The overvoltage research on UHVDC when the UHVDC system runs in single pole way

Abstract

The ultra high voltage current (UHVDC) is the important technical means for the solution of high voltage, large capacity, and long distance power transmission. plusmn800 KV UHVDC transmission technology will be used in the project which transfer hydroelectric power in Yunnan Province and Sichuan Province to Guangdong Province and Shanghai and other east places in China. During the building course of double poles UHVDC system, one pole is often built up and run firstly, then the other pole is built and run. Even double poles are finished and run, if one pole defaults, the UHVDC system will run in single pole way. So single running way is common in UHVDC system, it is necessary to do some overvoltage research on UHVDC when the system runs in single pole way. The Yunnan Province to Guangdong Province plusmn800 KV UHVDC system is taken as example to study the overvoltage, the single pole circuit of Yunnan Province to Guangdong Province UHVDC transmission system is given out, and the parameters of different electric equipments such as converter transformer, converter, electric line, reactor, filter are given out, too. Then this paper introduces some defaults which cause the overvoltage in UHVDC system, such as the AC defaults including three phases short circuit, two phases short circuit, one phase earthing and the DC transmission line default, the output breaker opening and so on. The PSCAD/EMTDC is used to simulate the UHVDC transmission system. Firstly, the model with PSCAD/EMTDC is built up, and then different defaults which cause overvoltage are simulated. The simulation result are given out and some useful conclusion are drawn in this paper.