In recent years several catastrophic power systems blackouts have occurred worldwide. Various reasons have been declared for these failures. Economical limitations due to power system restructuring restrictions, inadvertent operation of protective relays and inefficient design of conventional load shedding schemes are of the most important reasons causing these blackouts. In fact, due to both e...

Voltage stability is one of the most important factors in maintaining reliable operation of power systems. When a disturbance occurs in the power system, it usually causes instabilities and sometimes leads to voltage collapse (VC). To avoid such problems, a novel approach called Vector Analysis (VA) is proposed that exploits a new instability detection index to provide wide area voltage stabili...

The voltage instability phenomena occur in both transmission systems and distribution systems. The weakening of voltage stability level will limit the growth of load served by distribution companies. Voltage instability in power distribution systems could lead to voltage collapse and thus power blackouts. The integration of distributed generation (DG) in the distribution system has increased to...

This paper presents a new approach using fuzzy bet theory for voltage and reactive power control of power systems. The predication of steady state voltage stability conditions in a transmission network. The voltage stability is checked by formulating an L and the corresponding uncertainties input parameters are efficiently modeled in terms of fuzzy sets by using triangular membership function. ...

This paper provides an overview of a dynamic analysis carried out on the large-scale Queensland transmission network. This paper highlights how decaying voltages and the subsequent hyper-excitation of generators can lead to transient oscillatory instability because of insufficient damping torque. Different levels of voltage compensation have been implemented at critical generators in the model ...

As a perspective to ensure the power system stability and to avoid the vulnerability leading to the blackouts, several strategies are adopted. In order to avoid the voltage collapse, load shedding schemes represent a suitable action to maintain the power system service quality and to control its vulnerability. In this paper, we propose a new approach of a load shedding strategy based on fuzzy c...

The results of coating capacitive micromachined ultrasonic transducer (CMUT) arrays with two different biocompatible materials, parylene-c and polydimethylsiloxane (PDMS), are reported. These materials were characterized for use with CMUTs to enable direct contact transcutaneous and in vivo imaging. A passivation coating is required to provide electrical isolation to the active areas of the dev...

Voltage collapse and blackout can occur in an electric power system when load powers vary so that the system loses stability in a saddle node bifurcation. We propose new iterative and direct methods to compute load powers a t which bifurcation occurs and which are locally closest to the current operating load powers. The distance in load power parameter space to this locally closest bifurcation...

This paper describes the implementation of a fast and easy-to-use, intelligence-based algorithm to assess the risk of voltage collapse when risk is defined as the product of the event likelihood and a severity function. In the event likelihood, the effect of weather is taken into account; the failure rate of each transmission line under different weather conditions is calculated using real hist...

Part II of this paper elaborates on the unique capability of the proposed power flow analysis framework to obtain the true solution corresponding to the stable operating point of a network. It explains the significance of obtaining the true solution for an accurate assessment of the voltage collapse margin. This feature distinguishes the framework from all iterative and non-iterative heuristic ...