Electromechanical transients need to be controlled quickly. After deregulation, Transmission System Operators (TSOs) have direct control only on transmission facilities; consequently, the transmission grid has to be equipped with fast actuators in order to guarantee the fast response needed to control electromechanical transients. The possibility to change continuously impedances across the grid is given by modern electronic devices such as Thyristor-Controlled Series Capacitors (TCSCs) which can provide some ductility to the system and avoid cascade events. In this paper, a trajectory sensitivity-based approach for the corrective control of power system transient stability through dynamic series compensation is proposed.

The electric distribution systems of the 21st century are characterized by the huge diffusion of distributed generations (DG) units. Their always increasing number, however, asks for new and advanced technical solutions for management and optimization of low voltage grids, whose design and efficiency is still strictly dependent to old operative conditions and schemes. In this paper, a methodology aimed to achieve power flow control and optimization on low voltage distribution systems by means of an Unified Power Flow Controller (UPFC) is presented. Tests have been made on three different operating conditions and their numerical results demonstrate how this device can be positively applied even to electric distribution networks in order to solve some typical issues such as loss reduction, power flows inversion and so on.

With the diffusion of standardized communication protocols in smart transmission systems, it is expected that digital distance relays will become active elements in monitoring and control architecture. Real-time tuning of distance relays settings will allow to overcome the classical conflict between dependability and security, or to avoid improper operation of such devices in vulnerable conditions and during major blackout events. In this paper, along with the presentation of a monitoring and control architecture that integrates such devices into SCADA/EMS, a system security monitoring function, based on simulated system trajectories and their closeness to distance relay zones, is proposed for system operation and contingency analysis.

This paper summarizes all research advancements obtained by the Politecnico di Bari through the RES NOVAE Project activities in the field of the smart grids. Such activities have been aimed at bringing substantial contributions in the development of smart grid in medium-voltage and low-voltage distribution systems. Since the scientific approach to smart grids is intrinsically multidisciplinary, specific researches were addressed in all the fields of electrical and information engineering that are involved in the creation of future distribution systems. The paper is organized in seven sections, each providing description of the research results developed in a specific field (power systems, communication systems, power electronics, electric measurements, circuits and systems, information processing systems, automatic control).