supply type, self-healing control is performed on the ungrounded system of the power grid according to the type of the target branch, including: when the branch where the first transformer is located is the target branch, controlling the fifth circuit breaker connected to the second transformer in the branch where the second transformer is located to close; when a third closing signal of the fifth circuit breaker connected to the second transformer is obtained, controlling the sixth circuit breaker connected to the first transformer to open; when a third opening signal of the sixth circuit breaker connected to the first transformer is obtained, determining that the branch where the first transformer is located has been isolated.

[0011] Optionally, after performing self-healing control on the ungrounded system of the power grid according to the type of the target branch, the method further includes: obtaining the three-phase voltage value of the bus; when the three-phase voltage value of the bus is within a normal range, determining that the fault has been eliminated; when the three-phase voltage value of the bus is not within the normal range, determining that the fault has not been eliminated.

[0012] According to another aspect of the present application, a self-healing control device for an ungrounded power grid system is provided, comprising: a selection unit, used to select a target branch from the ungrounded power grid system, wherein the ungrounded power grid system includes multiple branches, and the target branch is a branch that has a ground fault among the multiple branches; a first acquisition unit, used to acquire the type of the target branch, wherein the type includes a power supply type and a motor type, the power supply type is the branch connecting the power supply and the transformer, the motor type is the branch connecting the motor, and the branches and the types correspond one to one; a control unit, used to perform self-healing control on the ungrounded power grid system according to the type of the target branch, wherein the self-healing control is to isolate the faulty target branch from the ungrounded power grid system.

[0013] According to another aspect of the present application, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, the steps of any one of the self-healing control methods for an ungrounded power grid system are implemented.

[0014] According to another aspect of the present application, a self-healing control system is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include a method for executing any one of the self-healing control methods for an ungrounded power grid system.

[0015] By applying the technical solution of the present application, when a grounding fault occurs in an ungrounded power grid system, the faulty branch can be automatically selected to ensure operational continuity. At the same time, the grounding fault branch can be automatically cut off and isolated without the need for manual processing, thus avoiding delays and misoperations caused by manual intervention and improving the efficiency and accuracy of fault recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 A hardware structure block diagram of a mobile terminal for executing a self-healing control method for an ungrounded power grid system provided in an embodiment of the present application is shown;

[0018] Figure 2 A schematic flow chart of a self-healing control method for an ungrounded power grid system provided according to an embodiment of the present application is shown;

[0019] Figure 3 A schematic diagram of the structure of a motor type compartment is shown;

[0020] Figure 4 A schematic diagram of the structure of a power supply type bay is shown;

[0021] Figure 5 A flow chart showing another self-healing control method for an ungrounded power grid system is shown;

[0022] Figure 6 A schematic diagram of the structure of a self-healing control system is shown;

[0023] Figure 7 A schematic flow chart of a self-healing control method for an ungrounded power grid system is shown;

[0024] Figure 8 A structural block diagram of a self-healing control device for an ungrounded power grid system provided according to an embodiment of the present application is shown.

[0025] The above drawings include the following reference numerals:

[0026] 102. Processor; 104. Memory; 106. Transmission device; 108. Input / output device; 11. CPU module; 12. LCD display module; 13. Key module; 14. Current acquisition module; 15. Voltage acquisition module; 16. Signal input module; 17. Signal output module; 18. Power supply module. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] For the convenience of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0031] Grid ungrounded system: also known as insulated grid or neutral point ungrounded system, is a power system design strategy in which the neutral point of the power system (usually the neutral point of the transformer) is not directly grounded, or is grounded through a high impedance. The main purpose of this design is to improve the stability and safety of the system in the event of a single-phase grounding fault. In an ungrounded system, when a single-phase grounding fault occurs, a current path is formed between the faulty phase and the earth, but because the system neutral point is not directly connected to the ground, the fault current is relatively small and will not immediately cause the system to collapse. This provides time for fault detection and isolation, thereby minimizing the power outage time and the impact on the power grid. However, in order to ensure the safe operation of the system and timely response to faults, a device that can accurately detect and locate grounding faults is required, which is a small current grounding line selection device.

[0032] Small current grounding line selection device: It is a fault detection device specially used in ungrounded systems or high-impedance grounding systems. Its main function is to quickly and accurately identify the feeder branch where the fault is located when a single-phase grounding fault occurs in the system. Under normal operating conditions, since the neutral point is not grounded, the zero-sequence current in the power grid (that is, the current component relative to the earth that does not exist in the three-phase current) is almost zero. However, when a single-phase grounding fault occurs, the zero-sequence current will increase significantly, and the zero-sequence current on the faulty feeder branch will be the largest. The small current grounding line selection device realizes the identification of the faulty feeder by monitoring the zero-sequence current in the system. It usually includes a zero-sequence current transformer, a signal processing unit, and a fault judgment logic. The zero-sequence current transformer is connected to the neutral line of each feeder branch to detect the zero-sequence current. The signal processing unit analyzes the detected zero-sequence current signal, and by comparing the zero-sequence current on each feeder branch, the feeder with the largest zero-sequence current can be found, that is, the feeder with the grounding fault. The principle of the small current grounding line selection device is based on the distribution characteristics of zero-sequence current and the difference in zero-sequence current between the fault feeder and the non-fault feeder. Through this device, the single-phase grounding fault in the ungrounded power grid system can be quickly located and isolated, thereby improving the reliability and safety of the system.

[0033] In order to avoid a grounding fault in another phase, causing a two-phase grounding short circuit and expanding the fault, a special small current grounding line selection device is installed in the neutral point ungrounded system. When a single-phase grounding fault occurs in the ungrounded system, the small current grounding line selection device selects the grounding interval and sends an alarm signal. The operating personnel will cut off the grounding interval to ensure long-term operation of the power system.

[0034] When the grounding interval selected by the single-phase grounding monitoring device is the motor interval, the electrical operation personnel need to contact the process personnel. The grounding interval can only be cut off after the process personnel start the standby pump through the DCS system. This process is time-consuming. If a grounding fault occurs again in the ungrounded phase during this process, the grounding interval will trip due to a two-phase short circuit and cause the system to shake, which can easily cause the process equipment to stop.

[0035] When the grounding interval selected by the single-phase grounding monitoring device is a power supply interval, the electrical operation personnel need to connect the corresponding busbars and then cut off the grounding interval. This process is time-consuming. If a grounding fault occurs again in the ungrounded phase during this process, the grounding interval will trip due to a two-phase short circuit. The lower-level fast-cut device can only switch through analog start-up. The switching time is long, which can easily cause the lower-level load to shake and trip, ultimately causing large-scale shutdown of the process equipment.

[0036] Therefore, the existing scheme cannot detect the grounding fault in time and deal with it in time. When the grounding interval is determined to be a motor interval, the standby motor cannot be automatically started and the grounded motor interval cannot be cut off. When the grounding interval is determined to be a power supply interval, the busbar cannot be automatically closed and the grounded power supply interval cannot be cut off.

[0037] As introduced in the background technology, the manual processing method in the prior art cannot handle the fault in time when a single-phase grounding occurs in an ungrounded power grid system. To solve the above problem, the embodiments of the present application provide a self-healing control method, device, computer program product and self-healing control system for an ungrounded power grid system.

[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0039] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 1 1 is a hardware structure block diagram of a mobile terminal of a self-healing control method for an ungrounded power grid system according to an embodiment of the present invention. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is for illustration only and does not limit the structure of the mobile terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations are shown.

