Protection Configuration Method and Device for High-Voltage AC / DC Hybrid Distribution Network

Abstract

The present invention discloses a protection configuration method and device for a high-voltage AC / DC hybrid distribution network. Among them, the method includes: obtaining a line to be protected in the high-voltage AC / DC hybrid distribution network; determining whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located; if the line to be protected is the flexible DC line, determining that the main protection method of the protection device in the line to be protected is traveling wave protection; determining whether the line to be protected meets the determination conditions of distance protection to obtain a determination result, where the determination conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device; determining the backup protection method of the protection device according to the determination result. The present invention solves the technical problems of low applicability and poor protection effect existing in the protection configuration method of the high-voltage AC / DC hybrid distribution network in the related art.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid protection configuration, and in particular, to a protection configuration method and device for a high-voltage AC / DC hybrid distribution network. Background Art

[0002] With the rapid development of power electronics technology and control technology, voltage source converters (VSCs) composed of fully controlled devices such as insulated gate bipolar transistors (IGBTs) and integrated gate commutated thyristors (IGCTs) have been widely used in DC power transmission systems and successfully applied in multiple fields. Due to the fast response of power electronic devices and control systems, it will have an impact on the relay protection devices of the AC system. The relay protection device of the power system is an important part of the power system and plays an important role in ensuring the safe operation of the system when a fault or abnormal operation occurs. Therefore, studying the impact of the DC system on the AC relay protection device in the AC / DC interconnected system has important theoretical significance and practical value.

[0003] However, due to the characteristics of the DC system such as small inertia and fast control response speed, traditional protection methods (such as differential protection) are no longer applicable to the AC / DC hybrid distribution network. Under the high-frequency control of power electronic devices, the external characteristics of the converter can change on a millisecond time scale. When a fault occurs, the operating conditions of the AC / DC system change, and the external characteristics of the converter will also change rapidly according to its control strategy. The principles of traditional protection are all based on power frequency electrical quantities, and their sampling rates generally do not exceed 1 kilohertz (kHz). On this time scale, the fault information extracted by traditional protection is actually the result of the combined action of system faults and converter control, so it generally lacks applicability and the protection effect is relatively poor.

[0004] In view of the above problems, no effective solution has been proposed yet. Summary of the Invention

[0005] Embodiments of the present invention provide a protection configuration method and device for a high-voltage AC / DC hybrid distribution network, so as to at least solve the technical problems of low applicability and poor protection effect existing in the protection configuration method for the high-voltage AC / DC hybrid distribution network in the related art.

[0006] According to one aspect of the embodiments of the present invention, a protection configuration method for a high-voltage AC / DC hybrid distribution network is provided, including: obtaining a line to be protected in the high-voltage AC / DC hybrid distribution network; determining whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located; if the line to be protected is the flexible DC line, determining that the main protection method of the protection device in the line to be protected is traveling wave protection; determining whether the line to be protected meets the determination conditions of distance protection to obtain a determination result, where the determination conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device; determining the backup protection method of the protection device according to the determination result.

[0007] Optionally, determining whether the line to be protected meets the determination conditions of distance protection to obtain a determination result includes: obtaining the positive direction of the distance protection corresponding to the protection device; determining the line end corresponding to the protection device according to the positive direction; determining whether the line end is equipped with the sectional interconnection device to obtain the determination result.

[0008] Optionally, determining the backup protection method according to the determination result includes: if the determination result indicates that the line end is connected to the sectional interconnection device, determining that the backup protection method is distance protection; if the determination result indicates that the line end is not connected to the sectional interconnection device, determining that the backup protection method is improved distance protection, where the improved distance protection is used to determine whether a fault exists at the target detection point based on the matching result of the measured impedance corresponding to the target detection point in the line to be protected and the converter impedance obtained in real time.

[0009] Optionally, if the line to be protected is the flexible DC line, determining that the main protection method of the protection device is traditional protection, and the backup protection method is distance protection, where the traditional protection at least includes: differential protection, phase current protection, and interphase distance protection.

[0010] Optionally, after determining that the main protection method of the protection device in the line to be protected is traveling wave protection, the method further includes: obtaining the voltage traveling wave polarity and current traveling wave polarity detected by a plurality of the protection devices in the line to be protected; determining a first fault detection result corresponding to the plurality of protection devices based on the voltage traveling wave polarity and the current traveling wave polarity; determining the current operating state of the line to be protected according to the first fault detection result.

[0011] Optionally, based on the first fault detection result, determine the current operating state of the line to be protected, including: if multiple first fault detection results are all positive-direction faults, determine that the current operating state is a fault operating state; if there is a first fault detection result that is a negative-direction fault, obtain the voltage traveling wave impedance and current traveling wave impedance detected by multiple protection devices in the line to be protected; based on the voltage traveling wave impedance and the current traveling wave impedance, determine the second fault detection results corresponding to the multiple protection devices; and determine the current operating state according to the first fault detection result and the second fault detection results.

