Protection method and device for frequency-division alternating-current power transmission system

Abstract

The invention provides a protection method and device for a frequency division alternating current power transmission system. And collecting a first power frequency zero-sequence current component and a first pilot frequency zero-sequence current component of the first alternating current side, and realizing protection and fault location of the frequency division alternating current power transmission system according to the first power frequency zero-sequence current component and the first pilot frequency zero-sequence current component. Therefore, according to the technical scheme provided by the invention, on the basis of the protection strategy of the current converter in the frequency division alternating current power transmission system, the systematic protection of the current converter can be realized, and the overall systematic protection of the frequency division alternating current power transmission system is further realized. Even if any node in the frequency division alternating current power transmission system has a fault and lasts for a long time, the protection method provided by the invention can prevent the fault removal range from becoming large, that is, the power failure range is prevented from becoming large, the converter is prevented from being damaged as far as possible, and the protection reliability is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alternating current transmission, in particular to a protection method and device of a split-frequency alternating current transmission system. BACKGROUND

[0002] With the rapid development of power transmission technology, the split-frequency alternating current transmission system has been widely applied. The split-frequency alternating current transmission system can include a converter, the first alternating current side of the converter can be connected to a power frequency system, and the second alternating current side of the converter can be connected to a different frequency system (which can be a low frequency system). The protection of the split-frequency alternating current transmission system can quickly realize fault location and then remove the faulty element, which can ensure the safety of the equipment and maintain the stable operation of the split-frequency alternating current transmission system.

[0003] The related technology usually protects the first alternating current side, the second alternating current side and other related equipment of the converter systemically, and the converter can only rely on the protection strategy it has to realize protection. Due to the lack of system protection for the converter, in the case that any node in the split-frequency alternating current transmission system fails and lasts for a long time, it is easy to cause the fault removal range to become larger, that is, the power outage range becomes larger, and also causes the converter to be damaged. SUMMARY

[0004] In order to solve the problem of large power outage range and damaged converter in the prior art, the present application provides a protection method and device of a split-frequency alternating current transmission system.

[0005] In a first aspect, the present application provides a protection method of a split-frequency alternating current transmission system, the split-frequency alternating current transmission system including a first transformer, a converter and a second transformer. The first alternating current side of the converter is connected to a power frequency system through the first transformer, and the second alternating current side of the converter is connected to a different frequency system through the second transformer. The protection method can include:

[0006] Collecting a first power frequency zero sequence current component and a first different frequency zero sequence current component of the first alternating current side.

[0007] Protecting the split-frequency alternating current transmission system and locating the fault according to the first power frequency zero sequence current component and the first different frequency zero sequence current component.

[0008] In some possible implementation manners, protecting the split-frequency alternating current transmission system and locating the fault according to the first power frequency zero sequence current component and the first different frequency zero sequence current component include:

[0009] In the case that the first power frequency zero sequence current component exceeds a preset first current component threshold and the duration exceeds a preset first time threshold, starting the protection device to protect the split-frequency alternating current transmission system, and determining that a first part in the split-frequency alternating current transmission system fails. The first part includes the first alternating current side and the first transformer.

[0010] In a case that the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, and the first foreign frequency zero sequence current component exceeds a preset second current component threshold and a duration exceeds a preset second time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the second part has a fault. The second part includes the converter, the second alternating current side and the second transformer.

[0011] Further, the protection method further includes:

[0012] The second power frequency zero sequence current component and the second foreign frequency zero sequence current component of the second alternating current side are collected.

[0013] The frequency division alternating current power transmission system is protected and fault positioning is performed according to the second power frequency zero sequence current component and the second foreign frequency zero sequence current component.

[0014] Optionally, the frequency division alternating current power transmission system is protected and fault positioning is performed according to the second power frequency zero sequence current component and the second foreign frequency zero sequence current component, including:

[0015] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the first part has a fault. The first part includes the second alternating current side and the second transformer.

[0016] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, and the second foreign frequency zero sequence current component exceeds a preset fourth current component threshold and a duration exceeds a preset fourth time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the second part has a fault. The second part includes the converter, the first alternating current side and the first transformer.

