Convex Relaxation of OPF in Multiphase Radial Networks with Wye and Delta Connections

Conference · Tue Aug 01 04:00:00 EDT 2017

OSTI ID:1374123

Zhao, Changhong ^[1]; Dall-Anese, Emiliano ^[1]; Low, Steven ^[2]

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1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2. California Institute of Technology

This panel presentation focuses on multiphase radial distribution networks with wye and delta connections, and proposes a semidefinite relaxation of the AC optimal power flow (OPF) problem. Two multiphase power flow models are developed to facilitate the integration of delta-connected loads or generation resources in the OPF problem. The first model is referred to as the extended branch flow model (EBFM). The second model leverages a linear relationship between phase-to-ground power injections and delta connections that holds under a balanced voltage approximation (BVA). Based on these models, pertinent OPF problems are formulated and relaxed to semidefinite programs (SDPs). Numerical studies on IEEE test feeders show that the proposed SDP relaxations can be solved efficiently by a generic optimization solver. Numerical evidence also indicates that solving the resultant SDP under BVA is faster than under EBFM. Moreover, both SDP solutions are numerically exact with respect to voltages and branch flows. It is further shown that the SDP solution under BVA has a small optimality gap, and the BVA model is accurate in the sense that it reproduces actual system voltages.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Advanced Research Projects Agency-Energy (ARPA-E)
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1374123
• Report Number(s): NREL/PR-5D00-68859
• Country of Publication: United States
• Language: English

Related Subjects

24 POWER TRANSMISSION AND DISTRIBUTION
convex relaxation
multiphase distribution network
optimal power flow