[0012] Optionally, based on the first fault detection result and the second fault detection result, determine the current operating state, including: if both the first fault detection result and the second fault detection result of the protection device are negative-direction faults, determine that the current operating state is a normal operating state; otherwise, determine that the current operating state is the fault operating state.

[0013] According to another aspect of the embodiments of the present invention, there is also provided a protection configuration device for a high-voltage AC / DC hybrid distribution network, including: a first acquisition module, configured to acquire a line to be protected in the high-voltage AC / DC hybrid distribution network; a first judgment module, configured to judge whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC power transmission system is located; a determination module, configured to, if the line to be protected is the flexible DC line, determine that the main protection method of the protection device in the line to be protected is traveling wave protection; a second judgment module, configured to judge whether the line to be protected meets the determination conditions of distance protection to obtain a judgment result, where the determination conditions at least include: whether the line end corresponding to the protection device is provided with a sectional interconnection device; and a second acquisition module, configured to determine the backup protection method of the protection device according to the judgment result.

[0014] According to another aspect of the embodiments of the present invention, there is also provided a non-volatile storage medium storing multiple instructions, and the instructions are suitable for being loaded and executed by a processor to perform any one of the above-mentioned protection configuration methods for a high-voltage AC / DC hybrid distribution network.

[0015] According to another aspect of the embodiments of the present invention, there is also provided an electronic device including a memory and a processor, where a computer program is stored in the memory, and the processor is configured to run the computer program to execute any one of the above-mentioned protection configuration methods for a high-voltage AC / DC hybrid distribution network.

[0016] In an embodiment of the present invention, a protection configuration method for a high-voltage AC / DC hybrid distribution network is adopted. By obtaining a line to be protected in the high-voltage AC / DC hybrid distribution network; determining whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located; if the line to be protected is the flexible DC line, determining that the main protection method of the protection device in the line to be protected is traveling wave protection; determining whether the line to be protected meets the determination conditions of distance protection to obtain a determination result, where the determination conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device; determining the backup protection method of the protection device according to the determination result, achieving the purpose of determining the main protection method and backup protection method of the line to be protected according to the type of the protected line, thereby realizing the technical effect of improving the protection configuration efficiency of the high-voltage AC / DC hybrid distribution network and enhancing the operation reliability of the high-voltage AC / DC hybrid distribution network, and further solving the technical problems of low applicability and poor protection effect existing in the protection configuration method of the high-voltage AC / DC hybrid distribution network in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0018] Figure 1 is a flowchart of a protection configuration method for a high-voltage AC / DC hybrid distribution network according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of an optional protection configuration scheme for a high-voltage AC / DC hybrid distribution network according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of an optional traveling wave polarity comparison type direction protection principle according to an embodiment of the present invention;

[0021] Figure 4 is a flowchart of an optional traveling wave direction protection according to an embodiment of the present invention;

[0022] Figure 5 is a schematic structural diagram of a protection configuration device for a high-voltage AC / DC hybrid distribution network according to an embodiment of the present invention;

[0023] Figure 6 is a schematic block diagram of an electronic device for implementing the protection configuration method of the high-voltage AC / DC hybrid distribution network according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order different from those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0026] Embodiment 1

[0027] According to an embodiment of the present invention, a method embodiment for protecting a high-voltage AC / DC hybrid distribution network is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0028] Figure 1 is a flowchart of a method for protecting a high-voltage AC / DC hybrid distribution network according to an embodiment of the present invention. As Figure 1 shown, the method includes the following steps:

[0029] Step S102, obtain the line to be protected in the high-voltage AC / DC hybrid distribution network;

[0030] Step S104, determine whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located;

[0031] Step S106, if the line to be protected is the flexible DC line, determine that the main protection method of the protection device in the line to be protected is traveling wave protection;

[0032] Step S108: Determine whether the line to be protected satisfies the judgment conditions for distance protection to obtain a judgment result, where the judgment conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device;

[0033] Step S110: Determine the backup protection method of the protection device according to the above judgment result.

[0034] Optionally, a sectional interconnection device is provided in the flexible DC line; the protection devices in the line to be protected at least include: a first protection position connected to the bus and a second protection position connected to the sectional interconnection device.

