Z. An et al.
When the SVC capacity increases to 270 MVar, the amplitude of power fluctuation has become small. So the
system stability may be improved by adding more SVCs.
4.2. Enhancing the UHV Line
Reducing the original transmission power or adding SVCs at UHV buses can enhance the ability of UHV line to
resist impact by increasing stability margin and improve the ability of voltage recovery in transient process of
the UHV line, though the feasibility of these methods is smaller than methods in Section 4.1.
5. Conclusion
This paper described the new phenomeno n that faults at remote ends of the UHV interconnected grid would
cause significant power fluctuation and voltage drop on the UHV transmission line while faults at buses near the
UHV line with larger short-circuit current only have marginal effects. Then factors affecting the phenomenon
were analyzed through simulation, which include the transmission power on the UHV line, the power transmit-
ted from Sichuan to major Central China grid, the load model and the grid structure. Finally corresponding me-
thods to improve the system stability were presented and the effectiveness of those methods was verified.
Acknowledgem ents
This paper is supported by Major Projects on Planning and Operation Control of Large Scale Grid (SGCC-
MPLG001-2012) of State Grid Corporation of China.
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