Design method and device of direct current collection networking protection system, storage medium and equipment

Abstract

The invention belongs to the technical field of direct current collection networking, and provides a design method and device of a direct current collection networking protection system, a storage medium and equipment. The method comprises the following steps: dividing a direct current collection network into a plurality of protection areas, and determining protected equipment in each protection area; determining a configuration structure of each protection device according to the division of the protection area; setting a protection function and an action strategy of each protection device; setting each protection function of each protection device; electromagnetic transient simulation verification and adjustment are carried out on the steps, and the design of the direct current collection networking protection system is completed. The invention provides a traffic design thought for the protection system of the high-capacity new energy direct current collection networking.

Description

Technical Field

[0001] The present invention belongs to the technical field of direct current collection networking, and in particular, relates to a design method, device, storage medium and equipment for a direct current collection networking protection system. Background Art

[0002] DC collection technology can achieve efficient and flexible access to large-scale renewable energy, has the ability to independently control power, can significantly enhance the voltage support capability, collect and send unstable renewable energy at multiple points, achieve wide-area complementarity of renewable energy, and enhance the fault ride-through capability, grid-connected safety and stability of renewable energy.

[0003] In the existing DC collection network, the penetration rate of new energy is low (small capacity and small output proportion), and the distribution protection system of the same voltage level cannot directly meet the safety needs of large-capacity new energy DC collection network.

[0004] However, there is currently no mature protection solution for large-capacity new energy DC collection networking. Summary of the invention

[0005] To solve the above problems, the present disclosure provides a design method for a DC collection networking protection system, which configures reasonable protection devices for the DC collection networking to ensure the safe and stable operation of the entire DC collection networking.

[0006] The embodiments of the present disclosure may be implemented using the following solutions:

[0007] A design method for a DC collection network protection system comprises: dividing the DC collection network into a number of protection areas, and determining the protected equipment in each protection area; determining the configuration structure of each protection device according to the division of the protection areas; setting the protection function and action strategy of each protection device; setting each protection function of each protection device; and performing electromagnetic transient simulation verification and adjustment on the DC collection network protection system formed by the above steps to complete the design of the DC collection network protection system.

[0008] Furthermore,

[0009] The protection area includes a photovoltaic device protection area, a DC transformer protection area, a DC line protection area, a converter protection area, and an AC protection area.

[0010] Furthermore,

[0011] The setting of each protection function of each protection device also includes determining the coordination relationship between the main equipment protection device and the backup equipment protection device.

[0012] Furthermore,

[0013] The DC collection network is a partial DC collection network or a full DC collection network.

[0014] Furthermore,

[0015] The DC collection network includes a plurality of photovoltaic collection units, each of which includes a plurality of photovoltaic devices; the photovoltaic devices are located in a photovoltaic device protection zone, and each photovoltaic device includes a photovoltaic array and a distributed DC concentrator.

[0016] Furthermore,

[0017] The DC collection network includes a DC transformer, and the DC transformer is located in a DC transformer protection zone.

[0018] Furthermore,

[0019] The DC transformer protection zone is the area between the DC busbar on the DC high voltage side and the low voltage side of the Boost unit; the protected equipment in the DC transformer protection zone mainly includes: a Boost boost unit, an LLC boost device, and a DC collector device.

[0020] Furthermore,

[0021] The AC protection zone is the area between the AC side of the inverter and the remote circuit breaker of the AC connection line; the protected equipment in the AC protection zone mainly includes: the AC side of the inverter, the connecting transformer, the inverter output circuit breaker, the AC connection line, and the remote circuit breaker.

[0022] Based on the same inventive concept, the present disclosure also provides a design device for a DC collection network protection system, including a protection area division and protected equipment confirmation module, a protection device configuration structure determination module, a protection function and action strategy setting module for the protection device, a protection function setting module for the protection device, and an electromagnetic transient simulation verification and feature module;

[0023] The protection area division and protected device confirmation module is used to divide the DC collection network into several protection areas and determine the protected devices in each protection area;

[0024] The protection device configuration structure determination module is used to determine the configuration structure of each protection device according to the division of the protection area;

[0025] The protection function and action strategy setting module of the protection device is used to set the protection function and action strategy of each protection device;

[0026] The protection function setting module of the protection device is used to set each protection function of each protection device;

[0027] The electromagnetic transient simulation verification and feature module is used to perform electromagnetic transient simulation verification and adjustment on the DC collection networking protection system to complete the design of the DC collection networking protection system.