[0035] In the embodiment of the present invention, a protection configuration method for a high-voltage AC / DC hybrid distribution network is adopted. By obtaining the line to be protected in the high-voltage AC / DC hybrid distribution network; determining whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located; if the line to be protected is the flexible DC line, determining that the main protection method of the protection device in the line to be protected is traveling wave protection; determining whether the line to be protected satisfies the judgment conditions for distance protection to obtain a judgment result, where the judgment conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device; determining the backup protection method of the protection device according to the above judgment result, the purpose of determining the main protection method and the backup protection method of the line to be protected according to the type of the protected line is achieved, thereby realizing the technical effect of improving the protection configuration efficiency of the high-voltage AC / DC hybrid distribution network and enhancing the operation reliability of the high-voltage AC / DC hybrid distribution network, and further solving the technical problems of low applicability and poor protection effect existing in the protection configuration method of the high-voltage AC / DC hybrid distribution network in the related art.

[0036] Optionally, first determine whether the line to be protected is a flexible DC line, that is, whether the fault characteristics of the line to be protected will be affected by flexible direct current. If the judgment result is yes, use traveling wave protection as the main protection of the line to be protected; otherwise, use traditional protection as the main protection method of the line to be protected.

[0037] In an optional embodiment, determining whether the line to be protected satisfies the judgment conditions for distance protection to obtain a judgment result includes:

[0038] Obtain the positive direction of the distance protection corresponding to the protection device;

[0039] Determine the line end corresponding to the protection device according to the positive direction;

[0040] Determine whether the line end is equipped with the sectional interconnection device to obtain the above judgment result.

[0041] Optionally, if the above determination result indicates that the end of the above line is connected to the above sectional interconnection device, determine that the above backup protection method is distance protection; if the above determination result indicates that the end of the above line is not connected to the above sectional interconnection device, determine that the above backup protection method is improved distance protection, where the above improved distance protection is used to determine whether there is a fault at the above target detection point based on the matching result between the measured impedance corresponding to the target detection point in the above line to be protected and the converter impedance obtained in real time.

[0042] It should be noted that after a fault occurs, even if the control characteristics of the converter exist, the basic circuit equation is still satisfied from the measurement point to the fault point, and the measured value of its impedance is proportional to the fault distance. Therefore, distance protection can correctly identify the fault. The problem is that if there is a converter at the end of the line, its equivalent impedance is variable due to the influence of its control, and normal control actions may cause the measured impedance at the protection location to change and be misjudged as a fault. Therefore, there are problems of misoperation and inability to set the distance protection. If the control information of the DC control system can be utilized, the equivalent impedance of the converter station can be calculated in real time. Accordingly, an improved distance protection with real-time setting can be designed, which can also meet the reliability in the AC-DC hybrid distribution network. When there is a converter at the end of the line to be protected, the impedance measured under normal conditions is the superposition of the line impedance and the external equivalent impedance of the converter. If the protection device is allowed to exchange information with the controller, the protection device can calculate the equivalent impedance of the converter station in real time. When the calculation result does not match the measurement result, a fault has occurred.

[0043] Optionally, if the above matching result indicates that the measured impedance corresponding to the target detection point in the above line to be protected does not match the converter impedance obtained in real time, determine that there is a fault at the above target detection point; if the above matching result indicates that the measured impedance corresponding to the target detection point in the above line to be protected matches the converter impedance obtained in real time, determine that there is no fault at the above target detection point.

[0044] In an optional embodiment, if the above line to be protected is the above flexible DC line, determine that the above main protection method of the protection device is traditional protection, and the above backup protection method is distance protection, where the above traditional protection at least includes: differential protection, phase current protection, and interphase distance protection.

[0045] As an optional embodiment, Figure 2 is a schematic diagram of an optional protection configuration scheme for a high-voltage AC-DC hybrid distribution network according to an embodiment of the present invention, as Figure 2As shown, the protection device 3-6 is located on the line where the partition interconnection device (MMC1 converter and MMC2 converter) is located, that is, the protection device 3-6 is located on the flexible DC line. Therefore, the traveling wave protection is adopted as the main protection method for the protection device 3-6. The other protection devices are all located at the bus outlet in their respective lines, and no partition interconnection device is provided. The traditional protection (such as differential protection) is adopted as the main protection, and the distance protection is adopted as the backup protection.

