Revisiting the Tripping Logic of the DER_A Model for Power System Stability Studies

The increasing amount of Distributed Energy Resources (DERs) in Distribution Networks (DNs) has awakened the interest of system operators to represent how DERs will react to large disturbances. These units will respond according to the ride-through capability curves, the tripping logic settings, the local voltage magnitude, and frequency measurements. In this paper, we show the limitations of the well-known DER_A model and propose changes to represent better the ride-through capabilities and the tripping of a population of DERs units. We also show the need for more than one aggregation in the same bus to represent the response of the old and modern DERs technologies. To validate the new model, we run dynamic simulations of a Transmission Network (TNs) and DNs with hundreds of DER units modeled in detail. The simulation results show that the proposed changes improve the representation of a population of DERs during low-voltage and low-frequency events.