A Mixed-Integer QCQP Formulation of AC Power System Upgrade Planning Problems

This document describes the detailed reformulation of a power system upgrade planning problem into a more generic quadratically constrained quadratic problem (QCQP). The problem is one of deciding what lines to upgrade in an existing power system in order to enable it to handle specific load situations. The reformulation presented here is based on other formulations already used in the field, such as the ones presented in [1] and [2]. This document was created as a reference for publications by the author that refer to the planning problem but avoid outlining reformulation details.