Fuzzy-Differential Evolution Method for Optimal Capacitor Placement in Distribution Systems

Vol.4 No.3

Year: 2011

Issue: Jan-Mar

Title: Fuzzy-Differential Evolution Method for Optimal Capacitor Placement in Distribution Systems   

Author Name: Dinakara prasad Reddy, Usha Reddy   

Synopsis:   

This paper presents a fuzzy and Differential Evolution (DE) method for the placement of capacitors on the primary feeders of the radial distribution systems to reduce the power losses and to improve the voltage profile. Fuzzy approach is used to find the optimal capacitor locations. Differential Evolution method is used to find the sizes of the capacitors. The proposed method is tested on 10-Bus,15-Bus and 34-Bus test systems and the results are presented.

 

  

 

Adaptive Neuro-Fuzzy Dividing Frequency Controlfor the Development of Hybrid Active Power Filter

Vol.4 No.3

Year: 2011

Issue: Jan-Mar

Title: Adaptive Neuro-Fuzzy Dividing Frequency Controlfor the Development of Hybrid Active Power Filter   

Author Name: M.S. Sujatha, T. Susritha   

Synopsis:   

This paper deals with a hybrid active power filter with injection circuit (IHAPF). It shows great promise in reducing harmonics and improving the power factor with a relatively low capacity active power filter. To minimize the capacity of IHAPF, an adaptive fuzzy dividing frequency-control method is proposed which consists of two control units: a generalized integrator control unit and fuzzy adjustor unit. The generalized integrator is used for dividing frequency integral control, while fuzzy arithmetic is used for adjusting proportional-integral coefficients timely. And the control method is generally useful and applicable to any other active filters. Compared to other IHAPF control methods, the adaptive fuzzy dividing frequency control shows the advantages of shorter response time and higher control precision. The simulation and experimental results shows that the new control method is not only easy to be calculated and implemented, but also very effective in reducing harmonics. In this paper Adaptive Neuro-Fuzzy controller is also used to develop the Hybrid Active Power Filter which has the advantages of reduced rule-base and fast response compared to Adaptive Fuzzy dividing frequency control method [1].

 

Mobile Voting System using Iris Recognition and Cryptography Techniques

Vol.4 No.3

Year: 2011

Issue: Jan-Mar

Title: Mobile Voting System using Iris Recognition and Cryptography Techniques   

Author Name: K. Gopal, S. Praveen , N. Suthanthira Vanitha   

Synopsis:   

With the advancement of electronics and computer science, mobile communication technology leads us to a fast moving entirely different world. In this scenario, we have lot of responsibilities, one of it is voting for our country, but even we don’t have time for it, and also our votes may not useful to our nation, because of fake votes and cheating process happened during the election. This problem is rectified by the latest voting system as “Mobile Voting System” which is discussed in this paper. The mobile voting system uses the efficient techniques, iris recognition and cryptography for the secured voting process. The iris recognition and cryptography avoids the fake votes and cheating process. The election commission spends lot of money, for each election unnecessarily, which will be minimized by this system. This system enables the voter to vote to the Nation from his place itself.

Distribution Network Planning with Advanced Centralized Voltage Regulation System

Vol.4 No.3

Year: 2011

Issue: Jan-Mar

Title: Distribution Network Planning with Advanced Centralized Voltage Regulation System   

Author Name: S. Sankar   

Synopsis:   

Traditional voltage regulation systems for distribution networks fail to achieve their objective in presence of local generation resources as they are designed for passive distribution systems and based on assumptions that may not hold if distributed generation (DG) is connected to the network. An advanced centralised voltage regulation system has been studied by the Authors to allow a greater DG penetration and a high quality service to customers. However, depending on the characteristics of the specific network, it could be sometimes impossible to solve some operating conflicts between voltage regulation and correct DG operation. In practice, in order to connect a greater amount of DG, it might be necessary, not only to revise the employed regulation criteria, but also to act at the planning stage to make specific changes in the structure of a distribution system. In this view the paper presents a planning procedure that, besides existing distribution system data bases, load variation forecast,  environmental/climatic  conditions, and planners experience, takes into account information directly provided  by  the  operation  of  the  aforementioned  advanced voltage regulation system.

