Dynamic Vulnerability Assessment and Intelligent Control

Chapter 9Model-based Predictive Control for Damping Electromechanical Oscillations in Power Systems

Da Wang

Researcher of Intelligent Electrical Power Systems, Intelligent Electrical Power Grids (IEPG), TU Delft, Netherlands

9.1 Introduction

Electromechanical oscillations mean relative motions of generator shafts and resultant fluctuations of electrical variables (current, voltage, etc.) In modern large-scale electrical power systems, long transmission distances over weak grids, highly variable generation patterns, heavy loading, and so on, tend to increase the probability of appearance of sustained wide area electromechanical oscillations [1, 2]. Moreover, higher and higher penetration of renewable energy also changes current damping characteristics and increases the risk of oscillation instability [3]. Such oscillations threaten the security of power systems, and if they cause cascading faults, can lead to large-scale blackouts [4].

It is usually considered that electromechanical oscillations are caused by insufficient damping of power systems. Consequently, most researches on damping oscillations focus on developing different controllers, like Power System Stabilizers (PSSs), and Thyristor Controlled Series Compensators (TCSCs), in order to improve system damping [5]. Conventionally, these controllers use local measurements at their inputs. The control rules are determined in off-line studies using time domain simulations such as Prony or Eigen analysis, and remain fixed ...