A fault testing method of hvdc converter valve control unit based on TCU structure

Abstract

As the basic control unit of thyristor, the reliability of thyristor control unit (TCU) is a fatal device for the reliability of HVDC transmission system. However, the defects of TCU frequently occurred in ±500kV Gui Zhong converter station, such as IP loss, IP oscillation, protective triggering and other abnormal phenomena. Meanwhile, standard of test method and system specially designed for TCU neither existed in Chinese discipline nor in IEC-60700-1. So it is necessary to design special tests on TCU which aim to recover the fault and find out the causes before being put into use. The paper presented the TCU test method, which is used to analyze the fault part of TCU in the converter station. The defeated components are successfully proved to be clipped triode inside the TCU. The test method is necessary supplement for test standard, operation and overhaul of HVDC transmission projects.