Direct-current converter station and control method and system thereof

Abstract

The invention provides a direct-current converter station and a control method and system thereof. The control method of the direct-current converter station comprises: controlling a receiving end converter station by adopting an active-reactive control method; adding an input power regulation module at the input end of an active-reactive power control power loop, and connecting the input power regulation module with an active-reactive power control power loop; and adjusting, by the input power adjusting module, an input power instruction of active-reactive control according to the voltage ofthe receiving end power grid and the voltage of the receiving end direct-current bus. By utilizing the method, reactive power can be continuously provided for the power grid when the voltage of the receiving-end power grid drops, an over-current phenomenon does not occur in the converter station, the system can stably operate after fault recovery, the direct-current bus voltage can be stabilized when the voltage of the sending-end power grid drops, and the system can stably operate after fault recovery.

Description

technical field [0001] The invention relates to the technical field of electric power transmission and distribution, in particular to a DC converter station and its control method and control system. Background technique [0002] With the continuous adjustment of my country's energy structure, flexible direct current transmission (HVDC), as a new type of power transmission method, is suitable for medium and long-distance transmission, especially in the The long-distance transmission of renewable energy and the interconnection of power grids have been widely used. [0003] Low-voltage ride-through (LVRT) capability means that when a voltage drop occurs at the grid-connected point, the grid-connected converter system can maintain the grid-connected state, and the system can resume normal operation after the power grid recovers. The low-voltage ride-through capability has been used as the grid-connected system at present. An important indicator has received extensive attention ...

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Problems solved by technology

[0003] Low-voltage ride-through (LVRT) capability means that when a voltage drop occurs at the grid-connected point, the grid-connected converter system can maintain the grid-connected state, and the system can resume normal operation after the power grid recovers. An important indicator has received extensive attention in engineering practice. Most of the research on LVRT in the academic circles focuses on the low-voltage ride-through capability of the receiving-end converter station system. However, when the voltage drops in the sending-end converter station, the failure of the HVDC system There are relatively few studies on the phenomenon and crossing control, and in-depth research is needed

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