  

A 3P-3W UPQC integrated with Star-Hexagon Transformer for 3P-4W Distribution System

Vol.4 No.3

Year: 2011

Issue: Jan-Mar

Title: A 3P-3W UPQC integrated with Star-Hexagon Transformer for 3P-4W Distribution System   

Author Name: Yash Pal, A.Swarup , Bhim Singh   

Synopsis:   

In this paper, a new topology is proposed for a three-phase four-wire (3P4W) distribution system utilizing a star-hexagon transformer along with three-phase three-wire (3P3W) Unified Power Quality Conditioner (UPQC).In this proposed topology the neutral point of the star connected transformer, used for the connection of series active power filter (APF) of 3P3W UPQC, is utilized as a fourth wire for 3P4W distribution system. The star-hexagon transformer is connected near the load to compensate the neutral current that may flow toward the neutral point of the series transformer of series APF. The series and shunt APF of 3P-3W UPQC are realized by readily available three-leg voltage source inverters (VSIs). For the mitigation of different power quality problems a control technique based on synchronous reference frame (SRF) theory is used for the control of UPQC. In this control scheme of UPQC, the current/voltage control is applied over the fundamental supply currents/voltages instead of fast changing APFs currents/voltages, there by reducing the computational delay. With the connection of star-hexagon transformer, no extra control is required for the neutral current; hence required numbers of current sensors are reduced. The performance of the proposed topology of UPQC is analyzed through simulations results using MATLAB software with its Simulink and Power System Block set toolboxes.

 

A 10-bit Ultra-Low-Power SAR ADC with a Novel DAC Switching Method

Vol.4 No.3

Year: 2011

Issue: Jan-Mar

Title: A 10-bit Ultra-Low-Power SAR ADC with a Novel DAC Switching Method   

Author Name: Weibo Hu, Donald Lie   

Synopsis:   

A 10-bit single-ended ultra-low-power Successive Approximation Register ADC with a novel DAC switching technique is designed in the TSMC 0.18µm mixed-signal CMOS technology. This method uses a reference voltage of VR/2, rather than VR, as the only reference voltage to digitize the input signals with the amplitude range of [0, VR]. Compared with the conventional switching method, this work reduces the size of binary-weighted capacitor array by 50%, lowering the average power consumption in the DAC during digitizing by 87.5%, and it also reduces the power consumption during sampling by 63.5%. With the sampling frequency of 77 kHz, ADC’s post-layout simulation resolution is 8.84 bits and ERBW (Effective Resolution Bandwidth) is 60 kHz, and the post-layout simulation FOM of our 10-bit SAR ADC can reach 18.9 fJ/(conversion-step), which is among the best ADCs FOM reported in a CMOS 0.18 µm technology.

 

A Low Cost Microcontroller Based Triggering Circuit for Multilevel Inverter

Vol.4 No.3

Year: 2011

Issue: Jan-Mar

Title: A Low Cost Microcontroller Based Triggering Circuit for Multilevel Inverter   

Author Name: Adil Sarwar, M. S. Jamil Asghar   

Synopsis:   

Multilevel inverters have drawn increasing attention in recent years, especially in the distributed energy resources area. Several renewable energy sources (batteries, fuel cells, solar cells, wind turbines or micro turbines) can be easily connected through a multilevel inverter to feed a load (off-grid) or interconnect to the ac grid (grid-tie) without voltage balancing problems. Moreover, multilevel inverters have a lower switching frequency than standard PWM inverters and thus have reduced switching losses. The output waveforms of multilevel inverters are in a stepped form, resulting in reduced harmonics compared to a square-wave inverter. In the present work, PIC 16F877A microcontroller based triggering circuit has been designed to be used with various levels of multilevel inverter. Multiple pulses with relative delay and requirement of a single variable dc supply (0-5V) for the control of all delay angles, makes it cost effective and simple. In addition, PIC 16F877A are cheaper with respect to other 8 bits microcontrollers available in market. It is a RISC controller with only 25 instruction sets. The Harvard architecture makes it more attractive. The simulation is done using MPLAB IDE and PROTEUS 7. Practical circuit has been designed and successfully implemented.

