交直流混合模式下变压器动态电感参数辨识方法

Identification of Dynamic Inductance for Transformer Under AC-DC Hybrid Mode

电力变压器在交直流混合模式下运行时的电感和电流变化与传统情况具有明显区别,该文结合电磁耦合机理提出一种动态电感参数的辨识方法。建立磁场-电路耦合模型,以时域电流和动态电感为关键耦合参数,采用棱边有限元法求解磁场模型,利用局部线性化的方法获取系统能量,基于能量原理计算动态电感。采用四阶龙格库塔法计算时域电流,通过非线性磁场和微分电路迭代实现磁场与电路的耦合。研究无直流和交直流混合条件下变压器的电磁特性,结合励磁饱和状态,分析动态电感波动情况并总结其变化规律。通过仿真计算与实验数据对比,验证该文方法的有效性和所得结果的正确性。

The current and inductance of transformer under the AC-DC hybrid condition have significant differences from the traditional cases. An identification method is put forward through the electromagnetic mechanism in this paper. The field-circuit coupling model of transformer is established, which is decomposed into inductance calculation and current computation, as the key parameters to realize the coupling. By solving the magnetic field with the edge finite element method, the energy of systems is calculated using the local linearization method. And the inductance is computed based on the energy principle. Meanwhile, the time-domain electrical circuit model is calculated by the fourth order Runge-Kutta method. The electromagnetic characteristics of transformer are learned considering different conditions. The fluctuations of dynamic inductance is analyzed and summarized by combining with the saturated states of excitation. Comparing the computed results with the experimental data shows consistency. And the method proposed is proved.