Active distribution grids that contain energy sources (so-called distributed generation or DG) are nowadays a reality. Besides the many benefits DGs bring to the distribution grid, some challenges ...are associated with their integration. Since there are DGs now in the distribution grid, the occurrence of islanding operation is possible. Since an islanding operation can be dangerous, it is necessary to have an effective method to detect it. In the last decade, scientists have made a great effort to develop and test various islanding detection methods (IDMs). Many approaches have been tested, and the methods based on computational intelligence (CI) have shown great potential. Among them, artificial neural networks (ANNs) gained most of the research attention. This paper focuses on ANN application for islanding detection. It gives an exhaustive review of the ANN types used for islanding detection, the types of input data, and their transformation to fit the ANNs. Furthermore, various applications based on specific input data, preprocessing types, different learning algorithms, real-time implementation, and various distribution models used for ANN are reviewed. This paper investigates the potential of ANNs to enhance islanding detection accuracy, reduce non-detection zone (NDZ), and contribute to an overall efficient detection method.
In this paper, a fuzzy expert off-line system has been developed for fault diagnosis in the distribution network based on the structural and functional operation of the relay and circuit breakers. ...Functional operations (correct operation, false operation and
failure to operate) of the relays and circuit breakers are described by fuzzy logic. Input data for the proposed fuzzy expert fault diagnosis system (FDS) are status and time stamps of the alarms, associated with relays and circuit breakers. The diagnostic system
from a huge number of alarms sets, logically organizes and quantifies the diagnosis. FDS can diagnose correct operation, false
operation and failure to operate of the relays and circuit breakers. Also, it can identify and quantify fault location based on the
Hamacher’s operator of a fuzzy union. The additional contribution of this paper is in modeling unknown information using linear
fuzzy membership function. Statuses of certain components may be unknown due to telemetry failures or are simply unavailable to
the operator and proposed FDS can make diagnosis in such a situation. Developed fuzzy expert FDS is tested on the two examples
of faults in real life distribution network
Provider: - Institution: Josip Juraj Strossmayer University of Osijek. Faculty of Electrical Engineering. Department of Power Engineering. Chair of Power Systems and Substations. - Data provided by ...Europeana Collections- U doktorskoj disertaciji razvijen je neizraziti ekspertni sustav (off-line) za dijagnozu kvara u
distributivnoj mreţi na bazi strukturalnog i funkcionalnog djelovanja releja i prekidača.
Prikazan je novi način modeliranja funkcionalnog djelovanja releja i prekidača koji je opisan
pomoću neizrazite logike. Neizrazita logika (više-vrijednosna logika) je metoda koja se bavi
modeliranjem nepreciznosti, nesigurnosti kod donošenja odluka. Poboljšava i povećava
potencijal kod modeliranja ljudskog razmišljanja koje koristi lingvističke varijable. Neizrazita
logika (teorija) je u suprotnosti s klasičnom teorijom vjerojatnosti, jer je prva deterministička,
a druga stohastička u naravi. Teorija vjerojatnosti se koristi bi-vrijednosnom logikom (0 ili 1),
dok neizrazita teorija moţe poprimiti bilo koju vrijednost izmeĎu 0 i 1. Neizrazita logika nudi
jednostavan pristup modeliranju nejasnih, neprecizni, izobličeni i nepostojećih ulaznih
informacija. Neizraziti dijagnostički sustav kao ulazne podatke koristi statuse releja i
prekidača te njihove vremenske oznake. Dijagnostički sustav iz ogromnog broja alarma
postavlja, logički organizira i kvantificira dijagnoze. Razvijeni dijagnostički sustav za
dijagnozu kvara uspješno dijagnosticira djelovanje, krivo djelovanje i otkazivanje djelovanja
releja i prekidača. TakoĎer ima mogućnost lociranja (identificiranja) kvara te njegovog
kvantificiranja na bazi hibridnog operatora unije koji je iskazan kao aritmetička sredina
Hamackerovog i Schweizerovog operatora unije. Pored navedenog uspješno se nosi i s
kvarovima telemetrije koristeći novi način modeliranja nepostojećih informacija pomoću
linearne funkcije pripadnost u odnosu na vrijeme.- In this doctoral dissertation was developed off-line fuzzy expert system for fault diagnosis in
distribution network based on the structural and functional operation of relays and circuit
breakers. Functional operation of relays and circuit breakers is described by fuzzy logic as a
new way of modeling. Fuzzy logic (multiple-value logic) is a method that deals with the
modeling of imprecision, uncertainty in decision-making process. It improves and increases
the potential in the modeling of human thinking which uses linguistic variables. Fuzzy logic
(theory) is in contrast with the classical theory of probability, since the first is deterministic
and the other is stochastic in nature. Probability theory uses bi-value logic (0 or 1), while
fuzzy theory can take any value between 0 and 1. Fuzzy logic offers a simple approach for
modeling vague, inaccurate, distorted and missing informations. Imput information of fuzzy
diagnostic system are the status of relays and circuit breakers and their time stamps.
