Optimal placement of branch PMUs for specified redundancy and line observability

This paper presents a solution for the optimal placement of branch PMUs (PMUs that measure a single set of three-phase voltage and current phasors) considering specific measurement redundancy requirements for the observability of buses. The classical bus observability condition in optimal PMU placement assumes the measurement of currents of all lines connected to the PMU bus, making most developed optimisation methods impractical in real-world systems. Compared to existing methods for the optimal placement of branch PMUs (or PMUs with input channel limits), the proposed method inherently enables to consider the outages of all lines or PMUs, distinguishes between the ends of the branches (i.e. for each branch PMU the optimal bus is also chosen), enables to specify conditions for direct observability of transmission lines, and is simple to implement and solve.