Modeling and Fault Characteristics Analysis of Ultra High Voltage Direct Current Transmission System

With the increasing demand for energy, the ultra high voltage direct current (UHVDC) transmission system has received extensive attention. Line commutated converter (LCC) is the most commonly used converter technology in HVDC system. The analysis of its fault characteristics is very significant for the system. In this article, the system structure and basic principle of LCC UHVDC transmission are described, and the situations of normal operation and fault are analyzed theoretically. Based on the actual engineering parameters of the project, the simulation model of ±800 kV UHVDC transmission system is built by using electromagnetic transient simulation software PSCAD/EMTDC. And the fault characteristics are simulated to validate the accuracy of the theoretical analysis.