Diagnostic system logically organize and quantifie diagnosis from the huge alarm
streams.Operation, false operation and failure of operation for circuit brakers and realays can
be diagnosed with the developed diagnostic system. Fault location (identification) is
quantified with hybrid union operator which is discribed as the arithmetic mean of Hamackers
and Schweizers operator. New method of modeling the missng information as linear
membership functions with respect to time is used for dealing with failures of telemetry.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
The distributed generation within the distribution and low voltage network is a result of decentralizing electrical power production by introducing the electricity market as well as trying to reduce ...the greenhouse effect. A new optimum solution has to be found while planning the electro energetic system which includes building new production capacity, a new network and expansion of reactive capacity. The benefits that can be obtained from this optimum solution are of economical, technical and ecological nature. Analytical methods have proven less successful in dealing with nonlinear optimization problems. Evolution algorithms have proven most applicable onto real systems. The aim of this project is to determine the location and the capacity of distributed generation by using genetic algorithms at feeder 10 kV Strizivojna Hrast. The given results have determined the optimum locations and capacity in the 10 kV Strizivojna Hrast feeder.Original Abstract: Pojava distribuirane proizvodnje u distribucijskoj i niskonaponskoj mrezi rezultat je decentralizacije proizvodnje elektricne energije uvodenjem trzista elektricne energije i napora radi smanjenja efekta staklenika. Kod planiranja elektroenergetskog sustava, a u sto spada izgradnja novih proizvodnih kapaciteta, izgradnja mreze i ekspanzija reaktivnih kapaciteta, mora se pronaci optimalno rjesenje. Koristi koje se mogu dobiti iz optimalnog rjesenja su ekonomske, tehnicke i ekoloske naravi. Analiticke metode imaju vrlo malo uspjeha u rjesavanju nelinearnih optimizacijskih problema. Evolucijski algoritmi pokazali su najvecu stopu primjenjivosti na realne sustave. Cilj ovog rada je odrediti lokaciju i snagu distribuirane proizvodnje primjenom genetskog algoritma na vodnom polju 10 kV Strizivojna Hrast. Dobiveni rezultati odredili su dvije najoptimalnije lokacije i snage u napojnom vodu 10 kV Strizivojna Hrast.
Emergence of failure within a power system is an unwanted situation when certain parts of the network become separated from the other parts unaffected by this failure. Relay protection system has the ...task of isolating the sections that are faulty. By activating the protection an alarm is sent to the substation and the dispatch centre. Alarms in the dispatch centre come in the short period of time which can confuse the dispatcher and lead him towards making an error. The proper approach and selection of methods for analysing alarms are both very essential for locating the faulty section. There are two well-known methods for analysing failures; one is a method of finger printing and the other a method of hypothesis. The analysed alarms were the ones in the TS 35/10 kV Istok detachment from the rest of the power system. The aim of this paper is to analyse the alarms that have occurred in the dispatch centre during the 35/10 kV Istok detachment by using the finger print method and the method of hypothesis. The results have been found and the cause of section 35/10 kV Istok failure from the rest of the power system. The given results have confirmed the unit and the cause of the TS 35/10 kV Istok detachment from the rest of the power system.Original Abstract: Pojava kvara je nezeljena situacija u elektroenergetskom sustavu prilikom cega se odredeni dijelovi mreze odvajaju od ostatka koji nije zahvacen kvarom. Sustav relejne zastite ima zadatak izoliranja dionica koje se nalaze u kvaru. Aktivacija odredene zastite salje alarm u trafostanicu i dispecerski centar. Alarmi u dispecerski centar dolaze u kratkom vremenu sto moze dispecera zbuniti i navesti na pogresku. Pravilan pristup i odabir metode za analiziranje alarma vrlo su bitna stvar za lociranje dionice u kvaru. Poznate su dvije metode za analiziranje kvara a to su metoda niza i metoda hipoteza. Analizirani su alarmi koji se pojavljuju prilikom odvajanja TS 35/10 kV Istok od ostatka elektroenergetskog sustava. Cilj ovog rada je analiziranje alarma koji su se pojavili u dispecerskom centru prilikom ispada TS 35/10 kV Istok metodom niza i metodom hipoteza. Dobiveni rezultati su utvrdili dionicu i uzrok ispada TS 35/10 kV Istok od ostatka elektroenergetskog sustava.
