With consideration to importance of power quality in power systems especially in distribution systems and with increasing application of electronic devices which have higher sensitivity to fed powers quality, in this paper voltage profile in distribution systems has been surveyed. Improvement of voltage profile via injection of reactive power has been depicted. Presence of loads which is genera...

The main aim of this project is ,this topology enables UPQC to have a reduced dc-link voltage without compromising its compensation capability. Three-phase, four-wire unified Power Quality (UPQC) to improve power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a t...

Power transformers are among the most important and expensive equipments in the electric power systems. Consequently the transformer protection is an essential part of the system protection. This paper presents a new method for locating transformer winding faults such as turn-to-turn, turn-to-core, turn-totransformer body, turn-to-earth, and high voltage winding to low voltage winding. In this ...

This paper, electronic resonant ballast for a small photovoltaic powered street lighting system in remote rural area was proposed. The street lighting system was designed for rural area where the electrical transmission line cannot be commonly serviced and it is the cascade systems of the solar arrays, switching battery charger, and electronics ballast with small fluorescent lamp. The ballast i...

Usually, harmonics are the base point when engineers start to analyze waveform distortion. Frequencies of these voltage and current waveforms are integer multipliers of the base frequency of power system (50 Hz or 60 Hz). If it is not the case then these are named as intermediate harmonics. The sinusoidal waveforms of voltage characterize the ideal power system with the highest clarity of base ...

The estimation of harmonic components of power voltage signals is one of the measurements prescribed by the power quality (PQ) standards (IEC 61000-4-30, 2008). In general, the harmonic components originate from non-linear elements connected to the power system such as non-linear loads (e.g., switched-mode power supplies) or transformers. An example of a distorted voltage measured in an office ...

A simple interferometric method is described to measure the time-dependent deformation of piezoelectric bimorphs driven by ac voltage. Applying this method to a bimorph assembly used to measure viscoelastic forces in a surface forces apparatus, we find that a sinusoidal-shaped harmonic drive voltage generates sinusoidal deformation but that a triangular-shaped harmonic drive voltage fails to pr...

Presence of distributed generation (DG) in distribution systems has significant impacts on the operational characteristics of these systems, also using capacitor for reactive compensation and loss reduction is so common. Injected harmonic currents from nonlinear loads into distribution system distort all of voltages and currents and must be considered when placing the capacitor banks so that th...

This paper presents design consideration and analysis for an interleaved boundary conduction mode power factor correction buck converter. A thorough analysis on the harmonic content of the AC line current is presented to examine the allowable voltage gain (K value) for meeting EN61000-3-2, Class D while maximizing the efficiency. Results of the harmonic analysis are used to derive the required ...

The firing angle control of thyristor full wave ac-dc converters to set the desired DC bus voltage in Uninterruptible Power Supply (UPS) systems have drawbacks of pulsating input current, high harmonic content, low pf, low efficiency and large size of inductors and filters. International standards impose several constraints concerning the electric power quality and harmonic content of the line ...