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Koordinacija nekih funkcija sistema relejne zaštite i sistema regulacije pobude sa pogonskim dijagramom
Coordination between relay protection functions and excitation system with generator capability curve
Keywords: loss of excitation protection; minimum excitation limiter; maximum stator current limiter; stator overload protection; overcurrent protection; allowed stator overload
Sažetak
Uobičajena je praksa da se relejna zaštita i funkcija sistema regulacije pobude nezavisno podešavaju, što često dovodi do nekoordiniranog delovanja nekih funkcija. U ovom radu su prikazani proračuni nekih značajnih funkcija zaštite. Prvi proračun se odnosi na funkciju zaštite od gubitka pobude, kao i na koordinaciju iste sa limiterom minimalne pobude. Analizirajući podešenja koordinacije ove zaštite sa limiterom minimalne pobude zapaženo je da su neadekvatno podešene tako da ne omogućuju da se kapacitivni deo pogonskog dijagrama optimalno iskoristi, za šta u prenosnom sitemu postoji velika potreba. Drugi proračun se odnosi na koordinaciju limitera maksimalne struje statora u sistemu regulacije pobude sa zaštitama od preopterećenja statora, prekostrujnom zaštitom i dozvoljenim preopterećenjem statora generatora. Ovde je zapaženo da ova koordinacija često nije adekvatno podešena što dovodi do sledećih neregularnih delovanja: - do pogrešnog rada automatskog regulatora napona u određenim pogonskim situacijama što može dovesti do kolapsa napona u prenosnom sistemu; - da u nekim pogonskim situacijama ne dolazi do forsiranja pobude kada je to najpotrebnije.
Abstract
It is common practice for relay protection and excitation systems to be adjusted independently. That practice leads to the uncoordinated operation of some protective functions. This article presents the tuning of some important protection functions. The first step is loss of excitation protection adjusting and its coordination with the minimum excitation limiting function. Analyzing the coordination settings of this protection with the minimum excitation limiter in practice, it is often noticed that these functions are inadequately adjusted, so the capacitive part of the generator capability curve is not optimally used. That is in contradiction with the high need for capacitive reactive power in the transmission system. The second step refers to the coordination of the maximum stator current limiter in the excitation system with stator overload protection, overcurrent protection, and permitted generator stator overload. It is noted here that this coordination is often not adequately adjusted, leading to the following irregularities: -malfunction of the automatic voltage regulator in certain operating situations, which can lead to voltage collapse in the transmission system; -in some operating situations, there is no forcing of excitation current when it is most needed to preserve system stability.
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