Direct current transmission device suitable for new energy sending and control method and equipment thereof

Abstract

The application relates to a direct-current transmission device suitable for new energy sending and a control method and equipment thereof, which is applied to a converter station of a sending terminal system, the converter station comprises at least one sending line, each sending line comprises a converter connected with a converter transformer, the direct-current transmission device comprises a voltage support module with an energy consumption function connected in parallel between the converter transformer and the converter, and the voltage support module is used for providing reactive power required by the converter for operation and adjusting the voltage of an alternating-current side of the converter. The direct-current transmission device provides the required reactive power for the operation of diodes in the converter through the voltage support module, adjusts the output power of the direct-current side of the converter station by adjusting the voltage of the alternating-current side of the diodes in the converter, enhances the controllability of the converter station, and reduces the overall cost of the sending terminal system; when a fault occurs on the direct-current side of the converter transformer, the voltage support module can be timely put into energy consumption, so that the power of the sending terminal system reaches a balanced state.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct current energy consumption, and in particular to a direct current transmission device suitable for new energy sending and a control method and equipment thereof. BACKGROUND

[0002] A large-scale new energy system is constructed in a high-altitude area. The external insulation problem of the large-scale new energy system is not suitable for the construction of a direct current converter station. Meanwhile, the grid framework of the large-scale new energy system is weak. The large-scale new energy system sending out leads to the fact that the near-area alternating current system cannot bear excessive load, and needs to be sent out in the form of an isolated network, that is, not connected with the local grid.

[0003] At present, the main sending topology proposed by the power grid for new energy sending is a flexible direct current transmission topology. However, the flexible direct current transmission topology has two problems: first, the cost of the flexible direct current transmission topology is relatively high, which increases the total investment of the project. Second, when the sending end of the island sending system has energy imbalance, a power consumption device needs to be put into operation to balance energy, as shown in FIG. 1. As shown in FIGS. 2 and 3, but in the existing new energy system, if a converter based on a diode or a thyristor is used, although the cost is relatively low, the problem of safe and stable operation of the sending end system cannot be solved, and an alternating current power consumption device is still needed to balance energy. Figure 5 Figure 6 and Figure 7 SUMMARY

[0004] The present application provides a direct current transmission device suitable for new energy sending and a control method and equipment thereof, which are used to solve the technical problems of the existing large-scale new energy system, that is, the sending mode of the existing large-scale new energy system has energy imbalance, which affects the operation of the system, and the construction cost is high.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] On the one hand, a direct current transmission device suitable for new energy sending is provided, which is applied to a converter station of a sending end system. The converter station includes at least one sending line. Each sending line includes a converter transformer and a converter connected with the converter transformer. The direct current transmission device includes a voltage support module with a power consumption function connected in parallel between the converter transformer and the converter. The voltage support module is also used to provide reactive power required for operation of the converter and adjust the voltage on the alternating current side of the converter.

[0007] Preferably, the voltage support module includes a first full-bridge module, a first switching element, a power consumption element, a second switching element and a second full-bridge module connected in sequence. The first full-bridge module and the second full-bridge module are respectively connected with the converter transformer.

[0008] ​​Preferably, the converter transformer is used for regulating the voltage of the AC side of the converter; and / or, the first full-bridge module and the second full-bridge module are used for providing the reactive power required for the operation of the converter; and / or, the first switching element and the second switching element are used for controlling the input or output of the energy consumption element; and / or, the energy consumption element is used for consuming the active power.

[0009] Preferably, the energy consumption element is a resistor.

[0010] Preferably, the first switching element and the second switching element are both full-controlled devices.

[0011] Preferably, the first full-bridge module and the second full-bridge module each include at least four full-controlled devices connected in series and a capacitor, the four full-controlled devices being a first full-controlled device, a second full-controlled device, a third full-controlled device and a fourth full-controlled device respectively, the third terminal of the first full-controlled device being connected with the second terminal of the second full-controlled device and the connection node being recorded as a first node, the third terminal of the second full-controlled device being connected with the third terminal of the third full-controlled device, the second terminal of the third full-controlled device being connected with the third terminal of the fourth full-controlled device and the connection node being recorded as a second node, the second terminal of the fourth full-controlled device being connected with the second terminal of the first full-controlled device, the first terminal of the capacitor being connected with the first node, and the second terminal of the capacitor being connected with the second node.

