Study On Control System Of Uhvdc High Voltage Direct Current Transmission Project

With the operation of Yunnan to Guangdong±800kV UHVDC project, it is one new voltage level in the electric power construction of the world.Yun-Guang project is the demonstration project of China, and is also the first ultra high voltage direct current transmission project in the world. It is a project with a rated voltage of±800kV,a rated power transmission capacity of 5000 MW. This project started construction in December 2006,single pole have been putting into operation in 2009,and bipolar put into operation in 2010.It transmits power from Xiaowan hydropower station and Jin'anqiao hydropower station to Guangdong province.The configuration of Yun-Guang project is consist of two serial connected 12-pulse-valve-groups(400kV+400kV), with high voltage, large transmission capacity, for valve complex, and many other features.The control system is mainly to achieve the AC and DC equipment monitoring and control functions,reliable, rapid, coordinated control of bipolar operation mode, transmission power,coordination of the two group per pole DC current, DC voltage, and control mode, so that reliable and stable operation of the UHVDC.UHVDC control system uses a hierarchical distributed structure, fully redundant configuration,including operator control level, control level, field level.The control level is main level of control system,from the pole control system, group control system, AC and DC station control system.DC pole control functions also uses a hierarchical structure,including bipolar control level functions, pole control level functions, converter control level functions.This article from the AC and DC station control system, the pole control system, the function of group control system working principle, control strategy, implementation, in-depth analysis and research.Fully detailed description of the UHVDC control system functions.By reactive power control function, converter Deblock/Block, step response, control mode switching, transfers between DC configurations, commutation failure, the DC line fault recovery sequence, stability control, and other over-voltage suppression test debug, further verify this UHVDC control system with stability control and fully functional features, a single valve group to achieve a smooth sequence of input and output control, further verify the characteristics of a good control system can effectively suppress AC system over-voltage level in the DC system power loss extreme cases.