Dynamic Equivalent of a Distribution Grid Hosting Dispersed Photovoltaic Units

peer reviewedThis paper deals with the derivation of a simplified model of a distribution network hosting dispersed photovoltaic units. The model is aimed at short-term dynamic simulations of a transmission grid in response to large disturbances. In a first step, a generic dynamic model of a photovoltaic unit is proposed, focusing on its interactions with the grid, in particular the controls triggered by voltage disturbances. The model takes into account various present and near-future grid codes. In a second step, a dynamic equivalent is derived accounting for the distribution network, the dispersed photovoltaic units, as well as static and dynamic (motor) loads. This equivalent is of the “grey-box” type and its parameters are tuned in the least-square sense to match the dynamic response of the original, unreduced system. Simulation results are reported on a detailed 913-bus distribution system subject to faults at transmission level