Hardware-In-The-Loop Testing of Power Swing Protection for Low Inertia Systems

Abstract

The dynamic interaction between wind farms, serving as power plants directly connected to transmission networks is increasingly significant as they replace conventional synchronous machine-based generation. These interactions are particularly vital as power swing rates rise due to reduced system inertia. This thesis focuses on the analysis of power swing blocking protection element performance in the context of the widespread adoption of Type 4 grid-integrated wind turbine systems. The study involves designing and integrating converter models for large Type 4 wind turbine plants into a 12-bus benchmark power system that is modeled using a Real Time Digital Simulator (RTDS). The research assesses dynamic response characteristics of integrated wind generation systems in comparison to synchronous generators during the system recovery following fault events. This analysis uses a SEL 421 distance protective relay to examine the effective impedance seen by the relay during a power swing. The study compares differences in the response and operation of distance protection element and an enhanced protection element to ensure the correct functioning of the relay in response to stable and unstable power swings.