Flexible direct current fault processing method, device and equipment for maintaining power transmission, storage medium and computer program product

Abstract

The invention relates to a flexible direct-current fault processing method and device for maintaining power transmission, equipment, a storage medium and a computer program product, and the method comprises the steps: controlling the voltage of a power transmission end and the voltage of a power receiving end in a direct-current control and protection system to be first preset voltages when the direct-current control and protection system detects a fault of a line; and controlling the current of the power transmitting end and the current of the power receiving end to be first preset current so as to eliminate the fault, and after a preset time period after the fault is eliminated, controlling the voltage of the power transmitting end to recover to the original initial voltage of the power transmitting end and controlling the voltage of the power receiving end to recover to the original initial voltage of the power receiving end, and stopping controlling the current of the power transmitting end and the current of the power receiving end. According to the method, when the line has the grounding fault, the resistance value of the grounding line is large, so that the current flowing through the branch where the line fault point is located can be zero by setting the current and the voltage of the power transmitting end and the power receiving end to be the same value, and the line fault point is forced to extinguish arc to eliminate the fault.

Description

Technical Field

[0001] The present application relates to the field of flexible direct current power transmission, and in particular to a flexible direct current fault processing method, device, equipment, storage medium and computer program product for maintaining power delivery. Background Art

[0002] In the scenario of large-scale new energy transmission over long distances via flexible direct current, due to the weak overvoltage and overcurrent capabilities of the capacitors in the flexible direct current converter valve submodules and the large amount of energy stored in the long-distance transmission lines, if a DC line fails, the DC will be unable to maintain power transmission, and a power surplus will appear on the AC side at the sending end. The flexible direct current converter valve will also suffer from serious overvoltage problems, which may lead to large-scale disconnection of new energy at the sending end and damage to the power components of the flexible direct current converter valve.

[0003] DC fault ride-through refers to the process in which the DC transmission system can take certain measures to quickly isolate the fault and maintain or quickly recover to normal operation when a DC fault occurs in the DC transmission system. In order to prevent DC line faults from causing serious consequences in the scenario of large-scale new energy long-distance transmission via flexible direct current, research on fault ride-through strategies for DC line faults is of great significance to the safe and stable operation of DC transmission systems.

[0004] At present, the flexible DC fault ride-through strategy is mainly based on the topological structure of the full-bridge sub-module (FBSM) in the full-half-bridge hybrid converter valve. After a DC line fault occurs, the converter valve uses the negative pressure operation capability of the full-bridge sub-module to achieve non-lockout fault clearing. However, during the fault clearing process, the flexible DC controls the DC side voltage to zero or a small negative pressure, resulting in active power transmission interruption, and there is a problem that the power surplus problem on the AC side of the sending end and the overvoltage problem of the converter valve sub-module cannot be alleviated. Summary of the invention

[0005] Based on this, it is necessary to provide a flexible DC fault handling method, device, equipment, storage medium and computer program product that can maintain power delivery and alleviate the power surplus problem on the sending end AC side and the overvoltage problem of the converter valve submodule in order to address the above technical problems.

[0006] In a first aspect, the present application provides a flexible direct current fault processing method for maintaining power delivery, the method comprising:

[0007] When the DC control and protection system detects a line fault, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be a first preset voltage, and the current at the power transmission end and the current at the power receiving end are controlled to be a first preset current, so as to eliminate the fault; the first preset current is greater than a preset current threshold;

[0008] After a preset period of time after the fault is eliminated, the voltage of the power transmitting end is controlled to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is controlled to be restored to the original initial voltage of the power receiving end, and the current of the power transmitting end and the current of the power receiving end are stopped.

[0009] In one embodiment, controlling the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system to be a first preset voltage includes:

[0010] Obtain fault line information in the DC control and protection system when a line fault occurs;

[0011] According to the fault line information and the expected line information, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be the first preset voltage.

[0012] In one embodiment, controlling the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system to be a first preset voltage according to the fault line information and the expected line information includes:

[0013] Determine a first quantity and a second quantity according to the fault line information and the expected line information;

[0014] A first number of voltage submodules in the power transmitting end are controlled to be withdrawn, and a second number of voltage submodules in the power receiving end are controlled to be withdrawn, so that the voltage of the power transmitting end and the voltage of the power receiving end are both the first preset voltage.