 

A Survey on Hardware and Software Optimization of Microprocessors for Low Power Consumption

Vol.4 No.3

Year: 2011

Issue: Jan-Mar

Title: A Survey on Hardware and Software Optimization of Microprocessors for Low Power Consumption   

Author Name: Ananthi Kaliyamoorthy, S. Manoharan   

Synopsis:

Today there is a growing need for reducing the power consumption of microprocessors, because they form a major share of the power budget of equipment. Power consumption in microprocessors can be reduced either by hardware, software or both. The power consumption of the processors increases along with increase in transistor count and clock frequencies. Thus there is a need to design a processor which consumes less power without affecting its performance and efficiency. Likewise, each instruction involves specific part of the microprocessor. Therefore, by selecting the correct instruction it is possible to reduce the power consumed by the processor. This paper presents a survey on hardware and software power reduction techniques used for several microprocessors.

Modeling Of Smoothing Reactor for HVDC Transmission System

Vol.4 No.2                      

Year: 2010

Issue: Oct-Dec

Title: Modeling Of Smoothing Reactor for HVDC Transmission System   

Author Name: L. Devi, Saibabu , S. Sivanagaraju   

Synopsis:   

The HVDC transmission system is becoming ever more complex, further, demand for reliable supply of electricity is growing, increasing the need for a higher level of system reliability. A probable solution might be to incorporate controllable power components within the system. One such important is smoothing reactor or DC reactor. In this paper the effect of failure rate and repair time on expected capacity level or power transmission capacity of smoothing reactor at different inductance values with one, two and without spares is analyzed and compared. And also effect of number of spares on expected capacity level is presented.

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Analysis of Induction Motor Efficiency Enhancement

Vol.4 No.2                      

Year: 2010

Issue: Oct-Dec

Title: Analysis of Induction Motor Efficiency Enhancement   

Author Name: S. Sankar   

Synopsis: 

This paper deals with the possibility of the efficiency improvement for the three-phase, low voltage, squirrel cage motor, using copper for the rotor cage. The analyze was made for single speed, three-phase squirrel cage induction motors with the rated power between 0.55 and 45 kW; 2,4,6 and 8 poles. Both the materials costs increase and the saved energy during the machine life were considered.

   

 

    

 

Automatic Generation Control of Interconnected Power System with Static Synchronous Series Compensator (SSSC) Unit Considering Governor Dead–Band and GRC

Vol.4 No.2                      

Year: 2010

Issue: Oct-Dec

Title: Automatic Generation Control of Interconnected Power System with Static Synchronous Series Compensator (SSSC) Unit Considering Governor Dead–Band and GRC   

Author Name: C.H. Vinothsna, Saibabu   

Synopsis:   

The analysis of Automatic Generation Control (AGC) of a two area interconnected power system considering Static Synchronous Series Compensator (SSSC) in series with the tie-line is presented. This paper proposes a new application of one of the sophisticated FACTS (Flexible AC Transmission Systems) devices, i.e. Static Synchronous Series Compensator (SSSC) to stabilize the frequency of oscillations in an interconnected power system. The SSSC located in series with the tie line between any interconnected areas is applicable to stabilize the area frequency of oscillations by high-speed control of tie-line power through the interconnection. The mathematical model of SSSC is derived from its characteristics of power flow control. The idea based on a dynamic control of tie-line power is applied to stabilize the frequency oscillations of inter area mode. Simulation study exhibits the significant effects of the proposed control.

  

 

    

 

Simulation of Multiple Output AC/DC Converter

Vol.4 No.2                      

Year: 2010

Issue: Oct-Dec

Title: Simulation of Multiple Output AC/DC Converter   

Author Name: T. Saravanan, Rama Reddy 

Synopsis:   

This paper deals with simulation of open loop and closed loop controlled multiple output AC to DC converter using Matlab simulink. The multiple outputs AC to DC converter are capable of giving 12V and 5V DC. This conversion has advantages like reduced transformer size and reduced filter size. The results of closed loop system are presented.

