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An increasing part of low voltage standard induction motors operates with PWM voltage source inverters using IGBTs and they are applied to a wide range of power 0.1 kW up to some MW. The PWM (pulse width modulation) inverter mode of control generates a large frequency spectrum of overvoltages. The resulting undesired overvoltages at the motor terminals stress the motor insulation. Usual standards...
The definition of reactive power in three phase system under non sinusoidal situation by various methods are discussed. The effect on power factor improvement and harmonic distortion by energy storage compensation by various definitions is compared using matlab simulation. Adequate filter capacitors are designed to attain the desired power factor and to reduce the distortion factor.
The objective of optimal relay coordination in interconnected power system is to achieve selectivity without sacrificing sensitivity & fast fault clearance time. This paper presents the effect of fault location on the flow of current direction & optimal coordination of directional over current relay. In this coordination problem Time Dial Setting (TDS) & Pick up Current Setting (Ip) of...
This paper describes the analysis and design of a grid connected wind generating system with voltage source converter (VSC). When wind generating system (WGS) is connected to grid create a problem of power quality such as poor power factor, voltage distortion, and harmonic distortion on the grid. The grid connection is realized by a controlled PWM voltage source inverter. The VSC is operated in hysteresis...
In the recent years charge coupled devices (CCDs) and CMOS image sensors are widely being used for capturing a digital image. The current resolution level will not satisfy the requirements for certain applications. One of the solutions for satisfying all requirements is Super Resolution. Super resolution is a process of increasing the density of pixels by extrapolating the spectrum of an object beyond...
This paper presents a STATCOM (static compensator) based voltage controller for an isolated asynchronous generator (IAG) driven by bio-gas, diesel engine and gasoline and feeding 3-phase 4-wire consumer loads. The proposed controller consists of an IGBT (Insulated Gate Bipolar junction Transistor) based voltage source converter (VSC) and capacitor at its DC link. The neutral point for the consumer...
This paper shows the application of S-transform in identifying the voltage disturbances such as sag, interruption, swell and harmonics. S-transform is suitable for the analysis of power quality disturbances under noisy condition as it has excellent time-frequency resolution characteristics and has the ability to detect the disturbance correctly. Various voltage disturbances are generated as per IEEE...
We propose a simple formulation for regularized kernel function approximation. The regression function is obtained by minimizing an unconstrained quadratic function. Further reduced kernel technique is also employed in its formulation which enables it to handle large database. The solution of this objective function is obtained by solving a system of linear equations and thus no need for any quadratic...
This paper presents Wavelet based back propagation algorithm for classifying the power system faults, which is quite reliable, fast and computationally efficient. The proposed technique consists of a preprocessing unit based on discrete wavelet transform (DWT) in combination with an artificial neural network (ANN). The DWT acts as extractor of distinctive features in the input current signal which...
Delay margin means the maximum delayed time that power system can sustain without losing its stability. Since, there exists significant time delay in the data of phasor measurement unit (PMU) and wide-area measurement system (WAMS), to evaluate system delay margin is very important for power system online stability assessment and controller design in the wide-area environment. In this paper, we use...
It is not quite uncommon, in general, to use DC motors in industrial applications, but after the introduction of power electronics, AC motors grabbed much importance. Of these, induction motors are widely used in industrial and domestic applications due to the advantages like simple construction, ruggedness, flexible control, good efficiency and low cost. In order to control the stator voltage and...
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