[0012] Preferably, the converter is a diode-based converter.

[0013] In another aspect, a control method for a direct current transmission device suitable for new energy sending is provided, which is applied to the direct current transmission device suitable for new energy sending described above, and includes the following steps:

[0014] Obtaining a direct current fault signal of a converter transformer in a converter station of a sending end system;

[0015] Controlling the input of an energy consumption element in a voltage support module according to the direct current fault signal to maintain the power balance of the sending end system.

[0016] Preferably, the control method for the direct current transmission device suitable for new energy sending includes: controlling the operation of a first full-bridge module and a second full-bridge module and the switching of a corresponding capacitor according to the direct current fault signal; and controlling the conduction of a first switching element and a second switching element at the same time to put the energy consumption element into operation to consume the active power.

[0017] In another aspect, a terminal device is provided, which includes a processor and a memory.

[0018] The memory is configured to store program code and transmit the program code to the processor.

[0019] The processor is configured to execute the control method for the direct current transmission device for new energy sending according to instructions in the program code.

[0020] The direct current transmission device for new energy sending, the control method and the equipment thereof are applied to a converter station of a sending terminal system, the converter station comprises at least one sending line, each sending line comprises a converter transformer and a converter connected with the converter transformer, the direct current transmission device comprises a voltage support module with energy consumption function connected in parallel between the converter transformer and the converter, and the voltage support module is further configured to provide reactive power required for operation of the converter and adjust voltage on an alternating current side of the converter.

[0021] From the above technical solutions, it can be seen that the present application has the following advantages: the direct current transmission device for new energy sending provides reactive power required for operation of diodes in the converter through the voltage support module, adjusts voltage on an alternating current side of the diodes in the converter, thereby adjusts output power of the converter station, enhances controllability of the converter station, and reduces overall cost of the sending terminal system; when a direct current side of the converter transformer fails, the voltage support module can be timely put into energy consumption, so that power of the sending terminal system reaches a balanced state, and the technical problems of energy imbalance affecting operation of the system and high construction cost of the existing large-scale new energy system in the sending mode are solved.

[0022] The control method of the direct current transmission device for new energy sending controls operation of the voltage support module through a direct current fault signal, so that the sending terminal system is in a power balanced state, energy balance and voltage support of new energy isolated network sending can be effectively solved, overall cost of the sending terminal system is reduced, and the technical problems of energy imbalance affecting operation of the system and high construction cost of the existing large-scale new energy system in the sending mode are solved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 The topological structure diagram of the direct current transmission device for new energy sending described in the embodiments of the present application;

[0025] Figure 2A topological structure diagram of a voltage support module suitable for a new energy sending out direct current transmission device according to an embodiment of the present application;

[0026] Figure 3 A step flow chart of a control method of a new energy sending out direct current transmission device according to an embodiment of the present application;

[0027] Figure 4 A schematic diagram of a terminal device according to an embodiment of the present application;

[0028] Figure 5 A topological diagram of an existing flexible direct current based sending out system;

[0029] Figure 6 A topological diagram of an existing diode based sending out system;

[0030] Figure 7 A topological diagram of an existing thyristor based sending out system. DETAILED DESCRIPTION

[0031] In order to make the objectives, features, and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the embodiments described below are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0032] In the description of the embodiments of the present application, the terms “first” and “second” are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with “first” and “second” can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of “multiple” is two or more, unless otherwise specifically limited.

[0033] In the embodiments of the present application, unless otherwise specifically defined and limited, the terms “mounting”, “connection”, “connecting”, “fixing” and the like should be understood in a broad sense, for example, can be fixed connection, or detachable connection, or integrated; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0034] The embodiment of the present application provides a DC power transmission device suitable for new energy sending and a control method and equipment thereof, and solves the technical problems of energy imbalance affecting system operation and high construction cost of the existing large-scale new energy system.

[0035] Embodiment one:

[0036] Figure 1 A topological structure diagram of the DC power transmission device suitable for new energy sending is provided in the embodiment of the present application.

[0037] As Figure 1 shown, the embodiment of the present application provides a DC power transmission device suitable for new energy sending, which is applied to a converter station of a sending end system, and the converter station comprises at least one sending line, and each sending line comprises a converter transformer 10 and a converter 20 connected with the converter transformer 10. The DC power transmission device comprises a voltage support module 30 with energy consumption function connected in parallel between the converter transformer 10 and the converter 20, and the voltage support module 30 is further used for providing reactive power required by operation of the converter 20 and adjusting voltage of an alternating current side of the converter 20.

