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∑ Ëesti problem sliËnih baza podataka relejnezaπtite je redovno odræavanje zbog velikog brojarazliËitih komponenti baze (tablica, upita,izvjeπÊa) prilagoappleenih raznim vrstama i generacijamareleja [1]. O ovom problemu takoappleertreba voditi raËuna prilikom dizajniranja baze,∑ podaci pohranjeni u bazi takoappleer mogu sluæitinizu aplikacijskih programa koji se koriste uodjelima zaπtite pri proraËunu raznih parametaraelemenata sustava relejne zaπtite (npr.proraËunu kratkog spoja u elektroenergetskojmreæi) i sl. Pripremu podataka za aplikacijskeproraËune moguÊe je automatizirati koristeÊidodatne programske rutine za povezivanje iprilagoappleene podataka iz baze i aplikacijskihprograma [2]. Takoappleer je moguÊe oko bazepodataka izgraditi cijeli sustav za rukovanjepodacima zaπtitnih ureappleaja, proraËunavanje ianalizu kvarova, postavljanje parametara releja,provjeravanje, simulaciju itd. [3], [4] i[5]. U ovoj fazi razvoja prikazane baze podatakanije predviappleeno automatsko povezivanjeaplikacijskih proraËuna s podacima u bazi πtoznaËajno smanjuje informacijske zahtjeve tekoliËinu potrebnih podataka,∑ opseg podataka koje Êe baza obuhvatiti i pravapristupa odreappleenim skupinama podataka trebaprilagoditi postojeÊoj organizacijskoj strukturiodjela relejne zaπtite, a takoappleer mjestu odjelarelejne zaπtite u organizacijskoj shemi cjelokupnogpoduzeÊa. Informacijski zahtjevi kojisu postavljeni na bazu podataka relejne zaπtiteu jednom tipiËnom odjelu relejne zaπtite, baru ovom trenutku, nisu obuhvatili i nekakvepomoÊne procese kao voappleenje knjigovodstva iizdavanje knjigovodstvenih izvjeπÊa, proraËunamortizacije pojedine opreme, obavljanje financijskihtransakcija i sliËno.3 MODELIRANJE PODATAKAModeliranje podataka je proces koji poËinje analiziranjeminformacijskih zahtjeva, a zavrπavaizgradnjom baze podataka [6] i [7]. Postupnimrazvojem i transformacijom modela podataka kroztri razine, πto je uobiËajeni postupak pri modeliranjupodataka, doπlo se do realizacije konaËnogimplementacijskog modela na raËunalu i stvaranjabaze podataka relejne zaπtite.3.1 Konceptualni model podatakaSukladno zahtjevima koji su postavljeni na bazupodataka u prvom koraku, razvijen je konceptualnimodel tipa entiteti-veze. Model tipa entiteti-vezejedan je od najËeπÊe koriπtenih modela podatakatreÊe generacije zato πto raspolaæe sa semantiËki∑ a frequent problem with similar relay protectiondatabases is regular maintenance due tothe large number of various base components(tables, queries and reports) adapted to varioustypes and generations of relays [1]. This problemmust also be taken into account whendesigning the database,∑ data stored in the base can also be used in aseries of application programs employed by protectiondepartments for the computation of variousparameters of the relay protection systemelements (e.g., calculation of a short circuit inthe electric power network). Preparation of datafor calculation applications can be automatedby using additional program routines for linkingand adapting data from the base and ∑ applicationprograms [2]. Furthermore, it is possibleto construct an entire system around the databasefor the data management of protectiveequipment, calculation and analysis of faults,establishment of relay parameters, verification,simulation etc. [3], [4] and [5]. In this phaseof the development of the database presented,automatic linking of the application softwarewith data in the base has not been anticipated,thereby significantly reducing the informationrequirements and the quantity of data needed,∑ the range of data that the base will cover and theright to access certain groups of data should beadjusted to the existing organizational structureof the relay protection department and the positionof the relay protection department within theorganizational schema of the entire enterprise.Information requirements placed upon the relayprotection database in a typical relay protectiondepartment, at least at the moment, do not coverany auxiliary processes such as bookkeeping andissuing bookkeeping reports, calculation of thedepreciation of individual equipment items, performanceof financial transactions etc.3 DATA MODELINGData modeling is a process that begins with theanalysis of information requirements and ends withthe construction of a database [6] and [7]. The progressivedevelopment and transformation of a datamodel through three levels, which is the customaryapproach in data modeling, resulted in the implementationof the model on the computer and thecreation of the relay protection database.3.1 Conceptual data modelBased upon the requirements established for thedatabase in the first step, a conceptual model ofthe entity-relationship type was developed. A modelSutloviÊ, E., Petric, K., Baza podataka relejne zaštite, Energija, god. 56(2007), br. 5., str. 618-633SutloviÊ, E., Petric, K., Relay Protection Database, Energija, vol. 56(2007), No. 5, pp. 618-633622