Method and device for monitoring interelectrode short circuit fault of direct current transmission line, controller, storage medium and computer program product

Abstract

The invention relates to an interelectrode short circuit fault monitoring method and device of a direct current transmission line, a controller, a storage medium and a computer program product. The method comprises the following steps: acquiring a local-pole direct-current line current and an antipode direct-current line current of a rectifier station and an antipode direct-current line current and an antipode direct-current line current of an inverter station; and if the absolute value of the difference value between the current of the pole direct-current line of the rectifier station and the current of the pole direct-current line of the inverter station is greater than a first preset threshold value and the absolute value of the difference value between the current of the pole direct-current line of the rectifier station and the current of the antipode direct-current line of the rectifier station is less than a second preset threshold value in a preset time, the inverter station is switched on. If yes, determining that the direct-current transmission line has an inter-electrode short-circuit fault; the first preset threshold value is different from the second preset threshold value. By adopting the method, the interelectrode short circuit fault in the direct current transmission line can be accurately identified.

Description

Technical Field

[0001] The present application relates to the field of direct current transmission technology, and in particular to a method, device, controller, storage medium and computer program product for monitoring short-circuit faults between poles of a direct current transmission line. Background Art

[0002] As an efficient high-power long-distance power transmission technology, DC transmission has been widely used in the field of high-voltage power transmission. As an important component of DC transmission lines, the failure rate is relatively high due to their long length and harsh working environment.

[0003] When a DC line fault occurs, traveling wave protection and low voltage protection are used as the main protection means, while the DC line longitudinal differential protection is used as the backup protection. When a high-resistance grounding fault occurs, traveling wave protection and low voltage protection may not work. At this time, longitudinal differential protection is needed to identify and remove the fault.

[0004] However, conventional DC line longitudinal differential protection is usually designed for single-pole DC line short-circuit faults, with each pole configured separately. When a severe fault such as a short circuit between poles occurs, conventional DC line longitudinal differential protection cannot effectively identify such faults, which poses a challenge to the safe and stable operation of the DC transmission system. Summary of the invention

[0005] Based on this, it is necessary to provide a method, device, controller, storage medium and computer program product for monitoring inter-pole short-circuit faults in DC transmission lines, which can accurately identify inter-pole short-circuit faults in DC transmission lines, in order to solve the above technical problems.

[0006] In a first aspect, the present application provides a method for monitoring short-circuit faults between poles of a DC transmission line, wherein the DC transmission line is a connection line between the bipolar poles of a rectifier station and an inverter station of a DC transmission project, and the method comprises:

[0007] Obtaining the local-pole DC line current and the opposite-pole DC line current of the rectifier station, and the local-pole DC line current and the opposite-pole DC line current of the inverter station;

[0008] If within the preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than the first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is less than the second preset threshold, it is determined that there is an inter-pole short circuit fault in the DC transmission line; the first preset threshold is different from the second preset threshold.

[0009] In one embodiment, the method further comprises:

[0010] When it is determined that there is an inter-pole short circuit fault in the DC transmission line, the two poles of the rectifier station are controlled simultaneously to restart the DC line fault.

[0011] In one embodiment, the method further comprises:

[0012] When it is determined that there is an inter-pole short circuit fault in the DC transmission line, an alarm signal is output.

[0013] In one embodiment, the method further comprises:

[0014] If within a preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is greater than a second preset threshold, it is determined that a DC line single-pole to-ground short circuit fault exists in the DC transmission line.

[0015] In one embodiment, the method further comprises:

[0016] If within a preset time, the absolute value of the difference between the pole-to-pole DC line current of the rectifier station and the pole-to-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the pole-to-pole DC line current of the rectifier station and the local-pole DC line current of the rectifier station is greater than a second preset threshold, it is determined that a single-pole short circuit fault exists in the DC transmission line.

[0017] In one embodiment, the method further comprises:

[0018] When it is determined that a single-pole-to-ground short-circuit fault exists in the DC transmission line, the rectifier station is controlled to perform a DC line fault restart on one pole where the single-pole-to-ground short-circuit fault exists in the DC line.

[0019] In a second aspect, the present application also provides a device for monitoring short-circuit faults between poles of a DC transmission line, the device comprising:

[0020] A current acquisition module is used to obtain the local-pole DC line current and the opposite-pole DC line current of the rectifier station, and the local-pole DC line current and the opposite-pole DC line current of the inverter station;

[0021] The inter-pole short-circuit fault determination module is used to determine that an inter-pole short-circuit fault exists in the DC transmission line if, within a preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is less than a second preset threshold; the first preset threshold is different from the second preset threshold.

