不对称运行条件下VSC-HVDC动态相量建模

Dynamic Phasors Modeling of the VSC-HVDC Under Unbalanced Conditions

为了提高仿真精度和减少计算量,采用动态相量法,针对不对称运行条件下的基于电压源型换流器的直流输电系统(VSC-HVDC)进行建模。动态相量法基于时变傅立叶级数,所建模型为近似时不变的大信号模型。该模型比准稳态模型精确,同时与详细电磁暂态模型相比,能够显著提高计算效率。使用动态相量模型对不对称条件下的VSC-HVDC响应特性进行了仿真,并与电磁暂态程序的计算结果对比表明,此模型是精确有效的。

We established a dynamic model for VSC-HVDC systems on the basis of the dynamic phasors approach. The model was derived in a synchronous dq reference frame, and could be used to simulate the behavior of VSCHVDC systems under unbalanced conditions. The dynamic phasors were based on the time-varying Fourier coefficient series and the established model was an approximate time-invariant large-signal model. The dynamic phasors model was more accurate than quasi-steady state model, and it was more efficient than detailed electromagnetic model. The dynamic phasors model was validated via simulation of a VSC-HVDC system under unbalanced conditions through PSCAD/EMTDC. The results show the dynamic phasors model is accurate and efficient.