Optimal µPMU Placement Based on Hybrid Current Channels Selection for Distribution Grids

Abstract

This article presents a new method for the optimal microphasor measurement units placement (OµPP) for distribution grids. A general integer linear programming framework has been defined by dividing the distribution grid into two parts: nonbranching bus series (NBS) and overlapped buses. An objective function is defined for each part associated with observability constraints. Also, a region matrix is used to describe a grid configuration instead of defining a much larger grid connectivity matrix. Based on the region matrix definition, the search space reduction technique is used for the NBS region that results in a reduction of the number of decision variables and the number of constraints is reduced. The main objective goal of the optimization problem is to find the optimal number of units and the current channels used by each unit for the distribution grid. To evaluate the efficiency of installing the microphasor measurement units (µPMUs), which use different numbers of current channels, a cost model for the µPMU is defined and used for the optimization problem. The cost model of the unit is divided into development and running costs as a function of the current channels number. The proposed method is tested for the IEEE 33 and 69 bus distribution grid and compared with the conventional OµPP. Three cases are studied in the comparison considering redial, microgrid configuration, and current channels limitations. The proposed method shows the ability to find the optimal number of current channels with the same number of units of the conventical method.