[0017] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, and the second foreign frequency zero sequence current component exceeds a preset fourth current component threshold and a duration exceeds a preset fourth time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the second part has a fault. The second part includes the converter, the first alternating current side and the first transformer.

[0018] The second power frequency zero sequence current component and the second foreign frequency zero sequence current component of the second alternating current side are collected.

[0019] The frequency division alternating current power transmission system is protected and fault positioning is performed according to the second power frequency zero sequence current component and the second foreign frequency zero sequence current component.

[0020] In some possible implementations, the protection of the frequency-division alternating current power transmission system and fault location according to the second power frequency zero sequence current component and the second off-power frequency zero sequence current component includes:

[0021] In a case where the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a first part in the frequency-division alternating current power transmission system has a fault. The first part includes the second alternating current side and the second transformer.

[0022] In a case where the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, and the second off-power frequency zero sequence current component exceeds a preset fourth current component threshold and a duration exceeds a preset fourth time threshold, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a second part has a fault. The second part includes the converter, the first alternating current side, and the first transformer.

[0023] Further, the protection method further includes:

[0024] The first power frequency zero sequence current component and the first off-power frequency zero sequence current component of the first alternating current side are collected.

[0025] The frequency-division alternating current power transmission system is protected and fault location is performed according to the first power frequency zero sequence current component and the first off-power frequency zero sequence current component.

[0026] Optionally, the protection of the frequency-division alternating current power transmission system and fault location according to the first power frequency zero sequence current component and the first off-power frequency zero sequence current component includes:

[0027] In a case where the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a first part in the frequency-division alternating current power transmission system has a fault. The first part includes the first alternating current side and the first transformer.

[0028] In a case where the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, and the first off-power frequency zero sequence current component exceeds a preset second current component threshold and a duration exceeds a preset second time threshold, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a second part has a fault. The second part includes the converter, the second alternating current side, and the second transformer.

[0029] In a third aspect, the present application provides a protection device for a frequency-split AC power transmission system. The frequency-split AC power transmission system comprises a first transformer, a converter and a second transformer. A first AC side of the converter is connected to a power frequency system through the first transformer, and a second AC side of the converter is connected to a different frequency system through the second transformer. The protection device comprises:

[0030] a collecting module configured to collect a first power frequency zero sequence current component and a first different frequency zero sequence current component of the first AC side.

[0031] a protection module configured to protect the frequency-split AC power transmission system and locate a fault according to the first power frequency zero sequence current component and the first different frequency zero sequence current component.

[0032] In some possible implementation manners, the protection module is specifically configured to:

[0033] when the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration thereof exceeds a preset first time threshold, the protection device is started to protect the frequency-split AC power transmission system, and it is determined that a first part of the frequency-split AC power transmission system has a fault, wherein the first part comprises the first AC side and the first transformer.

[0034] when the first power frequency zero sequence current component exceeds the preset first current component threshold and the duration thereof exceeds the preset first time threshold, and the first different frequency zero sequence current component exceeds a preset second current component threshold and a duration thereof exceeds a preset second time threshold, the protection device is started to protect the frequency-split AC power transmission system, and it is determined that a second part has a fault, wherein the second part comprises the converter, the second AC side and the second transformer.

[0035] Further, the collecting module is further configured to collect a second power frequency zero sequence current component and a second different frequency zero sequence current component of the second AC side.

[0036] The protection module is further configured to protect the frequency-split AC power transmission system and locate a fault according to the second power frequency zero sequence current component and the second different frequency zero sequence current component.

[0037] Optionally, the protection module is specifically configured to:

[0038] when the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration thereof exceeds a preset third time threshold, the protection device is started to protect the frequency-split AC power transmission system, and it is determined that the first part of the frequency-split AC power transmission system has a fault, wherein the first part comprises the second AC side and the second transformer.

[0039] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, and the second foreign frequency zero sequence current component exceeds a preset fourth current component threshold and a duration exceeds a preset fourth time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the second part has a fault. The second part includes the converter, the first alternating current side and the first transformer.