[0046] It should be noted that still as Figure 2 shown, for the flexible DC line with a partition interconnection device (DC back-to-back device) (that is, the line where the protection device 3-6 is located), in order to ensure the safety of DC equipment, it is necessary to configure protection at the outlet of the converter station of the partition interconnection device. The protection device 4 is configured on the rectifier side, and the protection device 5 is configured on the inverter side. At the same time, when analyzing the line, this flexible DC line needs to be split into two parts, one part is the line segment 3-4, and the other part is the line segment 5-6. After such processing, the MMC converter is sandwiched between the two end lines. When a fault occurs in one of these two lines, the distribution network AC protection device 4 (or protection device 5) is located at the converter station outlet, and the DC and AC connections can be quickly cut off to ensure the safety of the distribution network. For the line segment 3-4, both the protection device 3 and the protection device 4 adopt the traveling wave direction protection as the main protection. For the backup protection method, since the protection device 4 is located at the converter station outlet, the positive direction of its distance protection is from the protection device 4 to the protection device 3, and the line end does not have a partition interconnection device, that is, the impedance measurement is not affected by the partition interconnection device. Therefore, the protection 4 can adopt the traditional distance protection. The protection device 3 is located at the bus outlet, and the positive protection direction is from the protection 3 to the protection 4. The line end has a partition interconnection device, and the impedance measurement is affected by the partition interconnection device. Therefore, an improved distance protection with real-time setting is required. The line 5-6 is similar to the line 3-4, and will not be elaborated here. In summary, for the above flexible DC line (that is, the line 3-6), the main protection method of the protection devices 3 and 6 at the bus outlet adopts the traveling wave direction protection, and the backup protection method adopts the improved distance protection with real-time setting; the main protection of the protection devices 4 and 5 at the converter station outlet adopts the traveling wave protection, and the backup protection adopts the traditional distance protection. The protection devices 1, 2, 7-14 adopt the traditional protection (such as differential protection) as the main protection method and the distance protection as the backup protection method.

[0047] In an optional embodiment, after determining that the main protection method of the protection device in the above-mentioned line to be protected is the traveling wave protection, the above method further includes:

[0048] Obtain the voltage traveling wave polarity and current traveling wave polarity detected by multiple protection devices in the above-mentioned line to be protected;

[0049] Based on the above voltage traveling wave polarity and the above current traveling wave polarity, determine the first fault detection results corresponding to multiple said protection devices;

[0050] According to the above first fault detection results, determine the current operating state of the line to be protected.

[0051] Optionally, if the voltage traveling wave polarity and the current traveling wave polarity of the said protection device are opposite, determine that the above first fault detection result is a forward fault; if the voltage traveling wave polarity and the current traveling wave polarity of the said protection device are the same, determine that the above first fault detection result is a forward fault.

[0052] Optionally, if multiple above first fault detection results are all forward faults, determine that the above current operating state is a fault operating state; if there is a first fault detection result that is a reverse fault, further obtain the voltage traveling wave impedance and the current traveling wave impedance detected by multiple said protection devices in the line to be protected, and further determine the current operating state of the line to be protected by means of assigning values and comparing the voltage traveling wave impedance and the current traveling wave impedance.

[0053] Optionally, the protection devices in the line to be protected at least include: a first protection device connected to the above partition interconnection device, a second protection device connected to the bus, which are respectively located at both ends of the line to be protected shown. If the voltage traveling wave polarity and the current traveling wave polarity in both the first protection device and the second protection device are opposite, that is, both the first protection device and the second protection device indicate that the first fault detection result is a forward fault, determine that the current operating state of the line to be protected is a fault operating state. Otherwise, further obtain the voltage traveling wave impedance and the current traveling wave impedance detected by multiple said protection devices in the line to be protected, and further determine the current operating state of the line to be protected by means of assigning values and comparing the voltage traveling wave impedance and the current traveling wave impedance.

[0054] It should be noted that since traveling waves have the characteristics of high frequency and short existence time, the sampling rate of protection based on the traveling wave principle is generally in the range of 10 kHz - 500 kHz. On this time scale, the control of the converter is not yet sufficient to change. Therefore, the traveling wave characteristics after a fault are only the result of a system fault and have nothing to do with the control of the power electronic converter. The protection based on the traveling wave principle can meet the requirements of high-voltage AC / DC hybrid distribution networks and is applicable to different control strategies. In a high-voltage AC / DC hybrid distribution network, although the steady-state electrical quantities after a fault are affected by the converter control strategy and cannot be determined, the polarity of the initial traveling wave after a fault has nothing to do with the converter control strategy. Assume that line MN is the line to be protected in an AC / DC hybrid distribution network, where the M side is connected to a converter station, Figure 3It shows the polarities of the voltage traveling wave and current traveling wave mutations detected by the protection devices on the M side and N side when positive and reverse faults occur. Taking the protection device on the M side as an example, when a fault occurs in the positive direction, the polarities of the voltage traveling wave and current traveling wave detected by the protection device on the M side are opposite; when a reverse fault occurs, the polarities of the voltage traveling wave and current traveling wave detected by the M side protection are the same. If the polarity discrimination results of the M and N side protections are represented by PM and PN, the fault direction can be determined according to PM and PN. The fault direction judgment results at both ends are transmitted to the opposite end through the channel and compared. When both ends of the protection judge that it is a positive direction fault, it indicates that the fault occurs inside the protected line, and the two sections of protection operate and trip simultaneously; when only one side of the protection device judges that it is a positive direction fault, it means that the fault occurs outside the protected line, and neither of the two side protection devices operates.

