Priority Assessment of Online Monitoring Investment for Power System Circuit Breakers—Part II: Determination of Optimum Number

2013 ◽  
Vol 28 (3) ◽  
pp. 1440-1446 ◽  
Author(s):  
Ali Asghar Razi-Kazemi ◽  
Mehdi Vakilian ◽  
Kaveh Niayesh ◽  
Matti Lehtonen
Keyword(s):  
Power System ◽  
Online Monitoring ◽  
Optimum Number ◽  
Circuit Breakers ◽  
Priority Assessment

scholarly journals Risk Assessment of Circuit Breakers Using Influence Diagrams with Interval Probabilities

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 737
Author(s):  
Jelena D. Velimirovic ◽  
Aleksandar Janjic
Keyword(s):  
Power System ◽  
Predictive Modelling ◽  
Optimal Time ◽  
Influence Diagrams ◽  
Circuit Breakers ◽  
Interval Probability ◽  
Complex Power ◽  
Interval Width ◽  
Credal Sets ◽  
The One

This paper deals with uncertainty, asymmetric information, and risk modelling in a complex power system. The uncertainty is managed by using probability and decision theory methods. More specifically, influence diagrams—as extended Bayesian network functions with interval probabilities represented through credal sets—were chosen for the predictive modelling scenario of replacing the most critical circuit breakers in optimal time. Namely, based on the available data on circuit breakers and other variables that affect the considered model of a complex power system, a group of experts was able to assess the situation using interval probabilities instead of crisp probabilities. Furthermore, the paper examines how the confidence interval width affects decision-making in this context and eliminates the information asymmetry of different experts. Based on the obtained results for each considered interval width separately on the action to be taken over the considered model in order to minimize the risk of the power system failure, it can be concluded that the proposed approach clearly indicates the advantages of using interval probability when making decisions in systems such as the one considered in this paper.

Optimization of Cutting Conditions in Multi-Pass Milling

2016 ◽  
Vol 823 ◽  
pp. 525-530
Author(s):  
Abderrahim Belloufi ◽  
Mekki Assas ◽  
Mabrouk Hecini ◽  
Imane Rezgui
Keyword(s):  
Hybrid Genetic Algorithm ◽  
Cutting Parameters ◽  
Cutting Conditions ◽  
Optimum Number ◽  
Optimization Strategy ◽  
Milling Operations ◽  
Optimal Values ◽  
Number Of Passes ◽  
Fine Tune

In this paper, a new, optimization strategy is used for the determination of the optimum cutting parameters for multipass milling operations. This strategy is based on the “minimum production time” criterion. The optimum number of passes is determined via dynamic programming, and the optimal values of the cutting conditions are found based on the objective function developed for the typified criterion by using a hybrid genetic algorithm with SQP. GA is the main optimizer of this algorithm, whereas SQP is used to fine-tune the results obtained from the GA. Furthermore, the convergence characteristics and robustness of the proposed method have been explored through comparisons with results reported in literature. The obtained results indicate that the proposed strategy is effective compared to other techniques carried out by different researchers.

Circuit breakers in the Bonneville power system

1952 ◽  
Vol 71 (8) ◽  
pp. 721-721
Author(s):  
O. A. Demuth ◽  
Alexander Dovjikov
Keyword(s):  
Power System ◽  
Circuit Breakers

scholarly journals Determination of multi-class herbicides in soil by liquid-solid extraction coupled with headspace solid phase microextraction method

2016 ◽  
Vol 81 (8) ◽  
pp. 923-934 ◽  
Author(s):  
Rada Djurovic-Pejcev ◽  
Tijana Djordjevic ◽  
Vojislava Bursic
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Soil Samples ◽  
Gas Chromatography Mass Spectrometry ◽  
Optimum Number ◽  
Polydimethyl Siloxane ◽  
Headspace Solid Phase Microextraction ◽  
Relative Standard ◽  
Detection And Quantification

A method is described for simultaneous determination of five herbicides (metribuzin, acetochlor, clomazone, oxyfluorfen and dimethenamid) belonging to different pesticides groups in soil samples. Developed headspace solid phase microextraction method (HS-SPME) in combination with liquid-solid sample preparation (LS) was optimized and applied in the analysis of some agricultural samples. Optimization of microextraction conditions, such as temperature, extraction time and sodium chloride (NaCl) content was perfor-med using 100 ?m polydimethyl-siloxane (PDMS) fiber. The extraction effi-ciencies of methanol, methanol:acetone=1:1 and methanol:acetone:hexane= =2:2:1 and the optimum number of extraction steps during the sample prepa-ration, were tested, as well. Gas chromatography-mass spectrometry (GC-MS) was used for detection and quantification, obtaining relative standard deviation (RSD) below 13%, and recovery values higher than 83% for multiple analyses of soil samples fortified at 30 ?g kg-1 of each herbicide. Limits of detection (LOD) were less than 1.2 ?g kg-1 for all the studied herbicides.

scholarly journals A GENETIC BASED TECHNIQUE FOR THE DETERMINATION OF POWER SYSTEM TOPOLOGICAL OBSERVABILITY

2014 ◽  
pp. 16-21
Author(s):  
S. Vazquez-Rodriguez ◽  
R. J. Duro
Keyword(s):  
Genetic Algorithms ◽  
Power Systems ◽  
Power System ◽  
Spanning Tree ◽  
Point Of View ◽  
Genetic Operators ◽  
Building Process ◽  
Phenotype Transformation

In this paper we have addressed the problem of observability of power systems from the point of view of topological observability and using genetic algorithms for its determination. The objective is to find a way to determine if a system is observable by establishing if a spanning tree of the system that verifies certain properties with regards to the use of available measurements can be obtained. To this end we have developed a genotype-phenotype transformation scheme for genetic algorithms that permits using very simple genetic operators over integer based chromosomes which after a building process can become very complex trees. The procedure was successfully applied to standard benchmark systems and we present some results for one of them.

Fuzzy Logic Based Approach for Power System Fault Section Analysis

Fuzzy Systems ◽  
2017 ◽  
pp. 987-1002
Author(s):  
Neeti Dugaya ◽  
Smita Shandilya
Keyword(s):  
Decision Making ◽  
Expert System ◽  
Power System ◽  
Fuzzy Expert System ◽  
Circuit Breakers ◽  
Membership Grade ◽  
Protective Relays ◽  
Basic Network ◽  
The One ◽  
Maximum Selection

In this chapter, a fuzzy expert system is developed to assist the operators in fault detection. It requires much less memory to store the database (power system topology and the post fault status of circuit breakers and protective relays). The fuzzy expert system identifies two basic network section sets, Shealthy for the healthy sub network and Sisland for the fault islands, using the post fault status of circuit breakers and relays. It then calculates membership function for each possible fault section. The objective of this calculation is to determine the likelihood of each candidate fault section as the actual fault section. Moreover membership functions provide a convenient means of ranking among possible (or candidate) fault sections, and are the most important factors in decision making. During decision making, the most possible fault section is determined by maximum selection method. In this method most possible fault section is the one which is having highest membership grade. MATLAB code for the proposed scheme is developed and the results obtained in four cases for a power- system network.

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