The Coupling of Voltage and Frequecncy Response in Splitting Island and Its Effects on Load-shedding Relays
- 1 School of Electrilcal Engineering, Xi’an Jiaotong University, Xi’an, China
- 2 School of Electrilcal Engineering, Xi’an Jiaotong University, Xi’an, China
Abstract
The voltage and frequency dynamics interact with each other in the island after splitting. The current frequency response model without considering the voltage effect would bring remarkable errors when anal yzing the frequency dynamic progress in the island with large-capacity active-power shortage. In this paper, coupling effects of voltage and frequency are studied to indicate that initial reactive-power deficit and load characteristics have strong effects on the coupling effects of the voltage and frequency. Moreover, control effects of currently used under frequency load-shed ding relays (UFLS) and under voltage load-shedding relays (UVLS) which are installed and executed independently are examined to find that it would sometimes cause excessive or inadequate control without considering the coupling, suggesting that it is necessary to develop coordinate control methods for voltage and frequency problems.
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