[0055] In an optional embodiment, according to the above first fault detection result, determining the current operating state of the to-be-protected line includes:

[0056] If multiple above first fault detection results are all positive direction faults, then determine the above current operating state as a fault operating state;

[0057] If there is a negative direction fault in the above first fault detection result, then obtain the voltage traveling wave impedance and current traveling wave impedance detected by multiple above protection devices in the to-be-protected line;

[0058] Based on the above voltage traveling wave impedance and the above current traveling wave impedance, determine the second fault detection results corresponding to multiple above protection devices;

[0059] According to the above first fault detection result and the above second fault detection result, determine the above current operating state.

[0060] Optionally, if both the above first fault detection result and the above second fault detection result of the above protection device are the above negative direction faults, then determine the above current operating state as a normal operating state; otherwise determine the above current operating state as the above fault operating state.

[0061] Optionally, if the above first fault detection result is a negative direction fault, then obtain the voltage traveling wave impedance and current traveling wave impedance detected by multiple above protection devices in the to-be-protected line, and further determine the current operating state of the to-be-protected line by means of assignment comparison of the voltage traveling wave impedance and the current traveling wave impedance.

[0062] Optionally, the protection devices in the above-mentioned line to be protected at least include: a first protection device connected to the above-mentioned partition interconnection device and a second protection device connected to the busbar, which are respectively located at both ends of the line to be protected. If the voltage traveling wave polarity and the current traveling wave polarity of the first protection device are opposite, and the voltage traveling wave polarity and the current traveling wave polarity of the second protection device are the same, that is, the first fault detection result of the first protection device is a positive-direction fault and the first fault detection result of the second protection device is a reverse-direction fault, then further obtain the voltage traveling wave impedance and the current traveling wave impedance detected by the first protection device and the second protection device, and based on the voltage traveling wave impedance and the current traveling wave impedance, determine the second fault detection results corresponding to the first protection device and the second protection device; if the first fault detection results and the second fault detection results of the first protection device and the second protection device are both reverse-direction faults, then determine that the current operating state of the line to be protected is the normal operating state, otherwise determine that the current operating state is the fault operating state.

[0063] It should be noted that for the acquisition order of the first fault detection results and the second detection results of the first protection device and the second protection device, they can be acquired simultaneously or in a certain sequence. The present application does not make specific limitations. For example, Figure 4 is a flowchart of an optional traveling wave direction protection according to an embodiment of the present invention, as Figure 4As shown, the method includes: reading the monitored voltage and the monitored current, performing modulo-phase transformation and wavelet transformation processing on the monitored voltage and the monitored current, and using the obtained transformation results to perform traveling-wave impedance judgment and traveling-wave polarity judgment; detecting whether the fault damage is caused by lightning strike. If there is fault damage caused by lightning strike, directly restore the scene and open the interrupt. If there is no fault damage caused by lightning strike, determine whether the current line is a flexible DC bus. If the current line is a flexible DC bus, judge whether the first protection device at one end of the current line has a positive-direction fault through traveling-wave polarity (i.e., voltage traveling-wave polarity and current traveling-wave polarity). If the judgment result is yes, send a traveling-wave polarity judgment request to the second protection device at the opposite end of the first protection device, and obtain the first judgment result of the second protection device at the opposite end. If the traveling-wave polarity judgment result indicates that the first protection device at one end of the current line has an anti-direction fault, further judge whether the first protection device has a positive-direction fault through traveling-wave impedance (i.e., voltage traveling-wave impedance and current traveling-wave impedance). If the judgment result is yes, send a traveling-wave impedance judgment request to the second protection device at the opposite end of the first protection device, and obtain the second judgment result of the second protection device at the opposite end. Based on the judgment results of both ends (i.e., the first protection device and the second protection device), judge whether the first protection device and the second protection device operate to trip. If the traveling-wave impedance judgment result indicates that the first protection device at one end of the current line has an anti-direction fault, directly restore the scene and open the interrupt.

[0064] It should be noted that the embodiment of the present invention proposes an action criterion based on wavelet transformation, and gives a direction comparison type traveling-wave protection scheme constituted by using the principle of polarity comparison type traveling-wave direction protection and the principle of wave impedance direction relay. The proposed traveling-wave direction protection is not affected by the control characteristics of the converter, and can meet the requirements of line protection for AC-DC hybrid power grids.

[0065] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, some steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0066] Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by means of software plus a necessary general hardware platform. Of course, it can also be implemented by hardware, but in many cases, the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions for causing a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in various embodiments of the present invention.

