This paper proposes a sensitivity based technique for optimal placement of Unified Power Flow Controller (UPFC) to enhance voltage stability margin under contingencies. The sensitivity of system loading factor with respect to the reactive power flowing through lines computed for the system intact case and critical contingency cases have been used to decide optimal location for the placement of ...

this paper investigates the stability analysis of fuzzy relational dynamic systems. a new approach is introduced and a set of sufficient conditions is derived which sustains the unique globally asymptotically stable equilibrium point in a first-order fuzzy relational dynamic system with sumproduct fuzzy composition. this approach is also investigated for other types of fuzzy relational composit...

In emerging electric power systems, increased transactions often lead to the situations where the system no longer remains in secure operating region. The flexible Ac transmission system (FACTS) controllers can play an important role in the power system security enhancement. However, due to high capital investment, it is necessary to locate these controllers optimally in the power system. FACTS...

this paper presents a method for damping of low frequency oscillations (lfo) in a power system. the powersystem contains static synchronous series compensators (sssc) which using a chaotic harmony searchalgorithm (chsa), optimizes the lead-lag damping stabilizer. in fact, the main target of this paper isoptimization of selected gains with the time domain-based objective function, which is solve...

In this paper, to enhance voltage stability of distribution systems, a Network Topology based load flow results are used to calculate Voltage Stability Index (VSI). Then an algorithm for capacitor placement (CP) based on this voltage stability index is implemented to determine the optimal locations, number and size of fixed and/or switched shunt capacitors for voltage stability enhancement, in ...

In this paper, transient stability improvement using bridge type fault current limiter (FCL) is presented in single machine infinite bus (SMIB) system with a double circuit transmission line. Three single-phase sets of the proposed FCL are installed at the beginning of feeder. The proposed FCL inserts an inductance and a resistance in the fault current pass. The insertion inductance and resista...

In this paper, the goal is the improvement of transient condition in a single machine system with designing of the nonlinear controllers for static Synchronous Compensator (STATCOM). By obtaining the Lyapunov function in presence of compensator in the system, some controllers are designed for it which by satisfying the Lyapunov stability criteria will increase the margin of transient stability ...

Power system stability enhancement by simultaneous tuning of a Power System Stabilizer (PSS) and a Static Var Compensator (SVC)-based controller is thoroughly investigated in this paper. The coordination among the proposed damping stabilizers and the SVC internal voltage regulators has also been taken into consideration. The design problem is formulated as an optimization problem with a time-do...