Mixed integer linear programming and nonlinear programming for optimal PMU placement

Phaser measurement units (PMUs) provide synchronized measurements of voltage and current phasors and can make state estimation more accurate. The objective of optimal PMU placement (OPP) problem is to minimize the number of PMUs required for the system to be completely observable. This paper presents two different formulations of optimal PMU placement (OPP) problem: mixed integer linear programming (MILP) and nonlinear programming (NLP). For each formulation, modeling of power flow measurements, zero injection, limited communication facility, and single PMU failure is studied. The contribution of our paper is to conduct a comparison between the MILP and NLP formulations and show the advantages and disadvantages of each formulation.