[0040] In a fourth aspect, the application further provides a protection device of a frequency division alternating current power transmission system. The frequency division alternating current power transmission system includes a first transformer, a converter and a second transformer. A first alternating current side of the converter is connected to a power frequency system through the first transformer, and a second alternating current side of the converter is connected to a foreign frequency system through the second transformer. The protection device includes:

[0041] The acquisition module is configured to acquire a second power frequency zero sequence current component and a second foreign frequency zero sequence current component of the second alternating current side.

[0042] The protection module is configured to protect the frequency division alternating current power transmission system and locate a fault according to the second power frequency zero sequence current component and the second foreign frequency zero sequence current component.

[0043] In some possible implementation manners, the protection module is specifically configured to:

[0044] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that a first part of the frequency division alternating current power transmission system has a fault. The first part includes the second alternating current side and the second transformer.

[0045] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, and the second foreign frequency zero sequence current component exceeds a preset fourth current component threshold and a duration exceeds a preset fourth time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the second part has a fault. The second part includes the converter, the first alternating current side and the first transformer.

[0046] Further, the acquisition module is further configured to acquire a first power frequency zero sequence current component and a first foreign frequency zero sequence current component of the first alternating current side.

[0047] The protection module is further configured to protect the frequency division alternating current power transmission system and locate a fault according to the first power frequency zero sequence current component and the first foreign frequency zero sequence current component.

[0048] Optionally, the protection module is specifically configured to:

[0049] In a case that the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a first part in the frequency-division alternating current power transmission system is faulty. The first part includes the first alternating current side and the first transformer.

[0050] In a case that the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, and the first alien frequency zero sequence current component exceeds a preset second current component threshold and a duration exceeds a preset second time threshold, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a second part is faulty. The second part includes the converter, the second alternating current side and the second transformer.

[0051] In another aspect, the present application further provides a computer device, comprising: one or more processors.

[0052] The processor is configured to execute one or more programs.

[0053] When the one or more programs are executed by the one or more processors, the protection method provided by the first aspect and possible implementation manners thereof is implemented, or the protection method provided by the second aspect and possible implementation manners thereof is implemented.

[0054] In another aspect, the present application further provides a computer readable storage medium, which has a computer program stored thereon. When the computer program is executed, the protection method provided by the first aspect and possible implementation manners thereof is implemented, or the protection method provided by the second aspect and possible implementation manners thereof is implemented.

[0055] Compared with the prior art, the present application has the following beneficial effects:

[0056] In the protection method of the frequency-division alternating current power transmission system provided by the present application, the first power frequency zero sequence current component and the first alien frequency zero sequence current component of the first alternating current side are collected, and the protection of the frequency-division alternating current power transmission system and the fault positioning are realized according to the first power frequency zero sequence current component and the first alien frequency zero sequence current component. It can be seen that, on the basis of the protection strategy of the converter itself in the frequency-division alternating current power transmission system, the present application can realize the systematic protection of the converter, and further realize the overall systematic protection of the frequency-division alternating current power transmission system. Even in a case that any node in the frequency-division alternating current power transmission system is faulty and the duration is long, the protection method provided by the present application can avoid the increase of the fault removal range, that is, the increase of the power outage range, and avoid damaging the converter as much as possible, and improve the reliability of the protection.

[0057] The protection method provided in the application can accurately identify the grounding fault by collecting the hetero-frequency zero sequence current component, and by setting the current component threshold and the duration threshold, the protection method is matched with the main protection of the converter and other protections of the frequency-division alternating current power transmission system to form a complete protection measure of the frequency-division alternating current power transmission system, and the reliability and safety of the frequency-division alternating current power transmission system are improved.

[0058] The technical scheme provided in the application can realize fault positioning by the power frequency zero sequence current component and the hetero-frequency zero sequence current component, that is, the position of the grounding fault can be determined, and the maintenance of the frequency-division alternating current power transmission system is provided with reference. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical scheme in the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0060] Figure 1 It is a schematic structural diagram of the frequency-division alternating current power transmission system in the embodiments of the application.

[0061] Figure 2 It is a schematic flow chart of the protection method in the embodiments of the application.

