Lyapunov exponent‐based optimal PMU placement approach with application to transient stability assessment

Abstract

This study presents a Lyapunov exponent-based approach for optimal placement of phasor measurement units (PMUs) to achieve full network observability and improve real-time system stability monitoring and assessment. To that end, a new optimisation formulation, which maximises measurement redundancy for critical buses without increasing the minimum number of PMUs required for full network observability, is proposed first. Next, considering the role of each bus in the overall system stability, critical buses are identified using a Lyapunov exponent-based approach. After that, a method is proposed to determine the significance of each critical bus for measurement redundancy analysis. The significance of critical buses is then incorporated into the proposed optimisation formulation and PMU locations are specified. At the end, system stability assessment following disturbances is performed using the PMUs data at critical buses. The proposed optimal PMU placement method is tested on the IEEE 39 bus test system and the results are presented. The robustness of the proposed method with respect to changes in operating point is verified. The results show that besides full network observability with the least number of PMUs in normal condition, the proposed method facilitates stability monitoring and assessment following disturbances despite limited coverage of PMUs.