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The Unified Power Quality Conditioner (UPQC) is a versatile device which could function as series active filter and shunt active filter. UPQC can simultaneously fulfill different objectives like, maintaining a balanced sinusoidal (harmonic free) nominal voltage at the load bus, eliminating harmonics in the source currents, load balancing and power factor correction. Keeping the cost effectiveness of UPQC, it is desirable to have a minimum VA loading of the UPQC, for a given system without compromising compensation capability. Hence, a methodology has been proposed in this work to minimize VA loading of UPQC considering the effects of source voltage and load current distortion. The series active filter of UPQC can be made to inject voltages in such a way that a minimum VA loading of UPQC is possible. The optimal angle at which series voltage has to be injected so as to have minimum VA loading of UPQC is computed by Particle Swarm Optimization (PSO) technique. The proposed method has been validated through detailed simulation studies. The VA loading without optimization and with optimization has been compared.

Dynamic Voltage Restorer (DVR) restores the distribution system load voltage to a nominal balanced sinusoidal voltage, when the source voltage has distortions, sag/swell and unbalances. DVR has to inject a required amount of Volt-Amperes (VA) into the system to maintain a nominal balanced sinusoidal voltage at the load. Keeping the cost effectiveness of DVR, it is desirable to have a minimum VA rating of the DVR, for a given system without compromising compensation capability. In this regard, a methodology has been proposed in this work to minimize VA rating of DVR. The optimal angle at which DVR voltage has to be injected in series to the line impedance so as to have minimum VA loading on DVR as well as the removal of phase jumps in the three-phases is computed by the Particle Swarm Optimization (PSO) technique. The proposed method is able to compensate voltage sags with phase jumps by keeping the DVR voltage and power ratings minimum, effectively. The proposed PSO methodology together with adaptive neuro-fuzzy inference system used to make the DVR work online with minimum VA loading. The proposed method has been validated through detailed simulation studies.

Ultra-wideband (UWB) phased array antennas are more essential for radar, communication and EW applications. Systems can operate over wide band coverage. The high gain systems require wideband, wide angle scanning, good radiation pattern and returnloss over multioctave bandwidth. This review discusses the problems present in this system, which include mutual coupling, grating lobe rejection, active return loss, gain fluctuation with scanning, and multiple beam generation. In this, the aperture size of the array is limited by the overall gain requirement of the system. On the other hand low gain systems require wideband with good radiation pattern and axial ratio. Here the matching over wideband is simpler as it depends on broadband balun configuration. This system has limited bandwidth over scan angles. These antennas more preferred as wearable antennas in communication applications. This paper mainly discusses the existing UWB phased array antennas such as Vivaldi Arrays, All-Metal Arrays, Spiral Arrays, Sinuous Arrays, and Coupled Arrays. This review paper presents a correct direction for selecting the type of antenna in terms of impedance bandwidth, gain, and materials influencing antenna performance, suited for different applications.

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