构网变流器故障期间维持电压源特征的暂态电流解析计算及参数可行域分析OA

To address the key challenge of quantitatively characterizing the ability and conditions for grid-forming converters to maintain voltage source characteristics during fault conditions,this paper first proposes an analytical method for fault current calculation by decoupling the reactive power-voltage control loop from the electromagnetic transient behavior of the network.This method transforms the originally complex and analytically intractable second-order differential equations into two simple first-order differential equations that can be solved sequentially.Then,to quantify and characterize the capability and boundary conditions for grid-forming converters to maintain voltage source characteristics during faults,this paper defines a two-dimensional visualizable parameter feasible region with the fault voltage drop at the point of common coupling(UgF)and the virtual inductance(Lv)as key parameters.A practical characterization method for the parameter feasible region based on the boundaries and vertices is proposed for the first time.Specifically,the critical vertices of the UgF-Lv feasible region are determined based on the constraints of the maximum overcurrent capability of grid-forming converters and the internal potential saturation limit.Subsequently,the practical boundary of the UgF-Lv feasible region is characterized based on its near-linear geometric property.Finally,the effectiveness of the characterized parameter feasible region is validated through experiments on an RT-Lab-based hardware-in-the-loop experimental platform.