Određivanje preostalog životnog veka i strategije zamene malouljnih prekidača na osnovu dinamičke analize rizika: doktorske disertacije

The main goal of this dissertation is to estimate the remaining useful life of minimum oil circuit breakers (CB) based on data collected during their regular inspection. Using the proposed approach, CB’s with the highest risk can be identified, whose failure can cause the greatest economic consequences, but also consequences for the stability of the power system. By determining the reliability and risk of minimum oil CB’s, it is possible to see what influence has the place of installation on the aging process. In this way, a correlation is established between the values of voltage drops and other categories such as: feeder type, voltage level, year of production, number of disconnected short-circuit currents. The end result of the CB’s analysis is the possibility of knowing its aging process, classification of the state of all CB’s based on the risk of failure, knowledge of the impact of CB’s replacement on the availability of the power station, without additional investment in new equipment or labor

Određivanje preostalog životnog veka i strategije zamene malouljnih prekidača na osnovu dinamičke analize rizika: doktorske disertacije

The main goal of this dissertation is to estimate the remaining useful life of minimum oil circuit breakers (CB) based on data collected during their regular inspection. Using the proposed approach, CB’s with the highest risk can be identified, whose failure can cause the greatest economic consequences, but also consequences for the stability of the power system. By determining the reliability and risk of minimum oil CB’s, it is possible to see what influence has the place of installation on the aging process. In this way, a correlation is established between the values of voltage drops and other categories such as: feeder type, voltage level, year of production, number of disconnected short-circuit currents. The end result of the CB’s analysis is the possibility of knowing its aging process, classification of the state of all CB’s based on the risk of failure, knowledge of the impact of CB’s replacement on the availability of the power station, without additional investment in new equipment or labor

Semiharmonic graphs with fixed cyclomatic number ∗

Let the trunk of a graph G be the graph obtained by removing all leaves of G. We prove that, for every integer c ≥ 2, there are at most finitely many trunks of semiharmonic graphs with cyclomatic number c — in contrast to the fact established by the last two of the present authors in their paper Semiharmonic Bicyclic Graphs (this journal) that there are infinitely many connected semiharmonic graphs with given cyclomatic number. Further, we prove that there are at most finitely many semiharmonic but not almost semiregular graphs with cyclomatic number c. MSC Classification: 05C7

ON THE ORIENTED INCIDENCE ENERGY AND DECOMPOSABLE GRAPHS

Let G be a simple graph with n vertices and m edges. Let edges of G be given an arbitrary orientation, and let Q be the vertex-edge incidence matrix of such oriented graph. The oriented incidence energy of G is then the sum of singular values of Q. We show that for any n ∈ N, there exists a set of n graphs with O(n) vertices having equal oriented incidence energy