[0062] Figure 3 It is a schematic structural diagram of the protection device in the embodiments of the application.

[0063] Figure 4 It is a schematic flow chart of the protection method in the embodiments of the application.

[0064] Figure 5 It is a schematic structural diagram of the protection device in the embodiments of the application. DETAILED DESCRIPTION

[0065] The technical scheme in the application will be described below with reference to the drawings.

[0066] The terms "first", "second", etc. in the description of the embodiments of the application and the claims and the drawings are only used for distinguishing the purposes of description, and cannot be understood as indicating or implying relative importance, and cannot be understood as indicating or implying sequence. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, including a series of steps or units. The method, system, product or device is not necessarily limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0067] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0068] Example 1:

[0069] This application provides a protection method for a frequency-division AC transmission system. For example... Figure 1 As shown, the frequency-divided AC transmission system 100 may include a first transformer T1, a converter 10, and a second transformer T2. The first AC side of the converter 10 is connected to the power frequency system S1 through the first transformer T1, and the second AC side of the converter 10 is connected to the frequency-differentiated system S2 through the second transformer T2. Figure 1 In the diagram, P1 is the sampling point on the first AC side, and P2 is the sampling point on the second AC side.

[0070] like Figure 2 As shown, the protection method 200 may include the following steps:

[0071] Step S1: Collect the first power frequency zero-sequence current component and the first different frequency zero-sequence current component on the first AC side.

[0072] Step S2: Protect the frequency-division AC transmission system 100 and locate the fault based on the first power frequency zero-sequence current component and the first different frequency zero-sequence current component.

[0073] In some possible implementations, step S2 above, which involves protecting the frequency-division AC transmission system 100 and locating faults based on the first power frequency zero-sequence current component and the first heterofrequency zero-sequence current component, may specifically include:

[0074] If the first power frequency zero-sequence current component exceeds a preset first current component threshold and the duration exceeds a preset first time threshold, a protection device (which may be a microprocessor-based protection device, etc.) is activated to protect the frequency-divided AC transmission system 100 and to determine that a fault has occurred in the first part of the frequency-divided AC transmission system 100. The first part includes the first AC side and the first transformer T1.

[0075] In a case that the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, and the first foreign frequency zero sequence current component exceeds a preset second current component threshold and a duration exceeds a preset second time threshold, the protection device is started to protect the frequency division alternating current power transmission system 100, and it is determined that the second part has a fault. The second part includes the converter 10, the second alternating current side and the second transformer T2.

[0076] It is conceived that the case that the first foreign frequency zero sequence current component exceeds the preset second current component threshold and the first power frequency zero sequence current component does not exceed the preset first current component threshold, or the case that only the first foreign frequency zero sequence current component exceeds the preset second current component threshold, does not occur.

[0077] Further, the protection method 200 can further include:

[0078] The second power frequency zero sequence current component and the second foreign frequency zero sequence current component of the second alternating current side are collected.

[0079] The frequency division alternating current power transmission system 100 is protected and fault location is performed according to the second power frequency zero sequence current component and the second foreign frequency zero sequence current component.

[0080] Optionally, the frequency division alternating current power transmission system 100 is protected and fault location is performed according to the second power frequency zero sequence current component and the second foreign frequency zero sequence current component, including:

[0081] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, the protection device is started to protect the frequency division alternating current power transmission system 100, and it is determined that the first part has a fault. The first part includes the second alternating current side and the second transformer T2.

[0082] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, and the second foreign frequency zero sequence current component exceeds a preset fourth current component threshold and a duration exceeds a preset fourth time threshold, the protection device is started to protect the frequency division alternating current power transmission system 100, and it is determined that the second part has a fault. The second part includes the converter 10, the first alternating current side and the first transformer T1.

[0083] It is conceivable that the zero sequence component current component only exists when the ground fault occurs in the frequency division alternating current power transmission system, and has high sensitivity to indicate whether the ground fault occurs. When the ground fault occurs in the frequency division alternating current power transmission system, the loop of the zero sequence current is from the fault point to the grounding point of the frequency division alternating current power transmission system. When the frequency power source is included in the fault loop, the frequency zero sequence current is generated. When the different frequency power source exists in the fault loop, the different frequency zero sequence current component is generated. When the fault point is located at different positions, such as the frequency system, the different frequency system, and the inside of the converter, the zero sequence current loop formed is different. Therefore, the content of the zero sequence component current component is different when the ground fault occurs at different positions.

