Ricerc@Sapienza

The paper proposes a generic Matlab-Simulink model to represent quasi-static time-varying non-linear loads in power systems. The methodology presented allows to combine both deterministic and a probabilistic approaches. The procedure is able to evaluate voltage and current harmonic spectra under uncertainty scenarios in a power system allowing a preevaluation of harmonic disturbances.

The paper proposes a computational procedure able to control in real-time the harmonic disturbance injected by nonlinear loads in an islanded MV/LV Smart Grid, characterized by low short circuit power. Aim of the proposed procedure is to keep automatically under acceptable values the penetration of harmonic disturbances caused by different loads, by means of a control algorithm suitable to a Smart Grid context.

The paper proposes a novel approach to modelling time-varying non-linear loads in power systems, based on demand conditions. The model allows a pre-evaluation of harmonic disturbances under variable conditions using normal and uniform distribution to randomize the electrical values of the non-linear loads and the related harmonic spectra. A measurement campaign conducted on an industrial area, a deposit/maintenance and repair site utilized for trains in operation on the metro line B of Rome, has been taken into account to verify the model performance.

The paper presents a vector control with two cascaded loops to improve the properties of Dynamic Voltage Restorer (DVR) to minimize Voltage Sags on the grid. Thereby, a vector controlled structure was built on the rotating dq-coordinate system with the combination of voltage control and the current control. The proposed DVR control method is modelled using MATLAB-Simulink. It is tested using bal-anced/unbalanced voltage sags as well as fluctuant and distorted voltages. As a result, by using this controlling method, the dynamic characteristics of the system have been improved significantly.

The paper describes a measurement campaign conducted at the Engineering Department of Astronautics, Electrical and Energetic, Sapienza University of Rome. Starting from measurement campaign, in the context of building an urban microgrid, a PV plant and a energy storage system has been proposed. The measurements were conducted in two relevant period of the year in order to know the power consumption of the facility.