Chapter One - Overview of renewable energy power system dynamics

Abstract

Contemporary proliferation of renewable power generation is causing an overhaul in the topology, composition, and dynamics of electrical grids. Over recent decades, the penetration of renewable energy sources (RESs), especially photovoltaic, micro hydro, and wind power plants, has been promoted in most countries. However, as these both alternative sources have power electronics at the grid interface (inverters), they are electrically decoupled from the grid. Subsequently, the stability and reliability of power systems are compromised. Inertia in power systems has been traditionally determined by considering all the rotating masses directly connected to the grid. However, as the penetration of grid-connected RES increases, the inertia of the power system decreases due to the reduction of the directly connected rotating machines. Consequently, modern power systems require a new set of strategies to include RESs. In fact, “hidden inertia,” “synthetic inertia,” and “virtual inertia” are terms currently used to represent artificial inertia created by inverter-dominating generating units like RESs. This chapter provides an overview of RESs and highlights the inertia concept and methods to estimate rotational inertia in different parts of the world. In addition, an extensive discussion on wind and photovoltaic power plants and their contribution to inertia and power system stability is also presented.