[0015] In one embodiment, controlling the voltage of the power transmitting end to be restored to the original initial voltage of the power transmitting end and controlling the voltage of the power receiving end to be restored to the original initial voltage of the power receiving end include:

[0016] Control the input of a first number of voltage submodules to the power transmission end, and control the input of a second number of voltage submodules to the power receiving end, so that the voltage of the power transmission end is restored to the original initial voltage of the power transmission end and the voltage of the power receiving end is restored to the original initial voltage of the power receiving end.

[0017] In one of the embodiments, the value range of the first preset voltage is 0.01pu~0.025pu.

[0018] In one embodiment, the first preset current is the rated current of the current controller in the DC control and protection system.

[0019] In a second aspect, the present application further provides a flexible DC fault handling device for maintaining power delivery, the device comprising:

[0020] The elimination module is used to control the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system to be a first preset voltage, and to control the current of the power transmission end and the current of the power receiving end to be a first preset current, so as to eliminate the fault when the DC control and protection system detects that a line fault occurs; the first preset current is greater than a preset current threshold;

[0021] The recovery module is used to control the voltage of the power transmitting end to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end to be restored to the original initial voltage of the power receiving end after a preset time period after the fault is eliminated, and to stop controlling the current of the power transmitting end and the current of the power receiving end.

[0022] In a third aspect, the present application further provides a computer device, the computer device comprising a memory and a processor, the memory storing a computer program, and the processor implementing the following steps when executing the computer program:

[0023] When the DC control and protection system detects a line fault, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be a first preset voltage, and the current at the power transmission end and the current at the power receiving end are controlled to be a first preset current, so as to eliminate the fault; the first preset current is greater than a preset current threshold;

[0024] After a preset period of time after the fault is eliminated, the voltage of the power transmitting end is controlled to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is controlled to be restored to the original initial voltage of the power receiving end, and the current of the power transmitting end and the current of the power receiving end are stopped.

[0025] In a fourth aspect, the present application further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0026] When the DC control and protection system detects a line fault, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be a first preset voltage, and the current at the power transmission end and the current at the power receiving end are controlled to be a first preset current, so as to eliminate the fault; the first preset current is greater than a preset current threshold;

[0027] After a preset period of time after the fault is eliminated, the voltage of the power transmitting end is controlled to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is controlled to be restored to the original initial voltage of the power receiving end, and the current of the power transmitting end and the current of the power receiving end are stopped.

[0028] In a fifth aspect, the present application further provides a computer program product, the computer program product comprising a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0029] When the DC control and protection system detects a line fault, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be a first preset voltage, and the current at the power transmission end and the current at the power receiving end are controlled to be a first preset current, so as to eliminate the fault; the first preset current is greater than a preset current threshold;

[0030] After a preset period of time after the fault is eliminated, the voltage of the power transmitting end is controlled to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is controlled to be restored to the original initial voltage of the power receiving end, and the current of the power transmitting end and the current of the power receiving end are stopped.

[0031] The above-mentioned flexible DC fault handling method, device, equipment, storage medium and computer program product for maintaining power delivery, the method controls the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system to be the first preset voltage, and controls the current of the power transmission end and the current of the power receiving end to be the first preset current, so as to eliminate the fault, and after a preset time period after the fault is eliminated, controls the voltage of the power transmission end to be restored to the original initial voltage of the power transmission end and controls the voltage of the power receiving end to be restored to the original initial voltage of the power receiving end, and stops controlling the current of the power transmission end and the current of the power receiving end. In the above-mentioned method, when a ground fault occurs in the line, since the resistance of the grounding line is large, by setting the current and voltage of the power transmission end and the power receiving end to the same value, the current flowing through the branch where the line fault point is located can be made zero, forcing the line fault point to extinguish the arc to eliminate the fault. Moreover, in the process of eliminating the fault, setting the voltage value of the line to a smaller value and setting the current to a larger value can ensure that a certain amount of active power transmission is still retained in the line, so it can alleviate the power surplus problem on the AC side of the sending end and the overvoltage problem of the converter valve submodule to a certain extent. In addition, the above control method only needs to control the voltage and current of the power transmission end and the power receiving end, and there is no need to install a full-bridge submodule in the converter to output negative pressure or zero pressure to block the fault current, saving the investment cost and operating loss of the converter valve project. The implementation process of this method is simple and convenient, and can save the investment cost of the converter valve project to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A structural diagram of a DC control and protection system in an embodiment;

