Modeling and assessment of the fault ride-through capabilities of grid supporting inverter-based microgrids

Abstract

Grid-connected micro-grids are subject to grid disturbances. This has undesirable effects on system operation. Riding through fault conditions is a crucial technical challenge. Evolving grid codes require micro-grids to possess fault ridethrough capabilities and support the grid voltage recovery to imitate the behavior of the traditional electrical power systems. The paper proposes two models of a grid supporting inverterbased microgrid; the first controlled as a current source with a parallel impedance suitable for grid feeding applications; the second regulated as a voltage source with a virtual impedance suitable for grid forming applications. The main objective of these two systems is to achieve controlled power delivery to the grid using grid voltage and frequency regulation. This paper discusses power interaction under steady states and transient conditions. Grid voltage parameters, such as amplitude, phase angle, and frequency, are estimated using a synchronization system, as these are necessary for precise active and reactive power control. Results obtained provide an understanding of grid fault impact on grid supporting systems and fault ridethrough compliance and evaluates the impacts of the virtual impedances on fault ride through and power interaction.