Optimal power quality monitor placement to ensure reliable monitoring of sensitive loads in the presence of voltage sags and harmonic resonances conditions

Nowadays, sensitive nonlinear loads such as load commutated inverter drives are increasingly being used by industrial consumers. In one hand, sensitive nonlinear loads can induce parallel resonance condition to the network and in the other hand their continuous operation may be interrupted due to voltage sags. Therefore, power quality parameters associated with the secure performance of sensitive nonlinear loads must be monitored to avoid the adverse effects of parallel resonances and financial losses due to voltage sags. In this paper, a new approach based on the area of vulnerability to voltage sags and harmonic resonance mode analysis is proposed to determine the optimal number and the best location of power quality monitors (PQMs). The proposed method is formulated as a linear integer optimization problem which is simply solved. In addition, in case where a budget limitation does not allow to purchase the required number of monitors and the optimization problem does not converge an alternative approach is proposed for allocating very limited number of monitors in a hierarchical manner to ensure monitoring of the most severe conditions. The proposed approach is applied on the IEEE 30-bus system and an Iranian real industrial network. (C) 2017 Elsevier Inc. All rights reserved.