[0022] In a third aspect, the present application further provides a controller, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any one of the above-mentioned methods when executing the computer program.

[0023] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of any one of the methods described above when the computer program is executed by a processor.

[0024] In a fifth aspect, the present application also provides a computer program product, including a computer program, which implements the steps of any one of the methods described above when the computer program is executed by a processor.

[0025] The above-mentioned method, device, controller, storage medium and computer program product for monitoring short-circuit faults between poles of a DC transmission line have at least the following beneficial effects:

[0026] Combined with the current change when an inter-pole short-circuit fault occurs in a DC transmission line, by monitoring the local-pole DC line current and the opposite-pole DC line current of the rectifier station in the DC transmission line, as well as the local-pole DC line current and the opposite-pole DC line current of the inverter station, it is determined whether there is a large difference in the current of the DC line between the two stations at the same pole within a period of time, and whether the difference in the current of the DC line between the two poles of the same station is very small. If so, it can be determined that an inter-pole short-circuit fault occurs in the DC transmission line, thereby effectively identifying the inter-pole short-circuit fault occurring in the DC transmission line operating on a bipolar line, thereby improving the safety and stability of the DC transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0028] FIG1 is a diagram showing an application environment of a method for monitoring inter-pole short-circuit faults in a DC transmission line according to an embodiment;

[0029] FIG2 is a schematic diagram of current flow when a single-pole line is short-circuited to ground in a DC transmission line according to an embodiment;

[0030] 3 is a schematic diagram of waveforms of the local-pole DC line current and the opposite-pole DC line current of the rectifier station, and the local-pole DC line current and the opposite-pole DC line current of the inverter station when a single-pole line short-circuit occurs in the DC transmission line in one embodiment;

[0031] FIG4 is a schematic diagram of current flow when an inter-pole short circuit fault occurs in a DC transmission line according to an embodiment;

[0032] FIG5 is a schematic flow chart of a method for monitoring an inter-pole short-circuit fault of a DC transmission line in one embodiment;

[0033] 6 is a schematic diagram of waveforms of the local-pole DC line current and the opposite-pole DC line current of the rectifier station, and the local-pole DC line current of the inverter station when an inter-pole short circuit fault occurs in the DC transmission line in one embodiment;

[0034] FIG7 is a structural block diagram of a device for monitoring short-circuit faults between poles of a DC transmission line according to an embodiment;

[0035] FIG. 8 is a schematic diagram of the internal structure of a controller in one embodiment. DETAILED DESCRIPTION

[0036] 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.

[0037] The method for monitoring the inter-pole short-circuit fault of a DC transmission line provided in an embodiment of the present application can be applied to a DC transmission line as shown in FIG1. ​​Wherein, the DC transmission line is a connection line between a DC engineering rectifier station and an inverter station. By obtaining the local-pole DC line current and the opposite-pole DC line current of the rectifier station, as well as the local-pole DC line current and the opposite-pole DC line current of the inverter station; if within a preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is less than a second preset threshold, it is determined that there is an inter-pole short-circuit fault in the DC transmission line; the first preset threshold is not equal to the second preset threshold. Wherein, the rectifier station is connected to the inverter station through a bipolar DC line for DC transmission, and the bipolar DC line includes a pole 1 DC line and a pole 2 DC line as shown in FIG1. The local-pole DC line current of the rectifier station refers to the current IdL flowing from the rectifier station to the pole 1 DC line, the opposite-pole DC line current of the rectifier station refers to the current IdL_op flowing from the pole 2 DC line to the rectifier station, the local-pole DC line current of the inverter station refers to the current IdL_os flowing from the pole 1 DC line to the inverter station, and the opposite-pole DC line current of the inverter station refers to the current IdL_op_os flowing from the inverter station to the pole 2 DC line.