[0067] Embodiment 2

[0068] In this embodiment, a protection configuration device for a high-voltage AC / DC hybrid distribution network is further provided. This device is used to implement the above embodiments and preferred implementation methods, and those that have been described will not be repeated. As used below, the terms "module" and "device" can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0069] According to an embodiment of the present invention, an apparatus embodiment for implementing the protection configuration method for the above high-voltage AC / DC hybrid distribution network is also provided. Figure 5 is a schematic structural diagram of a protection configuration device for a high-voltage AC / DC hybrid distribution network according to an embodiment of the present invention. As Figure 5 shown, the above protection configuration device for a high-voltage AC / DC hybrid distribution network includes: a first acquisition module 500, a first judgment module 502, a determination module 504, a second judgment module 506, and a second acquisition module 508, where:

[0070] The above first acquisition module 500 is used to acquire the line to be protected in the high-voltage AC / DC hybrid distribution network.

[0071] The above first judgment module 502 is connected to the above first acquisition module 500 and is used to judge whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located.

[0072] The above determination module 504 is connected to the above first judgment module 502 and is used to determine that if the line to be protected is the above flexible DC line, the main protection method of the protection device in the line to be protected is traveling wave protection.

[0073] The above-mentioned second determination module 506 is connected to the above-mentioned determination module 504 and is used to determine whether the line to be protected meets the determination conditions for distance protection, and obtain a determination result, where the determination conditions at least include: whether the end of the line corresponding to the protection device is equipped with a sectional interconnection device;

[0074] The above-mentioned second acquisition module 508 is connected to the above-mentioned second determination module 506 and is used to determine the backup protection method of the protection device according to the above-mentioned determination result.

[0075] In the embodiment of the present invention, by setting the above-mentioned first acquisition module 500, which is used to acquire the line to be protected in the high-voltage AC / DC hybrid distribution network; the above-mentioned first determination module 502, which is connected to the above-mentioned first acquisition module 500 and is used to determine whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located; the above-mentioned determination module 504, which is connected to the above-mentioned first determination module 502 and is used to determine that if the line to be protected is the above-mentioned flexible DC line, the main protection method of the protection device in the line to be protected is traveling wave protection; the above-mentioned second determination module 506, which is connected to the above-mentioned determination module 504 and is used to determine whether the line to be protected meets the determination conditions for distance protection, and obtain a determination result, where the determination conditions at least include: whether the end of the line corresponding to the protection device is equipped with a sectional interconnection device; the above-mentioned second acquisition module 508, which is connected to the above-mentioned second determination module 506 and is used to determine the backup protection method of the protection device according to the above-mentioned determination result, the purpose of determining the main protection method and backup protection method of the line to be protected according to the type of the protected line is achieved, thereby realizing the technical effect of improving the protection configuration efficiency of the high-voltage AC / DC hybrid distribution network and enhancing the operation reliability of the high-voltage AC / DC hybrid distribution network, and further solving the technical problems of low applicability and poor protection effect existing in the protection configuration method of the high-voltage AC / DC hybrid distribution network in the related art.

[0076] It should be noted that the above-mentioned each module can be implemented by software or hardware. For example, for the latter, it can be implemented in the following way: the above-mentioned each module can be located in the same processor; or, the above-mentioned each module is located in different processors in any combination.

[0077] It should be noted here that the above-mentioned first acquisition module 500, first determination module 502, determination module 504, second determination module 506, and second acquisition module 508 correspond to steps S102 to S110 in Embodiment 1. The examples and application scenarios implemented by the above-mentioned modules and the corresponding steps are the same, but are not limited to the content disclosed in the above-mentioned Embodiment 1. It should be noted that the above-mentioned modules can run in a computer terminal as a part of the device.

[0078] It should be noted that the optional or preferred implementation manners of this embodiment can refer to the relevant descriptions in Embodiment 1, and will not be elaborated here.

[0079] The above protection configuration device for a high-voltage AC / DC hybrid distribution network may further include a processor and a memory. The above first acquisition module 500, first judgment module 502, determination module 504, second judgment module 506, second acquisition module 508, etc. are all stored in the memory as program units, and the processor executes the above program units stored in the memory to implement corresponding functions.

[0080] The processor contains a kernel, and the kernel retrieves the corresponding program units from the memory. One or more kernels can be set. The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash memory (flash RAM), and the memory includes at least one storage chip.

[0081] According to an embodiment of the present application, an embodiment of a non-volatile storage medium is also provided. Optionally, in this embodiment, the above non-volatile storage medium stores a program, and when the above program runs, it controls the device where the non-volatile storage medium is located to execute any one of the protection configuration methods for a high-voltage AC / DC hybrid distribution network.

[0082] Optionally, in this embodiment, the above non-volatile storage medium can be located in any one of the computer terminals in a computer terminal group in a computer network, or in any one of the mobile terminals in a mobile terminal group, and the above non-volatile storage medium stores a program.

