Sensitivity Analysis and Accuracy of Multiphase Linear Power Flow Models

Abstract

We analyze the accuracy of a linearized bus injection (LMBI) model for unbalanced multiphase networks with explicit models of common three-phase transformers and compare it to LinDistFlow, which uses simplified three-phase transformer models. First, we analytically study the sensitivity of the LMBI model approximation error to generalized load and network parameters in a two-bus network with common bus models. The analysis captures the sensitivity of the LMBI model to (i) loading, (ii) line losses, (iii) and direction of power flow. Comprehensive numerical studies of a modified IEEE 13-bus system are used to illustrate the analytical results and compare the accuracy of LMBI and LinDistFlow models. Results are presented for (i) common three-phase transformer connections, (ii) the integration of inverter-based resources (IBRs), and (iii) various load and generation profiles, including reverse power flow.