Low Frequency Oscillations (LFO) occur in power systems because of lack of the damping torque in order to dominance to power system disturbances as an example of change in mechanical input power. In the recent past Power System Stabilizer (PSS) was used to damp LFO. FACTs devices, such as Unified Power Flow Controller (UPFC), can control power flow, reduce sub-synchronous resonance and increase...

This paper presents a comprehensive approach for the design of UPFC controllers (i.e. power flow controller, DC voltage regulator and damping controller) for a multimachine system. UPFC controllers have been designed in the presence of conventional PSS. The interaction between the UPFC controllers and PSS has been studied. Investigations reveal that the system damping gets adversely affected wi...

In this paper an attempt has beenmade to investigate the transient stability enhancement of both SMIB and Multi-machine system using UPFC controller tuned by Particle Swarm Optimization. Power injection modelfor a series voltage source of UPFC has been implemented to replace UPFC by equivalent admittance. The admittance matrix of the power system is then modified according to the power injectio...

-This paper presents a systematic approach for designing Unified Power Flow Controller (UPFC) based damping controllers for damping low frequency oscillations in a power system. Detailed investigations have been carried out considering four alternative UPFC based damping controllers. The investigations reveal that the damping controllers based on UPFC control parameters δE and δB provide robust...

This paper explores the use of a Unified Power Flow Controller (UPFC) for global power system control. Coordinated control schemes are assigned to the UPFC, Power System Stabilizer (PSS) and generator excitation to maintain transient stability and voltage stability following a disturbance. The extension to use of UPFC in damping inter-area oscillation is also considered. Under the proposed coor...

This paper concerns the Optimal Power Flow [OPF] in multi machine Power System with UPFC using Genetic Algorithm [GA]. The objective is to minimize the cost of the power system, to enhance the power flow in transmission lines and to maintain the voltages at the buses using UPFC. Using the proposed method, the optimal cost and real power losses of the power system with UPFC is achieved by develo...

This paper presents the transient model of a new FACTS device, the center node unified power flow controller(C-UPFC), installed at the midpoint of a transmission line. The C-UPFC consists of three voltage source inverters (VSI) with common DC link. One of the converters is connected in parallel at the midpoint of line and the other two converters are connected in series. The simulation results ...

In this paper, power transfer capacity is investigated for systems with a unified power flow controller (UPFC). The combined effects of equipment constraints? system topology and installation locations on the UPFC real power transfer are studied. The P-Q characteristics of UPFC operation under different sets of constraints are determined. The admissible operational ranges of UPFC control output...

The paper presents an apparent impedance calculation procedure for distance relaying of transmission line involving FACTS devices, particularly the UPFC (unified power flow controller). The presence of UPFC significantly affects the trip boundaries which are also adversely affected by fault resistance combined with remote end infeed. Depending on the UPFC location, the trip boundary is influenc...

Unified power flow controller (UPFC), as one of the most important FACTS devices, can be used to increase the damping of power system oscillation. The effect rate of this controller on increasing oscillation damping depends on the appropriate selection of input controlling signal, optimal selection of UPFC controlling parameters, and its proper position in power system. In this paper, the capab...