[0040] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the display method of device information in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, the above method is implemented. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The above-mentioned specific examples of the network may include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0041] In this embodiment, a self-healing control method for an ungrounded power grid system running on a mobile terminal, a computer terminal or a similar computing device is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0042] Figure 2 FIG. 1 is a flow chart of a self-healing control method for an ungrounded power grid system according to an embodiment of the present application. Figure 2 As shown, the method comprises the following steps:

[0043] Step S201, selecting a target branch from an ungrounded power grid system, wherein the ungrounded power grid system includes multiple branches, and the target branch is a branch that has a ground fault among the multiple branches;

[0044] Specifically, in an ungrounded power grid system, when a single-phase grounding fault occurs, the fault current will generate a zero-sequence current in the system. Due to the characteristics of an ungrounded system, there is no obvious zero-sequence current in the system during normal operation, but after a fault occurs, the zero-sequence current will increase significantly on the grounding branch. Therefore, the key to step S201 is to identify the target branch with abnormally increased zero-sequence current, that is, the branch with fault grounding, by detecting the zero-sequence current of each branch. This identification process usually relies on a small current grounding line selection device, which can monitor and compare the zero-sequence currents of multiple branches, determine the branch with the largest zero-sequence current, and use it as the target branch.

[0045] Step S202, obtaining the type of the target branch, wherein the type includes a power supply type and a motor type, the power supply type is the branch connecting the power supply and the transformer, the motor type is the branch connecting the motor, and the branch and the type correspond one to one;

[0046] Specifically, once the target branch is determined, the next step S202 is to identify the type of the branch. The types of branches are mainly divided into power supply type and motor type. Power supply type branches usually refer to the lines connecting the grid power supply and the transformer, while motor type branches refer to the lines connecting the motor. Obtaining branch type information is helpful for the formulation of subsequent self-healing control strategies, because the self-healing processing methods of power supply type and motor type branches are different.

[0047] Each branch has its corresponding type identification, which is basic information in power grid design and maintenance, and can quickly determine the nature of the branch. In the self-healing control process, identifying the type of the target branch is a crucial step, which directly affects the fault isolation and recovery strategy.

[0048] Step S203, performing self-healing control on the ungrounded power grid system according to the type of the target branch, wherein the self-healing control is to isolate the faulty target branch from the ungrounded power grid system.

[0049] Specifically, different self-healing control strategies are adopted according to the type of target branch (power source type or motor type), with the aim of isolating the faulty branch from the ungrounded system of the power grid, thereby restoring the normal operation of the system.

[0050] For power supply branches: the upper and lower bus tie circuit breakers will be closed first to ensure that the lower power grid is not affected, and then the circuit breaker on the faulty branch will be opened to isolate the fault. This process ensures continuous power supply to the system and quickly eliminates the source of the fault.

[0051] For the motor branch, the circuit breaker of the standby motor will be automatically closed to ensure that the system load demand is met, and then the circuit breaker on the faulty motor branch will be disconnected. This not only ensures the operating efficiency of the system, but also achieves the isolation of the faulty branch.

[0052] Through this embodiment, when a grounding fault occurs in an ungrounded power grid system, the faulty branch can be automatically selected to ensure operation continuity. At the same time, the grounding fault branch can be automatically cut off and isolated without manual processing, avoiding delays and misoperations caused by manual intervention, and improving the efficiency and accuracy of fault recovery.

[0053] In the specific implementation process, the target branch is selected from the ungrounded system of the power grid through the following steps: obtaining a first initial branch, wherein the first initial branch is a fault branch selected from all the above branches by using a small current grounding line selection device; obtaining a second initial branch, wherein the second initial branch is the branch with the largest zero-sequence current value among all the above branches; in the case that the first initial branch and the second initial branch are the same, determining the first initial branch as the target branch; in the case that the first initial branch and the second initial branch are not the same, determining the second initial branch as the target branch.

[0054] In this scheme, the two links of small current line selection principle and zero-sequence current value comparison are combined. Through cross-validation of the two, the accuracy and reliability of target fault branch identification are further improved, thereby enabling more efficient and accurate fault detection.

[0055] Specifically, the zero-sequence current value of each feeder branch and the busbar section PT open triangle voltage value are collected, and the grounding interval branch Ni is selected using the traditional small current grounding line selection device; the feeder branch interval Mi with the largest zero line current value of all collected feeder branches is determined; Ni and Mi are compared to see if they are consistent. If they are consistent, the small current grounding line selection device selects the grounding interval branch as the target branch. If they are inconsistent, the feeder branch interval Mi with the largest zero line current value is the target branch. The interval branch is the branch of this solution.

[0056] Specifically, the first initial branch is a suspected fault branch selected by a small current grounding line selection device. Based on the analysis of zero-sequence current, the small current grounding line selection device can quickly identify the branch with abnormally increased zero-sequence current when a single-phase grounding fault occurs in the system. The small current line selection device identifies the fault branch based on the analysis of zero-sequence current. Under normal circumstances, the zero-sequence current in an ungrounded power grid system is almost zero. When a single-phase grounding fault occurs, the zero-sequence current on the fault branch will increase significantly. The small current grounding line selection device can quickly identify the branch with abnormally increased zero-sequence current by monitoring and comparing the zero-sequence current of all branches in the system, and use it as the first initial branch.

[0057] This fault detection method based on small current grounding line selection is a commonly used technical means in ungrounded systems. It can effectively identify single-phase grounding faults. However, in some complex or interference-intensive power grid environments, the small current line selection device alone may not be able to locate the fault 100% accurately. Therefore, it is necessary to combine other detection methods to enhance the accuracy of the judgment.

[0058] Specifically, the second initial branch refers to the branch with the largest zero-sequence current value among all branches. In an ungrounded system, a single-phase grounding fault will cause an abnormal increase in zero-sequence current, and the zero-sequence current of the faulty branch is usually significantly higher than the zero-sequence current of the non-faulty branch. Therefore, by monitoring and comparing the zero-sequence current values ​​of each branch, the branch with the largest zero-sequence current value, that is, the second initial branch, can be determined. Determine the branch with the largest zero-sequence current value from all branches, that is, the second initial branch. Although the first initial branch has been selected based on the principle of small current line selection, the direct measurement of the magnitude of the zero-sequence current provides another independent basis for fault detection. The confirmation of the second initial branch can be regarded as an enhanced verification of the detection result of the first initial branch.

[0059] Monitoring of zero-sequence current value is another effective way to detect single-phase grounding faults. It directly reflects the magnitude of the fault current, thus providing another important clue to the fault branch. In practical applications, the monitoring results of zero-sequence current value can be used as an independent basis for fault detection, or can be comprehensively analyzed with the results of other detection methods to improve the accuracy of fault location.

[0060] Specifically, after obtaining the first initial branch and the second initial branch, the next step is to compare the two. If the first initial branch and the second initial branch are the same branch, that is, the suspected fault branch selected by the small current line selection device is consistent with the branch with the largest zero-sequence current value, this means that the results of the two detection methods point to the same branch, and it can be determined that the first initial branch is the target fault branch. On the contrary, if the two branches are inconsistent, the second initial branch with the largest zero-sequence current value is preferentially selected as the target fault branch, because the magnitude of the zero-sequence current value directly reflects the severity and precise location of the fault.

[0061] By comparing the results of the two detection methods, the accuracy of fault location can be significantly improved. Even in a complex power grid environment, when the low-current line selection device may be interfered with or misjudged, the direct measurement of the zero-sequence current value can be used as a more direct and reliable basis for fault location. In addition, this dual detection mechanism can also serve as a redundant system. Even if one detection method fails, the other can still play a role in fault detection, thereby ensuring the overall stability and safety of the system.

