International Journal of Emerging Electric Power Systems

Published by De Gruyter

Volume 8 Issue 5

October 2007

Issue of International Journal of Emerging Electric Power Systems

Contents
Journal Overview

Article

October 2, 2007

A Novel Load Compensation Algorithm under Unbalanced and Distorted Supply Voltages

K. Karthikeyan, Mahesh Kumar Mishra

Abstract

In this paper, a novel control algorithm is proposed to compensate the unbalanced and non-linear loads in a three-phase four-wire system using active power filters. The algorithm results in balanced and sinusoidal source currents under unbalanced and distorted three-phase supply voltages. The algorithm makes use of the positive sequence extraction of the supply voltage and the theory of instantaneous symmetrical components. To illustrate the concept, a three-phase four-wire system with unbalanced and non-linear load is considered for compensation. The detailed simulation and experimental results are presented to validate the proposed method.

October 2, 2007

A New Linear Fractional Transformation Based Approach to Power System Robustness Analysis

Rafael Castellanos Bustamante, Arturo Roman Messina, Carlos Juarez

Abstract

Large power systems are highly complex systems that defy predictions with any degree of certainty. In this paper, an analytical framework for the assessment of small signal stability under operating uncertainty is presented.A rigorous analysis framework for the description of uncertainty in operating conditions is suggested. Using structured singular value theory and optimization tools, techniques for robust stability analysis of complex power systems are then derived and a method to quantify the effect of parametric uncertainties on the stability of critical inter-area modes is presented. A computationally-efficient method for modeling parametric uncertainty based on linear fractional transformation (LFT) theory is investigated and tested. With this approach, it becomes possible to estimate the effects of variations in the parameters of major transmission resources on the nominal stability of critical inter-area modes.The use of the analysis methods is demonstrated on two systems: i) a two-machine test system, and ii) a two-area, 11-bus, 4-machine test system.

November 21, 2007

Electric Load Management Using Electricity Tariff Algorithm

Soliman Abdel-hady Soliman, Ibrahim Helal, A.M. Youssef

Abstract

The tariff is the best incentive factor for the industrial customer today to reduce the peak load. This paper describes different methods of pricing electricity. It is important to study the influence of the tariff on the industrial loads and the costs of electricity before ILM can be implemented. This paper is interested in studying the economic aspects of fixed and operating cost, other factors affecting the generation economy, distribution of power, etc. Costs of supplying electricity to consumers are also considered. A utility can influence its customers' load by providing financial incentives through the prices charged for electricity at different times of use. By designing discriminatory time of use tariffs in which the prices of electricity corresponds to the marginal cost of supply, a utility provides appropriate signals to the customer to increase consumption of electricity at off peak periods. The proposed algorithm is implemented to a real system in operation.

November 21, 2007

Synchronous Generators Modeling and Control Using the Framework of Individual Channel Analysis and Design: Part 1

Carlos Ernesto Ugalde Loo, Luigi Vanfretti, Eduardo Liceaga-Castro, Enrique Acha

Abstract

In this paper a comprehensive dynamical assessment of a high order synchronous generator plant is carried out using the Individual Channel Analysis and Design (ICAD) framework a multivariable control engineering tool that allows robustness and system performance evaluations. The great benefits of ICAD are elucidated and contrasted to those provided by the long-time honored block diagram representations. Several models used for the small signal stability analysis of synchronous generators are evaluated under the framework of ICAD. The study, which builds on pioneering work, reveals the great advantages of carrying out control system analysis and design with higher order generator models. Moreover, careful analysis of the ICAD's Multivariable Structure Function (MSF) helps to explain, formally, why some operating conditions of the control system are more critical than others. Furthermore, correct interpretations of MSFs are amenable to robust and stable control system designs. Two kinds of studies are considered in the paper; one assesses operation under various power factor conditions and the other under a varying tie-line reactance. The control system design and stability and structural robustness assessment of the system are presented in the second part of this paper. Moreover, results obtained under the ICAD framework are compared with those arising from conventional controllers.

November 21, 2007

Extended Delta Based 15-Phase AC-DC Converter for Variable Frequency Induction Motor Drives

Vipin Garg, Bhim Singh, G. Bhuvaneswari

Abstract

This paper presents the design and analysis of a multi-phase ac-dc converter system for harmonic reduction at the point of common coupling (PCC) in vector controlled induction motor drives (VCIMD's). The design of the proposed 3-phase to 15-phase autotransformer is presented along with the VCIMD. The proposed 15-phase ac-dc converter is found capable of suppressing up to the 29th harmonic in the supply current, along with the power factor improvement close to unity in the wide operating range of the drive. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed ac-dc converter. A set of power quality indices on input ac mains and on dc bus for a VCIMD fed from existing 6-pulse and proposed 15-phase ac-dc converters are also given to compare their performance.

November 21, 2007

Identification of External Power System Linear Dynamic Equivalents as MIMO Feedback Blocks for the Study System

Hamed Shakouri G., Hamid Lesani, Ali Mohammad Ranjbar, Hamidreza Radmanesh

Abstract

The necessity of dynamic equivalents for power system analysis has been well known since the expansion of large interconnected power networks, and has been discussed during the last decades. The present paper proposes a new method for constructing dynamic equivalents of power systems. In this method, at the first step the ``study system" is modeled completely via a single machine-infinite bus modeling procedure. Then the ``external system" is identified as a MIMO feedback block of this model in such a manner that can include dynamic effects of the latter on the behavior of the former. The method is successfully experimented on a part of the Iranian southern network.

November 21, 2007

Novel Configuration of 60-Pulse Voltage Source Converter for STATCOM Application

Wulue Pan, Zheng Xu, Jing Zhang

Abstract

The proposed voltage source converter is composed of a series double bridge converter with an auxiliary circuit. The auxiliary circuit injects DC voltage via the mid point of the double bridge converter. The injection ratio and frequency are chosen to convert the standard 12-pulse into 60-pulse configuration without PWM or increasing the number of bridges, thus the voltage and current harmonic can fulfill the THD limit without a conventional filter. The converter is operated under fundamental frequency for the main bridges, thus its switching lose is low. The converter can be widely used in the STATCOM and HVDC system. The paper describes the principles and control strategies of the proposed converter. The operational feasibility of the proposed converter is verified by computer simulation using the PSCAD/EMTDC package.

About this journal

Objective
International Journal of Emerging Electric Power Systems (IJEEPS) publishes significant research and scholarship related to latest and up-and-coming developments in power systems. The mandate of the journal is to assemble high quality papers from the recent research and development efforts in new technologies and techniques for generation, transmission, distribution and utilization of electric power.

Topics
The range of topics includes:

electric power generation sources
integration of unconventional sources into existing power systems
generation planning and control
new technologies and techniques for power transmission, distribution, protection, control and measurement
power system analysis, economics, operation and stability
deregulated power systems
power system communication
metering technologies
demand-side management
industrial electric power distribution and utilization systems

Article formats
Research articles, reviews

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