devices [13,14]. In a coordinated control, a SMES is operated as the main
apparatus to absorb or supply the required active power for a SSSC. Study results
confirm that the frequency stabilisation effects of the coordinated SMES with
SSSC are almost the same as those of two units of SMES (placed in each area).
Besides, the MJ capacity of SMES in the case of the coordinated SMES with
SSSC is drastically reduced in comparison to that of two units of SMES. On the
other hand, system parameters variations, various load changes
use. These studies can suggest the better distribution of its generation sources, future
requirement of installation of new transmission lines, and the option of installation of
power flow control equipment to enhance the existing transmission transfer
capability. FlexibleACtransmissionsystem (FACTS) controllers have large potential
ability to make power systems to operate in a flexible, secure, and economical way
. The studies on FACTS are concerned with FACTS controller deployment, their
number and optimal placement in the power system
system damping, robust control, loop-shaping method
Author Notes: The authors wish to acknowledge the facilities provided at the King Fahd
University of Petroleum & Minerals.
The unified power flow controller (UPFC) is a flexibleACtransmissionsystem
(FACTS) device, which can be used to control the power flow on a transmission
line. This is achieved by regulating the controllable parameters of the system-- the
line impedance, the voltage magnitude and phase angle of the UPFC bus. The
usual form of this device consists of two voltage source
, voltage fluctuations, and harmonics, cannot be solved satisfactorily by them because these devices are not fast enough [ 6 ]. Therefore, a dynamic shunt reactive power compensator is needed to address these issues more effectively. This can be achieved by using FlexibleACTransmissionSystem (FACTS) devices such as the Static Var Compensator (SVC)and static synchronous compensator (STATCOM). SVC is being used extensively in power systems as it is simple and robust device in view of power system dynamic stability point. SVC can perform various tasks, such as regulating
1 Introduction Unified Power Flow Controller (UPFC) is one of the most versatile flexibleACtransmissionsystems (FACTS) devices [ 1 ]. UPFC offers new horizons in terms of power system control with the potential to independently control three important power system parameters, for instance, bus voltage, line active power and line reactive power. Hence, UPFCs are used extensively for improving the utilization of the existing transmission system [ 1 ]. While the use of the UPFC improves the power transfer capability and stability of a power system, certain other
of digital distance relays Elect Power Syst Res 1997 43 105 11 4. Hu Y, Novosel D, Saha MM, Leitloff V. An adaptive scheme for parallel-line distance protection. IEEE Trans Power Delivery 2002;17:105–10. 10.1109/61.974195 4. Hu Y Novosel D Saha MM Leitloff V An adaptive scheme for parallel-line distance protection IEEE Trans Power Delivery 2002 17 105 10 5. Dash PK, Pradhan AK, Panda G, Liew AC. Adaptive relay setting for flexibleACtransmissionsystems (FACTS). IEEE Trans Power Delivery 2000;15:38–43. 10.1109/61.847226 5. Dash PK Pradhan AK Panda G Liew AC
congestion relief actions as well as the related pricing mechanisms. Congestion can also be alleviated by cost-free methods such as; outaging of congested lines and re-dispatching of lines, operation of tap setting transformers, phase shifting transformers [ 13 ], and flexibleACtransmissionsystem (FACTS) devices. Remedial actions, such as erection of new transmission networks, upgrading of lines or facilities, and mitigation of the congested lines are also used for CM in the DPM. Nodal and zonal price based methods, optimal power flow (OPF) based methods, load
in . The effect of FACTS
controllers on the cost of congestion management was also studied. With the help
of FlexibleACTransmissionSystems (FACTS), the transmission network
capacity can be enhanced and transmission congestion can be managed in an
efficient manner [14,15]. Huang et al.  presented impact of TCSC and SVC
Singh et al.: Sensitivity Based Approach for Transmission Congestion Management
on the generation re-dispatch and load curtailment in congestion management.
However, the optimal location of the controllers has not been presented.
in der Regel aus
anderen netztechnischen oder -wirtschaftlichen Gründen
ohnehin sinnvoll bzw. erforderlich sind.
Regelbare Betriebsmittel in FlexibleACTransmissionSystems (FACTS-Geräte) bieten je nach Ausführung u. a.
die Möglichkeit, Wirk- und Blindleistungsflüsse zu steu-
ern, lastprofilabhängige Spannungsschwankungen zumi-
nimieren, die Stabilität zu verbessern und somit spezi-
ell auch Leistungspendelungen durch netzseitige Leis-
tungsmodulation imEinflussbereich desNetzbetreibers zu
dämpfen, insbesondere imHinblick auf den Interarea Mo-
de [5, 21, 64]. Das
TransmissionSystems (FACTS) demand controllers that have to tuned online, thus making the trivial decentralised control laws inadequate. The major contributions of nonlinear control in power systems is to; regulate frequency and voltage, adequately damp the oscillations and preserve synchronisation in the presence of disturbances. Relevant techniques with eminent recent advances include; Nonlinear PI [ 62 ], Optimal Control [ 63 ], MPC [ 64 ], Passivity-based control [ 65 ], SMC [ 66 ] and Observer-based SMC [ 67 ]. In power electronics, commonly encountered circuits