Coupled Transmission and Distribution Simulations to Assess Distributed Generation Response to Power System Faults

The historical simulation approach of aggregating distributed generation (DG) with load for transmission simulations is proving inadequate at capturing these DG dynamics. Presented is a methodology that uses interfacing data sets to couple disparate simulations in an iterative manner. This methodology was implemented with a Positive Sequence Load Flow (PSLF) dynamic model of the Western Interconnection with 9 GW of DG. A transmission fault leading to a fault-induced delayed voltage recovery (FIDVR) is analyzed with this iterative coupled simulation method, with more than 120 substation voltage profiles extracted, representing more than 4 GW of DG, and simulated in OpenDSS to capture the ride-through dynamics. OpenDSS simulations of feeders populated with photovoltaic DG and associated time-dependent tripping and momentary cessation criteria based on the IEEE 1547 standard are performed. Coupled simulation results show significant differences in DG responses, as well as overall system responses, between single PSLF and the coupled simulations.