[0038] For DC transmission lines, which are generally erected on the same tower, it is easy for inter-pole short-circuit faults to occur in the DC transmission lines when wind deviation or floating objects are suspended. Although the conventional longitudinal differential protection method of DC transmission lines has a relatively good effect in identifying and protecting single-pole to ground short-circuit faults in DC transmission lines, it cannot accurately identify whether inter-pole short-circuit faults occur in DC transmission lines operating on bipolar lines. Specifically, as shown in FIG2 , when a unipolar short-circuit fault occurs in a bipolar DC transmission line, the short-circuit current IdF formed at the short-circuit fault point of the DC transmission line flows back to the DC system through the grounding electrodes of the rectifier station and the inverter station. Because of the short-circuit current IdF flowing out of the short-circuit fault point of the DC line, there is a large difference between the local-pole DC line current of the rectifier station and the local-pole DC line current IdL_os of the inverter station; and because the short-circuit current IdF formed at the short-circuit fault point flows back to the DC system through the grounding electrode of the rectifier station, there is also a large difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station, as shown in FIG3 . As can be seen from Figure 3, when a single-pole short-circuit fault occurs in a bipolar DC transmission line, the DC line current of the rectifier station and the DC line current of the inverter station will be unequal, but it will not affect the DC line current of the rectifier station and the DC line current of the inverter station, that is, the DC line current of the rectifier station and the DC line current of the inverter station continue to remain equal. The conventional longitudinal differential protection method of the DC transmission line will determine that there is a single-pole short-circuit fault in the DC transmission line after a delay of a period of time, and trigger each pole line to perform a DC line fault restart instruction as long as it is detected that the absolute value ABS of the difference between the DC line current of the rectifier station and the DC line current of the inverter station exceeds the preset threshold, such as ABS=IdL-IdL_os>1.

[0039] However, when an inter-pole short circuit fault occurs in the DC transmission line, as shown in FIG4 , the local-pole DC line current of the rectifier station will form a short-circuit current IdF at the inter-pole DC line fault point, and flow back to the opposite-pole DC line of the rectifier station through the Pole 2 DC line. It may also cause the absolute value ABS of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station to exceed a preset threshold. If fault identification and protection are still performed according to the conventional longitudinal differential protection method of the DC transmission line, it is obviously impossible to accurately identify whether the cause of the above phenomenon is a single-pole to ground short circuit fault or an inter-pole short circuit fault, and perform corresponding protection actions.

[0040] Based on the above reasons, in an exemplary embodiment, as shown in FIG5 , the present application provides a method for monitoring an inter-pole short circuit fault of a DC transmission line, wherein the DC transmission line is a connection line between a rectifier station and an inverter station of a DC transmission project, and the method includes:

[0041] S502, obtaining the local-pole DC line current and the inter-pole DC line current of the rectifier station, and the local-pole DC line current and the inter-pole DC line current of the inverter station.

[0042] Among them, the specific meanings of the local-pole DC line current of the rectifier station, the opposite-pole DC line current of the rectifier station, the local-pole DC line current of the inverter station and the opposite-pole DC line current of the inverter station are as described above and will not be repeated here.

[0043] For example, during the DC power transmission process of the DC transmission line, the local-pole DC line current and the opposite-pole DC line current of the rectifier station, as well as the opposite-pole DC line current and the local-pole DC line current of the inverter station can be obtained by using devices such as current transformers installed on the pole 1 DC line and the pole 2 DC line to monitor whether there is a fault in the DC transmission line (such as an inter-pole short circuit fault) and determine the type of fault.

[0044] S504: If within a preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is less than a second preset threshold, it is determined that an inter-pole short circuit fault exists in the DC transmission line; and the first preset threshold is different from the second preset threshold.

[0045] Exemplarily, in a DC transmission line, the rectifier station is equivalent to the power supply side, and the inverter station is equivalent to the load side. When a pole-to-pole short circuit fault occurs in a DC transmission line operating in a bipolar line, as shown in FIG4 , the current of the local-pole DC line of the rectifier station no longer flows back to the pole-to-pole DC line of the rectifier station through the pole 1 DC line, the local-pole DC line of the inverter station, the pole-to-pole DC line of the inverter station, and the pole-to-pole DC line of the pole 2 DC line in sequence, but flows directly back to the pole-to-pole DC line of the rectifier station through the pole-to-pole DC line fault point via the pole-to-pole DC line. Since most of the local-pole DC line current of the rectifier station flows back to the pole 2 DC line through the inter-pole DC line fault point, there is a large difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station; there is also a large difference between the opposite-pole DC line current of the inverter station and the opposite-pole DC line current of the rectifier station; and because only the pole-to-pole short circuit occurs in the pole 1 DC line and the pole 2 DC line, no ground fault current path is formed between the fault point and the grounding pole, the waveforms of the local-pole DC line current of the rectifier station and the opposite-pole DC transmission line current of the rectifier station are basically the same, and the difference is small, as shown in Figure 6.