 

    

 

An Adaptive Distance Relay Setting For EHV Power Transmission Lines Using Fourier Transform

Vol.4 No.2                      

Year: 2010

Issue: Oct-Dec

Title: An Adaptive Distance Relay Setting For EHV Power Transmission Lines Using Fourier Transform   

Author Name: P.V. Prasad, S. Sivanagaraju   

Synopsis:   

This paper presents accurate calculation of apparent impedance of transmission lines by distance protection scheme.The apparent impedance equation, considering the transmission line capacitance by utilizing a double p model for a line is derived. The apparent impedance without and with considering the line capacitance is compared by considering the fault resistance. The quadrilateral characteristic of distance relay is compared in both the cases. Simulink model design and adaptive setting for a distance protection with consideration of transmission line capacitance is also investigated using Fourier transform. A 400 kV transmission line with 300km long is used in this study

   

 

Enhancement of Energy Efficiency in Squirrel Cage Induction Motors Using DCR Technology

Vol.4 No.2                      

Year: 2010

Issue: Oct-Dec

Title: Enhancement of Energy Efficiency in Squirrel Cage Induction Motors Using DCR Technology   

Author Name: S. Manoharan, N. Devarajan , M. Deivasahayam , G. Ranganathan   

Synopsis:   

In today's power production and utilization scenario, various types of problems are faced such as Depletion of fossil fuel sources, Increase in fuel cost, Deterioration of ecological balance due to carbon emission, Transmission and Distribution losses, Higher energy consumption due to poor efficiency drives and increased demand due to development taking place in many areas of the world which were hitherto undeveloped / under developed. Many of these problems can be addressed by adopting suitable technology resulting in energy saving. 'Energy conservation through Energy Efficiency' is the need of the hour and attempting to achieve this by developing higher efficiency motors with Die-cast Copper Rotor Motor (DCR) Technology. This paper covers the author's experiences so far and provides details of efficiency improvements, Energy saving potential ,case studies in the existing Die-cast Aluminium rotor motor (DAR) with the proposed DCR motor, especially in the industrial and agricultural sectors. This paper also includes some of the general Policy approaches for encouraging electrical energy efficiency.

  

 

Fuzzy Logic Power Oscillations Damping (Flpod) Controller for UPFC to Enhance the Transient Stability of Multi Machine Power System

Vol.4 No.2                      

Year: 2010

Issue: Oct-Dec

Title: Fuzzy Logic Power Oscillations Damping (Flpod) Controller for UPFC to Enhance the Transient Stability of Multi Machine Power System   

Author Name: I.Prabhakarreddy, B.V.Sankar Ram   

Synopsis:   

The Unified Power Flow Controller (UPFC) is one of the key Flexible AC Transmission System (FACTS) controller used to control active and reactive power flow in a transmission line and regulate the bus voltage within specified limits at which UPFC is connected. The Proportional and Integral (PI) controller of UPFC is not enough to damp power oscillations because of slow response of PI controller. This paper presents Fuzzy Logic Power Oscillation Damping (FLPOD) controller along with PI controller to improve the performance of UPFC in damping of power oscillations. The UPFC with the proposed controller effectively damps power oscillations after clearing fault in the power system. The UPFC with proposed controller is tested on Western System Coordinating Council (WSCC) — 9 Bus system through simulation by using SIMULINK.

 

High Power Factor Based Novel Design of Sodium Lamps

Vol.4 No.2                      

Year: 2010

Issue: Oct-Dec

Title: High Power Factor Based Novel Design of Sodium Lamps   

Author Name: S. Sankar, G. Gokula Krishnan   

Synopsis:   

In recent years many authors [1-4] are working to obtain single stage HPF electronic ballast for fluorescent and HID lamps to obtain cost reduction and to comply with international standard requirements. Usually to obtain HPF in electronic ballast for high pressure sodium lamps a Power Factor Preregulator (PFP) is used between the mains and the electronic ballast. In this paper will be reported the study and implementation of two single stage High Power Factor (HPF) electronic ballasts for high pressure sodium (HPS) lamps using a LCC filter, one using a half-bridge inverter and the second one using a full-bridge inverter. The main idea in this work is to compare two simple electronic ballasts topologies with HPF for HPS lamps working with a 220 VRMS mains voltage. Design criteria, simulation and experimental results will be also presented for a full bridge inverter in the final paper.

