Method for prejudging phase change failure of converter valve

Abstract

The invention provides a method for prejudging phase change failure of a converter valve. The method includes the steps of calculating an inverter side alternating current voltage amplitude per unit value and a direct current per unit value, calculating a fire angle upper limit of the converter valve on the inverter side and prejudging whether phase change is failed. According to the method for prejudging the phase change failure of the converter valve, phase change failure caused by inverter side alternating current system failure or direct current system overloading and other common reasons can be accurately judged, and information is provided for preventing the phase change failure. Judgment can be carried out quickly, phase change failure judgment information can be obtained in 1ms after the failure occurs, and measures can be quickly taken to prevent the phase change failure. Judgment is accurate, the calculation method of the fire angle upper limit is obtained through theoretical deduction, and the phase change failure can be accurately judged through the method.

Description

technical field [0001] The invention relates to a prediction method, in particular to a prediction method for commutation failure of a converter valve. Background technique [0002] After the thyristor valve period in the 1970s and 1980s, power electronics technology has greatly developed DC transmission, and has shown more advantages in the interconnection of large power grids. The traditional pure AC power grid has developed into an AC-DC hybrid power grid; Conventional grid commutation HVDC (Line-Commutated-Converter High Voltage Direct Current, LCC-HVDC) with thyristors as commutation components has gained rapid worldwide popularity due to its large-capacity, long-distance power transmission, and fast and controllable active power. development of. [0003] The commutation failure (CF) of the converter station and the fault of the DC line are relatively common fault forms of the DC system. When the power grid fails or the three-phase is seriously asymmetrical, the AC bu...

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Problems solved by technology

ABB, SIEMENS, etc. are the few companies in the world that can complete the design and manufacture of DC transmission control and protection systems. The control and protection systems currently used in China mainly adopt the solutions of the above two companies, and the domestic research on control and protection strategies for HVDC system failures and the commutation failure prediction method proposed by ABB can only judge the occurrence of AC side faults, but cannot judge whether this fault will cause commutation failure

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