Thyristor rectifiers are widely used in electric railways in order to control the speed. As a consequence of their usage in addition to substantial input lead current, an enormous amount of harmonics is injected into the grid. To avoid such harmonics as well as reactive power compensation, reactive power hybrid filters consisting of active and passive filters are utilized. Regarding different p...

This paper presents a control strategy for fuel cell/energy storage power generation system during voltage sag conditions. The hybrid DC power sources are connected to grid using power electronic converters include DC-DC converter and grid connected voltage source inverter. The power from hybrid power sources is controlled during voltage sag by designing of control strategy for DC-DC converter....

With the rapid developments and use of non linear loads, the controlling over the harmonic current to get and maintain power quality is becoming more important. Active power filters has been used to compensate the harmonic pollution in our power system. This paper presents a efficient model to compensate the current harmonics using the inverter based Shunt Active Power Filter, Passive Power Fil...

A transformer less hybrid series active filter is proposed to enhance the power quality in singlephase systems with critical loads. This thesis assists the energy management and power quality issues related to electric transportation and focuses on improving electric vehicle load connection to the grid. The control strategy is designed to prevent current harmonic distortions of nonlinear loads ...

This paper presents a particle swarm optimization (PSO) for reactive power and voltage control (Volt/Var Control: VVC) in electric power systems considering voltage security. VVC can be formulated as a mixed-integer nonlinear optimization problem (MINLP). The proposed method expands the original PSO to handle a MINLP and determines an on-line VVC strategy with continuous and discrete control va...

K E Y W O R D S This paper describes an active power filter (APF) control strategy, which eliminates harmonics and compensates reactive power in a three-phase four-wire power system supplying non-linear unbalanced loads in the presence of non-linear non-stationary currents. Empirical Mode Decomposition (EMD) technique developed as part of the Hilbert-Huang Transform (HHT) is used to singulate t...

electric arc furnace (eaf) is one of the largest loads in electric power systems. it is highly time varying and nonlinear. its reactive power variations cause voltage fluctuations in nearby system which is known as flicker. on the other hand the nonlinear voltage-current characteristic causes strong voltage and current harmonics in eaf. to this end flexible ac transmission systems (facts) techn...

The fast and coordinated voltage control of distributed nodes inside a large scale wind farm is a stringent issue. To achieve the reactive power compensation without a dedicated upper communication system, this paper proposes a relative control strategy based on the local reactive power regulation. This method can realize the voltage coordination of the key equipment and feeder line nodes, on t...

This paper mainly deals with the regulation of voltage at wind farm (WF) terminals and the improvement of power quality and WF stability in a WF to Weak-Grid connection. In facilities with moderated power generation, the WF are connected through medium voltage (MV) distribution headlines. A situation commonly found in such scheme is that the power generated is comparable to the transport capaci...

lots of papers has been written about iran’s military strategy explain military strategy of iran is deterrence, but there is a little paper that explain why iran chose this strategy? the paper tries to answer this question. two hypotheses are presented as probable answers to the question: 1-chang of balance power in the middle east 2- intensification of u.s pressure on iran for regime change.lo...