[0028] Based on the same inventive concept, the present disclosure also provides a computer-readable storage medium storing one or more programs, which can implement any of the aforementioned methods when the one or more programs are executed.

[0029] Based on the same inventive concept, the present disclosure also provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; the memory is the aforementioned computer-readable storage medium, used to store one or more programs.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The protection system according to the design method disclosed in the present invention is suitable for large-capacity and high-penetration new energy DC collection networking. In the case of large volatility and intermittency of new energy, the DC collection networking can also be effectively protected;

[0032] 2. A protection zoning method and idea is proposed for large-capacity and high-penetration new energy DC collection networking, which is suitable for DC collection networking of various scales.

[0033] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by practicing the present invention. The purpose and other advantages of the present disclosure can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 A schematic diagram showing a flow chart of a design method for a DC collection networking protection system according to an embodiment of the present disclosure;

[0036] Figure 2 A typical protection partition diagram of a local DC collection network including a large-capacity photovoltaic station in an embodiment of the present disclosure is shown;

[0037] Figure 3A schematic structural diagram of a DC collection network protection device according to an embodiment of the present disclosure is shown;

[0038] Figure 4 A schematic diagram showing the structure of a design device for a DC collection network protection system according to an embodiment of the present disclosure is shown;

[0039] Figure 5 A schematic diagram of the structure of an electronic device according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0041] The protection device of DC collection network is an important guarantee for quickly and reliably removing faults, reducing the scope of fault impact, and ensuring safe and stable operation of the system. It is an important part of research and design work.

[0042] Generally speaking, the design of the protection system of the DC power transmission and distribution system mainly includes the design of hardware and software. Among them, the software design mainly focuses on the formulation of the protection strategy, which is also the core of the entire protection system design; the hardware design is the operation carrier and circuit implementation of the software protection algorithm.

[0043] Compared with AC systems, DC systems have the characteristics of complex equipment structure, diverse fault types, small system time constants, and rapid fault development. Therefore, higher requirements are placed on fault location, fault isolation, and fault recovery of system protection.

[0044] The protection scope of the DC collection network should include: modular multilevel converters, DC transformers, DC circuit breakers, DC busbars, and the AC lines connecting the converters to the AC system. Possible faults in the DC collection network include:

[0045] ① AC fault, mainly including faults on the AC valve side of the converter and the AC line;

[0046] ②Converter failure, mainly including failure of the bridge arm equipment inside the converter;

[0047] ③ DC fault, mainly including DC bus fault;

[0048] ④ DC transformer failure, mainly includes failure of internal equipment of DC transformer.

[0049] For the above-mentioned types of faults, the protection system should be able to fully cover the protection of all equipment within the protection range without any dead zones.

[0050] See attached Figure 1 A design method of a DC collection network protection system according to an embodiment of the present disclosure includes:

[0051] S1. Divide the DC collection network into several protection areas and determine the protected equipment in each protection area.

[0052] Attached Figure 2 A typical protection partition diagram of a local DC collection network containing a large-capacity photovoltaic station according to an embodiment of the present disclosure is shown. Figure 2 The DC collection network is divided into photovoltaic device protection zone, DC transformer protection zone, DC line protection zone, converter protection zone and AC protection zone.

[0053] The protection areas are divided according to the protected objects, and each protection area should be distributed in layers to completely cover all equipment within the protection range without any dead zones.

[0054] 1) The photovoltaic device protection area is the photovoltaic collection and networking area. The protected equipment mainly includes: photovoltaic component strings, electromechanical circuits, photovoltaic brackets, etc.

[0055] 2) The DC transformer protection zone is the area between the DC bus on the DC high voltage side and the Boost unit low voltage side.