[0038] It should be noted that the converter 20 can be selected as a diode-based converter, and the voltage support module 30 is arranged at a valve side of the converter transformer 10. The voltage support module 30 can provide reactive power required by operation of diodes in the converter 20 on one hand, and on the other hand, the diode-based converter can adjust output power of the converter station through adjusting voltage of the alternating current side of the diodes of the converter 20, thereby enhancing controllability of the converter station. Meanwhile, when a direct current side of the converter transformer 10 fails, the voltage support module 30 can be timely put into energy consumption, so that power of the sending end system reaches a balanced state, thereby reducing injected direct current fault current, achieving the function of inhibiting process current and assisting fault recovery. In the embodiment, the converter station takes two sending lines as a case for illustration, and the voltage support module 30 is arranged on each sending line, so that the DC power transmission device suitable for new energy sending can combine the diodes to form the sending end system of the converter station, can effectively solve the energy balance and voltage support device of the new energy isolated network sending, and simultaneously reduces overall cost of the sending end system.

[0039] The application provides a direct current transmission device suitable for new energy sending, which is applied to a converter station of a sending terminal system, the converter station comprises at least one sending line, each sending line comprises a converter transformer and a converter connected with the converter transformer, and the direct current transmission device comprises a voltage support module with energy consumption function connected in parallel between the converter transformer and the converter, and the voltage support module is further used for providing reactive power required by the converter for operation and adjusting voltage on an alternating current side of the converter. The direct current transmission device suitable for new energy sending provides the reactive power required by diodes in the converter for operation through the voltage support module, adjusts the output power of the converter station direct current by adjusting the voltage on the alternating current side of the diodes in the converter, enhances the controllability of the converter station, and reduces the overall cost of the sending terminal system. When a direct current side of the converter transformer fails, the voltage support module can be used to consume energy in time, so that the power of the sending terminal system reaches a balanced state, and the technical problems of the existing large-scale new energy system, i.e., energy imbalance affecting system operation and high construction cost, are solved.

[0040] Figure 2 A topological structure diagram of the voltage support module in the direct current transmission device suitable for new energy sending is shown in the embodiment of the application.

[0041] As shown in Figure 2 In one embodiment of the application, the voltage support module 30 comprises a first full-bridge module 32, a first switching element 33, an energy consumption element 34, a second switching element 35 and a second full-bridge module 36 connected in sequence, and the first full-bridge module 32 and the second full-bridge module 36 are connected with the converter transformer 10. The converter transformer 10 is used for adjusting the voltage on the alternating current side of the converter 20, and the first full-bridge module 32 and the second full-bridge module 36 are used for providing the reactive power required by the converter 20 for operation; the first switching element 33 and the second switching element 35 are used for controlling the input or output of the energy consumption element 34; and the energy consumption element 34 is used for consuming active power.

[0042] It should be noted that the energy consumption element 34 can be selected as a resistor. The first switching element 33 and the second switching element 35 can both be selected as full-controlled devices. In the embodiment, the converter transformer 10 is used for realizing voltage change, reducing the alternating current voltage requirement of the power electronic equipment, reducing the number of full-controlled devices, and thus reducing the overall equipment cost.

[0043] As shown in Figure 2As shown in the embodiments of this application, both the first full-bridge module 32 and the second full-bridge module 36 include at least four fully controllable devices connected in series and a capacitor. The four fully controllable devices are a first fully controllable device, a second fully controllable device, a third fully controllable device, and a fourth fully controllable device. The third terminal of the first fully controllable device is connected to the second terminal of the second fully controllable device, and the connection node is denoted as the first node. The third terminal of the second fully controllable device is connected to the third terminal of the third fully controllable device. The second terminal of the third fully controllable device is connected to the third terminal of the fourth fully controllable device, and the connection node is denoted as the second node. The second terminal of the fourth fully controllable device is connected to the second terminal of the first fully controllable device. The first terminal of the capacitor is connected to the first node, and the second terminal of the capacitor is connected to the second node.