Analysis and Comparison of Harmonic Reduction in Multilevel Inverters

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: Analysis and Comparison of Harmonic Reduction in Multilevel Inverters   

Author Name: Mahesh Manivanna Kumar, Rama Reddy   

Synopsis:   

This paper presents a multilevel inverter with harmonics reduction along with the reduction in number of switches. The reduction in harmonic content in the three-level neutral-point-clamped (NPC), capacitor clamped inverter with inductive load is obtained by simulation. Similarly the reduction in harmonic content in the cascaded multilevel inverter is obtained. The percentage (%) THD is calculated for various levels (3, 7 and 9 level). Finally the percentage (%) THD obtained from various levels is compared. The functionality verification of the multilevel inverter circuit is done using PSPICE and MATLAB. The harmonic reduction is achieved by selecting appropriate switching angles.

Evaluation of First Swing Stability of a Large Power System Using UPFC

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: Evaluation of First Swing Stability of a Large Power System Using UPFC   

Author Name: Srikanth B, CH. Chengaiah   

Synopsis:   

This paper presents a simple method of evaluating the first swing stability of a large power system in the presence of Unified Power Flow Controller (UPFC) device. First a UPFC and the associated transmission line are considered and represented by an equivalent p—circuit model. The above model is then interfaced to the power network to obtain the system reduced admittance matrix which is needed to generate the machine swing curves. The above p —circuit model can also be used to represent other FACTS devices (SSSC and STATCOM) by selecting appropriate values of control parameters of the UPFC. The complex voltage at two end buses of the p-circuit model is also evaluated during simulation to implement various existing control strategies of FACTS devices and to update the reduced admittance matrix. The effectiveness of the proposed method of generating dynamic response and hence evaluating first swing stability of a power system in the presence of UPFC device will be tested on the ten-machine New England system.

Combined Optimization for Loss Reduction of Radial Distribution System Using Genetic Algorithm

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: Combined Optimization for Loss Reduction of Radial Distribution System Using Genetic Algorithm 

Author Name: P.V. Prasad, S. Sivanagaraju , S. Sathyanarayana , T.Ramana   

Synopsis:   

Feeder reconfiguration and capacitor placement are generally used for power loss reduction and voltage profile enhancement in radial distribution systems. This paper presents a joint optimization algorithm of combining feeder reconfiguration and capacitor placement for loss reduction. Genetic Algorithm (GA) is chosen to solve this combined optimization problem. The advantage of this method is that it can provide a global or near global optimum for feeder reconfiguration and capacitor placement. The effectiveness of the proposed method is illustrated with 33-node radial distribution system.

  

 

Optimal Power Flow Using Particle Swarm Optimization Technique

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: Optimal Power Flow Using Particle Swarm Optimization Technique   

Author Name: M.G. Amith Kumar, CH. Chengaiah   

Synopsis:   

Optimal Power Flow (OPF) is allocating loads to plants for minimum cost while meeting the network constraints .It is formulated as an optimization problem of minimizing the total fuel cost of all committed plant while meeting the network constraints or power flow constraints. The variants of the problem are numerous which model the objective and the constraints in different ways. Optimal Power flow deals with minimizing generation cost while maintaining set of equality and equality constraints. Power system must be operated in such a way that both real and reactive powers are optimized simultaneously. Reactive powers should be optimized to provide better voltage profile as well as to reduce system losses. Thus the objective of reactive power optimization problem can be seen as minimization of real power loss over the transmission lines. In this paper an attempt has been made to optimize each objective individually using Particle Swarm Optimization (PSO). In this method the system is initialized with a population of random solutions and searches for optima by updating generations. PSO has no evolution operators such as crossover and mutation. In PSO, the potential solutions called particles fly through the problem space by following the current optimum particles. The so developed algorithm for Optimization of each objective is tested on two systems i.e. on IEEE 26 and IEEE 30 bus system. Simulation results of IEEE 26 bus and IEEE 30 bus network are presented to show the effectiveness of the proposed method.