[0046] Based on the above phenomenon, the first preset threshold value can be set as "threshold 1" to represent the difference between the local DC line current of the rectifier station and the local DC line current of the inverter station, and the second preset threshold value can be set as "threshold 2" to represent the difference between the local DC line current of the rectifier station and the opposite DC line current of the rectifier station. It should be noted that the setting of the above first preset threshold value and the second preset threshold value can be set according to the actual detection accuracy requirements, which is only used as an example here without specific limitation. If, over a period of time, it is continuously detected that the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than threshold 1 (i.e. |IdL-IdL_os|>threshold 1), and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is less than threshold 2 (i.e. |IdL-IdL_op|<threshold 2), it means that at this time, there is a large difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station, while the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is small. At this time, it can be determined that there is an inter-pole short circuit fault in the DC transmission line.

[0047] The above-mentioned method for monitoring the inter-pole short-circuit fault of the DC transmission line is combined with the current change when the inter-pole short-circuit fault occurs in the DC line. By monitoring the local-pole DC line current and the opposite-pole DC line current of the rectifier station in the DC transmission line, as well as the local-pole DC line current and the opposite-pole DC line current of the inverter station, it is determined whether there is a large difference in the current of the DC line between the two stations of the same pole (between the rectifier station and the inverter station) within a period of time, and whether the difference in the current of the DC line between the two poles of the same station is small. If so, it can be determined that the DC line inter-pole short-circuit fault occurs in the DC transmission line, thereby effectively identifying the inter-pole short-circuit fault occurring in the bipolar DC transmission line, thereby improving the safety and stability of the DC transmission system.

[0048] In an exemplary embodiment, the method further comprises:

[0049] When it is determined that there is an inter-pole short circuit fault in the DC transmission line, the two poles of the rectifier station are controlled simultaneously to restart the DC line fault.

[0050] In this embodiment, when it is determined that there is an inter-pole short circuit fault in the DC transmission line, the rectifier station is controlled to synchronously perform the longitudinal differential protection action on both poles to quickly isolate the fault area and prevent the fault from further spreading, thereby improving the safety and stability of the DC transmission system and ensuring that timely measures can be taken when a serious inter-pole short circuit fault occurs to avoid system collapse, thereby ensuring the normal operation of the DC transmission system.

[0051] In an exemplary embodiment, the method further comprises:

[0052] When it is determined that there is an inter-pole short circuit fault in the DC transmission line, an alarm signal is output.

[0053] In this embodiment, when it is determined that there is an inter-pole short circuit fault in the DC transmission line, an alarm signal is output to quickly notify the operator to take corresponding measures, thereby improving the safety and stability of the DC transmission system and ensuring that measures can be taken in time when a serious fault such as an inter-pole short circuit occurs to avoid system collapse, thereby ensuring the normal operation of the DC transmission system.

[0054] In an exemplary embodiment, the method further comprises:

[0055] If within the preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than the first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is greater than the second preset threshold, it is determined that a single-pole short circuit fault exists in the DC transmission line.

[0056] Alternatively, in an exemplary embodiment, the method further includes: if within a preset time, the absolute value of the difference between the pole-to-pole DC line current of the rectifier station and the pole-to-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the pole-to-pole DC line current of the rectifier station and the local-pole DC line current of the rectifier station is greater than a second preset threshold, then it is determined that a DC line single-pole to ground short circuit fault exists in the DC transmission line.

