the effect of different solvent systems on the extraction of antioxidant and anti radical agents of grape seed was studied. for this purpose 6 different solvent systems with similar polarity and different selectivity were used to prepare grape seed extract. extraction efficiency, reducing activity, radical scavenging property and the effect of each extract on the increase of thermal resistance ...

Congestion in the transmission lines is one of the technical problems that appear particularly in the deregulated environment. The voltage stability issue gets more important because of heavy loading in this environment. The main factor causing instability is the inability of the power system to meet the demand for reactive power. This paper presents a new approach for alleviation congestion re...

this paper presents a novel indirect adaptive power system stabilizer (pss) via a developed synergetic control methodology and fuzzy systems. fuzzy system is utilized in an adaptive scheme to estimate the system using a nonlinear model. the synergetic control guarantees robustness of the controller and makes the controller easy to implement because of using a chatter free continuous control law...

power system blackouts have become a serious problem for electric utilities especially in recent years. different forms of system instability have emerged in recent blackouts, such as voltage instability and frequency instability. to counteract each form of system instability, special algorithms have been designed in the protection system, e.g. under frequency load shedding (ufls) and under vol...

Over the last few years, the problem of voltage stability has received a lot of attraction from the power system community. This type of stability is now a major concern for utilities in both planning and operating conditions. Both static and dynamic aspects of the problem have been discussed and investigated by the researchers. The present paper concentrates on a Voltage Stability Analysis fun...

in this paper, a consistent pattern with the optimal coordinated design of pss and sssc controller to improve the damping of low frequency oscillations is shown. in this design, sensing and signal transmission time delays are considered as effectiveness parameters. the design problem has been considered an optimization problem and biogeography-based optimization (bbo) algorithm is used for sear...

In this paper, a robust local controller has been designed to balance the power for distributed energy resources (DERs) in an islanded microgrid. Three different DER types are considered in this study; photovoltaic systems, battery energy storage systems, and synchronous generators. Since DER dynamics are nonlinear and uncertain, which may destabilize the power system or decrease the performanc...