Optimal Multistage Placement of PMUs with Limited Channel Capacity for a Smart Grid

Phasor measurement units (PMUs) are being deployed by the utilities in their power networks throughout the world for better monitoring of dynamic operating conditions. Installation of a sufficient number of PMUs will convert the nonlinear iterative state estimation problem into a linear non iterat ive state measurement problem. However the power networks are huge networks and this minimum number of PMUs may still be too high to be installed in one stage. Therefore the placement of PMUs has to be scheduled in mult iple stages. Earlier work on multistage scheduling assumed an infinite channel capacity of PMUs available. However, in practice PMUs are manufactured with limited number of channels and it may happen that on a particu lar bus the number of branches connected is more than the channel capacity of PMUs. Under this condition some criterion should be devised to identify the branches to be monitored by the PMUs or the branches to be monitored in the init ial stages of PMU installation. In the present work ‘Branch Vulnerability Index’ has been defined as the criterion to be used for this purpose. The algorithm has been applied on IEEE 14 bus system and a practical power network of the Indian grid.