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The first swing rotor angle stability is still an important stability challenge for modern power systems integrated with a large number of renewable energy-based sources, such as wind farms and solar-photovoltaic farms. Therefore, innovative strategies must be developed to exploit the full potential of doubly fed induction generators (DFIGs) to improve the first swing rotor angle stability in the system. This study presents a new active power logic (APL) controller for DFIGs which can reduce the active power during the fault and slowly recover it after the fault to allow synchronous generators to increase the electrical power during and after the fault; thus, enabling synchronous generators to improve the first swing rotor angle stability. The feasibility of the proposed control scheme is investigated via theoretical analysis and simulation studies. The reliability and voltage stability test system is used to demonstrate the effectiveness of the proposed scheme for local and remote faults and increased DFIG penetration conditions. The comparative results show that the proposed APL controller of the DFIG improves the first swing rotor angle stability, specifically when the DFIGs are located near the synchronous generators. [ABSTRACT FROM AUTHOR]

Electromechanical wave propagation is present in power systems as a transient spatial delay of generator rotor angle variations when a disturbance occurs. The control and mitigation of the this wave phenomenon, which spreads out to different locations at a comparably slow speed, is important for enhancing power system transient stability, as shown in part two of this two-paper series. In an idealized power system consisting of infinitesimal generators and line impedances, this traveling wave can exist to infinite frequencies, its speed can be derived from a wave equation and its reflection can be eliminated by a characteristic termination. Part one of this paper series examines realistic power systems with finite size generators and line impedances. It shows that there is a finite approximation of the traveling wave in real power systems as the wave can exist only within a finite frequency range. This paper also examines aspects such as reflections due to discrete elements, controller design based on the load modulation effect, and the existence of traveling wave and its attenuation in the Australian power system. [ABSTRACT FROM AUTHOR]