Análise da estabilidade de tensão considerando distorções harmônicas em sistemas elétricos de potência: uma abordagem utilizando multiplicadores de Lagrange a partir de um fluxo de potência ótimo

Abstract

This work presents a novel methodology for power systems voltage stability assessment considering harmonic distortions. An optimal power flow is formulated considering the impact of the insertion of loads with non-linear characteristics into electrical networks, to quantify the maximum loadability point of a power system. Voltage magnitudes, demand and generated active and reactive powers, individual and total harmonic distortion limits are considered as inequality constraints. The proposed optimization problem is solved by interior point method. Based on the Lagrange multipliers determined by the solution of the problem, voltage stability indices are established, aiming to identify the most sensitive buses in the system due to power quality degradation and voltage instability, which is the main contribution of this work. Computational simulations are carried out using the IEEE 30-bus test system, considering the insertion of non-linear loads to show the applicability of the indices for evaluating voltage stability and harmonic distortions. The results obtained are compared with the traditional modal analysis method to validate the proposed methodology for identifying the critical bus of the system.