LCC-VSC多端混合直流电网潮流计算方法

Power Flow Calculation Method of Multi-Terminal Hybrid LCC-VSC DC Grid

提出了基于多种控制方式下的LCC-VSC多端混合直流电网潮流计算方法。首先,分析了直流电网元件的稳态模型,建立了混合直流电网的稳态模型,然后根据换流器的类型、控制方式及直流电网的控制策略,建立了多种控制方式下的潮流方程,并采用经典的牛顿-拉夫逊法进行求解,进而在此基础上采用顺序法对交直流混合电网进行解耦,并处理直流电网边界信息和交流电网的边界信息,然后采用交直流混合电网交替迭代求解。最后在改进的PSS/E算例验证了本文所提方法的有效性和准确性,为多端混合直流电网机电暂态仿真提供了准确的初值。

A power flow calculation method of multi-terminal hybrid LCC-VSC DC grid based on multiple control modes is proposed.Firstly,the power flow model of the DC network component is analyzed,and the steady-state model of the hybrid DC grid is established.Then the classical Newton Raphson method is used to solve the equation which is established according to the control mode,the control strategy of the DC grid and the power flow equations under various control mode according to the type of converter.Thirdly,the AC/DC hybrid network is decoupled by sequential method,and boundary information of DC network and the AC grid are processed,and the AC/DC hybrid grid is solved iteratively.Finally,an improved PSS/E example is given to verify the validity and accuracy of the proposed method which provides an accurate initial value for the electromechanical transient simulation of the multi-terminal hybrid DC grid.