Robustness margins in electric power systems

Before the first connection to the French transmission grid, a power producer must perform stability analysis and verify if the generator meets the requirements imposed by the transmission system operator. These analysis concern both transient and small signal stability but the present paper focuses on small signal stability only. The robustness margins represent an interesting way to quantify the small signal stability of a generator. A global robustness description of controlled systems is a complex issue. Nevertheless, systems robustness characterization through stability margins is widely used because it has the advantage of being relatively simple. Robustness margins can quantify the small stability status for very complex systems, such as power systems. The present paper presents basic theoretical concepts linked to robustness margins and also the results of a transmission grid connection study.