Classical grid control: Frequency and voltage stability

Maintaining voltage and frequency within their allowed ranges guarantees the stability of the power system. Hence, understanding the causes that affect these two state quantities is very important, because this allows to take the appropriate correction actions to avoid reaching operation points that result dangerous for the power system. This chapter can be successfully used by educators because it includes (i) the essential explanations of the phenomena affecting the frequency and voltage stability, (ii) high quality drawings of the control schemes, and (iii) numerical simulation graphs. Novel measurement results from the Romanian power system are presented as well, which allow to demonstrate the importance of the mechanical inertia for frequency stability.