The quality of voltage and current delivered by the power utilities has become a major concern of the modern industries. The common power quality problems are voltage sag, voltage imbalance, transients, interruptions and harmonics. The two major power quality disturbances are voltage sag and harmonic distortion. In this paper, a Quality Power Provider (QPP) based on voltage source inverter is m...

The operation and control of fuel cell (FC) distributed generation (DG) systems combined with energy storage are studied in this paper. For this purpose, modeling of hybrid FC/energy storage DG system is developed. Dynamic models for proton exchange membrane fuel cell (PEMFC), supercapacitor, DC–DC converters, and grid connected inverter are described. Then a PI controller for the FC converter ...

This paper presents the custom power devices to improve the power quality by using a Distribution Static Compensator (DSTATCOM). Custom power is a technology driven product and service solution which embraces a family devices such as DSTATCOM. It describes the techniques of correcting the supply voltage sag in a distribution system by DSTATCOM. The steady state performance of system with or wit...

This paper describes the effectiveness of using dynamic voltage restorer (DVR) in order to mitigate voltage sags and swells in low voltage distribution systems. A dynamic voltage restorer based on the dqo algorithm is discussed. The proposed control scheme is very effective to detect any disturbance in low voltage distribution systems. Simulation results using Matlab/Simulink are presented to v...

This paper compares fault position and Monte Carlo methods as the most common methods in stochastic assessment of voltage sags. To compare their abilities, symmetrical and unsymmetrical faults with different probability distribution of fault positions along the lines are applied in a test system. The voltage sag magnitude in different nodes of test system is calculated. The problem with the...

In this paper, the voltage sag ride-through capabilities of the line-connected electrically excited synchronous machine with damper windings (EESM) is investigated. We will design an algorithm for voltage sag ride through by controlling the flux. Two aspects are investigated, first the capability to keep the nominal speed and second the damping of speed oscillations. We will show through simula...

Perfusion of the renal medulla plays an important role in salt and water balance. Pericytes are smooth muscle-like cells that impart contractile function to descending vasa recta (DVR), the arteriolar segments that supply the medulla with blood flow. DVR contraction by ANG II is mediated by depolarization resulting from an increase in plasma membrane Cl(-) conductance that secondarily gates vol...