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Mani P.K.,Vel Technology Multitech | Siddappa Naidu K.,Vel Technology University
International Journal of Applied Engineering Research | Year: 2015

In years past, most electrical equipment operated on an ideal voltage and current waveform. However, in the past couple of decades there has been an explosion in the use of solid-state electronic technology. This new, highly efficient, electronic technology provides improved product quality with increased productivity by the use of smaller and lighter electrical components. Today we are able to produce products that cost less than in years past, but this new technology requires clean electric power and is highly sensitive to power distortions. Electronic equipment (switching power supplies) draws current differently than non-electronic equipment. Instead of a load having a constant impedance drawing current in proportion to the sinusoidal voltage, electronic devices change their impedance by switching on and off near the peak of the voltage waveform. Switching loads on and off during part of the waveform results in short, abrupt, non-sinusoidal current pulses during a controlled portion of the incoming peak voltage waveform. These abrupt pulsating current pulses introduce unanticipated reflective currents (harmonics) back into the power distribution system. The currents operate at frequencies other than the fundamental 50 Hz. Harmonic currents can be likened to the vibration of water in a water line when a valve is open and closed suddenly. In this paper power quality analysis done based on the real field measurements in a spinning mill reported and the recommendations are suggested. © Research India Publications.


Jayaraman A.,VelTech Multitech | Jebarani Sargunar P.N.,Vel Technology Multitech
International Journal of Applied Engineering Research | Year: 2015

Spread spectrum communication, with its unique characteristics and inherent noise cancellation capability becomes an increasingly popular technique for use in many different systems like military applications. In addition to that, Wavelets had been developed and has attracted much attention in signal processing that provides an effective alternative to conventional transforms. A new method for Wavelet denoising, that uses a Wavelet shrinkage estimate via Wiener filtering, is proposed. The main aspect of the proposed method is its use of two Wavelet bases-one for the design of the empirical Wiener filter, and other for its application. In addition to Wavelet denoising, the Wiener filter is used to process the signals corrupted by additive Gaussian noise; i.e., denois-ing is performed with a Wavelet-based method, and suppressing the coeffi-cients using the Wiener filter approach. The impulse response of the Wiener filter is calculated from the Wavelet transformed coefficients. One of the possible measurements of denoising quality is the mean Bit Error Rate. The simulation of the proposed method shows a low BER for higher values of SNR, than the system that uses conventional shrinkage methods, and the con-ventional spread spectrum receiver. © Research India Publications.


Mani P.K.,Vel Technology Multitech | Siddappa Naidu K.,Technology University
International Journal of Applied Engineering Research | Year: 2015

The STATCOM used in distribution systems is called DSTACOM (Distribution-STACOM) and its configuration is the same, but with small modifications. It can exchange both active and reactive power with the distribution system by varying the amplitude and phase angle of the converter voltage with respect to the line terminal voltage. A multilevel inverter can reduce the device voltage and the output harmonics by increasing the number of output voltage levels. There are several types of multilevel inverters: cascaded H-bridge (CHB), neutral point clamped, flying capacitor. In particular, among these topologies, CHB inverters are being widely used because of their modularity and simplicity. Various modulation methods can be applied to CRB inverters. CHB inverters can also increase the number of output voltage levels easily by increasing the number of H -bridges. This paper presents a DSTATCOM with a proportional integral controller based CHB multilevel inverter for the harmonics and reactive power mitigation of the nonlinear loads. This type of arrangements have been widely used for PQ applications due to increase in the number of voltage levels, low switching losses, low electromagnetic compatibility for hybrid filters and higher order harmonic elimination. © Research India Publications.


Manila P.K.,Vel Technology Multitech | Siddappa Naidu K.,Vel Technology University
ARPN Journal of Engineering and Applied Sciences | Year: 2016

This paper presents a Fuzzy Logic Control Based (FLCB) Shunt Active Filter (SAF) capable of reducing the total harmonics distortion (THD) in Power System (PS). SAF is one of the key controllers in Flexible Alternating Current Transmission System (FACTS) to control the transmission line voltage and can be used in PS to enhance the power transmission capacity and extend the transient stability. In order to improve the power factor, compensate the reactive power and suppress the total harmonic distortion (THD) drawn from a Non-Linear Diode Rectifier Load (NLDRL) of SAF, we propose a Hysteresis Current Pulse Width Modulation (HCPWM) technique which is used as control for the switches of the Voltage Source Inverter (VSI) or SAF. The synchronous reference D-Q frame theory is used to generate the reference compensating currents for SAF. A fuzzy logic based control is developed to regulate the voltage of the DC capacitor. The system with control scheme is implemented in MATLAB/Simulink. The simulation results show the effectiveness of the proposed method for harmonic damping and voltage regulation. © 2006-2016 Asian Research Publishing Network (ARPN).


Mani P.K.,Vel Technology Multitech | Siddappa Naidu K.,Vel Technology University
ARPN Journal of Engineering and Applied Sciences | Year: 2016

Power quality has become an important factor in power systems, for consumer and household appliances with proliferation of various electric and electronic equipment and computer systems. The main causes of a poor power quality are harmonic currents, poor power factor, supply-voltage variations, etc. A technique of achieving both active current distortion compensation, power factor correction and also mitigating the supply-voltage variation at the load side is compensated by unique devices S-D (STATCOM and DVR) in this paper. The proposed S-D system can improve the power quality at the point of common coupling on power distribution systems under unbalanced and distorted load conditions. The STATCOM is connected across the load to compensate for current-related problems such as reactive power compensation. The series component of the S-D device is Dynamic Voltage Restorer which inserts a voltage so as to maintain the voltage at the load terminals balanced and free of distortion. © 2006-2016 Asian Research Publishing Network (ARPN).

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