Adaptive OOS protection scheme to enhance rotor stability of the system

Abstract

The impact of large-scale deployment of Renewable Energy Sources, especially inverter-connected wind turbines and photovoltaics, on the variability of RES generation shares globally. This is a critical point as it emphasizes the transition from conventional generators to RES, which lack rotational inertia. The usual assumption of high grid inertia with minor variations is no longer valid in power networks with significant RES shares. This is crucial, as it sets the stage for understanding the subsequent challenges related to frequency dynamics and power system stability. The lack of rotational inertia in RES-connected devices affects frequency dynamics and power system stability. Understanding and addressing these issues are essential for ensuring the reliability and security of power systems with a substantial share of RES. The key contribution of the research work is in the area of Out-of-Step (OOS) protection systems. This system becomes particularly important in handling unpredictable contingencies and preventing angular instability that could lead to blackouts. Identifying and isolating unstable swings after disruptions is a significant advancement in power system stability. The development of a framework to investigate power system rotor angle stability during steady state and transient stability occurrences using DIgSILENT PowerFactory® software. The application of the proposed protection scheme on the modified Eskom transmission network is a practical demonstration of its applicability. A critical aspect of power systems ensuring stability in the face of increasing RES penetration. The focus on Out-of-Step protection systems, along with the application on a real-world transmission network, adds practical significance to the research. This work is valuable for ensuring the reliability and resilience of power systems undergoing a transition to higher levels of renewable energy integration.