[0057] Exemplarily, as shown in FIG2 , when a single-pole to ground short-circuit fault occurs in a DC transmission line operating in bipolar line mode, taking the Pole 1 DC line as an example, a short-circuit current IdF is formed between the Pole 1 DC line and the ground, and the short-circuit current IdF flows back to the rectifier station through the grounding pole of the rectifier station as current IdF1, and flows back to the inverter station through the grounding pole of the inverter station as current IdF2, resulting in the inequality between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station (i.e., IdL≠IdL_os), but the opposite-pole DC line current of the rectifier station and the opposite-pole DC line current of the inverter station remain equal (i.e., IdL_op=IdL_op_os), as shown in FIG3 . Among them, the rectifier station's own-pole DC line current IdL (A) in Figure 3 is the current IdL output from the rectifier station to the pole 1 DC line, the inverter station's own-pole DC line current IdL_os (A) is the current IdL_os input from the pole 1 DC line to the inverter station, the rectifier station's pole-to-pole DC line current IdL_op is the current IdL_op input from the pole 2 DC line to the rectifier station, and the inverter station's pole-to-pole DC line current IdL_op_os is the current IdL_op_os output from the inverter station to the pole 2 DC line. As shown in Figure 3, due to the partial current flowing out of the fault point of the inter-pole DC line, a large difference occurs between the local DC line current of the rectifier station and the local DC line current of the inverter station. When, within a period of time, it is monitored that the absolute value of the difference between the local DC line current of the rectifier station and the local DC line current of the inverter station is greater than the first preset threshold, that is, |IdL-IdL_os|>threshold 1, and the absolute value of the difference between the local DC line current of the rectifier station and the opposite DC line current of the rectifier station is greater than the second preset threshold, that is, |IdL- When IdL_op|>threshold 2, or when, within a period of time, the absolute value of the difference between the pole-to-pole DC line current of the rectifier station and the pole-to-pole DC line current of the inverter station is monitored to be greater than the first preset threshold, that is, |IdL_op-IdL_op_os|>threshold 1, and the absolute value of the difference between the pole-to-pole DC line current of the rectifier station and the pole-to-pole DC line current of the rectifier station is greater than the second preset threshold, |IdL_op-IdL|>threshold 2, then it is determined that a single-pole to ground short circuit fault exists in the DC transmission line.

[0058] In this embodiment, a specific and feasible implementation method is provided for determining the presence of a single-pole-to-ground short-circuit fault in a DC transmission line, so that the inter-pole short-circuit fault monitoring method of a DC transmission line of the present application not only has the function of identifying inter-pole short-circuit faults, but also has the ability to identify single-pole-to-ground short-circuit faults, thereby further ensuring the normal operation of the DC transmission system.

[0059] In an exemplary embodiment, the method further comprises:

[0060] When it is determined that a single-pole-to-ground short-circuit fault exists in the DC transmission line, the rectifier station is controlled to perform a DC line fault restart on one pole where the single-pole-to-ground short-circuit fault exists in the DC line.

[0061] In this embodiment, when it is determined that a single-pole-to-ground short-circuit fault exists in the DC transmission line, the rectifier station performs a DC line fault restart on one pole where the DC line single-pole-to-ground short-circuit fault exists, thereby ensuring that timely measures can be taken when a single-pole-to-ground short-circuit fault occurs to avoid system collapse, thereby ensuring the normal operation of the DC transmission system.

[0062] 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.

[0063] Based on the same inventive concept, the embodiment of the present application also provides a device for monitoring the inter-pole short-circuit fault of a DC transmission line for realizing the above-mentioned method for monitoring the inter-pole short-circuit fault of a DC transmission line. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in the embodiments of the device for monitoring the inter-pole short-circuit fault of a DC transmission line provided below can refer to the limitations of the method for monitoring the inter-pole short-circuit fault of a DC transmission line above, and will not be repeated here.

[0064] In an exemplary embodiment, as shown in FIG7 , a device for monitoring an inter-pole short-circuit fault of a DC transmission line is provided, comprising: a current acquisition module 702 and an inter-pole short-circuit fault determination module 704, wherein:

[0065] The current acquisition module 702 is used to obtain the local-pole DC line current and the opposite-pole DC line current of the rectifier station, and the local-pole DC line current and the opposite-pole DC line current of the inverter station;

[0066] The inter-pole short-circuit fault determination module 704 is used to determine that an inter-pole short-circuit fault exists in the DC transmission line if, within a preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is less than a second preset threshold; and the first preset threshold is less than the second preset threshold.

[0067] In an exemplary embodiment, the above-mentioned inter-pole short-circuit fault monitoring device for a DC transmission line further includes:

[0068] The first short-circuit protection module is used to control the bipolar of the rectifier station to restart the DC line fault when it is determined that there is an inter-pole short-circuit fault in the DC transmission line.

[0069] In an exemplary embodiment, the above-mentioned inter-pole short-circuit fault monitoring device for a DC transmission line further includes:

[0070] The alarm module is used to output an alarm signal when it is determined that there is an inter-pole short circuit fault in the DC transmission line.

[0071] In an exemplary embodiment, the above-mentioned inter-pole short-circuit fault monitoring device for a DC transmission line further includes:

[0072] The first determination module for a DC line single-pole short-circuit fault is used to determine that a DC line single-pole short-circuit fault exists in a DC transmission line when, within a preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is greater than a second preset threshold.