[0083] Optionally, when the program runs, it controls the device where the non-volatile storage medium is located to execute the following functions: obtaining a line to be protected in a high-voltage AC / DC hybrid distribution network; determining whether the line to be protected is a flexible DC line, where the flexible DC line is the line where a flexible DC transmission system is located; if the line to be protected is the flexible DC line, determining that the main protection method of the protection device in the line to be protected is traveling wave protection; determining whether the line to be protected meets the determination conditions for distance protection to obtain a determination result, where the determination conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device; determining the backup protection method of the protection device according to the determination result.

[0084] Optionally, when the program runs, it controls the device where the non-volatile storage medium is located to execute the following functions: obtaining the positive direction of the distance protection corresponding to the protection device; determining the line end corresponding to the protection device according to the positive direction; determining whether the line end is equipped with the sectional interconnection device to obtain the determination result.

[0085] Optionally, when the program is running, control the device where the non-volatile storage medium is located to perform the following functions: if the above determination result indicates that the end of the above line is connected to the above partition interconnection device, determine that the above backup protection method is distance protection; if the above determination result indicates that the end of the above line is not connected to the above partition interconnection device, determine that the above backup protection method is improved distance protection, where the above improved distance protection is used to determine whether there is a fault at the above target detection point based on the matching result of the measured impedance corresponding to the target detection point in the above line to be protected and the converter impedance obtained in real time.

[0086] Optionally, when the program is running, control the device where the non-volatile storage medium is located to perform the following functions: if the above line to be protected is the above flexible DC line, determine that the above main protection method of the protection device is traditional protection, and the above backup protection method is distance protection, where the above traditional protection at least includes: differential protection, phase current protection, and interphase distance protection.

[0087] Optionally, when the program is running, control the device where the non-volatile storage medium is located to perform the following functions: obtain the voltage traveling wave polarities and current traveling wave polarities detected by multiple above protection devices in the above line to be protected; based on the above voltage traveling wave polarities and the above current traveling wave polarities, determine the first fault detection results corresponding to the multiple above protection devices; according to the above first fault detection results, determine the current operating state of the above line to be protected.

[0088] Optionally, when the program is running, control the device where the non-volatile storage medium is located to perform the following functions: if all of the above first fault detection results are positive direction faults, determine that the above current operating state is a fault operating state; if there is a negative direction fault in the above first fault detection results, obtain the voltage traveling wave impedances and current traveling wave impedances detected by multiple above protection devices in the above line to be protected; based on the above voltage traveling wave impedances and the above current traveling wave impedances, determine the second fault detection results corresponding to the multiple above protection devices; according to the above first fault detection results and the above second fault detection results, determine the above current operating state.

[0089] Optionally, when the program is running, control the device where the non-volatile storage medium is located to perform the following functions: if both the above first fault detection result and the above second fault detection result of the above protection device are the above negative direction faults, determine that the above current operating state is a normal operating state; otherwise, determine that the above current operating state is the above fault operating state.

[0090] According to the embodiments of the present application, an embodiment of a computer program product is further provided, which is suitable for executing a program that initializes the steps of the protection configuration method for a high-voltage AC-DC hybrid distribution network of any one of the above when executed on a data processing device.

[0091] Optionally, when the above computer program product is executed on a data processing device, it is adapted to execute a program initialized with the following method steps: obtaining a line to be protected in a high-voltage AC / DC hybrid distribution network; determining whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located; if the line to be protected is the flexible DC line, determining that the main protection method of the protection device in the line to be protected is traveling wave protection; determining whether the line to be protected meets the determination conditions of distance protection, obtaining a determination result, where the determination conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device; determining the backup protection method of the protection device according to the determination result.

[0092] According to an embodiment of the present application, an embodiment of an electronic device is further provided, as Figure 6 shown. The electronic device 10 includes a processor, a memory, and a program stored on the memory and executable on the processor. When the processor executes the program, the following steps are implemented: obtaining a line to be protected in a high-voltage AC / DC hybrid distribution network; determining whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located; if the line to be protected is the flexible DC line, determining that the main protection method of the protection device in the line to be protected is traveling wave protection; determining whether the line to be protected meets the determination conditions of distance protection, obtaining a determination result, where the determination conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device; determining the backup protection method of the protection device according to the determination result.

[0093] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments.

[0094] In the above embodiments of the present invention, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0095] In several embodiments provided by the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only illustrative. For example, the division of the units can be a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the units or modules can be in an electrical or other form.

[0096] The unit described as a separation component may or may not be physically separated. The component shown as a unit may or may not be a physical unit, that is, it may be located in one place or distributed over multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0097] In addition, each functional unit in various embodiments of the present invention can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0098] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable non-volatile storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a non-volatile storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned non-volatile storage medium includes: USB flash drives, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), mobile hard disks, magnetic disks or optical discs and other various media that can store program codes.

