Testing step-size limits for solving the linearized current voltage AC optimal power flow - Campaigne, Clay; Lipka, Paula A; Pirnia, Mehrdad; O’Neill, Richard P; Oren, Shmuel (FERC Staff Technical Paper. http://www. ferc. gov/industries/electric/indus-act/market-planning/opfpapers/acopf-9-stepsizelimits-iliv-acopf. pdf, 2013)