A. Chovanec, A. Breznická

USE OF A DISCRETE SIMULATION FOR AN ASSESSMENT OF THE MISSION COMPLETION

FROM A VIEWPOINT OF MAINTENANCE COSTS

An anticipated simulation is an experimental method of study, using probability dynamic approaches using experimentation with a computer model generated in Matlab. Simulation is seen as a process of a gradual building up of a mathematical and logical model described with computer algorithms of a simulation program representing a model of a reviewed system and subsequently experimentation with such a model aiming to obtain estimates of results of the system activity. There are many positive reasons why to perform a simulation study, as for example a missing analytic description of a system or an assessment of a capacity value of an existing system within other operational conditions.  Major problems, rising in respect to a model implementation in a program, are recording the model structure, obtaining random parameter values, recording the dynamic features of models. Additional issues are added as experimentation with a model or development of resulting output in a suitable form. 

G.F. Kovalev, L.M. Lebedeva

ELIABILITY ASSESSMENT MODEL OF ELECTRIC POWER SYSTEMS IN LONG-TERM OPERATION PLANNING

The paper presents a conceptual statement of the problem of determining the reliability indices of electric power systems of random configuration, mathematical formulation of the problem, and problem-solving methods. The authors provide the reference data on the computer program developed for solving the given problem and recommend possible application areas for the program.

R.I. Mustafayev, L.H. Hasanova, Q.M. Aliyev, M.M. Musayev

THE EXCITATION CONTROL AND STABILITY OF SMALL HYDROELECTRIC POWER STATIONS SYNCHRONOUS GENERATORS WHEN OPERATION IN POWER SYSTEM

The article discusses the minimization of active power losses depending on the mode of operation of the generator and the load profile. The optimal law of control of synchronous generator excitation in small hydroelectric power plants, at which the energy losses are minimized due to the optimal reactive power interchange, was determined.

V.Kh. Nasibov

APPLICATION OF THE FUZZY-SET THEORY TO THE TASKS OF AZERBAIJAN ELECTROENERGETICS SECURITY

FOR SHORT-TERM PERIODS

Electric power industry for short-term tasks of security is presented by the combination of four subsystems, namely: fueling subsystem, electricity production subsystem, transmission and distribution of electricity subsystem, export and import of electricity. To evaluate the security of each subsystem the linguistic variables, rules and membership functions have been defined. The resultant level of short-term security of Azerbaijan republic's electric power industry is determined on the basis of each subsystem's security by developed table.

I. Yusuf

COMPARATIVE RELIABILITY ANALYSIS OF FIVE REDUNDANT NETWORK FLOW SYSTEMS

In this paper, probabilistic models for five repairable redundant network flow systems have been developed to analyze and compare their availability and profit. Explicit expressions for steady-state availability, busy period of repairman and profit function for the five redundant network flow systems are developed. Furthermore, we compare the five redundant network flow systems based on their availability and profit and found that configuration II is more reliable and profitable than the remaining configurations.

Yu. Paramonov, R. Chatys. Cimanis, S. Varickis

MODIFIED CONCEPT OF DANIELS' SEQUENCE AND ITS APPLICATION TO ANALYSIS

OF THE RELIABILITY OF SERIES-PARALLELS SYSTEM AND FATIGUE LIFE

OF UNIDIRECTIONAL FIBROUS COMPOSITE

This is short review of previous publications and new development of the concept of Daniels' sequence (DS) which can be used to consider the association of distribution of the static strength of unidirectional fiber composite (UFC) component with distributions of its fatigue life and residual strength of the UFC itself. A generalization of the model of series-parallel system as description of structure of UFC is given. A new description of the defected structural longitudinal element (LE) of UFC, new condition of failure of UFC, a definition of residual Daniels’ function is introduced. Numerical examples of processing of experimental data (data of fatigue test of glass-fiber composite) are presented. The estimates of the parameters of the corresponding nonlinear regression model for simultaneous processing of result of the fatigue test and test of residual tensile strength are obtained (parameters of the distribution of the local strength parameters of structural LE).

Sadia Anwar, Arif Ul Islam

ESTIMATION AND OPTIMAL DESIGN OF CONSTANT STRESS PARTIALLY

ACCELERATED LIFE TEST FOR GOMPERTZ DISTRIBUTION WITH TYPE I CENSORING

This study deals with simple Constant Stress Partially Accelerated life test (CSPALT) using type-I censoring. The lifetime distribution of the test item is assumed to follow Gompertz distribution. The Maximum Likelihood (ML) Estimation is used to estimate the distribution parameters and acceleration factor. Asymptotic confidence interval estimates of the model parameters are also evaluated by using Fisher information matrix. Statistically optimal PALT plans are developed such that the Generalized Asymptotic Variance (GAV) of the Maximum Likelihood Estimators (MLEs) of the model parameters at design stress is minimized. In the last, to illustrate the statistical properties of the parameters, a simulation study is performed.