 

Distributed-Multiresolution-Dct-Svd (D-Mr-Dct-Svd) Watermarking of Rgb Images

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: Distributed-Multiresolution-Dct-Svd (D-Mr-Dct-Svd) Watermarking of Rgb Images   

Author Name: M.L. Srinivas, T. Ramashri   

Synopsis:   

In this paper an image authentication technique that embeds a color watermark into a host color image is proposed. Watermarking is used for copyright protection using Distributed multiresolution discrete cosine transform (D-MR-DCT) and singular value decomposition. The core idea of the proposed scheme is to decompose an image into four frequency sub-bands using D-MR-DCT and then singular values of every sub-band are modified with the singular values of the watermark.

Optimal Design of Hydropower Generation and Supervision

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: Optimal Design of Hydropower Generation and Supervision   

Author Name: S. Sankar, G. Gokula Krishnan   

Synopsis:   

The purpose of this study is to develop a general algorithm to solve the short-term hydroelectric scheduling problem in a robust, flexible and fast way, and which retains the same performances for either a small or a large-scale problem. The solution is based on the discrete maximum principle. Gradient method is used to solve the two-point boundary value problem. To deal with difficulties posed by the state variable constraints we use the augmented Lagrangian method. This paper is particularly concerned with the handling of bonds on the state variables utilizing augmented Lagrangian method

Recognition of Digitally Modulated Signals Using Statistical Parameters

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: Recognition of Digitally Modulated Signals Using Statistical Parameters   

Author Name: Jaspal Bagga, Neeta Tripathi   

Synopsis:   

Modulation scheme is one of the most important characteristics to note in the monitoring activity and identification of radio signals. Modulation recognition system must be able to make the correct classification of the modulation scheme of the received signal under interference. AMR is required in both military and civilian applications, such as surveillance, electronic warfare, threat assessment, signal confirmation, interference identification, software defined radio, and spectrum management. AMR is also believed to play an important role in the implementation of the 4th-Generation (4G) communication system. A generalized modulation identification scheme is developed and presented. With the help of this scheme, the automatic modulation classification and recognition of digitally modulated speech signals with a priori unknown parameters are possible effectively. The developed scheme based on wavelet transform and statistical parameters has been used to identify M-ary PSK, M-ary QAM, and M-ary FSK modulations. Various speech signals corrupted by noise have been used as sample signals .Statistical parameters are calculated and compared against certain threshold values to detect the modulation type. The simulated results show that the correct modulation identification is possible to a lower bound of 15 dB.

A Neuro-Fuzzy Controller for Doubly Fed Asynchronous Motor Drive

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: A Neuro-Fuzzy Controller for Doubly Fed Asynchronous Motor Drive   

Author Name: Chaiba Azeddine, Rachid Abdessmed , M. Lokmen Bendass   

Synopsis:   

In this paper neuro-fuzzy controller for Doubly Fed Asynchronous Motor (DFAM) drive is proposed. First, a mathematical model of DFAM written in an appropriate d-q reference frame is established to investigate simulations. In order to control the rotor currents of DFAM, a torque tracking control law is synthesized using PI controllers, under conditions of the stator side power factor is controlled at unity level. A four layer Neural Network (NN) is used to adjust input and output parameters of membership functions in a fuzzy logic controller (FLC). The back propagation learning algorithm is used for training this network. The performances of neuro-fuzzy controller (NFC) which is based on the torque tracking control algorithm are investigated and compared to those obtained from the PI controller. Results obtained in Matlab/Simulink environment show that the NFC is more robust, superior dynamic performance and hence found to be a suitable replacement of the conventional PI controller for the high performance drive applications.

Smart Sensors for a More Reliable and Environment Friendly Power Grid

Vol.4 No.1

Year: 2010

Issue: Jul-Sep

Title: Smart Sensors for a More Reliable and Environment Friendly Power Grid   

Author Name: Mohd. Rihan, Mukhtar Ahmad , M. Salim Beg   

Synopsis:   

The implementation of a smart power grid is at present, an active area of research for different utilities and countries. Functionally, a smart grid should be able to provide new capabilities such as self-healing, high reliability, energy management, and real-time pricing. A smart grid is expected to respond to threats, material failures, and other destabilizing influences by preventing or containing the spread of disturbances. In addition Smart grid can have major impacts on improving energy distribution and optimising energy usage which will result in reduction of CO2 emission. The Smart Grid will rely on smart sensors deployed across the grid to monitor the system and provide data to enable applications. These sensors must be reliable, have low installed cost and leverage existing communications infrastructure that may include automatic metering infrastructure or even the public cellular networks. This article describes the basic features of smart grid and the role of smart sensors and the accompanying technology in the implementation of a smart grid.

