The stability of the upstream shell of the dams is changed under the rapid drawdown
condition where the pore water pressure has a different values according to the soil
permeability. This paper considers the stability of the upstream shell of the "
Braddon" dam
with many types of soil and analyses each type under two rapid drawdown programs, the
first program is when the discharge happens, according to the irrigation outlet by 25 m3/s,
and the second program is when the discharge happens according to the tunnel conversion
of the river by 500 m3/s. The obtained results show, that the stability of the upper slope
under considered boundary conditions changed according to the soil type. Some soil have
good stability factor while other soil collapsed .Accordingly, we can conclude that the
type of soil of the upper dam slope is important and we could chose the appropriate type
which does not cause dangerous during the rapid drawdown. Also the study shows that:
the highest values of the safety factors result when the slopes are formed of high
permeability soils as well as the slopes of homogeneous soil, while the soils formed of
materials between them appeared decreasing values of safety factors.
In this research we study the numerical solution of Burgere
equation by using three methods, The first explicit scheme
method, and the second Crank-Nicolson method, and the thirst
weighted average method for explicit scheme method and Crank-
Nicolson method, Also the studying of numerical stability of all this
methods.
Unified Power Flow Controller (UPFC) is one of the most effective Flexible AC
Transmission Systems (FACTS) devices for controlling power flow and improving stability
of power system. To achieve the functionality of UPFC, a proper and sufficient con
trol
system should be designed for this device. Our research proposes a Fuzzy Logic control
approach to control UPFC. The proposed control scheme is used to control and coordinate
voltage and phase angle signals of Voltage Source Converters (VSCs) of UPFC, where
these two signals are used to control active and reactive power flow in transmission line.
To validate the proposed control scheme, a single-machine double line infinite bus power
system equipped with UPFC is modeled using PSCAD/EMTDC software package. Three
phase fault with ground case is simulated and investigated under the proposed controller.
The modeling and simulation results show the effectiveness of the UPFC under the
proposed control scheme for improving power system stability under the three phase fault
case. The results also show the robustness and superiority of the proposed controller
compared to conventional PI controller as well as it guarantees the closed-loop stability
system and has a good tracking behavior.