[0056] The protected equipment mainly includes: Boost boost unit, LLC boost device and DC collector device.

[0057] 3) The DC line protection zone is the area between the outlet side of each DC transformer and the DC side of the inverter valve.

[0058] The protected equipment mainly includes: medium voltage DC busbars and DC transmission lines on both sides.

[0059] 4) The converter protection zone is the area between the AC side of the inverter and the DC bus.

[0060] The protected equipment mainly includes: converter arm reactor, inverter body and converter DC bus.

[0061] 5) The AC protection zone is the area between the AC side of the inverter and the remote circuit breaker of the AC connection line.

[0062] The protected equipment mainly includes: the AC side of the inverter, the connecting transformer, the inverter output circuit breaker, the AC connecting line, and the remote circuit breaker.

[0063] Figure 2In the DC collection network, there are several photovoltaic collection units, each of which contains several photovoltaic devices, and each photovoltaic device contains a photovoltaic array and a distributed DC combiner. The core equipment of the DC collection network is the DC transformer. The DC transformer (DCT) is located in the DC transformer protection area and is closely integrated with the DCT control device. Its protection functions include:

[0064] a. Current type: DC overcurrent protection, DC low voltage overcurrent protection, DC grounding overcurrent protection;

[0065] b. Voltage: DC voltage unbalance protection, DC low voltage protection, DC overvoltage protection;

[0066] c. Differential type: DC transformer differential protection.

[0067] The measurement points and function configuration of the DC transformer protection in the DC collection network in this embodiment are shown in the attached figure. Figure 3 As shown. Among them: I PV1P ,I PV1N are the positive and negative DC currents on both sides of the first photovoltaic array; U PV1P , U PV1N are the positive and negative DC voltages on both sides of the first photovoltaic array respectively; I dcP ,I dcN are the positive and negative DC currents on both sides of DCT; U dc1P , U dc1N are the positive and negative DC voltages on both sides of DCT; I grid1 They are respectively the currents of the DC grounding resistances on both sides of the DCT in the DC collection network backup power supply operation mode.

[0068] S2. Determine the configuration structure of each protection device according to the division of the protection area.

[0069] The protection device shall be configured according to the principle of proximity and simplicity, and full use shall be made of the power electronic devices with fast switching capabilities in the system to ensure close coordination between the protection system and the control system.

[0070] S3. Set the protection function and action strategy of each protection device.

[0071] For those skilled in the art, the above protection functions and action strategies are set according to the protection principles of DC power distribution equipment and power distribution systems.

[0072] The protection function of the protection device should be able to cover all types of faults in each protection area, and for the same fault, at least two protection functions with different principles should be configured.

[0073] S4. Adjust the protection functions of each protection device.

[0074] The setting of each protection function shall meet the minimum requirements for the transient characteristics of the DC collection network, and the main equipment protection device and the backup equipment protection device shall be clear, and the protection functions shall be coordinated to prevent refusal to operate or false operation due to unreasonable setting.

[0075] For those skilled in the art, the above-mentioned setting and determination of the coordination relationship are performed according to the operating characteristics and fault characteristics of the DC collection network.

[0076] S5. Perform electromagnetic transient simulation verification and adjustment on the DC collection networking protection system formed in the above steps S1-S4, and finally complete the design of the DC collection networking protection system.

[0077] Based on the same inventive concept, Figure 4 As shown, an embodiment of the present disclosure also provides a design device for a DC collection networking protection system, including a protection area division and protected equipment confirmation module, a protection device configuration structure determination module, a protection function and action strategy setting module of the protection device, a protection function setting module of the protection device, and an electromagnetic transient simulation verification and feature module.

[0078] The protection area division and protected device confirmation module is used to divide the DC collection network into several protection areas and determine the protected device in each protection area.

[0079] The protection device configuration structure determination module is used to determine the configuration structure of each protection device according to the division of the protection area.

[0080] The protection function and action strategy setting module of the protection device is used to set the protection function and action strategy of each protection device.

[0081] The protection function setting module of the protection device is used to set each protection function of each protection device.