[0033] Figure 2 A schematic flow chart of a method for handling a flexible DC fault in an embodiment of maintaining power delivery;

[0034] Figure 3 A schematic flow chart of a method for handling a flexible DC fault for maintaining power delivery in another embodiment;

[0035] Figure 4A schematic flow chart of a method for handling a flexible DC fault for maintaining power delivery in another embodiment;

[0036] Figure 5 The present invention is a structural block diagram of a flexible DC fault processing device for maintaining power delivery in one embodiment. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] In the scenario of large-scale new energy transmission over long distances via flexible direct current, due to the weak overvoltage and overcurrent capabilities of the capacitors in the flexible direct current converter valve submodules and the large amount of energy stored in the long-distance transmission lines, if a DC line fails, the DC will be unable to maintain power transmission, and a power surplus will appear on the AC side at the sending end. The flexible direct current converter valve will also suffer from serious overvoltage problems, which may lead to large-scale disconnection of new energy at the sending end and damage to the power components of the flexible direct current converter valve.

[0039] DC fault ride-through refers to the process in which the DC transmission system can take certain measures to quickly isolate the fault and maintain or quickly recover to normal operation when a DC fault occurs in the DC transmission system. In order to prevent DC line faults from causing serious consequences in the scenario of large-scale new energy long-distance transmission via flexible direct current, research on fault ride-through strategies for DC line faults is of great significance to the safe and stable operation of DC transmission systems.

[0040] At present, the flexible DC fault ride-through strategy is mainly based on the topological structure of the full-bridge sub-module (FBSM) in the full-half-bridge hybrid converter valve. After a DC line fault occurs, the converter valve uses the negative pressure operation capability of the full-bridge sub-module to achieve non-lockout fault clearing. However, during the fault clearing process, the flexible DC controls the DC side voltage to zero or a small negative pressure, resulting in active power transmission interruption, and there is a problem that the power surplus problem on the AC side of the sending end and the overvoltage problem of the converter valve sub-module cannot be alleviated.

[0041] The present application provides a flexible DC fault processing method for maintaining power delivery, aiming to solve the above-mentioned technical problems. The following embodiments will specifically illustrate the flexible DC fault processing method for maintaining power delivery described in the present application.

[0042] The flexible DC fault processing method for maintaining power delivery provided in the embodiment of the present application can be applied to Figure 1 In the DC control and protection system shown in FIG. 1 , the DC control and protection system can be a terminal or a server, and its internal structure diagram can be as shown in FIG. Figure 1As shown, the DC control and protection system includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the DC control and protection system is used to provide computing and control capabilities. The memory of the DC control and protection system includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the DC control and protection system is used to exchange information between the processor and the external device. The communication interface of the DC control and protection system is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a flexible DC fault handling method for maintaining power delivery is realized. The display unit of the DC control and protection system is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen. The input device of the DC control and protection system can be a touch layer covering the display screen, or a button, trackball or touchpad set on the DC control and protection system shell, or an external keyboard, touchpad or mouse.

[0043] Those skilled in the art will understand that Figure 1 The structure shown in the figure is only a block diagram of a part of the structure related to the scheme of the present application, and does not constitute a limitation on the DC control and protection system to which the scheme of the present application is applied. The specific DC control and protection system may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0044] In one embodiment, Figure 2 As shown in FIG. 1 , a flexible DC fault handling method for maintaining power delivery is provided, and the method is applied to Figure 1 The DC control and protection system in the example is used to illustrate, including the following steps:

[0045] S201, when the DC control and protection system detects a line fault, controls the voltage at the power transmission end and the voltage at the power receiving end in the DC control and protection system to be a first preset voltage, and controls the current at the power transmission end and the current at the power receiving end to be a first preset current, so as to eliminate the fault.