The occurrence of fault is an unwanted situation in electric power systems where certain network parts detach themselves from the remaining unaffected part of the network. The relay protection system ...has a task to isolate the faulty units or zone. When a certain protection level is being triggered alarms are sent to the transformer station and the dispatcher centre. These alarms reach the dispatcher centre in a short period of time which can lead the dispatcher to confusion and possible mistakes. To ease the dispatcher's position, an alarm processor is introduced. The alarm processor uses an expert system as its computer programme in the whole spectrum of variations. The analysed alarms are the ones being triggered while the TS 35/10 kV Istok is detaching from the rest of the electric power system. The objective of this project is to analyse alarms which have appeared in the dispatcher centre during the detachment of the TS 35/10 kV Istok, by using the expert system method. Final results have confirmed the section and cause of the TS 35/10 kV Istok detachment from the rest of the electric power system.Original Abstract: Pojava kvara je nezeljena situacija u elektroenergetskom sustavu prilikom koje se odredeni dijelovi mreze odvajaju od ostatka mreze koja nije zahvacena kvarom. Sustav relejne zastite ima zadatak da izdvoji dionice koje se nalaze u kvaru. Pobuda odredene zastite salje alarm u transformatorsku stanicu i dispecerski centar. Alarmi u dispecerski centar dolaze u kratkom vremenu sto moze dispecera zbuniti i navesti na pogresku. Kako bi se olaksao posao dispecerima uvodi se procesor alarma. Procesor alarma kao racunalni program koristi ekspertni sustav u cijelom nizu varijanti. Analizirani su alarmi koji se pojavljuju prilikom odvajanja TS 35/10 kV Istok od ostatka elektroenergetskog sustava. Cilj ovog rada je analiza alarma koji su se pojavili u dispecerskom centru prilikom ispada TS 35/10 kV Istok metodom ekspertnog sustava. Dobiveni rezultati su utvrdili dionicu i uzrok ispada TS 35/10 kV Istok od ostatka elektroenergetskog sustava.
Pojava kvara je neželjena situacija u elektroenergetskom sustavu prilikom čega se određeni dijelovi mreže odvajaju od ostatka koji nije zahvaćen kvarom. Sustav relejne zaštite ima zadatak izoliranja ...dionica koje se nalaze u kvaru. Aktivacija određene zaštite šalje alarm u trafostanicu i dispečerski centar. Alarmi u dispečerski centar dolaze u kratkom vremenu što može dispečera zbuniti i navesti na pogrešku. Pravilan pristup i odabir metode za analiziranje alarma vrlo su bitna stvar za lociranje dionice u kvaru. Poznate su dvije metode za analiziranje kvara a to su metoda niza i metoda hipoteza. Analizirani su alarmi koji se pojavljuju prilikom odvajanja TS 35/10 kV Istok od ostatka elektroenergetskog sustava. Cilj ovog rada je analiziranje alarma koji su se pojavili u dispečerskom centru prilikom ispada TS 35/10 kV Istok metodom niza i metodom hipoteza. Dobiveni rezultati su utvrdili dionicu i uzrok ispada TS 35/10 kV Istok od ostatka elektroenergetskog sustava.
Pojava kvara je neželjena situacija u elektroenergetskom sustavu prilikom koje se određeni dijelovi mreže odvajaju od ostatka mreže koja nije zahvaćena kvarom. Sustav relejne zaštite ima zadatak da ...izdvoji dionice koje se nalaze u kvaru. Pobuda određene zaštite šalje alarm u transformatorsku stanicu i dispečerski centar. Alarmi u dispečerski centar dolaze u kratkom vremenu što može dispečera zbuniti i navesti na pogrešku. Kako bi se olakšao posao dispečerima uvodi se procesor alarma. Procesor alarma kao računalni program koristi ekspertni sustav u cijelom nizu varijanti. Analizirani su alarmi koji se pojavljuju prilikom odvajanja TS 35/10 kV Istok od ostatka elektroenergetskog sustava. Cilj ovog rada je analiza alarma koji su se pojavili u dispečerskom centru prilikom ispada TS 35/10 kV Istok metodom ekspertnog sustava. Dobiveni rezultati su utvrdili dionicu i uzrok ispada TS 35/10 kV Istok od ostatka elektroenergetskog sustava.
Pojava distribuirane proizvodnje u distribucijskoj i niskonaponskoj mreži rezultat je decentralizacije proizvodnje električne energije uvođenjem tržišta električne energije i napora radi smanjenja ...efekta staklenika. Kod planiranja elektroenergetskog sustava, a u što spada izgradnja novih proizvodnih kapaciteta, izgradnja mreže i ekspanzija reaktivnih kapaciteta, mora se pronaći optimalno rješenje. Koristi koje se mogu dobiti iz optimalnog rješenja su ekonomske, tehničke i ekološke naravi. Analitičke metode imaju vrlo malo uspjeha u rješavanju nelinearnih optimizacijskih problema. Evolucijski algoritmi pokazali su najveću stopu primjenjivosti na realne sustave. Cilj ovog rada je odrediti lokaciju i snagu distribuirane proizvodnje primjenom genetskog algoritma na vodnom polju 10 kV Strizivojna Hrast. Dobiveni rezultati odredili su dvije najoptimalnije lokacije i snage u napojnom vodu 10 kV Strizivojna Hrast.
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