[0062] For example, an ungrounded power grid system contains 6 branches (branch 1 to branch 6), as shown below:

[0063] Branch 1: connected to the main power supply and operates normally;

[0064] Branch 2: with motor load, normal operation;

[0065] Branch 3: with transformer load, suspected single-phase ground fault;

[0066] Branch 4: connected to the backup power supply and operates normally;

[0067] Branch 5: with motor load, normal operation;

[0068] Branch 6: with transformer load, normal operation;

[0069] The small current grounding line selection device detects an abnormal zero-sequence current and preliminarily determines that branch 3 is a suspected fault branch, so branch 3 becomes the first initial branch. At the same time, the zero-sequence current of all branches is measured, and it is found that the zero-sequence current value of branch 3 is the largest, so branch 3 is confirmed as the second initial branch. Since the first initial branch (branch 3) and the second initial branch (branch 3) are consistent, it can be determined that branch 3 is the target branch, that is, the branch where the fault grounding occurs.

[0070] During the specific implementation process, when the above-mentioned type is the above-mentioned motor type, according to the above-mentioned type of the above-mentioned target branch, self-healing control of the above-mentioned ungrounded system of the power grid can be achieved through the following steps: when the above-mentioned branch where the i-th motor is located is the above-mentioned target branch, the first circuit breaker of the above-mentioned branch where the j-th motor is located is controlled to be closed, wherein i∈[1, N], j∈[N+1, M], N is the number of the above-mentioned motors that meet the process requirements, and M is the total number of the above-mentioned motors; when the first closing signal of the above-mentioned first circuit breaker of the above-mentioned branch where the j-th motor is located is obtained, the second circuit breaker of the above-mentioned branch where the i-th motor is located is controlled to be opened; when the first opening signal of the above-mentioned second circuit breaker of the above-mentioned branch where the i-th motor is located is obtained, it is determined that the above-mentioned branch where the i-th motor is located has been isolated.

[0071] In this scheme, when a branch (the branch where the i-th motor is located) is determined to be the target branch where a ground fault occurs, automatic ground fault isolation is achieved by controlling the first circuit breaker of the standby motor branch (the branch where the j-th motor is located) and the second circuit breaker of the faulty motor branch, thereby ensuring the continuous power supply capability of the power grid in the event of a fault, reducing the impact of the fault on the operation of the power grid, and improving the reliability and safety of the power grid.

[0072] Specifically, the above-mentioned scheme of the present application, when it is determined that the grounding interval is the motor interval, the standby motor circuit breaker is automatically closed through the preset standby motor interlocking condition. When the standby motor circuit breaker is detected to be in the closed position, the circuit breaker for disconnecting the grounded motor interval is automatically issued, which solves the problem that when a motor grounding fault occurs, the electrical operation personnel need to contact the process personnel, and the process personnel start the standby pump through the DCS system and then cut off the grounding interval. The method involves a long time, easy to cause two-phase short circuit and tripping, and other risks.

[0073] Specifically, Figure 3 As shown in the figure, the removal process and logical judgment of the grounding interval as the motor interval are explained. If a certain type of motor is designed with a total of M units, and N units of this type of motor need to run simultaneously to meet the process conditions (N<M), MN motors are used as spare motors. When the ungrounded system of the power grid detects that the identification code of the grounding interval is MOTOR, and the specific interval is motor i (i∈[1,N]), it will send a signal to close a spare motor ii circuit breaker of this type of motor (ii∈[N+1,M]); when it is detected that the spare motor ii circuit breaker is closed, it is determined that the spare motor has been put into operation, and then the grounding motor i (i∈[1,N]) circuit breaker is disconnected. When the position signal of the motor i (i∈[1,N]) circuit breaker of the grounding interval is detected, it is confirmed that the grounding interval has been removed. When the collected bus three-phase voltage returns to normal value, it can be determined that the grounding branch line selection is correct and the fault has been removed; if the bus three-phase voltage does not return to normal, the system will remove them one by one according to the predetermined sequence of removing feeder branches.

[0074] Specifically, when the system detects that the branch where the i-th motor is located is the target branch of the fault grounding. The system automatically controls the first circuit breaker of the branch where the j-th motor is located to close. Here, the j-th motor is one of the backup motors and is located in the motor sequence from N+1 to M. N represents the number of motors that must be operated to meet the process requirements, and M represents the total number of motors, which means that the j-th motor belongs to the sequence of backup motors that are not put into operation. By closing the first circuit breaker of the backup motor branch, the system can connect the backup motor to the power grid to compensate for the impact of the faulty motor branch on the load demand of the power grid after it is out of operation, and ensure the continuous power supply of the power grid.

[0075] Specifically, after obtaining the closing signal of the first circuit breaker of the backup motor branch (the first circuit breaker of the branch where the j-th motor is located) to confirm that the backup motor has been connected to the system. The system automatically controls the second circuit breaker of the faulty motor branch (the branch where the i-th motor is located) to disconnect, that is, the faulty motor is isolated from the power grid. By disconnecting the second circuit breaker of the faulty motor branch, it can be ensured that the faulty motor no longer obtains power from the power grid, thereby avoiding further deterioration of the fault and reducing the impact on the overall operation of the power grid.

[0076] Specifically, after obtaining the position signal of the second circuit breaker of the faulty motor branch (the second circuit breaker of the branch where the i-th motor is located), it is confirmed that the faulty motor branch has been isolated from the power grid by detecting the position signal of the second circuit breaker. Confirming the isolation status of the faulty motor branch is a key step in the system recovery process. It ensures that the faulty motor no longer affects the normal operation of the power grid and provides a safe environment for subsequent system recovery and fault repair.

[0077] After the faulty motor branch is isolated, the system will monitor the operating status of the power grid, such as whether the bus voltage has returned to normal. If the bus voltage returns to normal, the system will display the message "Correct line selection, faulty branch has been removed"; if the bus voltage has not recovered, the system will remove other branches one by one in a predetermined order until a new fault point is found and isolated, ensuring that the overall stability of the power grid and the quality of power supply are not affected.

[0078] For example, in an ungrounded grid system, there are 10 motors used to support a critical industrial production process (M = 10). Under normal operation, 6 motors (N = 6) are required to meet the process requirements, while the remaining 4 motors (j∈[7, 10]) are in standby mode to cope with load requirements in emergencies or failures.

[0079] The system detects that the branch where the third motor (i=3) is located has a ground fault and the zero-sequence current increases significantly, and identifies the branch where the third motor is located as the target branch.

[0080] The system automatically controls the first circuit breaker of the branch where the seventh standby motor (j=7) is located to close. This step ensures that even if the third motor is out of operation, the system load can still be met to maintain the continuity of the industrial production process.

[0081] When receiving the closing signal of the first circuit breaker of the branch of the seventh standby motor, the system immediately controls the second circuit breaker of the branch where the third motor is located to open, isolating the faulty motor from the power grid.

[0082] The system detects the trip signal of the second circuit breaker of the third motor branch and confirms that the faulty motor branch has been isolated. At this time, the system displays "the faulty branch has been isolated and the line selection is correct."

[0083] The system detects whether the bus voltage has returned to normal. If it has, the system enters normal operation; if it has not, the system will detect and switch other branches in a predetermined order until the grid returns to normal operation.

[0084] During the specific implementation process, before controlling the closing of the first circuit breaker of the branch where the j-th motor is located, the method also includes the following steps: obtaining the current state of the j-th motor; when the current state of the j-th motor is a maintenance state, deleting the j-th motor from the standby motor sequence, wherein the standby motor sequence is a MN sequence.

