Method and device for clearing DC line fault of hybrid multi-terminal DC transmission system

A technology for DC line faults and power transmission systems, applied to emergency protection circuit devices, electrical components, etc., can solve problems such as increasing line fault power loss, achieve the effects of protecting equipment safety, reducing power loss, and improving reliability

Active Publication Date: 2019-03-12
XUJI GRP +4
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is to provide a method and device for clearing DC line faults in a hybrid multi-terminal direct current transmission system to

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  • Method and device for clearing DC line fault of hybrid multi-terminal DC transmission system
  • Method and device for clearing DC line fault of hybrid multi-terminal DC transmission system
  • Method and device for clearing DC line fault of hybrid multi-terminal DC transmission system

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Example Embodiment

[0027] Method Example 1

[0028] In the following, a hybrid three-terminal DC transmission system is taken as an example to illustrate the DC line fault clearing method of the hybrid multi-terminal DC transmission system of the present invention.

[0029] The topology of the hybrid three-terminal DC transmission system is as figure 1 As shown, it includes a rectifier station LCC station and two inverter stations, namely MMC station 1 and MMC station 2.

[0030] LCC station, MMC station 1, and MMC station 2 are respectively equipped with line protection systems. The line protection of LCC station includes traveling wave protection, voltage mutation protection, DC line low-voltage protection, DC line longitudinal differential protection; MMC type converter with busbar Line protection of stations (such as MMC station 1) includes traveling wave protection, voltage mutation protection, and busbar differential protection; MMC converter stations that do not include busbars (such as MMC stat...

Example Embodiment

[0038] Method Example 2

[0039] In the following, a hybrid four-terminal DC transmission system is taken as an example to further illustrate the DC line fault clearing method of the hybrid multi-terminal DC transmission system of the present invention.

[0040] Its topology is as Figure 5 Shown in figure 1 On the basis of this, an inverter station MMC station 3 is added, and a DC line 3 is added accordingly.

[0041] When it is judged that the DC line 1 is faulty, the DC system first shifts the phase and clears the fault current. After the line de-freezing time, the DC system restarts. At this time, if the DC line 1 fault is cleared, the DC system establishes voltage and current to restore power transmission; The fault of DC line 1 still exists, and it is detected that the DC voltage has not been established, and all the converter stations are controlled to be extremely blocked.

[0042] When it is judged that the DC line 2 is faulty, the DC system first shifts the phase and clears...

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Abstract

The invention relates to a method and device for clearing a DC line fault of a hybrid multi-terminal DC transmission system. For a DC system composed of a rectifier station and N-1 inverter stations (N is greater than or equal to 3), there are N-2 busbar areas on a DC line for connecting the rectifier station on the head end and the inverter station on the tail end, each busbar area is connected with an intermediate inverter station, when the DC line between two adjacent busbar areas or the DC line between the busbar area on the tail end and the inverter station on the tail end is faulty, theDC system is controlled to be restarted; and if the DC system is restarted unsuccessfully, the inverter station at the downstream of the faulty DC line is locked, and the intermediate inverter stationand the rectifier station on the head end on the upstream of the faulty DC line are restarted. By adoption of the method and device provided by the invention, the power loss during the line fault andthe disturbance to an AC system are reduced, and the fault clearing of the line fault of the hybrid multi-terminal DC transmission system is realized through a specific line fault clearing method, sothat the reliability of the hybrid multi-terminal DC transmission system is improved.

Description

technical field [0001] The invention belongs to the technical field of hybrid direct current transmission, and in particular relates to a method and device for clearing DC line faults in a hybrid multi-terminal direct current transmission system. Background technique [0002] In recent years, HVDC transmission has become an important part of the West-to-East power transmission strategy due to its advantages of large capacity and long-distance transmission. HVDC power transmission projects mostly use conventional LCC (Line Commutated Converter) converters, which have the advantages of large transmission capacity, low cost, and strong overload capacity. The problem of failure. [0003] In recent years, the DC transmission system based on Modular Multilevel Converter (MMC) technology has made rapid progress. The MMC converter has many advantages such as independent control of active and reactive power, no commutation failure, and power supply for passive island systems. The ...

Claims

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Application Information

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IPC IPC(8): H02H7/26
CPCH02H7/268
Inventor 范子强吴庆范黄金海戴国安曹森周晓风许朋见付艳吴金波李传西
Owner XUJI GRP
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