关于RTDS直流换流器熄弧角计算方法的商榷

直流换流器熄弧角是直流输电系统的重要电气量，常被用于判断直流输电系统逆变器的换相失败．在电力系统分析中，一般当直流熄弧角小于阀去游离时间对应的最小角度，则判断直流输电系统发生了换相失败。近来研究发现．RTDS等电磁暂态仿真工具输出的“熄弧角”只能用于辨别是否发生了换相失败．但却并不能用来详细分析换相失败特征．即该熄弧角并不是直流换流器的真正熄弧角．通过与相关仿真技术人员的商榷．研究了RTDS的熄弧角角度的计算方法。RTDS通过不断刷新阀桥6个阀的最小熄弧角去得到熄弧角．而不是各阀组熄弧角的依次组合输出。基于RTDS和带有实际直流控制保护系统的闭环仿真案例研究进行了必要的说明．所阐述的换相失败发生过程及其各种电气量轨迹对研究和理解直流换相失败的特征具有一定的意义．基于对换相失败各电气量的轨迹的研究．对电磁暂态仿真的直流输电换相失败的判断和分析给出了建议的方法．

Discussion on Computation Method of the Extinction Angle of the DC Converter in RTDS

The extinction angle of the DC converter,which is usually used to study the commutation failure of the DC inverter,is an important parameter in the DC transmittal system.In the power system analysis,the commutation failure is considered to occur when the extinction angle is less than the least angle corresponding to deionization time of the valve.It is found recently that Gamma extinction angles produced by some electromagnetic transient simulation tools,such as RTDS,only can be used to determine whether the commutation failure have happened,but cannot be used to study the detailed characteristics of the communication failure.Through the discussions with the correlative simulation technology engineers,the calculation method of RTDS extinction angle is studied.RTDS gets the extinction angle from refreshing the minimum value of the six valves of the converter bridge,but not from the ordinal extinction angle of every valve.Some necessary explanations are given based on a research on a real-time closed-loop simulation of RTDS and actual DC control-protection system.The communication failure procedure and the correlative electrical parameters curves given in this paper are very meaningful for study and understanding of DC communication failure.Through the study on the curves of the parameters of communication failure,some methods in analyzing the characteristics of communication failure are given in the end.