[0084] It is also conceivable that the application can only collect the first frequency zero sequence current component and the first different frequency zero sequence current component of the first alternating current side, and realize protection and fault positioning of the frequency division alternating current power transmission system according to the first frequency zero sequence current component and the first different frequency zero sequence current component of the first alternating current side. Of course, on this basis, the application can also collect the second frequency zero sequence current component and the second different frequency zero sequence current component of the second alternating current side and realize protection and fault positioning of the frequency division alternating current power transmission system according to the second frequency zero sequence current component and the second different frequency zero sequence current component. Not only can the speed of fault positioning be improved, but the range of power failure can also be further avoided, and damage to the converter can be avoided as much as possible.

[0085] Embodiment 2

[0086] Based on the same inventive concept as embodiment 1, the application embodiment 2 provides a protection device of a frequency division alternating current power transmission system. For the introduction of the frequency division alternating current power transmission system, reference can be made to the foregoing and Figure 1 , and the application embodiment will not be described again. As shown in Figure 3 , the protection device 300 includes:

[0087] The acquisition module 301 is configured to acquire the first frequency zero sequence current component and the first different frequency zero sequence current component of the first alternating current side.

[0088] The protection module 302 is configured to protect the frequency division alternating current power transmission system and perform fault positioning according to the first frequency zero sequence current component and the first different frequency zero sequence current component.

[0089] In some possible implementation manners, the protection module 302 is specifically configured to:

[0090] In a case where the first frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that a first part in the frequency division alternating current power transmission system fails. The first part includes the first alternating current side and the first transformer T1.

[0091] In a case that the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, and the first foreign frequency zero sequence current component exceeds a preset second current component threshold and a duration exceeds a preset second time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the second part has a fault. The second part includes the converter 10, the second alternating current side and the second transformer T2.

[0092] Further, the collection module 301 is further configured to collect a second power frequency zero sequence current component and a second foreign frequency zero sequence current component of the second alternating current side.

[0093] The protection module 302 is further configured to protect the frequency division alternating current power transmission system and perform fault positioning according to the second power frequency zero sequence current component and the second foreign frequency zero sequence current component.

[0094] Optionally, the protection module 302 is specifically configured to:

[0095] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the first part has a fault in the frequency division alternating current power transmission system. The first part includes the second alternating current side and the second transformer T2.

[0096] In a case that the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, and the second foreign frequency zero sequence current component exceeds a preset fourth current component threshold and a duration exceeds a preset fourth time threshold, the protection device is started to protect the frequency division alternating current power transmission system, and it is determined that the second part has a fault. The second part includes the converter 10, the first alternating current side and the first transformer T1.

[0097] Embodiment 3

[0098] Embodiment 3 of the present application provides a protection method of a frequency division alternating current power transmission system. For the introduction of the frequency division alternating current power transmission system, reference can be made to the foregoing and Figure 1 Embodiment 3 of the present application does not repeat the foregoing. As shown in Figure 4 The protection method 400 can include:

[0099] Step S1: collecting a second power frequency zero sequence current component and a second foreign frequency zero sequence current component of a second alternating current side.

[0100] Step S2: protecting the frequency division alternating current power transmission system and performing fault positioning according to the second power frequency zero sequence current component and the second foreign frequency zero sequence current component.

[0101] In some possible implementation manners, in step S2, the protection of the frequency-division AC power transmission system and fault location are performed according to the second power frequency zero sequence current component and the second off-power frequency zero sequence current component, including:

[0102] In a case where the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, the protection device is started to protect the frequency-division AC power transmission system, and it is determined that a first part in the frequency-division AC power transmission system is faulty. The first part includes the second AC side and the second transformer T2.