[0099] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A protection configuration method for a high-voltage AC / DC hybrid distribution network, characterized in that, Including: Obtain the line to be protected in the high-voltage AC / DC hybrid distribution network; Judge whether the line to be protected is a flexible DC line, where the flexible DC line is the line where the flexible DC transmission system is located; If the line to be protected is the flexible DC line and a sectional interconnection device is set on the flexible DC line, determine that the main protection method of the protection device in the line to be protected is traveling wave protection; Judge whether the line to be protected meets the judgment conditions of distance protection to obtain a judgment result, where the judgment conditions at least include: whether the line end corresponding to the protection device is equipped with a sectional interconnection device; Determine the backup protection method of the protection device according to the judgment result; Among them, determining the backup protection method of the protection device according to the judgment result includes: if the judgment result indicates that the line end is connected to the sectional interconnection device, determine that the backup protection method is distance protection; if the judgment result indicates that the line end is not connected to the sectional interconnection device, determine that the backup protection method is improved distance protection, where the improved distance protection is used to determine whether there is a fault at the target detection point based on the matching result of the measured impedance corresponding to the target detection point in the line to be protected and the converter impedance obtained in real time.

2. The method according to claim 1, characterized in that, Judging whether the line to be protected meets the judgment conditions of distance protection to obtain a judgment result includes: Obtain the positive direction of the distance protection corresponding to the protection device; Determine the line end corresponding to the protection device according to the positive direction; Judge whether the line end is equipped with the sectional interconnection device to obtain the judgment result.

3. The method according to claim 1, wherein If the line to be protected is the flexible DC line and no sectional interconnection device is set on the flexible DC line, determine that the main protection method of the protection device is traditional protection, and the backup protection method is distance protection, where the traditional protection at least includes: differential protection, phase current protection, interphase distance protection.

4. The method according to claim 1, characterized in that, After determining that the main protection method of the protection device in the line to be protected is traveling wave protection, the method further includes: Obtain the voltage traveling wave polarity and current traveling wave polarity detected by multiple protection devices in the line to be protected; Based on the voltage traveling wave polarity and the current traveling wave polarity, determine the first fault detection results corresponding to multiple protection devices; Determine the current operating state of the line to be protected according to the first fault detection result.

5. The method according to claim 4, wherein Determining the current operating state of the line to be protected according to the first fault detection result includes: If all the first fault detection results are positive direction faults, determine that the current operating state is a fault operating state; If there is a first fault detection result that is a negative direction fault, obtain the voltage traveling wave impedance and current traveling wave impedance detected by multiple protection devices in the line to be protected; Based on the voltage traveling wave impedance and the current traveling wave impedance, determine the second fault detection results corresponding to multiple protection devices; Determine the current operating state according to the first fault detection result and the second fault detection result.

6. The method according to claim 5, characterized in that, Determining the current operating state according to the first fault detection result and the second fault detection result includes: If both the first fault detection result and the second fault detection result of the protection device are negative direction faults, determine that the current operating state is a normal operating state; Otherwise, determine that the current operating state is the fault operating state.

7. A protection configuration device for a high-voltage AC-DC hybrid distribution network, characterized in that, Including: A first acquisition module, configured to acquire a line to be protected in a high-voltage AC / DC hybrid distribution network; A first judgment module, configured to judge whether the line to be protected is a flexible DC line, where the flexible DC line is the line where a flexible DC power transmission system is located; A determination module, configured to, if the line to be protected is the flexible DC line and a sectional interconnection device is provided on the flexible DC line, determine that the main protection method of the protection device in the line to be protected is traveling wave protection; A second judgment module, configured to judge whether the line to be protected meets the determination conditions of distance protection, and obtain a judgment result, where the determination conditions at least include: whether a sectional interconnection device is provided at the line end corresponding to the protection device; A second acquisition module, configured to determine the backup protection method of the protection device according to the judgment result; Wherein, the second acquisition module is further configured to: if the judgment result indicates that the line end is connected to the sectional interconnection device, determine that the backup protection method is distance protection; if the judgment result indicates that the line end is not connected to the sectional interconnection device, determine that the backup protection method is improved distance protection, where the improved distance protection is used to determine whether a fault exists at the target detection point based on the matching result between the measured impedance corresponding to the target detection point in the line to be protected and the converter impedance acquired in real time.

8. A non-volatile storage medium, characterized in that, The non-volatile storage medium stores multiple instructions, and the instructions are suitable for being loaded and executed by a processor to execute the protection configuration method of the high-voltage AC / DC hybrid distribution network according to any one of claims 1 to 6.

9. An electronic device, comprising a memory and a processor, characterized in that, A computer program is stored in the memory, and the processor is configured to run the computer program to execute the protection configuration method of the high-voltage AC / DC hybrid distribution network according to any one of claims 1 to 6.

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