基于改进的稳态法测量电力系统谐波阻抗

在实际电力系统运行过程中,三相系统不对称且各相间存在耦合阻抗,应用稳态法不能准确获取系统谐波阻抗,利用相模变换改进的稳态法来测量谐波阻抗。首先求取相模变换矩阵改进稳态法,将三相电力系统的三组可测数据解耦为单变量数据,简化计算过程。其次,在Matlab/Simulink中分别建立单相仿真模型和存在耦合阻抗且不对称运行的三相仿真模型,对比研究稳态法与改进的稳态法计算系统侧谐波阻抗。实验表明改进后的稳态法测量三相系统谐波阻抗,提高了测量准确率,并简化了计算过程。

The network harmonic impedance determination based on the improved steady-state methods

In this paper,the improved steady-state method is proposed to obtain the system harmonic impedance.Steady-state methods can't give the accurate results when three-phase unbalance load and the coupling impedance exist in power system.Firstly,the phase-mode transformation matrix is calculated to improve steady-state method.The transformation can de-couple the three measurements into a set of single variables and simplify the calculation process;Secondly, single-phase model and three-phase model are established by Matlab/Simulink to compare steady-state methods with the improved steady-state methods while the coupling impedance and three-phase unbalance load exist in the three-phase model.The steady-state methods and the improved steady-state methods is applied to calculate the the system harmonic impedance.The results show that the steady-state methods improved by the phase-mode transformation improves the accuracy and simplifies the process of calculation when the method is applied to obtain the three-phase system harmonic impedance.