T&D LIBRA: Simulation Framework for Transmission and Distribution Load and IBR Assessment

This paper introduces T&D LIBRA, a HELICS-based co-simulation framework designed for transmission and distribution (T&D) load and inverter-based resource assessment. This framework specifically models interactions between distributed energy resources (DERs) and the transmission network, emphasizing DER impacts on system stability during fault conditions. Collectively, PyDSS, PyPSSE, and the HELICS framework are used to model controllers for motor loads and DERs, manage the exchange of voltage and power values over time, and perform calibration operations between the T&D network models. Simulations are validated with a single distribution node and the IEEE 13-bus distribution test case, and the co-simulation results demonstrate that the proposed framework can capture DER behavior, such as motor load stalling and DER tripping, enhancing power system models for a more accurate assessment of T&D interactions.