[0046] Among them, the DC control and protection system is a control system in a flexible DC transmission line. Specifically, at the power transmission end, the DC control and protection system can be a DC control and protection system at the power transmission end, and at the power receiving end, the DC control and protection system can be a DC control and protection system at the receiving end. The DC control and protection system at the sending end and the DC control and protection system at the receiving end are connected in communication. The line fault is a ground fault in the line. The first preset current is greater than the preset current threshold, that is, the first preset current is a larger current. Specifically, the first preset current can be the rated current of the current controller in the DC control and protection system, for example, the first preset current is 1p.u. The value range of the first preset voltage is 0.01pu~0.025pu.

[0047] In the embodiment of the present application, when a fault occurs in the flexible DC transmission line, it can be specifically divided into a fault in the line at the sending end and a fault in the line at the receiving end. If a fault occurs in the line at the sending end, the DC control and protection system at the sending end can detect the line fault. When the DC control and protection system at the sending end detects that the line has failed, the line fault signal can be sent to the DC control and protection system at the receiving end, and the DC control and protection system at the receiving end can receive the line fault signal. After the DC control and protection system at the receiving end receives the line fault signal, it can be considered that both the DC control and protection system at the sending end and the DC control and protection system at the receiving end have detected the line fault. If a fault occurs in the line at the receiving end, the DC control and protection system at the receiving end can detect the line fault. When the DC control and protection system at the receiving end detects that the line has failed, the line fault signal can be sent to the DC control and protection system at the sending end, and the DC control and protection system at the sending end can receive the line fault signal. After the DC control and protection system at the sending end receives the line fault signal, it can be considered that both the DC control and protection system at the sending end and the DC control and protection system at the receiving end have detected the line fault. In the case where both the DC control and protection system at the sending end and the DC control and protection system at the receiving end detect a line fault, the DC control and protection system at the sending end can control the voltage at the sending end to be the first preset voltage and the current at the sending end to be the first preset current, and the DC control and protection system at the receiving end can control the voltage at the receiving end to be the first preset voltage and the current at the receiving end to be the first preset current, that is, the voltage at the sending end and the voltage at the receiving end are both the first preset voltage, and the current at the sending end and the current at the receiving end are both the first preset current, so as to eliminate the fault. The value range of the first preset voltage can be 0.01pu~0.025pu, that is, a smaller voltage, and the first preset current is the rated current, that is, a larger current.

[0048] S202, after a preset time period after the fault is eliminated, control the voltage of the power transmitting end to return to the original initial voltage of the power transmitting end and control the voltage of the power receiving end to return to the original initial voltage of the power receiving end, and stop controlling the current of the power transmitting end and the current of the power receiving end.

[0049] The preset time period is a de-isolation time period, which is used to ensure insulation recovery at the line fault point. The specific value can be set according to actual needs, for example, it can be set to 400ms.

[0050] In an embodiment of the present application, after the DC control and protection system eliminates the line fault based on the above steps, it can maintain the above state for a preset time period, for example, maintain the above state for 400ms, after which the DC control and protection system at the sending end controls the voltage of the sending end to be restored to the original initial voltage of the sending end and stops controlling the current of the sending end. As the voltage of the sending end gradually increases, the current of the sending end gradually decreases to gradually restore to the state of the sending end line before the fault occurs, and the DC control and protection system at the receiving end controls the voltage of the receiving end to be restored to the original initial voltage of the receiving end and stops controlling the current of the receiving end. As the voltage of the receiving end gradually increases, the current of the receiving end gradually decreases to gradually restore to the state of the receiving end line before the fault occurs.

[0051] The flexible DC fault handling method for maintaining power delivery provided in the embodiment of the present application is to control the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system to be the first preset voltage when the DC control and protection system detects that the line has a fault, and to control the current of the power transmission end and the current of the power receiving end to be the first preset current to eliminate the fault, and after a preset time period after the fault is eliminated, control the voltage of the power transmission end to restore to the original initial voltage of the power transmission end and control the voltage of the power receiving end to restore to the original initial voltage of the power receiving end, and stop controlling the current of the power transmission end and the current of the power receiving end. In the above method, when a ground fault occurs in the line, since the resistance of the grounding line is large, by setting the current and voltage of the power transmission end and the power receiving end to the same value, the current flowing through the branch where the line fault point is located can be made zero, forcing the line fault point to extinguish the arc to eliminate the fault. Moreover, in the process of eliminating the fault, setting the voltage value of the line to a smaller value and setting the current to a larger value can ensure that a certain amount of active power transmission is still retained in the line, so that the power surplus problem on the AC side of the sending end and the overvoltage problem of the converter valve submodule can be alleviated to a certain extent. In addition, the above control method only needs to control the voltage and current at the power transmission end and the power receiving end, and there is no need to install a full-bridge sub-module in the converter to output negative pressure or zero pressure to block the fault current, thereby saving the investment cost and operating loss of the converter valve project. The implementation process of this method is simple and convenient, and can save the investment cost of the converter valve project to a certain extent.

