Utjecaj zasićenja strujnih transformatora na rad zaštitnih releja

scientific master's theses

• Title (english): Impact of current transformer saturation on protection relays
• Author: Jasna Bančak; VIAF: 305688134
• Mentor: Ante Marušić (mentor)
• Committee member: Zlatko Maljković (predsjednik povjerenstva)
• Committee member: Ante Marušić (član povjerenstva)
• Committee member: Stjepan Štefan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Energy and Power Systems); Zagreb
• Defense date and country: 2009-02-06, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering; Power Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

Zadatak ovog rada je bio razvoj prihvatljivog modela zasićenja strujnog transformatora, čiji se rezultati mogu koristiti za proučavanje ponašanja strujnog transformatora tijekom zasićenja te utjecaja koje to zasićenje ima na rad zaštitnih releja. Model zasićenja strujnog transformatora je nakon potvrde točnosti iskorišten za ispitivanje utjecaja koje na zasićenje strujnog transformatora imaju sekundarno opterećenje, iznos struje kvara, vremenska konstanta primarnog sustava, istosmjerna komponenta i remanencija u jezgri. Utjecaj zasićenja na nadstrujnu i diferencijalnu zaštitu ispitivan je injektiranjem struja dobivenih simulacijama zasićenja. Rezultati ispitivanja su dobiveni usporedbom oscilograma struja i pokazali su da releji ponekad mogu ispravno i stabilno raditi čak i kada strujni transformatori ne odgovaraju zahtjevima proizvođača releja. Ispitivanja su dokazala da se model zasićenja strujnog transformatora može koristiti kao pripomoć u izboru ekonomičnijih strujnih transformatora.

Abstract (english)

The objective of this thesis was a development of an accurate model of saturated current transformer, with a results useful for an investigation of current transformer saturation and the impact of that saturation on protection relays. Model of current transformer saturation was validated, and afterwards used for an evaluation of factors that led to current transformer saturation, like secundary burden, short circuit level, DC components in fault current and remanent flux. Overcurrent and differential protection relays were testes to investigate the impact current transformer saturation had on them. Saturated currents were injected to the relays via a secondary injection device. Result comparison of current oscilograms obtained from simulation and from relay, showed that relays in some cases were able to accurately work even when current transformers didn't meet the requirements of relay manufacturer. This analysis demonstrated the helpfullnes of current transformer saturation model in selecting more apropriate current transformer for a specific cases.

• Keywords: strujni transformator; relej; zasićenje; nadstrujna zaštita; diferencijalna zaštita
• Keywords (english): current transformer; protection relay; saturation; overcurrent protection; differential protection
• Language: croatian
• URN:NBN: urn:nbn:hr:168:555874
• Study programme: Title: Postgraduate master programme in electrical engineering; Study programme type: university; Study level: postgraduate; Academic / professional title: Magistar znanosti elektrotehnike (Magistar znanosti elektrotehnike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2020-06-23 10:36:02