  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.
