Sharif Digital Repository

A novel system for decomposing a set of three-phase signals into its constituting symmetrical components is proposed. The system also estimates the frequency, the magnitudes and phase-angles of the sequence components. The system is useful for online estimation of instantaneous symmetrical components and their attributes in the presence of frequency variations. The proposed system can be considered as a fundamentally improved version of the conventional three-phase Phase-Locked Loop (PLL) system which is widely used in power system applications. From this viewpoint, the proposed system obviates the inherent shortcoming of the conventional PLL system which is its erroneous response in the... 

This paper presents a power flow controller for a matrix converter as the power electronic interface between a high-speed micro-turbine generator and a utility distribution system. The matrix converter converts the high-frequency of a micro-turbine generator to a conventional frequency of the utility system, based on a novel switching strategy. The controller regulates magnitude and phase-angle of the converter output voltage to accommodate real and reactive power flow requirements of the utility system. Performance of the matrix converter based microturbine generation system including the power flow controller is evaluated based on digital time-domain simulation studies in the PSCAD/EMTDC... 

This paper deals with the definition of power factor and reactive current component in a three-phase system. For a single-phase system, power factor and reactive current component are defined based on the phase-angle displacement between the measured voltage and current waveforms. This definition can be directly extended to balanced three-phase systems. However, this extension is not suitable when the three-phase system (voltages or currents) is unbalanced. Reason is that the conventional definition of phase-angle does not directly apply to an unbalanced three-phase system and needs further refinements. This paper defines the concept of symmetrical power factors and symmetrical reactive... 

Nowadays, with the increasing use of renewable energies in low voltage (LV) feeders, phase balancing research areas are of great importance. However, the lack of information about the hosting phase of customers and renewable sources is the missing link in such researches. To address this barrier, this paper proposes a mixed integer linear programming (MILP) method to identify the hosting phase of customers as well as renewable energies, such as photovoltaic (PV) panels. The model considers potential error in the input data. To overcome the complexity caused by data error, the input data in several time intervals are taken into account by the model. The model solves the phase identification...