[0085] In this scheme, if the current state of the motor is in the maintenance state, the backup motor sequence can be updated to ensure that the system selects the most suitable backup motor to deal with the fault, while avoiding selecting a motor in an unavailable state into the backup sequence.

[0086] Specifically, this solution can also determine whether the motor is in maintenance state. If it is in maintenance state, the system will not send out the sequence to use it as a standby motor. After the system detects that a branch motor has a fault (grounding), as part of the self-healing control, the system needs to understand the status of all standby motors to determine whether they can be used as replacements. The current status usually includes operating status, standby status, maintenance status, etc. The maintenance status means that the motor is currently undergoing maintenance or repair and cannot be put into use immediately.

[0087] When the system confirms that the jth motor (one of the backup motor sequence) is currently under maintenance, it will no longer be considered a viable backup motor. The system will remove the jth motor from the backup motor sequence to avoid selecting this motor that cannot be put into operation immediately during the self-healing control process, which helps improve the efficiency and reliability of fault recovery.

[0088] The spare motor sequence initially contains all motors that are not in operation (sequence of MN), where M is the total number of motors and N is the number of motors currently operating to meet process demand. After removing the motors under maintenance, the sequence will only contain motors that are in spare state and available, ensuring that the self-healing control method is more accurate and efficient in selecting spare motors.

[0089] In some embodiments, when the above-mentioned type is the above-mentioned power supply type, according to the above-mentioned type of the above-mentioned target branch, self-healing control is performed on the above-mentioned ungrounded system of the power grid, which can be specifically achieved through the following steps: when the above-mentioned branch where the above-mentioned transformer is located is the above-mentioned target branch, the third circuit breaker connected to the bus is controlled to be closed; when the second closing signal of the above-mentioned third circuit breaker connected to the above-mentioned bus is obtained, the fourth circuit breaker connected to the above-mentioned transformer is controlled to be opened; when the second opening signal of the above-mentioned fourth circuit breaker connected to the above-mentioned transformer is obtained, it is determined that the above-mentioned branch where the above-mentioned transformer is located has been isolated.

[0090] In this solution, in an ungrounded power grid system, when a transformer in a branch is identified as a target transformer with a ground fault, the relevant circuit breakers can be automatically operated to isolate the fault and maintain the continuity and stability of the power grid operation.

[0091] Specifically, Figure 4 As shown, the removal process and logical judgment of the grounding interval as a power supply interval are explained, and the situation where transformer A and transformer B are in separate operation state (5151, 5251, 401, 402 circuit breakers are closed, and 41200 circuit breaker is open) is given priority. When the ungrounded system of the power grid detects that the identification code of the grounding interval is POWER and the grounding interval is transformer 5151, it issues an instruction to close the bus tie 41200 circuit breaker, and connects to the closing circuit of the bus tie 41200 circuit breaker through a certain exit, closes the bus tie 41200 circuit breaker, and after collecting the closing signal of the bus tie 41200 circuit breaker, it issues the 401 incoming line circuit breaker and the 5151 feeder circuit breaker. After collecting the opening signals of the 401 incoming line circuit breaker and the 5151 feeder circuit breaker, it determines that the grounding interval has been cut off. When the collected three-phase voltage of the bus returns to normal, it can be determined that the grounding branch line selection is correct and the fault has been cut off. If the three-phase voltage of the bus has not recovered correctly, the system will cut off the feeder branches one by one according to the predetermined sequence of cutting off the feeder branches.

[0092] Specifically, when the system detects and confirms that the branch (transformer branch) where the target transformer is located has a fault, the self-healing control system will first control the third circuit breaker (also known as the bus tie circuit breaker or tie circuit breaker) connected to the bus to close. The purpose of this action is to ensure the connection between the main power grid and the backup or adjacent power grid. By closing the bus tie circuit breaker, the backup or adjacent power grid can temporarily support the load of the power grid where the faulty transformer is located, avoid load interruption, and maintain the continuity of power grid operation.

[0093] Specifically, after the third circuit breaker is closed and receives the second closing signal, the system will control the fourth circuit breaker directly connected to the faulty transformer to open. The purpose of this operation is to completely isolate the faulty transformer from the power grid to prevent the fault from further affecting the stable operation of the power grid, while providing a safe environment for subsequent fault repair or replacement of the transformer.

[0094] Specifically, when the fourth circuit breaker is disconnected and receives the second position signal, the system will confirm that the branch where the faulty transformer is located has been successfully isolated. This is achieved through the signal feedback mechanism. By monitoring the position signal of the circuit breaker, the system can accurately determine whether the faulty branch has been safely isolated.

[0095] Specifically, during the fault isolation process, the operation sequence of the circuit breakers is crucial. First, the third circuit breaker connected to the busbar is closed to ensure that the load has temporary power support; then the fourth circuit breaker connected to the faulty transformer is disconnected to achieve fault isolation. This operation sequence ensures that the load demand of the power grid is met during the fault isolation process, improving the efficiency of self-healing control and the continuity of power grid operation.

[0096] Specifically, the self-healing control system can intelligently select a backup or adjacent grid to temporarily support the load of the grid where the faulty transformer is located based on the current grid status and load demand. The system automatically makes the best circuit breaker operation decision by analyzing the load demand and the connection structure of the grid to maintain the stable operation of the grid.

[0097] Specifically, after the faulty transformer branch is isolated, the self-healing control system will monitor whether the bus voltage returns to normal. If it returns to normal, the system will display "faulty branch has been isolated, line selection is correct" and enter normal operation; if it does not return to normal, the system will detect and switch other branches in a predetermined order until the bus voltage returns to normal.

[0098] Specifically, through the automatic control and signal feedback mechanism of the circuit breaker, the self-healing control system can not only quickly isolate the fault, but also ensure the accuracy of the circuit breaker operation, avoiding secondary faults or system paralysis that may be caused by human operating errors.

[0099] In some embodiments, when the above-mentioned type is the above-mentioned power supply type, the ungrounded system of the above-mentioned power grid is self-healing controlled according to the above-mentioned type of the above-mentioned target branch, which can be specifically achieved through the following steps: when the above-mentioned branch where the first transformer is located is the above-mentioned target branch, the fifth circuit breaker connected to the above-mentioned second transformer in the above-mentioned branch where the second transformer is located is controlled to be closed; when the third closing signal of the above-mentioned fifth circuit breaker connected to the above-mentioned second transformer is obtained, the sixth circuit breaker connected to the above-mentioned first transformer is controlled to be opened; when the third opening signal of the above-mentioned sixth circuit breaker connected to the above-mentioned first transformer is obtained, it is determined that the above-mentioned branch where the above-mentioned first transformer is located has been isolated.

[0100] In this solution, when it is detected that the branch where the first transformer is located is the target branch where a fault occurs, the self-healing control system automatically operates the relevant circuit breakers to isolate the faulty transformer and maintain the continuous operation of the power grid.

[0101] Specifically, Figure 4As shown, the following describes the situation where a single transformer operates with two load sections (circuit breakers 5151, 401, 41200 are closed, and circuit breakers 5251, 402 are open). When the ungrounded system of the power grid detects that the identification code of the grounding interval is POWER, and the grounding interval is transformer 5151, the system issues an instruction to close the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker, and is connected to the closing circuit of the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker through a certain exit, closes the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker, and after collecting the closing signals of the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker, it issues the instructions to divide the 401 incoming line circuit breaker and the 5151 feeder circuit breaker. After collecting the opening signals of the 401 incoming line circuit breaker and the 5151 feeder circuit breaker, it is determined that the grounding interval has been removed. When the collected three-phase voltage of the bus returns to normal, it can be determined that the grounding branch line selection is correct and the fault has been removed. If the three-phase voltage of the bus has not recovered correctly, the system will remove the feeder branches one by one according to the predetermined sequence of removing the feeder branches.