[0052] In one embodiment, a specific implementation method for controlling the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system is also provided, such as Figure 3 As shown, the above step S201 of "controlling the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system to be the first preset voltage" includes:

[0053] S301, obtaining fault line information in a DC control and protection system when a line fault occurs.

[0054] Among them, the fault line information is the DC voltage, DC current and other electrical quantities as fault values.

[0055] In an embodiment of the present application, a variety of sensors can be pre-set in the line, and the DC control and protection system is connected to the multiple sensors respectively, and the DC control and protection system can pre-set thresholds of different electrical quantities, for example, pre-set voltage thresholds and current thresholds. The DC control and protection system can obtain the voltage value through the voltage sensor in the line in real time, and obtain the current value through the current sensor in the line. When it is detected that the line voltage exceeds the voltage threshold or the line current exceeds the current threshold, it can be determined that the line has a fault, and the DC voltage, DC current and other electrical quantities at this time are used as the fault line information. Specifically, the sending-end DC control and protection system determines the DC voltage, DC current and other electrical quantities of the current line as the sending-end fault line information, and the receiving-end DC control and protection system determines the DC voltage, DC current and other electrical quantities of the current line as the receiving-end fault line information.

[0056] S302: Control the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system to be a first preset voltage according to the fault line information and the expected line information.

[0057] The expected line information indicates that the line can extinguish the arc at the line fault point and ensure that a certain amount of active power transmission is still retained in the line, specifically including the expected line voltage and the expected line current.

[0058] In an embodiment of the present application, after the DC control and protection system obtains the fault line information of the sending end and the fault line information of the receiving end based on the above steps, it can control the voltage of the sending end to be the first preset voltage according to the fault line information of the sending end and the expected line information, and control the voltage of the receiving end to be the first preset voltage according to the fault line information of the receiving end and the expected line information.

[0059] Specifically, Figure 4 As shown, the above step S302 of "controlling the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system to be the first preset voltage according to the fault line information and the expected line information" includes:

[0060] S3021: Determine a first quantity and a second quantity according to the faulty line information and the expected line information.

[0061] The first number is the number of voltage submodules that need to be removed from the power transmission end, and the second number is the number of voltage submodules that need to be removed from the power receiving end.

[0062] In an embodiment of the present application, the DC control and protection system at the sending end determines the first quantity based on the fault line information and the expected line information at the sending end. Specifically, the first voltage value to be reduced can be first determined based on the fault line information and the expected line information at the sending end, and then the first quantity is determined based on the first voltage value of the voltage submodule and the first voltage value to be reduced. The DC control and protection system at the receiving end determines the second quantity based on the fault line information and the expected line information at the receiving end. Specifically, the second voltage value to be reduced can be first determined based on the fault line information and the expected line information at the receiving end, and then the second quantity is determined based on the second voltage value of the voltage submodule and the voltage value to be reduced. Among them, the first voltage value of the voltage submodule can be the same as or different from the second voltage value of the voltage submodule. The voltage values ​​of each voltage submodule can be the same or different. The voltage submodule can be a converter submodule.

[0063] S3022, controlling a first number of voltage submodules in the power transmitting end to be withdrawn, and controlling a second number of voltage submodules in the power receiving end to be withdrawn, so that the voltage of the power transmitting end and the voltage of the power receiving end are both a first preset voltage.

[0064] In an embodiment of the present application, after the DC control and protection system at the sending end determines the first quantity based on the above steps, it can control the exit of the first quantity of voltage sub-modules in the sending end, and after the DC control and protection system at the receiving end determines the second quantity based on the above steps, it can control the exit of the second quantity of voltage sub-modules in the receiving end, so that the voltage at the sending end and the voltage at the receiving end are both the first preset voltage.

