ANALYTICAL ESTIMATION OF RELIABILITY OF NETWORKS CONSISTING OF IDENTICAL ELEMENTS

In this work the analytical expressions for reliability factor of steady-state network consisting of identical elements are accomplished. For obtaining of the analytical expressions of considered factors, the Markov process characterized by a certain combination of failed elements and by a network state is considered. It is shown that for definition of values of the obtained expressions it is sufficient to define the number of combinations of set capacity elements at which failure the network passes in non-operable state. For small dimension networks this factor may be defined precisely by analysis of all possible combinations of failed elements. For large-scale networks it is necessary to use Monte Carlo method or combined method.

A General Analytical Solution for the Occurrence Probability

of a Sequence of Ordered Events following PoisSon Stochastic Processes

The author presents a general analytical solution determining “the Occurrence probability of a sequence of events, each following a Poisson Stochastic Process”. Generally, this probability is described under the form of an integral equation of order “n”. Where “n” is number of the elementary independent events in the examined sequence. As far as the author can tell, the solution is original. It is of a great interest to a wide range of system reliability problems such as: sequential calculations, dominos effects, dynamics fault trees, Markov systems, priority AND gates, stochastic optimization, acceleration techniques for Monte-Carlo simulation, …

OPTIMAL DISPATCHING OF GENERATORS WITH LOAD DEPENDENT FAILURE RATES

An optimally coordinated energy dispatching among generating units may contribute to attain higher performances of electric networks. Within this wide research field this paper focuses on a theoretical study aimed at proposing an optimal dispatching policy maximizing reliability and Mean Time To Fault of a park of programmable generating units whose failure rate models take into account the dependency from the instantaneous loading condition.

APPROXIMATION OF DOMAINS OF SERVICEABILITY AND ATTAINABILITY

OF CONTROL SYSTEM ON THE BASIS OF THE INDUCTIVE APPROACH

One of fundamental problems of the dynamic systems control theory is the problem of a finding or estimation of attainability sets. Their practical construction, especially in nonlinear systems of the high dimensionality, usually turns out hugely the complex problem demanding considerable computing resources. In this connection possibility of use of adaptive partition by means of a uniform grid as one of effective methods of approximation of such sets is analyzed. The choice of received net descriptions for specification of their unknown borders in the conditions of uncertainty on the basis of the inductive approach is substantiated, using available aprioristic and current information.

TECHNIQUE OF FORMATION HOMOGENEOUS SAMPLE SAME OBJECTS

Urgency of a problem. Reliability of electro power systems (EPS) in many respects depends on reliability of the capital equipment and devices (objects EPS). Modern objects EPS concern to a category of complex objects (CO). CO - multivariate, in other words, characterized greater number of attributes and their versions. As first approximation, these attributes presented by two groups. The first group of attributes characterizes a design CO and the second presented in characteristics sheet, and the second group -conditions of operation CO. If necessary estimations of a technical condition CO (for example, at an estimation of expediency of a conclusion CO on major overhaul), data on a technical condition of it CO, as a rule, it appears insufficient. Insufficient there are not only data on emergency and scheduled switching-off, but also data on size of deterioration and speed of its change. For this reason normative materials attraction of retrospective data about reliability same CO recommended. At this classification influence, the second group of attributes that increases risk of the erroneous decision is not considered.

DEVELOPMENT AND RESEARCH ON MATHEMATICAL MODELS, MODES OF WIND POWER PLANTS' ELECTROMECHANICAL CONVERTERS

A mathematical models of the following electromechanical converters, used in wind power, are presented: the asynchronous generator with a fed through a frequency converter stator, the generator, which is double fed asynchronous machine with rotor winding, fed through a frequency converter, and a synchronous generator with permanent magnets, with stator, fed through the frequency converter. For all converters the optimal control laws of amplitude and frequency of voltage on generator's terminals are obtained for all operating modes of wind power plants.

PROBABILITY-STATISTICAL ANALYSIS OF QUEUING NETWORKS WITH INFINITE NUMBER OF SERVERS

In this paper queuing networks with infinite number of servers and exponentially distributed service times are considered. Limit distributions for numbers of customers in aggregated nodes are calculated. Using these calculations statistical estimates of limit distributions parameters are constructed. Mean times of customer sojourn time in opened network and its analog for closed network are estimated also. Obtained results are spread onto estimates of populations and life cycle parameters.

POWER SUPPLY RESTORATION  IN DISTRIBUTIVE NETWORKS

The method and program complex realization for restoration scheme search of power consumption in networks on the basis of algorithm processing of the network count and artificial neural networks (ANN) are offered and given reason. Both algorithms work in a competing mode, mutually smoothing lacks of each separate method. Work complex principles, in particular, concerning application of the generalized error vector for ANN self-training and solution stability are theoretically proved. The program complex realized as a part for ‘the adviser of the distributive network dispatcher’, was tested on a 201 buses, 7 sources and 227 lines distribution network and one has shown good results.

ASYMPTOTIC FORMULA FOR DISCONNECTION PROBABILITY OF GRAPH ON TWO DIMENSIONAL MANIFOLD

A problem of a calculation of a graph disconnection probability is considered in a lot of papers.  But when a number of arcs increases this problem becomes much more complicated. So it is necessary to construct convenient asymptotic formulas for connectivity or disconnection probability of graph with high reliable arcs. In this paper such problem is solved for planar graphs or graphs arranged on two dimensional manifolds. Such graphs appear in honeycombed structures which are widely used in different applications.

MODELS AND METHODS FOR EStimation AND OPTIMIZATION OF ELECTRIC POWER SYSTEM RELIABILITY

The paper presents the results of the review of methods and models of an estimation and optimization of electric power systems (EPS) reliability. There are classification and characteristic of existing probabilistic methods used for an estimation of EPS reliability in the paper. The methodology of model for an estimation of systems reliability of EPS is described. Theoretical bases of system reliability optimization of EPS are stated. The description of the software YANTAR for estimation of EPS systems reliability is given.