Enhancing observability in MILP-based optimal joint allocation of PMU channels and conventional measurements with new security concepts

Abstract

Since buses in power systems have a different number of connected branches, they require Phasor Measurement Units (PMUs) with different number of measuring channels. In this paper, a multi-objective channel-based method is proposed for optimal allocation of PMU base units, PMU measuring channels, and Flow Measurements (FMs) for power system observability. The main objective function encompasses cost of PMU base units and their measuring channels as well as FMs. Unlike previous methods, PMU channels are modeled as binary optimization variables, the optimal assignment of which is decided by the optimization problem. Under this framework, a PMU assigns measuring channels to observe its adjacent buses only if they are economically justified. The second objective function maximizes measurement redundancy at selected buses in a more controlled way. For a more economical solution, existing FMs are employed as network resources along with placing new PMUs and FMs. Moreover, PMU failures and branch outages are modeled using a novel approach that is more cost-effective than existing methods. Furthermore, channel failure is also introduced and modeled as a new type of contingency. Results obtained from the proposed method clarify its efficiency from economic perspective.