Voltage Stability Monitoring by Synchronized Phasor Measurements of Transmission Line Flows

Abstract

With the advance of integration of renewable energy sources into the Power System (PS), especially wind and photovoltaic energy, operational uncertainties have risen due to the variable nature of these energy sources, which are not dispatchable but reliant on weather conditions. Because of this variability, there is a need to monitor operating margins and stability of power systems on real-time. Particularly, there is a growing urgency for real-time monitoring tools for voltage stability margins to ensure system reliability and safety. The installation of Phasor Measurement Units (PMUs) in power systems holds great potential for monitoring these margins. In this research project, we will investigate how synchronized phasor measurements can be used to monitor voltage stability margins. There are already studies involving measurements from PMUs for monitoring voltage stability margins. Established methods can be divided into 4 classes: (i) based on Thévenin Equivalent, (ii) voltage stability indices, (iii) machine learning, and (iv) Lyapunov exponent. Each one of these approaches has its limitations in obtaining correct voltage stability margins. Therefore, this project proposes to investigate a new method based on synchronized phasor measurements of power flows in transmission lines. We will study the relationship between the Maximum Loading Point (MLP) of a system and the loading of individual lines, aiming to develop an efficient real-time monitoring method for voltage stability margins. It is expected that this project will succeed in defining this relationship, as it would imply an improvement in performance in the areas of Generation, Transmission, and Distribution of electrical energy, contributing to enhanced reliability and operational safety of power systems.