[0082] The electromagnetic transient simulation verification and feature module is used to perform electromagnetic transient simulation verification and adjustment on the DC collection networking protection system to complete the design of the DC collection networking protection system.

[0083] The beneficial effect of the present disclosure is that it provides a common design idea for the protection system of large-capacity new energy DC collection networking, and lays a good technical foundation for the large-scale engineering application of DC collection networking.

[0084] Based on the same inventive concept, the present disclosure also provides a computer-readable storage medium storing one or more programs, which, when executed, can implement the aforementioned design method of the DC collection networking protection system.

[0085] As attached Figure 5As shown, an embodiment of the present disclosure further provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus.

[0086] The memory is a computer-readable storage medium for storing one or more programs.

[0087] The processor is used to execute the program stored in the computer-readable storage medium.

[0088] The computer-readable storage medium may be included in the device / apparatus described in the above embodiments; or may exist independently without being assembled into the device / apparatus.

[0089] Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; 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 disclosure.

Claims

1. A design method for a DC collection network protection system, characterized in that: The method comprises, Divide the DC collection network into several protection areas and determine the protected equipment in each protection area; Determine the configuration structure of each protection device according to the division of the protection area; Set the protection function and action strategy of each protection device; Set each protection function of each protection device; The DC collection networking protection system formed in the above steps is subjected to electromagnetic transient simulation verification and adjustment to complete the design of the DC collection networking protection system.

2. The method according to claim 1, characterized in that The protection area includes a photovoltaic device protection area, a DC transformer protection area, a DC line protection area, a converter protection area, and an AC protection area.

3. The method according to claim 1 or 2, characterized in that: The setting of each protection function of each protection device also includes determining the coordination relationship between the main equipment protection device and the backup equipment protection device.

4. The method according to claim 1, characterized in that The DC collection network is a partial DC collection network or a full DC collection network.

5. The method according to claim 2, characterized in that: The DC collection network includes a plurality of photovoltaic collection units, each of which includes a plurality of photovoltaic devices; The photovoltaic devices are located in a photovoltaic device protection zone, and each photovoltaic device includes a photovoltaic array and a distributed DC busbar.

6. The method according to claim 2, characterized in that The DC collection network includes a DC transformer, and the DC transformer is located in a DC transformer protection zone.

7. The method according to claim 2, 5 or 6, characterized in that: The DC transformer protection zone is the area between the DC busbar on the DC high voltage side and the Boost unit low voltage side; The protected equipment in the DC transformer protection zone mainly includes: a Boost boost unit, an LLC boost device, and a DC collector device.

8. The method according to claim 2, 5 or 6, characterized in that: The AC protection zone is the area between the AC side of the inverter and the remote circuit breaker of the AC connection line; The protected equipment in the AC protection zone mainly includes: the AC side of the inverter, the connecting transformer, the inverter output circuit breaker, the AC connecting line, and the remote circuit breaker.

9. A design device for a DC collection network protection system, characterized in that: The device includes a protection area division and protected equipment confirmation module, a protection device configuration structure determination module, a protection function and action strategy setting module, a protection function setting module and an electromagnetic transient simulation verification and feature module; The protection area division and protected device confirmation module is used to divide the DC collection network into several protection areas and determine the protected devices in each protection area; The protection device configuration structure determination module is used to determine the configuration structure of each protection device according to the division of the protection area; The protection function and action strategy setting module of the protection device is used to set the protection function and action strategy of each protection device; The protection function setting module of the protection device is used to set each protection function of each protection device; The electromagnetic transient simulation verification and feature module is used to perform electromagnetic transient simulation verification and adjustment on the DC collection networking protection system to complete the design of the DC collection networking protection system.

10. A computer-readable storage medium storing one or more programs, characterized in that: When the one or more programs are executed, the method described in any one of claims 1 to 8 can be implemented.

11. An electronic device comprising a processor, a communication interface, a memory and a communication bus, characterized in that: The processor, communication interface, and memory communicate with each other via a communication bus; The memory is the computer-readable storage medium according to claim 10, and is used to store one or more programs.

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