Equivalent Circuit for LVDC Grid Fault Analysis: Numerical Parameters Evaluation

LVDC systems have many well-known advantages, yet their diffusion is limited by many challenges related to the overall system control and stability, pre-charging and grounding practices, coordination of the protection devices and, moreover, lack of standardization. Both traditional and more recent methods for DC fault calculation often require detailed analysis of the entire grid, which is impractical, or are limited to simple grids and bolted faults. In this paper, a numerical method to determine an approximation of a portion of a DC system is explored. The proposed method allows the determination of a simple secondorder equivalent circuit, which correctly approximates the overall grid dynamic in the section of interest. This, in turn, enables a focused analysis of any device connected to a specific grid section, resulting in significant reduction of the complexity and computation times of fault analysis and protection devices selection.