[0102] Specifically, when the system confirms that the branch where the first transformer is located is the fault target branch, it will automatically control the fifth circuit breaker connected to the second transformer in the branch where the second transformer is located to close. This usually occurs when the two transformers are running in parallel or load transfer is possible. By closing the fifth circuit breaker, the second transformer can be connected to the power grid to replace the load of the first transformer and ensure continuous power supply to the power grid.

[0103] Specifically, after the fifth circuit breaker is closed and receives the third closing signal, the system controls the sixth circuit breaker directly connected to the first faulty transformer to be disconnected. The purpose of this step is to completely isolate the faulty transformer from the power grid to prevent the fault from further deteriorating and affecting the stability of the power grid.

[0104] Specifically, when the sixth circuit breaker is disconnected and receives the third position signal, the system will confirm that the branch where the first transformer is located has been successfully isolated. Through the position signal feedback of the circuit breaker, the self-healing control system can accurately determine whether the faulty branch has been safely isolated, providing guarantee for subsequent system recovery and fault repair work.

[0105] Specifically, the self-healing control system has the function of automatically controlling the fifth circuit breaker to close according to the grid status and load demand, transferring the load of the second transformer to the grid to replace the first transformer. This automatic load transfer mechanism not only improves the grid's response speed to faults, but also ensures continuous power supply to the load, reducing the impact of faults on production or life.

[0106] Specifically, the order of circuit breaker operation is an important consideration in the fault isolation process. First, the fifth circuit breaker is closed to connect the second transformer in standby or parallel operation to the power grid, and then the sixth circuit breaker is opened to isolate the faulty transformer. This orderly operation avoids load interruption and also ensures the stability and safety of the power grid during the fault isolation process.

[0107] Specifically, the self-healing control system can monitor the status of the transformer in real time, including operating status, fault status, etc. After detecting the fault of the first transformer, the system can not only quickly isolate the fault, but also quickly make a load transfer decision for the second transformer through real-time status monitoring, thereby improving the intelligent level of power grid operation.

[0108] Specifically, the self-healing control system can intelligently select backup transformers or parallel-operating transformers for load transfer according to the real-time status and load demand of the power grid, ensuring that the power grid can quickly make adaptive responses in the face of various fault conditions and maintain stable operation of the power grid.

[0109] Specifically, the above scheme of the present application, when the grounding interval is determined to be a power supply interval, automatically sends a signal to close the corresponding bus tie circuit breaker, and when the bus tie circuit breaker is detected to be in the closed position, automatically sends a signal to disconnect the circuit breaker of the grounding power supply interval. This solves the problem that when a grounding fault occurs in the transmission power supply interval, the electrical operation personnel need to close the corresponding bus tie and then cut off the grounding interval, which involves a long time and is prone to cause two-phase short circuit and tripping.

[0110] Specifically, the solution of the present application ensures operational continuity while automatically cutting off the ground fault branch, thereby solving the problem of missed inspections and failure to timely detect and handle ground faults in traditional manual inspections.

[0111] More specifically, the power feeder circuit breaker and the corresponding lower-level incoming line circuit breaker are opened and closed in sequence. When the power feeder circuit breaker and the corresponding lower-level incoming line circuit breaker need to be closed, the power feeder circuit breaker is closed first. Only when the closing position signal of the power feeder circuit breaker is detected, can the corresponding lower-level incoming line circuit breaker be closed; when the power feeder circuit breaker and the corresponding lower-level incoming line circuit breaker need to be opened, the corresponding lower-level incoming line circuit breaker is opened first. Only when the opening position signal of the corresponding lower-level incoming line circuit breaker is detected, can the power feeder circuit breaker be opened.

[0112] More specifically, if the bus three-phase voltage is not restored correctly, the system cuts off the feeder branches one by one according to the predetermined order of cutting off the feeder branches. The predetermined order is feeder 1, feeder 2...feeder N, feeder 1 is cut off first, and when feeder 1 is cut off, it is executed in sequence.

[0113] More specifically, the self-healing control device for the ungrounded system of the power grid adopts the zero-sequence current value and the bus section PT opening voltage value of all intervals of the same voltage level of the ungrounded system.

[0114] More specifically, the signal input module of the self-healing control device of the ungrounded grid system obtains the circuit breaker closing position nodes of all intervals.

[0115] More specifically, the signal output module of the self-healing control device of the ungrounded power grid system is connected to the closing circuit and opening circuit of all interval circuit breakers through the opening outlet, and can control the closing and opening of the corresponding interval circuit breakers.

[0116] More specifically, the self-healing control device for the ungrounded power grid system can detect whether the standby motor is in a maintenance state. If a standby motor in a maintenance state is detected, the self-healing control device for the ungrounded power grid system randomly excludes the motor in the maintenance state from the standby motor closing command.

[0117] In some embodiments, after performing self-healing control on the ungrounded system of the power grid according to the type of the target branch, the method further includes the following steps: obtaining the three-phase voltage value of the bus; when the three-phase voltage value of the bus is within a normal range, determining that the fault has been eliminated; when the three-phase voltage value of the bus is not within a normal range, determining that the fault has not been eliminated.

[0118] In this scheme, the measured three-phase bus voltage value is compared with the preset normal range. If the three-phase voltage values ​​are all within the normal range, this indicates that the system's self-healing control operation after the fault (such as isolating the fault branch, load transfer, etc.) has been successful, and the fault has been removed, and the power grid has returned to normal operation. On the contrary, if one or more of the three-phase voltage values ​​are outside the normal range, this usually means that the fault has not been completely cleared and the system is still in an abnormal state. The monitoring and analysis of the three-phase bus voltage value is a key step in confirming the removal of the fault. Only when the voltage value returns to normal can the system be ensured to be restored to stability, avoid subsequent misoperation or unnecessary load switching, and provide a safe working environment for fault repair.

[0119] For example, the three-phase voltage values ​​of the busbar are obtained, which reflect the voltage status of the power grid in real time. Assume that the normal voltage range is 10.5kV±5%. If the three-phase voltage values ​​are all within the normal range (for example, all phase voltage values ​​are between 10kV and 11kV), it indicates that the fault isolation operation is effective, the fault has been removed, and the power grid has returned to normal operation.

[0120] If one or more of the three-phase voltage values ​​are outside the normal range, for example, one phase voltage is lower than 9.5kV or higher than 11.5kV, the system determines that the fault has not been completely eliminated and the power grid is still in an abnormal state.

[0121] Specifically, the above-mentioned scheme of the present application obtains the zero-sequence current of all feeder branches of the bus of the voltage level and the bus PT opening voltage as the starting criteria; adopts the line selection principle of the traditional small current line selection device, and combines the size of the zero-sequence current value of all feeders as the criterion for determining the grounding branch, and determines that the interval with the largest zero-sequence current value is the grounding interval; when the type of the grounding branch interval is identified as a power supply interval (POWER), the control system automatically sends a signal to close the upper and lower bus tie circuit breakers. When it is detected that the lower bus tie circuit breaker is closed, the control system automatically sends a signal to open the circuit breaker of the grounding branch interval. ; When the type of the grounding branch interval is identified as a motor interval (MOTOR), the standby motor circuit breaker is automatically closed through the preset standby motor interlocking condition. When the standby motor circuit breaker is detected to be in the closed position, the circuit breaker for disconnecting the grounding motor interval is automatically issued; after the grounding branch is removed, the system detects whether the phase voltage of each phase of the bus has returned to normal. If it has returned to normal, the system displays "the line selection is correct, and the faulty branch has been removed"; if it has not returned to normal, the control system removes the feeder branches one by one according to the predetermined removal order until the phase voltage of each phase of the system bus returns to normal. This method solves the problem of automatically removing the grounding branch interval on the basis of ensuring the continuity of the power supply system.