[0073] In an exemplary embodiment, the above-mentioned inter-pole short-circuit fault monitoring device for a DC transmission line further includes:

[0074] The second determination module for a DC line single-pole-to-ground short-circuit fault is used to determine that a DC line single-pole-to-ground short-circuit fault exists in a DC transmission line when, within a preset time, the absolute value of the difference between the opposite-pole DC line current of the rectifier station and the opposite-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the opposite-pole DC line current of the rectifier station and the local-pole DC line current of the rectifier station is greater than a second preset threshold.

[0075] In an exemplary embodiment, the above-mentioned inter-pole short-circuit fault monitoring device for a DC transmission line further includes:

[0076] The second short-circuit protection module is used to control the rectifier station to restart the DC line fault on one pole with the DC line single-pole-to-ground short-circuit fault when it is determined that the DC transmission line has a single-pole-to-ground short-circuit fault.

[0077] Each module in the above-mentioned inter-pole short-circuit fault monitoring device for DC transmission lines can be implemented in whole or in part by software, hardware, or 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.

[0078] In an exemplary embodiment, a computer device is provided, which may be a controller, and its internal structure diagram may be shown in FIG8. The controller includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the controller is used to provide computing and control capabilities. The memory of the controller includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the controller is used to store the local DC line current and input current of the rectifier station, and the opposite DC line current and input current data of the inverter station. The input / output interface of the controller is used to exchange information between the processor and an external device. The communication interface of the controller is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for monitoring short-circuit faults between poles of a DC transmission line is implemented.

[0079] Those skilled in the art will understand that the structure shown in FIG. 8 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0080] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0081] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0082] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0083] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method 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 the present application can include at least one of non-volatile memory 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), magnetic 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, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0084] The technical features of the above embodiments may be combined arbitrarily. 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 application.

[0085] 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 method for monitoring short-circuit faults between poles of a DC transmission line, characterized in that: The DC transmission line is a connection line between the rectifier station and the inverter station bipolar of the DC transmission project, and the method comprises: Obtaining the local-pole DC line current and the opposite-pole DC line current of the rectifier station, and the local-pole DC line current and the opposite-pole DC line current of the inverter station; If within a preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is less than a second preset threshold, it is determined that an inter-pole short circuit fault exists in the DC transmission line; and the first preset threshold is different from the second preset threshold.

2. The method for monitoring short-circuit faults between poles of a DC transmission line according to claim 1, characterized in that: The method further comprises: When it is determined that there is an inter-pole short circuit fault in the DC transmission line, the bipolar of the rectifier station is controlled simultaneously to restart the DC line fault.

3. The method for monitoring short-circuit faults between poles of a DC transmission line according to claim 1, characterized in that: The method further comprises: When it is determined that there is an inter-pole short circuit fault in the DC transmission line, an alarm signal is output.

4. The method for monitoring short-circuit faults between poles of a DC transmission line according to claim 1, characterized in that: The method further comprises: If within the preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than the first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is greater than the second preset threshold, it is determined that a single-pole short-circuit fault exists in the DC transmission line.

5. The method for monitoring short-circuit faults between poles of a DC transmission line according to claim 1, characterized in that: The method further comprises: If within the preset time, the absolute value of the difference between the pole-to-pole DC line current of the rectifier station and the pole-to-pole DC line current of the inverter station is greater than the first preset threshold, and the absolute value of the difference between the pole-to-pole DC line current of the rectifier station and the local-pole DC line current of the rectifier station is greater than the second preset threshold, it is determined that a single-pole short-circuit fault exists in the DC transmission line.

6. The method for monitoring short-circuit faults between poles of a DC transmission line according to claim 4 or 5, characterized in that: The method further comprises: When it is determined that a single-pole-to-ground short circuit fault exists in the DC power transmission line, the rectifier station is controlled to perform a DC line fault restart on a pole where the single-pole-to-ground short circuit fault exists in the DC line.

7. A device for monitoring short-circuit faults between poles of a DC transmission line, characterized in that: The device comprises: A current acquisition module is used to obtain the local-pole DC line current and the opposite-pole DC line current of the rectifier station, and the local-pole DC line current and the opposite-pole DC line current of the inverter station; The inter-pole short-circuit fault determination module is used to determine that an inter-pole short-circuit fault exists in the DC transmission line if, within a preset time, the absolute value of the difference between the local-pole DC line current of the rectifier station and the local-pole DC line current of the inverter station is greater than a first preset threshold, and the absolute value of the difference between the local-pole DC line current of the rectifier station and the opposite-pole DC line current of the rectifier station is less than a second preset threshold; and the first preset threshold is less than the second preset threshold.

8. A controller comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: 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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