Restoration Modeling and Optimization of Hybrid Overhead-Underground Power Distribution Systems.

Disaster awareness increased in recent years among power system stakeholders to face many natural, technical, and malicious adversities. The smart distribution grid (SDG) is thereby at the core of proposed system enhancements, due to its high fragility as well as being the interface to most newly introduced grid applications (distributed energy resources, electrical vehicles, industrial Internet-of-Things, etc.). The SDG can be characterized by the type of lines composing the feeders (overhead and/or underground) and deployed intelligent electronic devices (IED) that allow efficient monitoring, protection, and control of the system. This paper proposes an optimization formulation to enhance the resilience of overhead and underground networks, while considering the coupling between power grid operation and the communicating remote-controlled switches (RCS). Novel radiality constraints are introduced to guarantee the tree structure during operation. Results from testing the model in a real network show the validity of proposed radiality constraints and quantify the gap in terms of achieved resilience between full overhead and hybrid overhead-underground networks.