[0044] It should be noted that the first, second, third, and fourth fully controlled devices can all be transistors. The emitter of the transistor serves as the third terminal of each device, and the collector serves as the second terminal. In this embodiment, both the first full-bridge module 32 and the second full-bridge module 36 use modules with the same structure (such as fully controlled devices) connected in series to control the voltage support module 30. The working principle of the full-bridge module is to control the switching of capacitors by controlling the on and off of the fully controlled devices, thereby controlling the reactive power output.

[0045] In this embodiment, the DC power transmission device suitable for transmitting new energy sources controls the DC side of the first full-bridge module 32 and the second full-bridge module 36 to form a certain DC voltage on both sides of the energy-consuming element 34, thereby consuming the externally fed active power. Simultaneously, a first switching element 33 and a second switching element 35, composed of fully controllable devices, are configured on both sides of the energy-consuming element 34 to control the energy consumption element's activation or deactivation, thereby controlling the energy of the energy-consuming element 34.

[0046] Example 2:

[0047] Figure 3 This is a flowchart illustrating the steps of a control method for a DC power transmission device suitable for transmitting new energy, as described in an embodiment of this application.

[0048] like Figure 3 As shown, this application provides a control method for a DC transmission device suitable for transmitting new energy, applied to the aforementioned DC transmission device suitable for transmitting new energy. The control method includes the following steps:

[0049] S1. Obtain the DC fault signal of the converter transformer in the converter station of the sending-end system.

[0050] It should be noted that the DC fault signal of the converter transformer in the converter station of the sending end system is acquired in step S1. In this embodiment, the content of the DC power transmission device suitable for new energy sending has been explained in Embodiment One.

[0051] S2. According to the DC fault signal, the input of the energy consumption element in the voltage support module is controlled to maintain the power balance of the sending end system.

[0052] It should be noted that in step S2, the operation of the voltage support module is controlled according to the DC fault signal in step S1, so that the sending end system is in a power balance state.

[0053] The control method of the DC power transmission device suitable for new energy sending provided by the present application comprises the following steps: acquiring a DC fault signal of a converter transformer in a converter station of a sending end system; and according to the DC fault signal, the input of an energy consumption element in a voltage support module is controlled to maintain the power balance of the sending end system. The control method of the DC power transmission device suitable for new energy sending controls the operation of the voltage support module through the DC fault signal, so that the sending end system is in a power balance state, which can effectively solve the energy balance and voltage support of new energy isolated grid sending, reduce the overall cost of the sending end system, and solve the technical problems of the existing large-scale new energy system, such as energy imbalance affecting system operation and high construction cost.

[0054] In an embodiment of the present application, the control method of the DC power transmission device suitable for new energy sending comprises the following steps: according to the DC fault signal, the operation of a first full-bridge module and a second full-bridge module is controlled, the corresponding capacitor is switched, the conduction of a first switching element and a second switching element is controlled, and the energy consumption element is put into operation to consume energy.

[0055] It should be noted that the operation of the voltage support module controlled by the control method of the DC power transmission device suitable for new energy sending can be understood as follows: the operation of the first full-bridge module and the second full-bridge module is controlled to switch the corresponding capacitor, the conduction of the first switching element and the second switching element is controlled, the energy consumption element is put into operation to consume fault energy, and the power of the sending end system reaches a balance state, thereby reducing the injected DC fault current, achieving the function of inhibiting the process current, and assisting fault recovery.

[0056] Embodiment Three:

[0057] Figure 4 The schematic diagram of the terminal device described in the embodiments of the present application.

[0058] As shown in Figure 4 , the terminal device provided by the embodiments of the present application comprises a processor and a memory;

[0059] a memory, configured to store the program code and transmit the program code to the processor;

[0060] a processor, configured to execute the control method for the direct current transmission device for new energy sending according to the instructions in the program code.

[0061] It should be noted that the processor is configured to execute the steps in the control method for the direct current transmission device for new energy sending according to the instructions in the program code. Alternatively, the processor executes the computer program to realize the functions of each module / unit in each system / device embodiment.

[0062] For example, the computer program can be divided into one or more modules / units, one or more modules / units are stored in the memory and executed by the processor to complete the present application. One or more modules / units can be a series of computer program instruction segments capable of completing a specific function, which is used to describe the execution process of the computer program in the terminal device.