Text Dependent Speaker Recognition system Using Vector Quantisation Technnique

Vol.3 No.4

Year: 2010

Issue: Apr-Jun

Title: Text Dependent Speaker Recognition system Using Vector Quantisation Technnique   

Author Name: Piyush Lotia, Kamal K Mehta, M.R.Khan   

Synopsis:   

Automatic speaker recognition is a field of study attributed in identifying a person from a spoken phrase. It is widely used in biometric security system, phone banking and other similar applications. This paper presents a development of a Matlab based text dependent speaker recognition system. The model used to derive a mathematical representation of the speech signal. Mel Frequency Cepstrum Coefficient Feature extraction method is used to extract a speaker’s discriminative features from the mathematical representation of the speech signal. After that a feature matching method known as Vector Quantization is implemented using the LBG Algorithm. Feature matching is carried out in order to cluster the speech features into groups of specific sound classes. Finally analysis is carried out to identify parameter values that could be used to increase the accuracy of the system. In this paper we have studied the effect of recording environment on the accuracy of speaker identification.

STATCOM –Its Control Algorthim

Vol.3 No.4

Year: 2010

Issue: Apr-Jun

Title: STATCOM –Its Control Algorthim   

Author Name: sandeep gupta, A.K.Sharma   

Synopsis:   

In this paper, a new type of single Phase static compensator (STATCOM) for low rating used in customer side is proposed. This new STATCOM is constructed by cascading a full-bridge (H Bridge) voltage-source inverter (VSI’s) to the point of common coupling (PCC.) A so-called sinusoidal pulse width modulation (SPWM) unipolar voltage switching scheme is applied to control the switching devices of each VSI. A new control strategy is adopted for compensating the harmonics and reactive current required by the load. The proposed STATCOM has the advantage of a fewer number of VSI’s, the VSI’s being identical and extremely fast in response to reactive power change and the control strategy adopted shows a good response.

Vector Controlled Doubly Fed Induction Generator for Wind Energy Applications

Vol.3 No.4

Year: 2010

Issue: Apr-Jun

Title: Vector Controlled Doubly Fed Induction Generator for Wind Energy Applications   

Author Name: P S Mayurappriyan, Jovitha Jerome , R.Senthil Kumar   

Synopsis:   

The paper presents the dynamic model of doubly fed induction generator (DFIG) and its control structures used for variable speed wind energy conversion (WEC) system. DFIG is often a natural choice for electricity generation from renewable energy source. The stator flux oriented vector control algorithm is implemented. The results show that how such a control strategy offers the possibility of controlling the power generated by the DFIG.

Diagnosis of Power Quality Disturbances Using Wavelet Transforms

Vol.3 No.4

Year: 2010

Issue: Apr-Jun

Title: Diagnosis of Power Quality Disturbances Using Wavelet Transforms   

Author Name: M.Sushma, Tulsi Ram Dhas , A.Jaya Laxmi   

Synopsis:   

A new method for detection of power quality disturbance is proposed: first, the original signals are de-noised by the wavelet transform; second, the beginning and ending time of the disturbance can be detected in  time, third, determining the cause of power quality disturbances using various approaches such as Multi Resolution Analysis (MRA) or Discrete Wavelet Transforms (DWT) In this paper, wavelet transform is proposed to identify the power quality disturbance at its instance of occurrence. Power quality disturbances like sag, swell, interruption, DC offset, frequency variation and harmonics are considered and are decomposed up to 4 levels using Db4 wavelet. For some disturbances it is sufficient to have only second or third level of decomposition. The exact location of the disturbance can also be found on the time scale. The application to a case study shows that this method is fast, sensitive, and practical for detection and identification of power quality disturbance.

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