Research On Modeling And Protection Setting Of Line Protection Of Xiangjiaba-shanghai UHVDC Transmission Project

In recent years, HVDC transmission technology developed very rapidly which has the ability of transmit power of long distance, high capacity and low loss, the line is cheap and the control performance is good.HVDC transmission technology has gradually become the main method to solve the problem of high voltage, large capacity,long distance transmission and power grid interconnection, and HVDC transmission become the hot spot of the electric power construction of our country because of the power of west to east, north and south for the national network.With HVDC transmission play a more and more importance role in power grid, how to enhance the security and reliability of the system has become a emergency problem to solve.The DC line in the HVDC system is long and has high failure rate, in recent years,the DC line protection has become an important part of the HVDC urgent need to improve and perfect the system of protection, so it’s necessary to make the simulation and research on the DC line protection, analyze its fault characteristics and improve its protection scheme further.Firstly, this paper briefly describes the overview of the HVDC system and HVDC protection system and then use PSCAD / EMTDC electromagnetic simulation software to built an bipolar 12-pulse HVDC system model based on Xiangjiaba-Shanghai ± 800 kV UHVDC transmission project. After analyzing the existing DC line characteristics and the principle of the protection,the DC protection models were built on the HVDC system model. On the basis of the different DC line fault simulation experiments and DC line fault dynamic analysis, tuning and analyzing for each protected setting value based on the simulation results, and take simulation of the protection scheme in the HVDC system model.