[0103] In a case where the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration exceeds a preset third time threshold, and the second off-power frequency zero sequence current component exceeds a preset fourth current component threshold and a duration exceeds a preset fourth time threshold, the protection device is started to protect the frequency-division AC power transmission system, and it is determined that a second part is faulty. The second part includes the converter 10, the first AC side and the first transformer T1.

[0104] Further, the protection method 400 further includes:

[0105] The first power frequency zero sequence current component and the first off-power frequency zero sequence current component of the first AC side are collected.

[0106] The protection of the frequency-division AC power transmission system and fault location are performed according to the first power frequency zero sequence current component and the first off-power frequency zero sequence current component.

[0107] Optionally, the protection of the frequency-division AC power transmission system and fault location are performed according to the first power frequency zero sequence current component and the first off-power frequency zero sequence current component, including:

[0108] In a case where the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, the protection device is started to protect the frequency-division AC power transmission system, and it is determined that a first part in the frequency-division AC power transmission system is faulty. The first part includes the first AC side and the first transformer T1.

[0109] In a case where the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, and the first off-power frequency zero sequence current component exceeds a preset second current component threshold and a duration exceeds a preset second time threshold, the protection device is started to protect the frequency-division AC power transmission system, and it is determined that a second part is faulty. The second part includes the converter 10, the second AC side and the second transformer T2.

[0110] Embodiment 4

[0111] Based on the same inventive concept as Embodiment 3, Embodiment 4 of the present application provides a protection device of a frequency-division alternating current power transmission system. For the introduction of the frequency-division alternating current power transmission system, reference can be made to the foregoing and Figure 1 The present application will not be described again. As shown in Figure 5 The protection device 500 includes:

[0112] The acquisition module 501 is configured to acquire the second power frequency zero sequence current component and the second off-frequency zero sequence current component of the second alternating current side.

[0113] The protection module 502 is configured to protect the frequency-division alternating current power transmission system and perform fault location according to the second power frequency zero sequence current component and the second off-frequency zero sequence current component.

[0114] In some possible implementation manners, the protection module 502 is specifically configured to:

[0115] In a case where the second power frequency zero sequence current component exceeds a preset third current component threshold value and a duration exceeds a preset third time threshold value, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a first part of the frequency-division alternating current power transmission system has a fault. The first part includes the second alternating current side and the second transformer T2.

[0116] In a case where the second power frequency zero sequence current component exceeds a preset third current component threshold value and a duration exceeds a preset third time threshold value, and the second off-frequency zero sequence current component exceeds a preset fourth current component threshold value and a duration exceeds a preset fourth time threshold value, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a second part has a fault. The second part includes the converter 10, the first alternating current side and the first transformer T1.

[0117] Further, the acquisition module 501 is further configured to acquire the first power frequency zero sequence current component and the first off-frequency zero sequence current component of the first alternating current side.

[0118] The protection module 502 is further configured to protect the frequency-division alternating current power transmission system and perform fault location according to the first power frequency zero sequence current component and the first off-frequency zero sequence current component.

[0119] Optionally, the protection module 502 is specifically configured to:

[0120] In a case where the first power frequency zero sequence current component exceeds a preset first current component threshold value and a duration exceeds a preset first time threshold value, the protection device is started to protect the frequency-division alternating current power transmission system, and it is determined that a first part of the frequency-division alternating current power transmission system has a fault. The first part includes the first alternating current side and the first transformer T1.

[0121] In a case that the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration exceeds a preset first time threshold, and the first frequency zero sequence current component exceeds a preset second current component threshold and a duration exceeds a preset second time threshold, the protection device is started to protect the frequency conversion AC power transmission system, and it is determined that the second part is faulty. The second part includes the converter 10, the second AC side and the second transformer T2.

[0122] Embodiment 5

[0123] Based on the same inventive concept, the embodiment of the present application further provides a computer device, which comprises a processor and a memory. The memory is used to store a computer program, and the computer program comprises program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, the processor is suitable for loading and executing one or more instructions in the computer storage medium to implement a corresponding method flow or a corresponding function, so as to implement the steps of the protection method provided in the above embodiment 1 or embodiment 3.

