Optimal PMU Allocation for Enhanced Gross Error Detection

Abstract

This paper presents an optimal phasor measurement unit (PMU) allocation strategy that focuses on the improvement of gross error detection and topological observability. In power systems analysis, the detection of gross errors in measurements depends on accurate state estimation (SE) as well as sufficient measurement redundancy. PMUs are excellent devices to improve both of these areas, and consequently are able to improve gross error detection. Since PMUs are costly to install, the current state of the art in PMU allocation strategies formulates the problem as a mixed integer linear programming (MILP) problem in which the objective is to minimize the cost of PMU installations. However, the structure of the problem is such that the number of PMUs allocated on the system will be kept small as long at the objective function remains a minimization problem, regardless of what is used for the “cost” values. This paper takes advantage of that structure and proposes a strategy to allocate PMUs for the purpose of enhancing gross error detection by using an Undetectability Index (UI) as the “costs” in the MILP. This strategy is implemented on the IEEE 14-bus system and validated through innovation based analysis and error detection tests.