A control method for reducing the short-circuit current of the converter station of the two-terminal flexible direct current transmission system

Abstract

The invention discloses a control method for reducing the short-circuit current of a converter station of a flexible DC power transmission system at both ends, which comprehensively considers the magnitude of the short-circuit current provided by the flexible DC converter station, its control mode, operating conditions, and the limiter of the inner and outer loop controllers. This control method utilizes the fast response characteristics of the flexible DC converter while ensuring that the flexible DC converter station is not blocked, and controls the converter station by adjusting the reactive shaft current reference value of the outer loop controller of the receiving end converter station. The AC current output when the AC system is short-circuited can reduce the short-circuit current provided to the fault point when the receiving-end converter station is short-circuited, and then reduce the short-circuit current level of the AC system. important reference.

Description

technical field [0001] The invention belongs to the technical field of flexible power transmission and distribution of power systems, and in particular relates to a control method for reducing the short-circuit current of a converter station of a flexible direct current transmission system at both ends. Background technique [0002] Flexible DC transmission is the third-generation DC transmission technology based on voltage source converter technology. Generally, the converter element used is a bidirectional controllable power electronic device that can control both conduction and shutdown. The typical representative is the insulation Gate Bipolar Transistor (IGBT). There are mainly three topologies of voltage source converters used in existing flexible HVDC projects, namely two-level converters, diode-clamped three-level converters and modular multilevel converters ( MMC); Each bridge arm of a modular multilevel converter cascaded with sub-modules (SM) is composed of multi...

AI Technical Summary

Problems solved by technology

[0005] When there is a short-circuit fault in the AC system near the DC converter station, especially at the PCC, there are generally two measures to reduce the short-circuit current provided by the converter station: one is to block the converter station. On the AC side, it is equivalent to an open circuit and will not provide short-circuit current, but the process of restarting after the converter station is blocked is cumbersome and time-consuming; the other is to limit the short-circuit through appropriate control measures when the DC converter station is not blocked. current, the fault ride-through of the flexible DC converter station is realized by using the fast control response of the flexible DC converter station

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