Modification of condition assessment for HVDC equipment used in high altitude area

In order to make a more accurate and effective assessment of the status of the main equipment of the ±400kV Qingzang HVDC project, which is the world's highest altitude transmission project, the impact of high altitude on the operation of HVDC equipment was studied, and the correction model of condition assessment of HVDC equipment was proposed. External insulation strength, heat-sinking capability, ultraviolet radiation, and temperature difference day and night in high altitude area were analyzed theoretically. The state parameters which need to be revised at high altitude were selected based on the correlation analysis. Referring to the Condition Evaluation Guide established by State Grid, the weight of the condition variables related to altitude was revised, and the evaluation method for HVDC equipment in high altitude area was proposed. The remote condition monitoring and operation condition evaluation system for primary equipment of ±400kV Qingzang HVDC project was established in the mode of concentrated construction. It is demonstrated that the altitude correction factors can effectively improve the accuracy of condition assessment of HVDC equipment operation in high altitude.