[0122] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the self-healing control method for an ungrounded power grid system of the present application will be described in detail below in combination with specific embodiments.

[0123] This embodiment relates to a specific self-healing control method for an ungrounded power grid system. Figure 5 As shown, the following steps are included:

[0124] Step S1: Obtain the zero-sequence current of all feeder branches of the bus of the voltage level and the bus PT opening voltage as the starting criterion;

[0125] Step S2: adopting the line selection principle of the traditional small current line selection device, and combining the magnitude of the zero-sequence current values ​​of all feeders as a criterion for determining the grounded branch, determining that the interval with the largest zero-sequence current value is the grounded interval;

[0126] Step S3: When the type of the grounding branch interval is identified as a power supply interval (POWER), the control system automatically sends a signal to close the upper and lower bus tie circuit breakers. When the lower bus tie circuit breaker is detected to be closed, the control system automatically sends a signal to disconnect the grounding branch interval. When the type of the grounding branch interval is identified as a motor interval (MOTOR), the standby motor circuit breaker is automatically closed according to the preset standby motor interlocking condition. When the standby motor circuit breaker is detected to be in the closed position, the control system automatically sends a signal to disconnect the grounding motor interval.

[0127] Step S4: After the grounding branch is removed, the system detects whether the phase voltage of each phase of the bus returns to normal. If it returns to normal, the system displays "The line selection is correct and the faulty branch has been removed"; if it does not return to normal, the control system removes the feeder branches one by one in a predetermined removal order until the phase voltage of each phase of the system bus returns to normal.

[0128] The self-healing control system includes a self-healing control device for an ungrounded grid system, such as Figure 6 As shown, the device includes: a CPU module 11, a liquid crystal display module 12, a key module 13, a current acquisition module 14, a voltage acquisition module 15, a signal input module 16, a signal output module 17 and a power supply module 18.

[0129] The CPU module 11 is a processor for data conversion, logic judgment and driver programs of other modules, and is the core of the ungrounded system self-healing control device;

[0130] The above-mentioned liquid crystal display module 12 is used to display the zero-sequence current of all intervals, the bus PT open delta voltage and the ground fault alarm, etc., and the various display interfaces can be switched through the key module 13. The ground fault alarm function has the function of accurately reporting which specific interval has a ground fault, storing historical ground fault alarm information, and displaying various parameter setting interfaces;

[0131] The current acquisition module 14 is used to acquire the zero-sequence current value of each interval;

[0132] The voltage acquisition module 15 is used to collect the open triangle voltage value of each bus PT and the three-phase voltage of each bus;

[0133] The signal input module 16 is used to collect the circuit breaker opening and closing position signals of each interval;

[0134] The signal output module 17 is used to close or open the circuit breakers of each bay (including motor, power supply bay and busbar bay);

[0135] The power module 18 provides power to other modules.

[0136] Specific as Figure 7 As shown, the specific steps include:

[0137] S10: The present invention proposes a self-healing control device and control system for an ungrounded power grid system to collect zero-sequence current values ​​of each feeder branch and the busbar section PT open triangle voltage value, and select the grounding interval branch Ni using a traditional small current grounding line selection device;

[0138] S20: The control system and the control device determine the feeder branch interval Mi with the largest zero-line current value of all collected feeder branches;

[0139] S30: Compare Ni and Mi to see if they are consistent. If they are consistent, execute step S40; if they are inconsistent, execute S41;

[0140] S40: Determine that the grounding branch is a Ni interval;

[0141] S41: Determine that the grounding branch is Mi interval;

[0142] S50: Determine whether the grounding branch interval Ni (or Mi) is a power supply interval. If it is a power supply interval (identification code: POWER), execute step S60; if it is a motor interval (identification code: MOTOR), execute step S61;

[0143] S60: The control system issues a signal to close the upper and lower bus tie circuit breakers through the signal output module 17;

[0144] S61: The control system issues a signal to close the standby motor compartment circuit breaker through the signal output module 17;

[0145] S70: The control system collects the closing signal of the lower circuit breaker through the signal input module 16. After the closing signal is in place, S80 is executed;

[0146] S71: The control system collects the closing signal of the standby motor bay circuit breaker through the signal input module 16. After the closing signal is in place, S81 is executed;

[0147] S80: The control system issues a signal to disconnect the ground power supply type interval circuit breaker through the signal output module 17;

[0148] S81: The control system sends a signal to disconnect the grounded motor circuit breaker through the signal output module 17;

[0149] S90: The control system collects the position signal of the grounding power supply type interval circuit breaker through the signal input module 16. After the position signal is in place, S100 is executed;

[0150] S91: The control system collects the grounding motor bay circuit breaker position signal through the signal input module 16. After the position signal is in place, S100 is executed;

[0151] S100: The control system detects whether the phase voltage of each phase of the system bus voltage returns to normal. If the voltage returns to normal, step S110 is executed to send a "line selection is correct, the fault has been removed" signal; if the voltage does not return to normal, step S111 is executed.

[0152] S111: according to the preset switching sequence, the feeder branches are cut off one by one, and the cutting step of each feeder branch needs to be executed according to the steps S50-S100 until the phase voltage of each phase of the bus returns to normal.

[0153] Combination Figure 7 and Figure 3 , the removal process and logical judgment of the grounding interval as the motor interval are explained. If a certain type of motor is designed with a total of M units, and N units of this type of motor need to run simultaneously to meet the process conditions (N<M), MN motors are used as backup motors. When the self-healing control system of the ungrounded power grid system detects that the identification code of the grounding interval is MOTOR, and the specific interval is motor i (i∈[1,N]), the self-healing control device will send a signal to close a backup motor ii circuit breaker of this type of motor (ii∈[N+1,M]); when the self-healing control device detects that the backup motor ii circuit breaker is closed through the signal input module (the signal input module takes the backup motor circuit breaker closing position node), it is determined that the backup motor has been put into operation, and then sends a signal to disconnect the grounding motor i (i∈[1,N]) circuit breaker. When the self-healing control device detects the grounding interval motor i (i∈[1,N]) circuit breaker opening signal through the signal input module, it is confirmed that the grounding interval has been removed. When the three-phase bus voltage collected by the self-healing control device through the voltage collection module 15 returns to normal value, it can be determined that the grounding branch line selection is correct and the fault has been removed; if the three-phase bus voltage has not recovered correctly, the system will remove the feeder branches one by one according to the predetermined removal order.

[0154] To explain further, the system can also determine whether the motor is in maintenance status. If it is in maintenance status, the system will not send a sequence to use it as a backup motor.

[0155] Combination Figure 7 and Figure 4 , the removal process and logical judgment of the grounding interval as a power supply interval are explained, and priority is given to the situation where transformer A and transformer B are in separate operation status (5151, 5251, 401, 402 circuit breakers are closed, and 41200 circuit breaker is open). When the self-healing control system of the ungrounded power grid system detects that the identification code of the grounding interval is POWER, and the grounding interval is transformer 5151, the system issues an instruction to close the bus tie 41200 circuit breaker, and is connected to the closing circuit of the bus tie 41200 circuit breaker through a certain outlet of the signal output module 17, and closes the bus tie 41200 circuit breaker. After the system signal input module 16 collects the closing signal of the bus tie 41200 circuit breaker, it sends out the 401 incoming line circuit breaker and the 5151 feeder circuit breaker. After the opening signals of the 401 incoming line circuit breaker and the 5151 feeder circuit breaker are collected through the signal input module 16, it is determined that the grounding interval has been cut off. When the three-phase voltage of the bus collected by the self-healing control device through the voltage collection module 15 returns to normal, it can be determined that the grounding branch line selection is correct and the fault has been cut off; if the three-phase voltage of the bus has not recovered correctly, the system cuts off the feeder branches one by one according to the predetermined sequence of cutting off the feeder branches.

