PNNL

Abstract

As Distributed Energy Resources (DER) projects grow in popularity, there has been little focus on thier ability to influence the transmission system's dynamic stability. If implemented in large enough numbers, it may be feasible to leverage DER to provide ancillary services such as Spinning Reserve, System Inertia, or System Stabilization. In an attempt to determine the potential impacts of DER on transmission grid stability, dynamic models of DER/load combinations were created, reduced in order, and scattered throughout Central and Southern California within an existing WSCC dynamic model. Evaluation of the composite WSCC/DER dynamic model allows correlations to be drawn between various DER properties and the transmission grid stability. Key findings show that increasing DER inertia tends to destabilize the transmission system. The cause of this counter-intuitive relationship requires further study, but is likely related to the high impedance separating the DER from the transmission grid.