On the Optimal Placement of Micro-PMU in Distribution Networks Considering Phase Strings

This paper proposes an optimal placement scheme of micro-phasor measurement units (µPMU) for multi-phase unbalanced distribution networks and introduces a novel notion of usable zero-injection phase strings (UZIP Strings). Traditional PMUs designed for the transmission network are unsuitable for distribution networks due to their high costs and outdated technology. Advanced µPMUs, which are designed for distribution level deployment, can provide simultaneous recording and real-time streaming of synchrophasor data at a decreased cost, increased speed, and higher accuracy. Despite this, µPMUs still have a high economic burden, and successful deployment in future smart grid applications heavily depend on their optimal placement. The proposed µPMU placement technique is evaluated using the IEEE-13 and IEEE-34 node distribution test networks. The optimization problem is solved using integer linear programming (ILP), genetic algorithm (GA) and particle swarm optimization (PSO). The comparative results indicate that the optimization algorithms yield almost similar results with the holistic approach able to accommodate for network reconfiguration and future distributed generation (DG) integration at any phase in the network without re-optimization. Moreover, the UZIP reduction method successfully reduced the number of µPMUs required while maintaining global observability.