[0156] Next, the case where a single transformer is running with two load sections (circuit breakers 5151, 401, and 41200 are closed, and circuit breakers 5251 and 402 are open) is described. When the self-healing control system of the ungrounded power grid system detects that the identification code of the grounding interval is POWER, and the grounding interval is transformer 5151, the system issues a command to close the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker, and connects to the closing circuit of the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker through a certain outlet of the signal output module 17, and closes the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker. When the system signal input module 16 collects the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker, the system generates a command to close the bus tie 5251 circuit breaker and the incoming line 402 circuit breaker. After the closing signal is received, the 401 incoming line circuit breaker and the 5151 feeder circuit breaker are issued. After the opening signals of the 401 incoming line circuit breaker and the 5151 feeder circuit breaker are collected through the signal input module 16, it is determined that the grounding interval has been removed. When the three-phase voltage of the bus collected by the self-healing control device through the voltage collection module 15 returns to normal, it can be determined that the grounding branch line selection is correct and the fault has been removed; if the three-phase voltage of the bus has not recovered correctly, the system will remove the feeder branches one by one according to the predetermined sequence of removing the feeder branches.

[0157] The embodiment of the present application also provides a self-healing control device for an ungrounded power grid system. It should be noted that the self-healing control device for an ungrounded power grid system in the embodiment of the present application can be used to execute the self-healing control method for an ungrounded power grid system provided in the embodiment of the present application. The device is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware for a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0158] The following is an introduction to the self-healing control device for an ungrounded power grid system provided in an embodiment of the present application.

[0159] Figure 8 1 is a structural block diagram of a self-healing control device for an ungrounded power grid system according to an embodiment of the present application. Figure 8 As shown, the device comprises:

[0160] A selection unit 100 is used to select a target branch from an ungrounded power grid system, wherein the ungrounded power grid system includes multiple branches, and the target branch is a branch that has a ground fault among the multiple branches;

[0161] A first acquisition unit 200 is used to acquire the type of the target branch, wherein the type includes a power supply type and a motor type. The power supply type is the branch connecting the power supply and the transformer, and the motor type is the branch connecting the motor. The branch and the type correspond to each other one by one.

[0162] The control unit 300 is used to perform self-healing control on the ungrounded power grid system according to the type of the target branch, wherein the self-healing control is to isolate the faulty target branch from the ungrounded power grid system.

[0163] Through this embodiment, when a grounding fault occurs in an ungrounded power grid system, the faulty branch can be automatically selected to ensure operation continuity. At the same time, the grounding fault branch can be automatically cut off and isolated without manual processing, avoiding delays and misoperations caused by manual intervention, and improving the efficiency and accuracy of fault recovery.

[0164] In the specific implementation process, the selection unit includes a first acquisition module, a second acquisition module, a first determination module and a second determination module. The first acquisition module is used to acquire the first initial branch, wherein the first initial branch is a fault branch selected from all the above branches by using a small current grounding line selection device; the second acquisition module is used to acquire the second initial branch, wherein the second initial branch is the branch with the largest zero-sequence current value among all the above branches; the first determination module is used to determine that the first initial branch is the target branch when the first initial branch and the second initial branch are the same; the second determination module is used to determine that the second initial branch is the target branch when the first initial branch and the second initial branch are not the same.

[0165] In this scheme, the two links of small current line selection principle and zero-sequence current value comparison are combined. Through cross-validation of the two, the accuracy and reliability of target fault branch identification are further improved, thereby enabling more efficient and accurate fault detection.

[0166] During the specific implementation process, when the above type is the above-mentioned motor type, the control unit includes a first control module, a second control module and a first determination module. The first control module is used to control the closing of the first circuit breaker of the branch where the j-th motor is located when the branch where the i-th motor is located is the above-mentioned target branch, wherein i∈[1, N], j∈[N+1, M], N is the number of the above-mentioned motors that meet the process requirements, and M is the total number of the above-mentioned motors; the second control module is used to control the opening of the second circuit breaker of the branch where the i-th motor is located when the first closing signal of the above-mentioned first circuit breaker of the branch where the j-th motor is located is obtained; the first determination module is used to determine that the branch where the i-th motor is located has been isolated when the first opening signal of the above-mentioned second circuit breaker of the branch where the i-th motor is located is obtained.

[0167] In this scheme, when a branch (the branch where the i-th motor is located) is determined to be the target branch where a ground fault occurs, automatic ground fault isolation is achieved by controlling the first circuit breaker of the standby motor branch (the branch where the j-th motor is located) and the second circuit breaker of the faulty motor branch, thereby ensuring the continuous power supply capability of the power grid in the event of a fault, reducing the impact of the fault on the operation of the power grid, and improving the reliability and safety of the power grid.

[0168] During the specific implementation process, the above-mentioned device also includes a second acquisition unit and a deletion unit. The second acquisition unit is used to obtain the current state of the j-th motor before controlling the closing of the first circuit breaker of the branch where the j-th motor is located; the deletion unit is used to delete the j-th motor from the standby motor sequence when the current state of the j-th motor is a maintenance state, wherein the standby motor sequence is a MN sequence.

[0169] In this scheme, if the current state of the motor is in the maintenance state, the backup motor sequence can be updated to ensure that the system selects the most suitable backup motor to deal with the fault, while avoiding selecting a motor in an unavailable state into the backup sequence.

[0170] In some embodiments, when the above type is the above power supply type, the control unit includes a third control module, a fourth control module and a second determination module, the third control module being used to control the closing of the third circuit breaker connected to the bus when the above branch where the above transformer is located is the above target branch; the fourth control module being used to control the opening of the fourth circuit breaker connected to the transformer when a second closing signal of the above third circuit breaker connected to the above bus is obtained; the second determination module being used to determine that the above branch where the above transformer is located has been isolated when a second opening signal of the above fourth circuit breaker connected to the above transformer is obtained.

[0171] In this solution, in an ungrounded power grid system, when a transformer in a branch is identified as a target transformer with a ground fault, the relevant circuit breakers can be automatically operated to isolate the fault and maintain the continuity and stability of the power grid operation.

[0172] In some embodiments, when the above type is the above power supply type, the control unit includes a fifth control module, a sixth control module and a third determination module. The fifth control module is used to control the fifth circuit breaker connected to the second transformer in the branch where the second transformer is located to close when the branch where the first transformer is located is the target branch; the sixth control module is used to control the sixth circuit breaker connected to the first transformer to open when a third closing signal of the fifth circuit breaker connected to the second transformer is obtained; the third determination module is used to determine that the branch where the first transformer is located has been isolated when a third opening signal of the sixth circuit breaker connected to the first transformer is obtained.

[0173] In this solution, when it is detected that the branch where the first transformer is located is the target branch where a fault occurs, the self-healing control system automatically operates the relevant circuit breakers to isolate the faulty transformer and maintain the continuous operation of the power grid.

