TITLE:
The Coupling of Voltage and Frequecncy Response in Splitting Island and Its Effects on Load-shedding Relays
AUTHORS:
Hao Yang, Baohui Zhang
KEYWORDS:
Frequency Response; Coupling Effects; Splitting Island; Coordination Control
JOURNAL NAME:
Energy and Power Engineering,
Vol.5 No.4B,
October
30,
2013
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 analyzing 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-shedding
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.