[0065] In one embodiment, a specific implementation method for restoring the initial voltage is also provided, and the "controlling the voltage of the power transmitting end to be restored to the original initial voltage of the power transmitting end and controlling the voltage of the power receiving end to be restored to the original initial voltage of the power receiving end" in the above step S202 includes: controlling the input of a first number of voltage sub-modules to the power transmitting end, and controlling the input of a second number of voltage sub-modules to the power receiving end, so that the voltage of the power transmitting end is restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is restored to the original initial voltage of the power receiving end.

[0066] In an embodiment of the present application, after the DC control and protection system eliminates the line fault based on the above steps, it can maintain the above state for a preset time period, for example, maintaining the above state for 400ms, after which the DC control and protection system at the sending end can control the first number of voltage sub-modules to be put into the power sending end so that the voltage of the power sending end is restored to the original initial voltage of the power sending end, and the DC control and protection system at the receiving end can control the second number of voltage sub-modules to be put into the power receiving end so that the voltage of the power receiving end is restored to the original initial voltage of the power receiving end.

[0067] Based on all the above embodiments, a flexible DC fault processing method for maintaining power delivery is also provided, and the method includes:

[0068] S401, when a DC control and protection system detects that a line fault occurs, obtaining fault line information in the DC control and protection system when the line fault occurs.

[0069] S402: Determine a first quantity and a second quantity according to the faulty line information and the expected line information.

[0070] S403, control the exit of the first number of voltage submodules in the power transmission end, and control the exit of the second number of voltage submodules in the power receiving end, so that the voltage of the power transmission end and the voltage of the power receiving end are both the first preset voltage, and control the current of the power transmission end and the current of the power receiving end to be the first preset current, so as to eliminate the fault. The first preset current is greater than the preset current threshold, and the value range of the first preset voltage is 0.01pu~0.025pu. The first preset current can be the rated current of the current controller in the DC control and protection system.

[0071] S404, after a preset time period after the fault is eliminated, controls the first number of voltage submodules to be put into the power transmitting end, and controls the second number of voltage submodules to be put into the power receiving end, so that the voltage of the power transmitting end is restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is restored to the original initial voltage of the power receiving end, and stops controlling the current of the power transmitting end and the current of the power receiving end.

[0072] The flexible DC fault handling method for maintaining power delivery provided in the embodiment of the present application eliminates the current at the fault point by current control at the sending end and the receiving end, and does not require the full-bridge submodule to output negative pressure or zero pressure to block the fault current, thereby saving the investment cost and operating loss of the converter valve project; during the fault crossing process, a certain level of active power transmission can be guaranteed, effectively alleviating the power surplus problem on the AC side of the sending end and the overvoltage problem of the converter valve submodule.

[0073] The methods described in the above steps are all described in the above embodiments. Please refer to the above description for details and will not be repeated here.

[0074] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0075] Based on the same inventive concept, the embodiment of the present application also provides a flexible DC fault handling device for maintaining power delivery for implementing the flexible DC fault handling method for maintaining power delivery involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of one or more flexible DC fault handling devices for maintaining power delivery provided below can refer to the limitations of the flexible DC fault handling method for maintaining power delivery above, and will not be repeated here.

[0076] In one embodiment, Figure 5 As shown, a flexible DC fault processing device for maintaining power delivery is provided, comprising:

[0077] The elimination module 11 is used to control the voltage of the power transmission end and the voltage of the power receiving end of the DC control and protection system to be the first preset voltage, and control the current of the power transmission end and the current of the power receiving end to be the first preset current, so as to eliminate the fault when the DC control and protection system detects that a line fault occurs; the first preset current is greater than the preset current threshold. The value range of the first preset voltage is 0.01pu~0.025pu, and the first preset current can be the rated current of the current controller in the DC control and protection system.

[0078] The recovery module 12 is used to control the voltage of the power transmitting end to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end to be restored to the original initial voltage of the power receiving end after a preset time period after the fault is eliminated, and to stop controlling the current of the power transmitting end and the current of the power receiving end.