[0063] The terminal device can be a desktop computer, a notebook computer, a palm computer, a cloud server and other computing devices. The terminal device can include, but is not limited to, a processor and a memory. Those skilled in the art can understand that it does not limit the terminal device, and can include more or less components than the illustration, or combine certain components, or different components, for example, the terminal device can also include an input / output device, a network access device, a bus, etc.

[0064] 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 general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0065] The memory can be an internal storage unit of the terminal device, such as a hard disk or a memory of the terminal device. The memory can also be an external storage device of the terminal device, such as a plug-in hard disk, a smart memory card (SMC), a secure digital (SD) card, a flash card, etc. Further, the memory can include both the internal storage unit and the external storage device of the terminal device. The memory is used to store the computer program and other programs and data required by the terminal device. The memory can also be used to temporarily store data that has been output or will be output.

[0066] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0067] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely schematic, and the division of the units is merely a logical function division, and there can be another division manner in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0068] The units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, that is, can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0069] In addition, each functional unit in the various embodiments of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0070] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a number of 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 the various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0071] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A DC power transmission device suitable for transmitting new energy, applied in a converter station of a sending-end system, the converter station comprising at least one sending line, each sending line comprising a converter transformer and a converter connected to the converter transformer, characterized in that, The DC transmission device includes a voltage support module connected in parallel between the converter transformer and the converter, which has an energy dissipation function. The voltage support module is also used to provide the converter with the reactive power required for operation and to regulate the voltage on the AC side of the converter. The voltage support module includes a first full-bridge module, a first switching element, an energy-consuming element, a second switching element, and a second full-bridge module connected in sequence. The first full-bridge module and the second full-bridge module are respectively connected to the converter transformer. The converter transformer is used to regulate the voltage on the AC side of the converter; and / or, the first full-bridge module and the second full-bridge module are used to provide the converter with the reactive power required for operation; and / or, the first switching element and the second switching element are used to control the activation or deactivation of the energy-consuming element; and / or, the energy-consuming element is used to consume active energy. The voltage support module is used to control the DC side of the first full-bridge module and the second full-bridge module, forming a DC voltage on both sides of the energy-consuming element to consume the active power fed into the converter from the outside; and controlling the energy-consuming element to be put on or taken off by the first switching element and the second switching element to realize the control of the energy of the energy-consuming element.

2. The DC power transmission device for transmitting new energy sources according to claim 1, characterized in that, The energy-consuming element is a resistor.

3. The DC power transmission device for transmitting new energy sources according to claim 1, characterized in that, Both the first switching element and the second switching element are fully controllable devices.

4. The DC power transmission device for transmitting new energy sources according to claim 1, characterized in that, Both the first full-bridge module and the second full-bridge module include at least four fully controllable devices connected in series and a capacitor. The four fully controllable devices are a first fully controllable device, a second fully controllable device, a third fully controllable device, and a fourth fully controllable device. The third terminal of the first fully controllable device is connected to the second terminal of the second fully controllable device, and the connection node is designated as the first node. The third terminal of the second fully controllable device is connected to the third terminal of the third fully controllable device. The second terminal of the third fully controllable device is connected to the third terminal of the fourth fully controllable device, and the connection node is designated as the second node. The second terminal of the fourth fully controllable device is connected to the second terminal of the first fully controllable device. The first terminal of the capacitor is connected to the first node, and the second terminal of the capacitor is connected to the second node.

5. The DC power transmission device for transmitting new energy sources according to any one of claims 1-4, characterized in that, The converter is a diode-based converter.

6. A control method for a DC transmission device suitable for transmitting new energy, applied to the DC transmission device for transmitting new energy as described in any one of claims 1-5, characterized in that, The control method includes the following steps: Acquire DC fault signals from converter transformers in the converter station of the sending-end system; The input of energy-consuming components in the control voltage support module is adjusted according to the DC fault signal to maintain the power balance of the sending-end system.

7. The control method for DC transmission devices for new energy transmission according to claim 6, characterized in that, include: The system controls the operation of the first full-bridge module and the second full-bridge module according to the DC fault signal, switching the capacitors corresponding to the first full-bridge module and the second full-bridge module; at the same time, it controls the conduction of the first switching element and the second switching element to put the energy-consuming element into operation to consume the active power.

8. A terminal device, characterized in that, Including the processor and memory; The memory is used to store program code and transmit the program code to the processor; The processor is configured to execute the control method for DC power transmission devices suitable for new energy transmission as described in claim 6 or 7, according to the instructions in the program code.

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