Tankut Yalcinoz

Robust Design using Pareto type optimization: A genetic algorithm with arithmetic crossover

In dual response systems (DRSs) optimization restrictions on the secondary response may rule out better conditions, since an acceptable value for the secondary response is usually unknown. In fact, process conditions that result in a smaller standard deviation are often preferable. Recently, several authors stated that the standard deviation of any performance property could be treated as a new property in its own right as far as Pareto optimizer was concerned. By doing this, there will be many alternative solutions (i.e., the trade-offs between the mean and standard deviation responses) of the DRS problem and Pareto optimization can explore them all. Such analysis is useful, and that is required in order to achieve an improved understanding of the problem before searching for a final optimal solution. In this paper, we again follow this new philosophy and solve the DRS problem by using a genetic algorithm with arithmetic crossover. The genetic algorithm is applied to the printing process problem for improving the quality of a printing process. Genetic algorithms, in contrast to the one-solution-at-a-time approach of most optimization algorithms, maintain a population of hundreds, or thousands, of solutions in speedy manner.

Mean square error criteria to multiresponse process optimization by a new genetic algorithm

The recent push for quality in industry has brought response surface methodology to the attention of many users. Most of the published literature on robust design methodology is basically concerned with optimization of a single response or quality characteristic which is often most critical to consumers. For most products, however, quality is multidimensional, so it is common to observe multiple responses in an experimental situation. In this paper, we present a methodology for analyzing several quality characteristics simultaneously using the mean square error (MSE) criterion when data are collected from a combined array. Problems with highly nonlinear, or multimodal, objective functions are extremely difficult to solve and are further complicated by the presence of multiple objectives. An alternative approach is to use a heuristic search procedure such as a genetic algorithm (GA). The GA generates a string of solutions using genetics-like operators such as selection, crossover and mutation. In this paper, a genetic algorithm based on arithmetic crossover for the multiresponse problem is proposed. The string of solutions highlight the trade-offs that one needs to consider in order to obtain a compromise solution. A numerical example has been presented to illustrate the performance and the applicability of the proposed method.

Hopfield neural network approaches to economic dispatch problems

This paper aims to identify and investigate a new Hopfield neural network structure suitable for application to economic dispatch problems such as unconstrained economic dispatch, economic dispatch with transmission capacity constraints and multi-area economic dispatch. A new mapping technique is described for quadratic programming problems with equality and inequality constraints. Side constraints are handled by a modified activation function. The proposed method is tested on different sizes of systems having between 3 and 240 generating units. The results of the proposed method are compared with those of a classical method and the improved Hopfield NN approach (IEE Proc Gen Transm Distrib 144(2) (1997) 181).

The behaviour of TSR-based SVC and TCR-based SVC installed in an infinite bus system

In this paper, effects of both Thyristor Switched Reactor-based Static VAr Compensator (TSR-based SVC) and Thyristor Controlled Reactor-based Static VAr Compensator (TCR-based SVC), which are two of shunt Flexible AC Transmission Systems (FACTS) devices, on load voltage in a single-machine infinite bus (SMIB) system are investigated. The modeling and simulation of TSR-based SVC and TCR-based SVC are verified using the Matlab7.04® SimPowerSystems Blockset. A six-pulse generator is used to control of TSR in the SVC. A fuzzy logic controller is used to control of TCR-based SVC. The studied power system consists of a synchronous generator connected to an infinite bus and a static load. The results show that improvement on reactive power compensation and load bus voltage regulation could be achieved by using the TSR-based SVC and TCR-based SVC.

The behavior of Thyristor Switched Capacitor (TSC) installed in an infinite bus system

This paper examines the effects of Thyristor Switched Capacitor (TSC) on load voltage in a single-machine infinite bus (SMIB) system. The modeling and simulation of TSC are verified using the Matlab/Simulink 7.04® and SimPowerSystems Blockset. The studied power system consists of a synchronous generator connected to an infinite bus and a static load. The results show that improvement on reactive power compensation and load bus voltage regulation could be achieved by using the TSC. Also, the test system with TSC is not needed a harmonic filter and low frequency voltage oscillations are damped by using TSC.

Transmission Line Shunt and Series Compensation with Voltage Sensitive Loads

This paper presents an analysis of the effects of shunt and series line compensation levels on the transmission line voltage profile, transferred power and transmission losses for different static load models. For this purpose, a simple model is developed to calculate the series and/or shunt compensated transmission line load voltage. Consequently, different shunt and series compensation levels are used with several voltage sensitive load models for two different line models. It is observed that the compensation level is significantly affected by the voltage sensitivities of loads. Moreover, the voltage level of the transmission is an important issue for the selection of the shunt and series capacitor sizes when load voltage dependency is used.

An Educational Software Package for Power Systems Analysis and Operation

This paper presents a software package developed in Matlab for teaching power systems analysis and operation. The software package is used to support and enhance power engineering education at both undergraduate and postgraduate levels. The application programs in this package include fault analysis, load flow analysis, transient stability, economic dispatch, unit commitment and load forecasting. All modules of the package are independent of each other. The students or researchers can make copies of the software to study and can modify any module of the package.

An educational software package for Thyristor Switched Reactive Power Compensators using Matlab/Simulink

Abstract In this paper, an educational software package called TSCOM (Thyristor Switched Reactive Power Compensators) has been developed. The TSCOM software package contains simulation models of Thyristor Switched Capacitor (TSC) and Thyristor Switched Reactor (TSR)-based Static VAr Compensator (SVC) which are two of the shunt Flexible AC Transmission Systems (FACTS) devices. The design and simulations of TSC and TSR-based SVC are proposed using the Matlab/Simulink 7.04® and SimPowerSystems. The TSC and TSR-based SVC devices are demonstrated at two bus, three bus, infinite-bus, single-phase, three-phase, static load, dynamic load and stair-case load conditions. The effects of TSC and TSR-based SVC devices on load voltage are also analyzed. Student feedback indicates that this package is user-friendly and considerably effective for students and researchers to study theory of switched compensators, the reactive power control and voltage regulation. The proposed package will help to design the practical prototypes for students and researchers.

A new algorithm and computation approach for economic dispatch with prohibited operating zones in power systems

This paper presents a new algorithm and computation approach to solve the economic load dispatch (ELD) in electrical power systems. We applied a new power formula to solve the ELD problem. If production units cost curves are represented properly then ELD becomes more correct. In this respect we assumed that production units have prohibited operating zones. Cost curves of the production units are generally accepted as piece-wise quadratic function. The power production is cheaper since we do not use the production units in the prohibited operating zones. The proposed method and algorithm are compared to other ELD methods on the standard test systems. The proposed method solve the dispatch problem faster than the other ELD methods.