SOME SUBJECTS OF COMPENSATION OF THE INDUCTION GENERATORS REACTIVE POWER IN WIND-POWER

AND SMALL HYDROELECTRIC POWER PLANTS

Reactive power compensation of asynchronous generators wind power and small hydroelectric power stations increases the reliability of connecting them to the so-called "weak" power grids of power systems. The methods of reactive power compensation for asynchronous generators of various designs.

MULTI PHASE RELIABILITY ANALYSIS WITH VARIABLE PHASE DURATION AND VARIABLE PHASE SEQUENCE

This paper proposes a new simulation model for evaluating reliability of phased mission systems with variable phase durations and variable sequencing. The model simulates the system failures within target operating period using a modularized phased mission system model. Monte Carlo method has been used to simulate the reliability of phased mission and mission phases. A case study on electronic lighting control system is given to demonstrate the proposed simulation model. The effects of assuming constant duration and constant sequencing in the mission have been discussed during the case study.

SEQUENTIAL ALGORITHMS OF GRAPH NODES FACTORIZATION

In this paper algorithms of a factorization of graph nodes which are used in a processing of data connected with different extreme situations are constructed. We assume that information about a new node and incident edges arrives at each step sequentially. In non oriented graph we suppose that two nodes are equivalent if there is a way between them. In oriented graph we assume that two nodes are equivalent if there is a cycle which includes these nodes. In this paper algorithms of such factorization are constructed. These algorithms need O(n2) arithmetic operations where n is a number of graph nodes.

DETECT FAILURES IN COMPLEX TECHNICAL SYSTEMS

The paper analyses possibilities of failures detection in specific technical systems. On the basis of preliminary analysis a suitable type of combined analysis is determined which detects failures with an emphasis on non-destructive approach. This method can be used for diagnostics and failure detection in systems of central power supplies used in transportation, especially in researching phase of the product life cycle. The paper presents the use of modern thermo visual technology which is documented by direct material and marking the measured temperatures on the locations of particular failures.   

MODELING THE DEPENDABILITY AND COST OF MAINTENANCE

The paper deals with possibilities of stochastic approaches in risk modelling from a point of costs and data relating reliability aiming to define needed parameters of distribution of stochastic variables. It presents outputs from developed and applied simulation models, to assess reliability, maintainability, availability, costs and risks from operational data.

SYNTHESIS BASE OF FAZZY KNOWLEDGE ANFIS-CONTROL OF REACTIVE CAPACITY AND VOLTAGE

IN DISTRIBUTIVE ELECTRIC NETWORKS

The question of synthesis of base of fuzzy knowledge ANFIS - networks for control streams of reactive capacity and voltage of knots considered in distributive electric networks. Synthesis base of fuzzy knowledge and term on basis of the received regime reports executed for schemes 14 knots electric networks with method application subtractive clustering. Root mean square error parameter adjustment of a method shows to adequacy of control of a mode in DEN.

SOFTWARE RELIABILITY. WHAT IS IT?

This article is about how the confusion of terms can give rise to confusion in the approaches and methods, and bring to a deadlock the whole research area. It doesn’t mean that we would like to teach someone or to present "the ultimate truth". It is rather another attempt to declare that "software reliability» does not exist in the form it is treated in most of "traditional" sources.

MODELS, METHODS AND MEANS FOR SOLVING THE CHALLENGES IN CO-DESIGN AND TESTING

OF COMPUTER SYSTEMS AND THEIR COMPONENTS

This paper is addressed to a problem of development of the resources used for solving challenges in co-design and testing of the computer systems and their components. Both target and natural are considered. Target resources include models, methods and means. Natural resources like particularities of the target resources are examined.  Natural development of target resources with structuring under particularities of the Universe which is considered like parallel and approximate is analysed. Natural resources in remove of contradicts between target resources are shown.

A NEW APPROACH TO PERFORM ACCELERATED RELIABILITY TESTING OF LOW TENSION MOTORS

Most of the engineers finds it very tedious to do accelerated reliability test of any motor product if it has to be mechanically loaded as it involves lot of difficulties in motor’s loading capabilities and its size, which also directly impacts the development time and cost. This is why all the sequences in accelerated reliability test are done on no-load condition which gives results but are not accurate since in field motors are always under loading condition. To overcome all these difficulties, the paper proposes a new approach to perform accelerated reliability testing of low tension 3 phase motors under full load without actually coupling mechanical load to the motor shaft. The approach is simple and easy to implement. In this approach, instead of mechanical loading motor is equivalently loaded just by giving a supply voltage approximately 20-25% greater than the rated voltage to get same load current similar to fully loaded motor across all the three phases. Therefore, the application of proposed approach to perform accelerated reliability testing is experimented on low tension motor and results were discussed in detailed in the paper. From our practical work, the proposed approach has proven more accurate results compared to the results of previously conducted Reliability analysis done on no-load condition. Hence, the approach will definitely leads to get faster and better results in a simple and cost effective way.

REGRESSION EQUATIONS FOR MARSHALL-OLKIN TRIVARIATE EXPONENTIAL DISTRIBUTION

AND RELIABILITY MEASURES OF RELATED THREE-UNIT SYSTEMS

Marshall and Olkin(1967) proposed a multivariate exponential distribution and derived some properties including the moment generating function. Proschan and Sullo(1976) provide  the probability density function which involves some tedious notations. In this paper, we provide an explicit expression for the probability density function in the trivariate case and derive the conditional distributions, regression equations and the moment generating function. By considering four three unit systems with trivariate exponential failure time distribution, we derive the reliability measures of the systems.

RELIABILITY OPTOMIZATION OF COMPLEX SYSTEMS

The method based on the results of the joint model linking a semi-Markov modeling of the system operation process with a multistate approach to system reliability and the linear programming are proposed to the operation and reliability optimization of complex technical systems at the variable operation conditions. The method consists in determining the optimal values of limit transient probabilities at the system operation states that maximize the system lifetimes in the reliability state subsets. The proposed method is applied to the operation and reliability optimization of the exemplary technical multistate non-homogeneous system composed of a series-parallel and a series-“m out of l” subsystems linked in series that is changing its reliability structure and its components reliability parameters at its variable operation conditions.

MODELLING RELIABILITY OF COMPLEX SYSTEMS

Modelling and prediction of the operation and reliability of  technical systems related to their operation processes are presented. The emphasis is on multistate systems composed of ageing components and changing their reliability structures and their components reliability parameters during their operation processes that are called the complex systems. The integrated general model of complex systems’ reliability, linking their reliability models and their operation processes models and considering variable at different operation states their reliability structures and their components reliability parameters is constructed. This theoretical tool is applied to modelling and prediction of the operation processes and reliability characteristics of the multistate non-homogeneous system composed of a series-parallel and a series-“m out of l” subsystems linked in series, changing its reliability structure and its components reliability parameters at variable operation conditions.