[0079] In one embodiment, the elimination module 11 includes:

[0080] The acquisition unit is used to acquire the fault line information in the DC control and protection system when a line fault occurs.

[0081] The control unit is used to control the voltage of the power transmission end and the voltage of the power receiving end in the DC control and protection system to be a first preset voltage according to the fault line information and the expected line information.

[0082] In one embodiment, the control unit comprises:

[0083] The determination subunit is used to determine the first quantity and the second quantity according to the fault line information and the expected line information.

[0084] The control subunit is used to control a first number of voltage submodules to exit the power transmitting end, and to control a second number of voltage submodules to exit the power receiving end, so that the voltage of the power transmitting end and the voltage of the power receiving end are both the first preset voltage.

[0085] In one embodiment, the recovery module 12 is specifically used to restore the voltage at the power transmitting end to the original initial voltage and the voltage at the power receiving end to the original initial voltage.

[0086] Each module in the above-mentioned flexible DC fault processing device for maintaining power delivery can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

[0087] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0088] When the DC control and protection system detects a line fault, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be the first preset voltage, and the current at the power transmission end and the current at the power receiving end are controlled to be the first preset current, so as to eliminate the fault; the first preset current is greater than the preset current threshold; wherein the value range of the first preset voltage is 0.01pu~0.025pu, and the first preset current can be the rated current of the current controller in the DC control and protection system;

[0089] After a preset period of time after the fault is eliminated, the voltage of the power transmitting end is controlled to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is controlled to be restored to the original initial voltage of the power receiving end, and the current of the power transmitting end and the current of the power receiving end are stopped.

[0090] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0091] Obtain fault line information in the DC control and protection system when a line fault occurs;

[0092] According to the fault line information and the expected line information, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be the first preset voltage.

[0093] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0094] Determine a first quantity and a second quantity according to the fault line information and the expected line information;

[0095] A first number of voltage submodules in the power transmitting end are controlled to be withdrawn, and a second number of voltage submodules in the power receiving end are controlled to be withdrawn, so that the voltage of the power transmitting end and the voltage of the power receiving end are both the first preset voltage.

[0096] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0097] Control the input of a first number of voltage submodules to the power transmission end, and control the input of a second number of voltage submodules to the power receiving end, so that the voltage of the power transmission end is restored to the original initial voltage of the power transmission end and the voltage of the power receiving end is restored to the original initial voltage of the power receiving end.

[0098] The above embodiment provides a computer device, whose implementation principle and technical effect are similar to those of the above method embodiment, and will not be repeated here.

[0099] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0100] When the DC control and protection system detects a line fault, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be the first preset voltage, and the current at the power transmission end and the current at the power receiving end are controlled to be the first preset current to eliminate the fault; the first preset current is greater than the preset current threshold; the first preset current is greater than the preset current threshold; wherein the value range of the first preset voltage is 0.01pu~0.025pu, and the first preset current can be the rated current of the current controller in the DC control and protection system;

[0101] After a preset period of time after the fault is eliminated, the voltage of the power transmitting end is controlled to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is controlled to be restored to the original initial voltage of the power receiving end, and the current of the power transmitting end and the current of the power receiving end are stopped.

[0102] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0103] Obtain fault line information in the DC control and protection system when a line fault occurs;

[0104] According to the fault line information and the expected line information, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be the first preset voltage.

[0105] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0106] Determine a first quantity and a second quantity according to the fault line information and the expected line information;

[0107] A first number of voltage submodules in the power transmitting end are controlled to be withdrawn, and a second number of voltage submodules in the power receiving end are controlled to be withdrawn, so that the voltage of the power transmitting end and the voltage of the power receiving end are both the first preset voltage.

[0108] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0109] Control the input of a first number of voltage submodules to the power transmission end, and control the input of a second number of voltage submodules to the power receiving end, so that the voltage of the power transmission end is restored to the original initial voltage of the power transmission end and the voltage of the power receiving end is restored to the original initial voltage of the power receiving end.

[0110] The above embodiment provides a computer-readable storage medium, whose implementation principle and technical effect are similar to those of the above method embodiment, and will not be repeated here.