[0124] Embodiment 6

[0125] Based on the same inventive concept, the embodiment of the present application further provides a computer readable storage medium, specifically, a computer readable storage medium (Memory). The computer readable storage medium is a memory device in a computer device, and is used to store programs and data. It can be understood that the computer readable storage medium herein can include an internal storage medium in the computer device, and of course can include an extended storage medium supported by the computer device. The computer readable storage medium provides a storage space, and the storage space stores an operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and the instructions can be one or more computer programs (including program codes). It should be noted that the computer readable storage medium herein can be a high-speed RAM memory, or a non-volatile memory such as at least one disk memory. One or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to implement the steps of the protection method provided in the above embodiment 1 or embodiment 3.

[0126] Those skilled in the art should understand that the embodiments of the application can be provided as a method, a system, or a computer program product. Therefore, the application can adopt a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the application can adopt a computer program product in the form of being implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0127] The application is described with reference to flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The means for implementing the functions specified in one or more flows and / or blocks.

[0128] These computer program instructions can also be stored in a computer readable memory capable of guiding the computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer readable memory produce a manufactured product including instruction means, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1the function(s) specified in the block or blocks.

[0129] These computer program instructions can also be loaded into computer or other programmable data processing devices, so that a series of operation steps are performed on the computer or other programmable data processing devices to generate computer-implemented processes, thus the instructions executed on the computer or other programmable data processing devices provide processes for implementing the flows Figure 1 the flow or flows and / or blocks Figure 1 the function(s) specified in the block or blocks.

[0130] The above merely provides the embodiments of the application and is not intended to limit the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the scope of the claims of the application to be granted.

Claims

1. A method of protection for a frequency-division alternating current power transmission system, characterized by, The frequency-division AC power transmission system comprises a first transformer, a converter and a second transformer; a first AC side of the converter is connected to a power frequency system through the first transformer, and a second AC side of the converter is connected to a different frequency system through the second transformer; the protection method comprises: collecting a first power frequency zero sequence current component and a first different frequency zero sequence current component of the first AC side; protecting the frequency-division AC power transmission system and locating a fault according to the first power frequency zero sequence current component and the first different frequency zero sequence current component.

2. The protection method of claim 1, wherein, The protection of the frequency-division AC power transmission system and the fault location according to the first power frequency zero sequence current component and the first different frequency zero sequence current component comprise: if the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration thereof exceeds a preset first time threshold, a protection device is started to protect the frequency-division AC power transmission system, and it is determined that a first part of the frequency-division AC power transmission system has a fault; wherein the first part comprises the first AC side and the first transformer; if the first power frequency zero sequence current component exceeds the preset first current component threshold and a duration thereof exceeds the preset first time threshold, and the first different frequency zero sequence current component exceeds a preset second current component threshold and a duration thereof exceeds a preset second time threshold, the protection device is started to protect the frequency-division AC power transmission system, and it is determined that a second part has a fault; wherein the second part comprises the converter, the second AC side and the second transformer.

3. The protection method of claim 1, wherein, The protection method further comprises: collecting a second power frequency zero sequence current component and a second different frequency zero sequence current component of the second AC side; protecting the frequency-division AC power transmission system and locating a fault according to the second power frequency zero sequence current component and the second different frequency zero sequence current component.

4. The protection method according to claim 3, characterized in that, The protection of the frequency-division AC power transmission system and the fault location according to the second power frequency zero sequence current component and the second different frequency zero sequence current component comprise: if the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration thereof exceeds a preset third time threshold, a protection device is started to protect the frequency-division AC power transmission system, and it is determined that a first part of the frequency-division AC power transmission system has a fault; wherein the first part comprises the second AC side and the second transformer; if the second power frequency zero sequence current component exceeds the preset third current component threshold and a duration thereof exceeds the preset third time threshold, and the second different frequency zero sequence current component exceeds a preset fourth current component threshold and a duration thereof exceeds a preset fourth time threshold, the protection device is started to protect the frequency-division AC power transmission system, and it is determined that a second part has a fault; wherein the second part comprises the converter, the first AC side and the first transformer.