[0174] In some embodiments, the above-mentioned device also includes a third acquisition unit, a first determination unit and a second determination unit. The third acquisition unit is used to obtain the bus three-phase voltage value after performing self-healing control on the above-mentioned ungrounded system of the power grid according to the above-mentioned type of the above-mentioned target branch; the first determination unit is used to determine that the fault has been eliminated when the above-mentioned bus three-phase voltage value is within a normal range; the second determination unit is used to determine that the fault has not been eliminated when the above-mentioned bus three-phase voltage value is not within the normal range.

[0175] In this scheme, the measured three-phase bus voltage value is compared with the preset normal range. If the three-phase voltage values ​​are all within the normal range, this indicates that the system's self-healing control operation after the fault (such as isolating the fault branch, load transfer, etc.) has been successful, and the fault has been removed, and the power grid has returned to normal operation. On the contrary, if one or more of the three-phase voltage values ​​are outside the normal range, this usually means that the fault has not been completely cleared and the system is still in an abnormal state. The monitoring and analysis of the three-phase bus voltage value is a key step in confirming the removal of the fault. Only when the voltage value returns to normal can the system be ensured to be restored to stability, avoid subsequent misoperation or unnecessary load switching, and provide a safe working environment for fault repair.

[0176] The self-healing control device for the ungrounded power grid system includes a processor and a memory. The selection unit, the first acquisition unit, the control unit, etc. are all stored in the memory as program units, and the processor executes the program units stored in the memory to implement corresponding functions. The modules are all located in the same processor; or, the modules are located in different processors in any combination.

[0177] The processor includes a kernel, which retrieves the corresponding program unit from the memory. One or more kernels can be set, and the problem that the manual processing method in the prior art cannot handle the fault in time when a single-phase grounding occurs in an ungrounded power grid system by adjusting kernel parameters is solved.

[0178] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0179] An embodiment of the present invention provides a computer-readable storage medium, which includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute the self-healing control method for the ungrounded power grid system.

[0180] An embodiment of the present invention provides a processor, and the processor is used to run a program, wherein the self-healing control method of the ungrounded power grid system is executed when the program is run.

[0181] An embodiment of the present invention provides a device, the device includes a processor, a memory, and a program stored in the memory and executable on the processor, and when the processor executes the program, at least the steps of the self-healing control method for an ungrounded power grid system are implemented. The device in this article can be a server, a PC, a PAD, a mobile phone, etc.

[0182] A computer program product includes a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the self-healing control method for the ungrounded power grid system in each embodiment of the present application are implemented.

[0183] The present application also provides a self-healing control system, comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include a method for executing any one of the above-mentioned self-healing control methods for the ungrounded power grid system.

[0184] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0185] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0186] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0187] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0188] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0189] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0190] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0191] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0192] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0193] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0194] 1) The self-healing control method for an ungrounded power grid system of the present application can automatically select a faulty branch when a grounding fault occurs in the ungrounded power grid system, thereby ensuring operation continuity and automatically cutting off and isolating the grounding fault branch without manual processing, thereby avoiding delays and misoperations caused by manual intervention and improving the efficiency and accuracy of fault recovery.

[0195] 2) The self-healing control device of the ungrounded power grid system of the present application can automatically select the faulty branch when a grounding fault occurs in the ungrounded power grid system, ensuring the continuity of operation, and can also automatically cut off and isolate the grounding fault branch without manual processing, thereby avoiding delays and misoperations caused by manual intervention and improving the efficiency and accuracy of fault recovery.

[0196] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A self-healing control method for an ungrounded power grid system, characterized in that: include: Selecting a target branch from an ungrounded power grid system, wherein the ungrounded power grid system includes multiple branches, and the target branch is a branch that has a ground fault among the multiple branches; Obtaining the type of the target branch, wherein the type includes a power supply type and a motor type, the power supply type is the branch connecting the power supply and the transformer, the motor type is the branch connecting the motor, and the branch and the type correspond one to one; According to the type of the target branch, self-healing control is performed on the ungrounded power grid system, wherein the self-healing control is to isolate the faulty target branch from the ungrounded power grid system.

2. The method according to claim 1, characterized in that Select the target branch from the ungrounded power grid system, including: Acquire a first initial branch, wherein the first initial branch is a fault branch selected from all the branches by using a small current grounding line selection device; Acquire a second initial branch, wherein the second initial branch is the branch with the largest zero-sequence current value among all the branches; In a case where the first initial branch and the second initial branch are the same, determining the first initial branch as the target branch; In a case where the first initial branch and the second initial branch are different, the second initial branch is determined to be the target branch.

3. The method according to claim 1, characterized in that In the case where the type is the motor type, self-healing control is performed on the ungrounded grid system according to the type of the target branch, including: When the branch where the i-th motor is located is the target branch, control the first circuit breaker of the branch where the j-th motor is located to close, wherein i∈[1,N], j∈[N+1,M], N is the number of the motors that meet the process requirements, and M is the total number of the motors; When a first closing signal of the first circuit breaker of the branch where the j-th motor is located is obtained, the second circuit breaker of the branch where the i-th motor is located is controlled to be opened; When the first trip signal of the second circuit breaker of the branch where the i-th motor is located is obtained, it is determined that the branch where the i-th motor is located has been isolated.

4. The method according to claim 3, characterized in that Before controlling the first circuit breaker of the branch where the j-th motor is located to close, the method further comprises: Obtaining the current state of the j-th motor; When the current state of the j-th motor is the maintenance state, the j-th motor is deleted from the spare motor sequence, wherein the spare motor sequence is the sequence of MN.

5. The method according to claim 1, characterized in that In the case where the type is the power supply type, performing self-healing control on the ungrounded system of the power grid according to the type of the target branch includes: When the branch where the transformer is located is the target branch, controlling a third circuit breaker connected to the busbar to close; When a second closing signal of the third circuit breaker connected to the bus is obtained, controlling the fourth circuit breaker connected to the transformer to be opened; When a second trip signal of the fourth circuit breaker connected to the transformer is obtained, it is determined that the branch where the transformer is located has been isolated.

6. The method according to claim 1, characterized in that In the case where the type is the power supply type, performing self-healing control on the ungrounded system of the power grid according to the type of the target branch includes: When the branch where the first transformer is located is the target branch, controlling a fifth circuit breaker in the branch where the second transformer is located and connected to the second transformer to close; When a third closing signal of the fifth circuit breaker connected to the second transformer is obtained, controlling the sixth circuit breaker connected to the first transformer to be opened; When the third trip signal of the sixth circuit breaker connected to the first transformer is obtained, it is determined that the branch where the first transformer is located has been isolated.

7. The method according to any one of claims 1 to 6, characterized in that After performing self-healing control on the ungrounded power grid system according to the type of the target branch, the method further includes: Get the bus three-phase voltage value; When the bus three-phase voltage value is within a normal range, determining that the fault has been cleared; When the bus three-phase voltage value is not within the normal range, it is determined that the fault has not been cleared.

8. A self-healing control device for an ungrounded power grid system, characterized in that: include: A selection unit, configured to select a target branch from an ungrounded power grid system, wherein the ungrounded power grid system includes a plurality of branches, and the target branch is a branch in which a fault grounding occurs among the plurality of branches; A first acquisition unit is used to acquire the type of the target branch, wherein the type includes a power supply type and a motor type, the power supply type is the branch connecting the power supply and the transformer, the motor type is the branch connecting the motor, and the branch and the type correspond one to one; A control unit is used to perform self-healing control on the ungrounded power grid system according to the type of the target branch, wherein the self-healing control is to isolate the faulty target branch from the ungrounded power grid system.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the self-healing control method for an ungrounded power grid system according to any one of claims 1 to 7 are implemented.

10. A self-healing control system, characterized in that: include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include a method for executing the self-healing control method of the ungrounded power grid system as described in any one of claims 1 to 7.

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