[0111] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0112] When the DC control and protection system detects a line fault, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be the first preset voltage, and the current at the power transmission end and the current at the power receiving end are controlled to be the first preset current to eliminate the fault; the first preset current is greater than the preset current threshold; the first preset current is greater than the preset current threshold; wherein the value range of the first preset voltage is 0.01pu~0.025pu, and the first preset current is the rated current of the current controller in the DC control and protection system;

[0113] After a preset period of time after the fault is eliminated, the voltage of the power transmitting end is controlled to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is controlled to be restored to the original initial voltage of the power receiving end, and the current of the power transmitting end and the current of the power receiving end are stopped.

[0114] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0115] Obtain fault line information in the DC control and protection system when a line fault occurs;

[0116] According to the fault line information and the expected line information, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be the first preset voltage.

[0117] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0118] Determine a first quantity and a second quantity according to the fault line information and the expected line information;

[0119] A first number of voltage submodules in the power transmitting end are controlled to be withdrawn, and a second number of voltage submodules in the power receiving end are controlled to be withdrawn, so that the voltage of the power transmitting end and the voltage of the power receiving end are both the first preset voltage.

[0120] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0121] Control the input of a first number of voltage submodules to the power transmission end, and control the input of a second number of voltage submodules to the power receiving end, so that the voltage of the power transmission end is restored to the original initial voltage of the power transmission end and the voltage of the power receiving end is restored to the original initial voltage of the power receiving end.

[0122] The above embodiment provides a computer program product, whose implementation principle and technical effect are similar to those of the above method embodiment, and will not be repeated here.

[0123] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0124] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A flexible DC fault handling method for maintaining power delivery, characterized in that: The method is applied to a DC control and protection system, and the method comprises: When the DC control and protection system detects a line fault, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be a first preset voltage, and the current at the power transmission end and the current at the power receiving end are controlled to be a first preset current, so as to eliminate the fault; the first preset current is greater than a preset current threshold; After a preset time period after the fault is eliminated, the voltage of the power transmitting end is controlled to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is controlled to be restored to the original initial voltage of the power receiving end, and the current of the power transmitting end and the current of the power receiving end are stopped from being controlled.

2. The method according to claim 1, characterized in that The step of controlling the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system to be a first preset voltage includes: Acquiring fault line information in the DC control and protection system when the line fails; According to the fault line information and the expected line information, the voltage at the power transmission end and the voltage at the power receiving end of the DC control and protection system are controlled to be a first preset voltage.

3. The method according to claim 2, characterized in that The step of controlling the voltage of the power transmission end and the voltage of the power receiving end of the DC control and protection system to be a first preset voltage according to the fault line information and the expected line information includes: Determine a first quantity and a second quantity according to the fault line information and the expected line information; A first number of voltage submodules in the power transmitting end are controlled to be withdrawn, and a second number of voltage submodules in the power receiving end are controlled to be withdrawn, so that the voltage of the power transmitting end and the voltage of the power receiving end are both the first preset voltage.

4. The method according to claim 3, characterized in that The controlling the voltage of the power transmitting end to be restored to the original initial voltage of the power transmitting end and the controlling the voltage of the power receiving end to be restored to the original initial voltage of the power receiving end include: Control the first number of voltage submodules to be put into the power transmitting end, and control the second number of voltage submodules to be put into the power receiving end, so that the voltage of the power transmitting end is restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end is restored to the original initial voltage of the power receiving end.

5. The method according to claim 1, characterized in that The value range of the first preset voltage is 0.01pu~0.025pu.

6. The method according to claim 1, characterized in that The first preset current is the rated current of the current controller in the DC control and protection system.

7. A flexible DC fault handling device for maintaining power delivery, characterized in that: The device comprises: an elimination module, configured to control the voltage of the power transmission end and the voltage of the power receiving end of the DC control and protection system to be a first preset voltage, and control the current of the power transmission end and the current of the power receiving end to be a first preset current, so as to eliminate the fault when the DC control and protection system detects a line fault; the first preset current is greater than a preset current threshold; A recovery module is used to control the voltage of the power transmitting end to be restored to the original initial voltage of the power transmitting end and the voltage of the power receiving end to be restored to the original initial voltage of the power receiving end after a preset time period after the fault is eliminated, and to stop controlling the current of the power transmitting end and the current of the power receiving end.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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