用瞬时值对称分量计算不对称短路电流直流分量衰减时间常数

Calculation of Attenuation Time Constant of DC Component of Unsymmetrical Short-circuit Current by Instantaneous Symmetrical Component

为解决电力系统不对称短路电流直流分量的衰减时间常数缺乏简便可行的计算理论与方法的问题,提出一种实用计算方法。该方法将基于120变换的瞬时值对称分量用于电力系统等值模型和不对称短路边界条件,导出120复合序网,通过分析特殊相直流分量的1、2、0序分量流经的120复合序网通路,导出相应时间常数的理论计算公式。EMTP仿真实验值和理论计算值验证了所提方法的正确性与适用性。

To solve the problem that there is a lack of simple and practical calculation theories and methods to calculate the attenuation time constant of DC component of unsymmetrical short-circuit current in power system,a practical calculation approach is proposed in this paper. By applying the instantaneous symmetrical component based on the 120-transformation method to the equivalent model of power system and the unsymmetrical short-circuit boundary condition,the interconnected 120-sequence network is deduced to analyze the flowing paths of 1-,2-and 0-sequence components of the DC component in particular phase,which in turn leads to the theoretical expression for calculating the corresponding attenuation time constant. The results from EMTP simulations and theoretical calculations verify the correctness and applicability of the proposed method.