TITLE:
Stability Enhancement of Small-Scale Power Grid with Renewable Power Sources by Variable Speed Diesel Power Plant*
AUTHORS:
Rion Takahashi, Atsushi Umemura, Junji Tamura
KEYWORDS:
Small-Scale Power Grid, Variable Speed Doubly-Fed Induction Generator (VS-DFIG), Diesel Power Plant, Wind Power, Battery Energy Storage System (BESS)
JOURNAL NAME:
Journal of Power and Energy Engineering,
Vol.8 No.3,
March
25,
2020
ABSTRACT: This
paper proposes a power control method to improve a stability of a small-scale
power grid with renewable energy sources. In an isolated small- scale power
grid such as an island, diesel power plant is main power source which has an
environmental burden and expensive running cost due to high priced fossil fuel.
Thus, expanding installation of the renewable energy sources such as a wind
power is strongly desirable. Such fluctuating energy sources, however, harm
power quality of the small-scale power grid, and in addition, conventional
power plant in the small-scale power grid cannot, in general, stabilize the
grid system with such fluctuating power sources. In this study, Variable Speed
Doubly-Fed Induction Generator (VS-DFIG) is proposed to be in-stalled at a
diesel power plant instead of a conventional Fixed Speed Synchronous Generator
(FS-SG), because quick control of a power balance in the small-scale power grid
can be achieved by using the inertial energy of VS-DFIG. In addition,
utilization of a Battery Energy Storage System (BESS) is also considered to
assist cooperatively the VS-DFIG control. As a result of the simulation
analysis by using the proposed method, it is verified that frequency
fluctuations due to renewable energy source can be effectively reduced by quick
power control of the VS-DFIG compared to the conventional FS-SG, and further
control ability can be obtained by utilizing BESS. Moreover, the transient
stability of a small-scale power grid during a grid fault can also be enhanced.