5. A method of protection for a frequency division electric power transmission system, characterized by The frequency-division AC power transmission system comprises a first transformer, a converter and a second transformer; a first AC side of the converter is connected to a power frequency system through the first transformer, and a second AC side of the converter is connected to a different frequency system through the second transformer; the protection method comprises: collecting a second power frequency zero sequence current component and a second different frequency zero sequence current component of the second AC side; protecting the frequency-division AC power transmission system and locating a fault according to the second power frequency zero sequence current component and the second different frequency zero sequence current component.

6. The protection method according to claim 5, characterized in that, The protection of the frequency-division AC power transmission system and the fault location according to the second power frequency zero sequence current component and the second different frequency zero sequence current component comprise: if the second power frequency zero sequence current component exceeds a preset third current component threshold and a duration thereof exceeds a preset third time threshold, a protection device is started to protect the frequency-division AC power transmission system, and it is determined that a first part of the frequency-division AC power transmission system has a fault; wherein the first part comprises the second AC side and the second transformer; if the second power frequency zero sequence current component exceeds the preset third current component threshold and a duration thereof exceeds the preset third time threshold, and the second different frequency zero sequence current component exceeds a preset fourth current component threshold and a duration thereof exceeds a preset fourth time threshold, the protection device is started to protect the frequency-division AC power transmission system, and it is determined that a second part has a fault; wherein the second part comprises the converter, the first AC side and the first transformer.

7. The protection method of claim 5, wherein, The protection method further comprises: collecting a first power frequency zero sequence current component and a first different frequency zero sequence current component of the first AC side; protecting the frequency-division AC power transmission system and locating a fault according to the first power frequency zero sequence current component and the first different frequency zero sequence current component.

8. The protection method according to claim 7, characterized in that, The protection of the frequency-division AC power transmission system and the fault location according to the first power frequency zero sequence current component and the first different frequency zero sequence current component comprise: if the first power frequency zero sequence current component exceeds a preset first current component threshold and a duration thereof exceeds a preset first time threshold, a protection device is started to protect the frequency-division AC power transmission system, and it is determined that a first part of the frequency-division AC power transmission system has a fault; wherein the first part comprises the first AC side and the first transformer; if the first power frequency zero sequence current component exceeds the preset first current component threshold and a duration thereof exceeds the preset first time threshold, and the first different frequency zero sequence current component exceeds a preset second current component threshold and a duration thereof exceeds a preset second time threshold, the protection device is started to protect the frequency-division AC power transmission system, and it is determined that a second part has a fault; wherein the second part comprises the converter, the second AC side and the second transformer.

9. A protection device for a frequency division electric power transmission system, characterized in that The frequency-division AC power transmission system comprises a first transformer, a converter and a second transformer; a first AC side of the converter is connected to a power frequency system through the first transformer, and a second AC side of the converter is connected to a different frequency system through the second transformer; The protection device comprises: a collecting module configured to collect a first power frequency zero sequence current component and a first different frequency zero sequence current component of the first AC side; a protection module configured to protect the frequency-division AC power transmission system and locate a fault according to the first power frequency zero sequence current component and the first different frequency zero sequence current component.

10. A protection device for a frequency division AC power transmission system, characterized in that The frequency-division AC power transmission system comprises a first transformer, a converter and a second transformer; a first AC side of the converter is connected to a power frequency system through the first transformer, and a second AC side of the converter is connected to a different frequency system through the second transformer; The protection device comprises: a collecting module configured to collect a second power frequency zero sequence current component and a second different frequency zero sequence current component of the second AC side; a protection module configured to protect the frequency-division AC power transmission system and locate a fault according to the second power frequency zero sequence current component and the second different frequency zero sequence current component.

11. A computer device, comprising: comprise: one or more processors; the processor is configured to store one or more programs; when the one or more programs are executed by the one or more processors, the protection method of any one of claims 1-4 is implemented, or the protection method of any one of claims 5-8 is implemented.

12. A computer-readable storage medium, characterized in that, a computer program is stored thereon, and when the computer program is executed, the protection method of any one of claims 1-4 is implemented, or the protection method of any one of claims 5-8 is implemented.

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