Analysis Of Operation Risk And Precontrol Of The Control And Protection System In±800kV Yun Guang UHVDC Transmission Project

With the continuous development of the power grid, new technologies are constantlyemerging and put into use in order to meet the increasing and various needs of the grid.Meanwhile, new theories should be studied to ensure the safe operation of the power gridafter the introduction of appropriate technologies. Currently, large-capacity and long-distancepower transmission has become the development trend in China, and the ultra-high voltageDC power transmission (UHVDC) technology occupies an extremely important position inhigh-capacity, long-distance power transmission. Therefore, to carry out research in UHVDCcutting-edge technologies, is of great significance to the building of UHV power grid and itssafe and stable operation.As the first commercially viable UHVDC power transmission project in the world,Yunnan-Guangdong±800kV DC power transmission project has no existing specificationsand technical standards, which needs to be explored in the actual operation and maintenance.Along with the launch of UHVDC projects, the primary tasks of UHVDC operation andmaintenance units, are to develop a deep understanding of the characteristics of UHVDCsystem and timely sum up on-site operation and maintenance experience of the ultra-highvoltage control and protection equipments.This paper takes the control system and protection system of the Yunnan-Guangdong±800kV UHVDC project as the research object. From the particular perspective of on-siteoperation and maintenance, with the accumulated experience of various stages includingproject acceptance, debugging and commissioning, it clarifies how the Yunnan-GuangdongUHVDC system runs, and thus provides an in-depth analysis of the strategies of its controlsystem and protection system.With the Series connection of double12-pulse valve groups, the Yunnan-Guangdong±800kV UHVDC project has flexible ways of operation, which on one hand improvesreliability of the system, but on the other makes the logic of its control and protection systemmore complex. The paper introduces the basic strategies of the Yunnan-Guangdong±800kVUHVDC project control system, and makes a detailed analysis of the valve control system,pole control system, DC station control system, communication system and the space stationcontrol unit. In terms of the protection strategies, the paper not only analyzes its reliability,but also focuses on the DC protection, AC filter protection and conservation and converterprotection.The risks of the Yunnan-Guangdong UHVDC control and protection system are also put forward in this paper. To prevent mutual influence between the bipolar or between thehomopolar double valve, it also proposes effective identify of the risks of the operation andmaintenance process, and gives corrective recommendations and pre-control measures for theexisting defects at the same time. The reasonable pre-control measures will help to solve theproblem of lack of experience in the UHVDC system operation and maintenance. This,therefore, will be useful for experience accumulation of the UHVDC operation andmaintenance, as well as its subsequent UHVDC construction.