Investigation Of Optimal PMU Placement For Zhejiang Power System

With phasor measurement unit (PMU) based on GPS being applied in the power system, taking advantage of PMU can directly measure amplitude and phase angle of bus voltage in high precision to achieve linear state estimation. Therefore the optimal allocation of PMU in the grid has become a research hotspot.In this paper, firstly, model of linear state estimation, dominating set based on graph theory and observable system are presented. Then it is proposed to consider dominating set theory and measurement conditions of power system to reduce the number of PMUs with the effect of zero-inject buses in the system. The optimal PMU placement problem is formulated as guaranteeing full network observable, having the minimal number of PMU. Then Tabu search method is proposed to solve the combinatorial optimization problem. The effectiveness of proposed method is verified by the stimulation results of IEEE 14-bus,30-bus,57-bus,,118-bus system, and ZheJiang 500kV power grid (76 buses). Only 1/5 to 1/3 buses in the grid need to be equipped with PMUs to make the entire system observable and leads to a simplified linear state estimation, the simulation results indicates that the optimal method is effective and feasible.Considering the need of a unified approach for PMU placement, this paper proposes a new unified PMU placement optimization algorithm based on 0-1 integer programming. Also four special models are derived to achieve the full observability of power grid:in normal condition regardless of zero-inject buses, regard of zero-inject buses, any line tripped or any PMU malfunctions. All of the PMU placement methods mentioned above have unified models, The numerical simulation on IEEE 14-bus,30-bus,57-bus,118-bus system and ZheJiang 220kV power grid (543 buses) and the effectiveness and flexibility of the proposed algorithms are verified.